FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
[See section 10, Rule 13]
CONTROL DEVICE AND DRIVE CONTROL METHOD
MITSUBISHI ELECTRIC CORPORATION, A CORPORATION
ORGANISED AND EXISTING UNDER THE LAWS OF JAPAN, WHOSE
ADDRESS IS 7-3, MARUNOUCHI 2-CHOME, CHIYODA-KU, TOKYO
1008310, JAPAN
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE
INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED
5
2
DESCRIPTION
Field
[0001] The present disclosure relates to a control
device and a drive control method for performing drive5
control of a rotary machine.
Background
[0002] For driving a rotary machine, position
information of the rotor is required. A position sensor10
can be used to detect the rotor position, but the use of
the position sensor causes problems such as an increase in
size, an increase in cost, and a decrease in environmental
resistance of the system.
[0003] As a countermeasure, Patent Literature 115
discloses a method for estimating the rotor position
without using a position sensor. With the method disclosed
in Patent Literature 1, the rotor position is estimated
using the fact that the change amount of the rotary machine
current during application of an effective voltage vector20
changes at a double angle of the rotor position.
Citation List
Patent Literature
[0004] Patent Literature 1: Japanese Patent Application25
Laid-open No. 2018-153027
Summary of Invention
Problem to be solved by the Invention
[0005] However, the above-described conventional30
technique is problematic in that a position estimation
error may increase in an appearance pattern of effective
voltage vectors in which differential information of the
3
rotary machine current becomes a fragmentary signal. For
example, in a case where current vector control is
performed using three-phase common triangular wave carrier
pulse width modulation (PWM), there is a correlation
between the type of the effective voltage vector appearing5
by current vector control and the rotor position, and when
the rotary machine is driven at a low speed, a specific
type of effective voltage vector appears for a long time.
In a case where the change amount of the rotary machine
current with respect to the effective voltage vector is10
acquired under such conditions, the change amount of the
rotary machine current becomes a fragmentary signal.
[0006] The present disclosure has been made in view of
the above, and an object thereof is to provide a control
device capable of estimating the rotor position with high15
accuracy even under a condition that the change amount of
the rotary machine current with respect to the effective
voltage vector is fragmentary.
Means to Solve the Problem20
[0007] In order to solve the above-described problems
and achieve the object, a control device according to the
present disclosure is a control device that performs drive
control of a multiphase rotary machine. The control device
includes: a current detection unit to detect a rotary25
machine current flowing through the rotary machine; a drive
voltage command calculation unit to generate a drive
voltage command for driving the rotary machine based on the
rotary machine current and an estimated value of a rotor
position of the rotary machine; a voltage applicator to30
apply a voltage to the rotary machine based on the drive
voltage command generated; and a position estimation unit
to estimate the rotor position based on the rotary machine
4
current. The position estimation unit determines a type of
a voltage vector output from the voltage applicator based
on a gate signal of the voltage applicator, calculates a
change amount of the rotator current for each type of the
voltage vector determined, generates an AC signal having a5
DC component of zero and changing at a double angle of the
rotor position based on a rotary machine current change
amount that is a calculation result, and estimates the
rotor position based on the AC signal.
10
Effects of the Invention
[0008] The present disclosure can achieve the effect of
obtaining a control device capable of estimating the rotor
position with high accuracy even under a condition that the
change amount of the rotary machine current with respect to15
the effective voltage vector is fragmentary.
Brief Description of Drawings
[0009] FIG. 1 is a diagram illustrating an exemplary
configuration of a control device for a rotary machine20
according to the first embodiment.
FIG. 2 is a diagram illustrating an exemplary circuit
configuration of the voltage applicator illustrated in FIG.
1.
FIG. 3 is a diagram illustrating an example of a25
correspondence relationship between the switching states of
each phase of the voltage applicator illustrated in FIG. 1
and the definitions of voltage vectors.
FIG. 4 is a diagram illustrating the eight switching
states and voltage vectors illustrated in FIG. 3.30
FIG. 5 is a diagram for explaining signal processing
in the position estimator illustrated in FIG. 1.
FIG. 6 is a diagram illustrating a detailed
5
configuration of the current differential information
calculation unit illustrated in FIG. 5.
FIG. 7 is a diagram illustrating DC components and AC
components included in current differential information.
FIG. 8 is a diagram illustrating output of the current5
differential information calculation unit illustrated in
FIG. 5.
FIG. 9 is a diagram for explaining classification
performed by the classifier.
FIG. 10 is an explanatory diagram regarding the10
operation of the classifier illustrated in FIG. 5.
FIG. 11 is a block diagram illustrating a
configuration of the phase synchronization calculation unit
illustrated in FIG. 5.
FIG. 12 is a diagram illustrating output of each unit15
of the position estimator illustrated in FIG. 5.
FIG. 13 is a diagram illustrating a first example of a
hardware configuration for implementing the functions of
the control device according to the first embodiment and
the second embodiment.20
FIG. 14 is a diagram illustrating a second example of
a hardware configuration for implementing the functions of
the control device according to the first embodiment and
the second embodiment.
25
Description of Embodiments
[0010] Hereinafter, a control device and a drive control
method according to embodiments of the present disclosure
will be described in detail with reference to the drawings.
[0011] First Embodiment.30
FIG. 1 is a diagram illustrating an exemplary
configuration of a control device for a rotary machine
according to the first embodiment. Hereinafter, a “control
6
device for a rotary machine” may be simply referred to as a
“control device”. The control device 100 illustrated in
FIG. 1 includes a rotary machine 1, a current detector 2, a
voltage applicator 3, a position estimator 4, and a
controller 5. The controller 5 includes a current5
controller 6, a rotating coordinate inverse converter 7, a
two-to-three phase converter 8, a three-to-two phase
converter 9, and a rotating coordinate converter 10.
[0012] The rotary machine 1 is a three-phase synchronous
reluctance motor (SynRM) that generates torque using10
saliency of the rotor. The voltage applicator 3 is
connected to the rotary machine 1. The current detector 2
is provided between the rotary machine 1 and the voltage
applicator 3.
[0013] The current detector 2 detects alternating15
currents supplied from the voltage applicator 3 to the
rotary machine 1, and outputs the detected values of the
alternating currents as rotary machine currents iu, iv, and
iw. The rotary machine currents iu, iv, and iw are supplied
to the rotary machine 1, and the values of rotary machine20
currents iu, iv, and iw are output to each of the position
estimator 4 and the controller 5.
[0014] The voltage applicator 3 supplies AC power to the
rotary machine 1 according to rotary machine voltage
commands vu*, vv*, and vw* supplied from the controller 5.25
[0015] The position estimator 4 calculates an estimated
rotor position using the rotary machine currents iu, iv,
and iw detected by the current detector 2 and gate signals
(to be described later) of the voltage applicator 3. In
the following description, the rotor position is30
represented by “θ”, and an estimated value of the rotor
position θ is represented by “θ” with “^” on it. Note that
a sign consisting of “θ” with “^” on it may be represented
7
by “θ” with “^” after it. Similarly, a sign consisting of
a symbol representing a certain parameter with “^” on or
after it represents an estimated value of the parameter.
The position estimator 4 outputs the estimated rotor
position θ^ to the controller 5.5
[0016] The controller 5 calculates the rotary machine
voltage commands vu*, vv*, and vw* for driving the rotary
machine 1 such that rotary machine currents id and iq in
the rotating coordinate system of the rotary machine 1 have
values indicated by rotary machine current commands id* and10
iq* in the rotating coordinate system, and outputs the
calculated rotary machine voltage commands vu*, vv*, and vw*
to the voltage applicator 3.
[0017] FIG. 2 is a diagram illustrating an exemplary
circuit configuration of the voltage applicator 315
illustrated in FIG. 1. FIG. 2 illustrates an exemplary
circuit configuration in a case where the voltage
applicator 3 is a three-phase PWM inverter. The voltage
applicator 3 includes a leg 30A in which a semiconductor
element UP of the upper arm and a semiconductor element UN20
of the lower arm are connected in series, a leg 30B in
which a semiconductor element VP of the upper arm and a
semiconductor element VN of the lower arm are connected in
series, and a leg 30C in which a semiconductor element WP
of the upper arm and a semiconductor element WN of the25
lower arm are connected in series. The leg 30A, the leg
30B, and the leg 30C are connected in parallel to each
other.
[0018] A bus voltage is applied to the voltage
applicator 3 through DC buses 35a and 35b. The voltage30
applicator 3 converts DC power of a power source 36
supplied through the DC buses 35a and 35b into AC power,
and supplies the resultant AC power to the rotary machine 1
8
to drive the rotary machine 1. In FIG. 2, the current
detector 2 is omitted.
[0019] FIG. 2 illustrates a case where the semiconductor
elements UP, UN, VP, VN, WP, and WN are metal-oxide-
semiconductor field-effect transistors (MOSFET). Each of5
the semiconductor elements UP, UN, VP, VN, WP, and WN
includes a transistor 30a and a diode 30b connected in
anti-parallel to the transistor 30a. The phrase “connected
in anti-parallel” means that the anode side of the diode is
connected to the first terminal corresponding to the source10
of the MOSFET and the cathode side of the diode is
connected to the second terminal corresponding to the drain
of the MOSFET.
[0020] Instead of MOSFETs, insulated gate bipolar
transistors (IGBTs) may be used as the semiconductor15
elements UP, UN, VP, VN, WP, and WN.
[0021] A connection point 32 between the semiconductor
element UP of the upper arm and the semiconductor element
UN of the lower arm is connected to the first phase, for
example, the u-phase, of the rotary machine 1. A20
connection point 33 between the semiconductor element VP of
the upper arm and the semiconductor element VN of the lower
arm is connected to the second phase, for example, the v
phase, of the rotary machine 1. A connection point 34
between the semiconductor element WP of the upper arm and25
the semiconductor element WN of the lower arm is connected
to the third phase, for example, the w phase, of the rotary
machine 1. In the voltage applicator 3, the connection
points 32, 33, and 34 constitute the AC terminal.
[0022] Here, the voltage vector output from the voltage30
applicator 3 will be described. The voltage applicator 3
is a three-phase PWM inverter as described above, and is a
power converter that obtains a desired voltage by
9
performing PWM control on the power source 36 supplied
through the DC buses 35a and 35b. The three-phase PWM
inverter includes two switching elements (upper and lower)
per phase, and the upper and lower switching elements
operate such that one of the switching elements is on.5
Therefore, a three-phase triangular wave comparison
inverter has 23, that is, eight switching states. Here,
the states of the gate signals of the upper arms of the u
phase, the v phase, and the w phase in the voltage
applicator 3 are defined as Gu, Gv, and Gw, respectively.10
When the values of Gu, Gv, and Gw are one, it means that the
semiconductor element of the upper arm of the corresponding
phase is in a conductive state, and when the values of Gu,
Gv, and Gw are zero, it means that the semiconductor
element of the lower arm of the corresponding phase is in a15
conductive state. For example, under the condition of (Gu,
Gv, Gw)=(1, 0, 0), it means a state in which the
semiconductor element of the upper arm of the u phase is
conductive and the semiconductor elements of the lower arms
of the v phase and the w phase are conductive.20
[0023] Here, voltage vectors in the eight switching
states of the voltage applicator 3 are defined as V0 to V7.
FIG. 3 is a diagram illustrating an example of a
correspondence relationship between the switching states of
each phase of the voltage applicator 3 illustrated in FIG.25
1 and the definitions of voltage vectors. The applied
voltage vector is defined as V0 under the condition of (Gu,
Gv, Gw)=(0, 0, 0), the applied voltage vector is defined as
V1 under the condition of (Gu, Gv, Gw)=(1, 0, 0), the
applied voltage vector is defined as V2 under the condition30
of (Gu, Gv, Gw)=(1, 1, 0), and the applied voltage vector is
defined as V3 under the condition of (Gu, Gv, Gw)=(0, 1, 0).
In addition, the applied voltage vector is defined as V4
10
under the condition of (Gu, Gv, Gw)=(0, 1, 1), the applied
voltage vector is defined as V5 under the condition of (Gu,
Gv, Gw)=(0, 0, 1), the applied voltage vector is defined as
V6 under the condition of (Gu, Gv, Gw)=(1, 0, 1), and the
applied voltage vector is defined as V7 under the condition5
of (Gu, Gv, Gw)=(1, 1, 1). Among the eight voltage vectors
V0 to V7, the voltage vectors V0 and V7 are referred to as
zero voltage vectors, and the other voltage vectors, namely,
the voltage vectors V1 to V6, are referred to as effective
voltage vectors. The voltage vectors V0 to V7 may be10
referred to as the voltage vectors V0–7 (alternatively, V0 to
7). Similarly, the effective voltage vectors V1 to V6 may
be referred to as the effective voltage vectors V1–6
(alternatively, V1 to 6).
[0024] FIG. 4 is a diagram illustrating the eight15
switching states and voltage vectors illustrated in FIG. 3.
FIG. 4 illustrates the voltage vector in each switching
state and the conduction state of each semiconductor
element of the voltage applicator 3.
[0025] FIG. 5 is a diagram for explaining signal20
processing in the position estimator 4 illustrated in FIG.
1. The position estimator 4 calculates an estimated rotor
position θ^ which is an estimated value of the position of
the rotor of the rotary machine 1 using the rotary machine
currents iu, iv, and iw detected by the current detector 225
and the gate signals Gu, Gv, and Gw of the voltage
applicator 3. Specifically, the position estimator 4
includes a current differential information calculation
unit 40, a classifier 41, a DC component remover 42, a
three-to-two phase converter 43, and a phase30
synchronization calculation unit 44.
[0026] The current differential information calculation
unit 40 calculates current differential information
11
corresponding to each of the effective voltage vectors V1
to V6. The current differential information calculation
unit 40 calculates current differential information
corresponding to the effective voltage vectors V1 to V6 for
the u-phase, v-phase, and w-phase rotary machine currents5
iu, iv, and iw. Therefore, the current differential
information output from the current differential
information calculation unit 40 is 3×6=18 types. The
current differential information is also referred to as a
rotary machine current change amount. The gate signals Gu,10
Gv, and Gw of the semiconductor element of the upper arm of
each phase of the voltage applicator 3 and the rotary
machine currents iu, iv, and iw are input to the current
differential information calculation unit 40.
[0027] FIG. 6 is a diagram illustrating a detailed15
configuration of the current differential information
calculation unit 40 illustrated in FIG. 5. The current
differential information calculation unit 40 includes a
voltage vector determiner 400 that determines the type of
the voltage vector output from the voltage applicator 3,20
and a current differential calculator 401 that calculates
current differential information of each phase
corresponding to the effective voltage vector using the
determination result of the voltage vector determiner 400
and the rotary machine currents iu, iv, and iw.25
[0028] The voltage vector determiner 400 determines the
type of the voltage vector output from the voltage
applicator 3 from the gate signals Gu, Gv, and Gw of the
semiconductor elements of the upper arm of each phase of
the voltage applicator 3 based on the definitions30
illustrated in FIG. 3. The voltage vector determiner 400
determines which of the voltage vectors V0–7 the type of the
voltage vector is, from the values of the gate signals Gu,
12
Gv, and Gw, and outputs the voltage vector V0–7 that is the
determination result to the current differential calculator
401.
[0029] The current differential calculator 401
calculates current differential information of each phase5
corresponding to each of the effective voltage vectors V1–6
based on the voltage vector V0–7 which is the determination
result of the voltage vector determiner 400 and the rotary
machine currents iu, iv, and iw. The current differential
calculator 401 stores the type of the current voltage10
vector V0–7 and the type of the voltage vector one control
cycle before, and if the same effective voltage vector
appears over two or more control cycles, calculates current
differential information of each phase corresponding to the
type of the effective voltage vector. The control cycle is15
set to a sufficiently short value with respect to the cycle
of the triangular wave carrier of the voltage applicator 3
in order to sample two or more points of the current during
application of the effective voltage vector. If the type
of the current voltage vector is VN and the type of the20
voltage vector one control cycle before is VN, the current
differential calculator 401 calculates the current
differential information of the u phase, the v phase, and
the w phase at the time of applying the voltage vector VN
as “diuVN/dt”, “divVN/dt”, and “diwVN/dt”, respectively. Here,25
N is an integer from one to six. The current differential
calculator 401 distinctively calculates the six types of
effective voltage vectors V1–6 and the three phases of
current differential information, thereby outputting 18
types of current differential information “diuV1–6/dt”,30
“divV1–6/dt”, and “diwV1–6/dt”.
[0030] Here, a total of 18 types of current differential
information output from the current differential calculator
13
401 will be described. Current differential information
includes a DC component and an AC component. FIG. 7 is a
diagram illustrating DC components and AC components
included in current differential information. In FIG. 7, a
signal name, a formula indicating a DC component, and a5
formula indicating an AC component are associated with each
of the 18 types of current differential information. In
the “signal name”, u, v, and w indicate corresponding
phases of the rotary machine 1, and V1 to V6 indicate
corresponding types of effective voltage vectors.10
[0031] Features of the “DC component” of the current
differential information illustrated in FIG. 7 will be
described. Here, defining A with Formula (1) below, the
“DC component” of the current differential information is
generated with a magnitude of “2/A” in a phase in the15
direction of the effective voltage vector, and is generated
with a magnitude of “1/A” with a reverse sign in a phase
other than the phase in the direction of the effective
voltage vector. Therefore, the sum of the u-phase DC
component, the v-phase DC component, and the w-phase DC20
component during application of the same effective voltage
vector is zero. Here, Vdc is the DC voltage of the power
source 36 of the voltage applicator 3.
[0032] Formula 1:𝐴 =
3𝐿0 1 − 𝐿1
2𝐿0
2
𝑉𝑑𝑐
･･･(1)
25
[0033] L0 in Formula (1) is expressed by Formula (2)
below. In addition, L1 in Formula (1) is expressed by
Formula (3) below. Here, Ld is the d-axis inductance of
the rotary machine 1, and Lq is the q-axis inductance of
the rotary machine 1.30
14
[0034] Formula 2:𝐿0 = 𝐿𝑑 + 𝐿𝑞
2 ･･･(2)
[0035] Formula 3:𝐿1 = −𝐿𝑑 + 𝐿𝑞
2 ･･･(3)
[0036] Next, features of the “AC component” of the5
current differential information will be described. Here,
given that the number of the effective voltage vector is N,
the AC component of the u-phase current differential
information is expressed by Formula (4), the AC component
of the v-phase current differential information is10
expressed by Formula (5), and the AC component of the w-
phase current differential information is expressed by
Formula (6).
[0037] Formula 4:𝑑𝑖𝑢 𝑉𝑁 𝐴𝐶
𝑑𝑡 = 1
𝐴
𝐿1
𝐿0
cos 2 𝜃 + 𝜋
6 𝑁 − 1 ･･･(4)
15
[0038] Formula 5:𝑑𝑖𝑣 𝑉𝑁 𝐴𝐶
𝑑𝑡 = 1
𝐴
𝐿1
𝐿0
cos 2 𝜃 − 2𝜋
3 + 𝜋
6 𝑁 − 1 ･･･(5)
[0039] Formula 6:𝑑𝑖𝑤 𝑉𝑁 𝐴𝐶
𝑑𝑡 = 1
𝐴
𝐿1
𝐿0
cos 2 𝜃 + 2𝜋
3 + 𝜋
6 𝑁 − 1 ･･･(6)
[0040] As shown in Formulas (4) to (6), the current20
differential information obtained by applying the effective
voltage vector has information of the rotor position θ. In
the column of “AC component” in FIG. 7, expanded forms are
15
shown for the phases in Formulas (4) to (6). As is clear
from FIG. 7 and Formulas (4) to (6), the AC components of
the current differential information during the application
period of the same effective voltage vector are
characterized in having a phase difference of “±2π/3” from5
each other, and having the respective reference phases
shifted depending on the application direction of the
effective voltage vector. The magnitude of the amplitude
of the AC component is equal for all combinations of
effective voltage vectors and phases, and is10
“(1/A)×(L1/L0)”. Note that, since the magnitude
relationship between the d-axis and q-axis inductances is
different between interior permanent magnet synchronous
motors (IPMSM) and synchronous reluctance motors, the value
of the coefficient “(1/A)×(L1/L0)” of the cosine function15
is a positive value in interior permanent magnet
synchronous motors, and is a negative value in synchronous
reluctance motors.
[0041] In each phase, current differential information
obtained by a combination of effective voltage vectors20
having a relationship of magnetization and demagnetization
directions has a relationship of reverse signs as expressed
by Formulas (7) to (9) below. In Formulas (7) to (9), n is
an integer from one to three. A combination of voltage
vectors having a relationship of magnetization and25
demagnetization directions is V1 and V4 in the u phase, V3
and V6 in the v phase, and V5 and V2 in the w phase.
[0042] Formula 7:𝑑𝑖𝑢 𝑉𝑛
𝑑𝑡 = − 𝑑𝑖𝑢 𝑉𝑛 +3
𝑑𝑡 ･･･(7)
[0043] Formula 8:30
16𝑑𝑖𝑣 𝑉𝑛
𝑑𝑡 = − 𝑑𝑖𝑣 𝑉𝑛 +3
𝑑𝑡 ･･･(8)
[0044] Formula 9:𝑑𝑖𝑤 𝑉𝑛
𝑑𝑡 = − 𝑑𝑖𝑤 𝑉𝑛 +3
𝑑𝑡 ･･･(9)
[0045] FIG. 8 is a diagram illustrating output of the
current differential information calculation unit 405
illustrated in FIG. 5. FIG. 8 shows a simulation result of
current vector control on a synchronous reluctance motor
rotating at a low speed, in which the PWM of the voltage
applicator 3 is based on three-phase common triangular wave
carrier comparison that is generally used. The voltage10
vectors of V0 and V7 are numbered zero for the sake of
explanation. Here, focusing on the rotor position and the
number of the applied voltage vector, a correlation can be
confirmed between the rotor position and the appearance
pattern of voltage vectors. In a period in which a15
specific effective voltage vector appears, current
differential information corresponding to other effective
voltage vectors cannot be acquired. Therefore, in an
appearance pattern of effective voltage vectors in which a
specific effective voltage vector occurs for a long time,20
the current differential information is fragmentary.
Further, each piece of current differential information has
a characteristic that timings at which the current
differential information can be acquired are different, and
the delay amount is different depending on the signal.25
From this characteristic, signal processing that is
performed without considering the appearance pattern of
voltage vectors results in unstable position sensorless
control. Here, “signal processing that is performed
17
without considering the appearance pattern of voltage
vectors” corresponds to, for example, a case where the type
of current differential information used for estimating the
rotor position is fixed regardless of the type of the
appearing voltage vector.5
[0046] Therefore, the position estimator 4 performs
signal processing of generating an AC component of
continuous current differential information having rotor
position information from fragmentary current differential
information. Hereinafter, a signal processing method that10
is implemented by the position estimator 4 will be
described. The current differential information has the
features indicated by Formulas (4) to (9) above. Utilizing
these features, the same waveform shape appears in the
current differential information under conditions of15
different voltage vectors and phases. Therefore, the
position estimator 4 interpolates fragmentary current
differential information using the waveform shape appearing
under conditions of different voltage vectors and phases,
and generates an AC component of continuous current20
differential information.
[0047] Returning to FIG. 5, the classifier 41 classifies
the current differential information output from the
current differential information calculation unit 40 into
any one of six types of signals based on the magnitude of25
the DC component and the reference phase. Based on the
features of Formulas (4) to (9) above, the classifier 41
makes classifications into six types: group (2/A, 0°),
group (−1/A, 120°), group (−1/A, −120°), group (2/A, −120°),
group (−1/A, 0°), and group (2/A, 120°), according to the30
magnitude of the DC component and the phase of the AC
component.
[0048] FIG. 9 is a diagram for explaining classification
18
performed by the classifier 41. FIG. 9 illustrates “group”,
“DC component”, “AC component”, and “symbol” for each of
the six groups classified by the classifier 41. Here,
“group” indicates the name of a group, and the group
described as group (X, Y°) means a group in which the DC5
component is X and the reference phase of the AC component
is Y°. For example, the reference phase Y in the cosine
component “cos (2θ+2π/3)” of the AC component in FIG. 9 is
2π/3[rad]=120[°]. “Symbol” indicates signals having the
same waveform shape. For example, in the group of group10
(2/A, 0°), it means that the waveform of the u-phase
current differential information at the time when the
effective voltage vector V1 is applied and the waveform of
the u-phase current differential information at the time
when the effective voltage vector V4 is applied are the15
same.
[0049] FIG. 10 is an explanatory diagram regarding the
operation of the classifier 41 illustrated in FIG. 5. When
the current differential information “diuV1–6/dt”, “divV1–
6/dt”, and “diwV1–6/dt” is input, the classifier 41 generates20
six types of signals based on the classification
illustrated in FIG. 9. Specifically, the classifier 41
operates to prepare variables corresponding to the six
types of groups, substitute current differential
information for the variables of the groups into which the25
current differential information input to the classifier 41
is classified, and hold the previous values for the
variables of the other groups. Here, the name of the group
is used as a variable name for description. Group (X, Y°)
is a variable of a group in which the DC component is X and30
the reference phase of the AC component is Y°. For example,
as for group (2/A, 0°), the classifier 41 substitutes
“diuV1/dt” under the condition that V1 is applied,
19
substitutes “−diuV4/dt” under the condition that V4 is
applied, and operates to hold the previous value under the
condition that the effective voltage vectors other than V1
and V4, that is, V2, V3, V5, and V6, are applied.
Similarly, as for group (−1/A, 120°), the classifier 415
operates to substitute “divV1/dt” under the condition that
V1 is applied, substitute “−divV4/dt” under the condition
that V4 is applied, substitute “diuV3/dt” under the
condition that V3 is applied, substitute “−diuV6/dt” under
the condition that V6 is applied, and hold the previous10
value under the condition that V2 and V5 are applied.
[0050] Returning to FIG. 5, the DC component remover 42
extracts a DC component from the output of the classifier
41, and subtracts the DC component from current
differential information obtained by applying the latest15
effective voltage vector, thereby generating a continuous
AC component. In the first embodiment, an example of
extracting a DC component using the three-phase equilibrium
condition will be described. In order to extract the DC
component “1/A” using the three-phase equilibrium condition,20
Formulas (10) to (14) below are used. That is, the DC
component remover 42 calculates the sum of the signals of
the combinations having phases of 0°, 120°, and −120° from
the output of the classifier 41, and multiplies the sum by
the coefficient of conversion to the DC component to25
calculate the DC component. Here, the five types of
Formulas (10) to (14) are shown, but the DC component
remover 42 only needs to perform computation by using at
least one appropriate formula by a combination of the
latest effective voltage vector and the nearest effective30
voltage vector having a different number from the latest
effective voltage vector.
[0051] Formula 10:
201
𝐴 = 1
6 𝑔𝑟𝑜𝑢𝑝 2
𝐴 , 0° + 𝑔𝑟𝑜𝑢𝑝 2
𝐴 , 120° + 𝑔𝑟𝑜𝑢𝑝 2
𝐴 , −120° ･･･(10)
[0052] Formula 11:1
𝐴 = − 1
3 𝑔𝑟𝑜𝑢𝑝 − 1
𝐴 , 0° + 𝑔𝑟𝑜𝑢𝑝 − 1
𝐴 , 120° + 𝑔𝑟𝑜𝑢𝑝 − 1
𝐴 , −120°
･･･(11)
[0053] Formula 12:1
𝐴 = 1
3 𝑔𝑟𝑜𝑢𝑝 2
𝐴 , 0° + 𝑔𝑟𝑜𝑢𝑝 2
𝐴 , 120° + 𝑔𝑟𝑜𝑢𝑝 − 2
𝐴 , −120°
･･･(12)
5
[0054] Formula 13:1
𝐴 = 1
3 𝑔𝑟𝑜𝑢𝑝 2
𝐴 , 0° + 𝑔𝑟𝑜𝑢𝑝 − 1
𝐴 , 120° + 𝑔𝑟𝑜𝑢𝑝 2
𝐴 , −120°
･･･(13)
[0055] Formula 14:1
𝐴 = 1
3 𝑔𝑟𝑜𝑢𝑝 − 1
𝐴 , 0° + 𝑔𝑟𝑜𝑢𝑝 2
𝐴 , 120° + 𝑔𝑟𝑜𝑢𝑝 2
𝐴 , −120°
･･･(14)
[0056] Specifically, the DC component remover 42 uses a10
formula that uses the latest effective voltage vector and
the nearest effective voltage vector having a different
number from the latest effective voltage vector among
Formulas (10) to (14). Here, for example, group (2/A, 0°)
is generated based on current differential information at15
the time when the effective voltage vector V1 or V4 is
applied, group (2/A, 120°) is generated based on current
21
differential information at the time when the effective
voltage vector V5 or V2 is applied, and group (2/A, −120°)
is generated based on current differential information at
the time when the effective voltage vector V3 or V6 is
applied. Therefore, Formula (10) can be said to be a5
formula that uses the effective voltage vectors V1 or V4,
V5 or V2, and V3 or V6. Similarly, Formula (11) is a
formula that uses the effective voltage vectors V2 or V5,
and V1 or V3 or V4 or V6. Formula (12) is a formula that
uses the effective voltage vectors V1 or V4 and V2 or V5.10
Formula (13) is a formula that uses the effective voltage
vectors V1 or V4 and V3 or V6. Formula (14) is a formula
that uses the effective voltage vectors V2 or V5 and V3 or
V6.
[0057] For example, when the combination of the latest15
effective voltage vector and the nearest effective voltage
vector having a different number from the latest effective
voltage vector is V1 and V2, at least one formula that uses
these voltage vectors is selected from Formulas (10) to
(14). Formulas that use the effective voltage vectors V120
and V2 are Formula (11) and Formula (12). Therefore, the
DC component remover 42 calculates the DC component “1/A”
using at least one of Formulas (11) or (12). When a
plurality of formulas are used, the DC component remover 42
can calculate the DC component “1/A” by using an average25
value of calculation results of the plurality of formulas.
[0058] Subsequently, the DC component remover 42 uses
the extracted DC component to subtract the DC component
from the current differential information obtained by
applying the latest effective voltage vector, thereby30
calculating the AC component of the latest current
differential information. The DC component remover 42 can
calculate the AC component of the latest current
22
differential information using Formulas (15) to (17) below.
The DC component remover 42 selects a formula based on the
type of the latest voltage vector among Formulas (15) to
(17).
[0059] Formula 15:5
[0060] Formula 16:
[0061] Formula 17:
10
[0062] The DC component remover 42 outputs the
calculation results, namely group (0, 0°), group (0, 120°),
and group (0, −120°), to the three-to-two phase converter
43. The outputs group (0, 0°), group (0, 120°), and group
(0, −120°) of the DC component remover 42 are continuous AC15
components including rotor position information.
Hereinafter, a method of calculating the rotor position
using the AC components will be described. As methods of
calculating the rotor position from AC components having a
phase difference of ±2π/3 from each other, for example,20
there are a method of performing three-phase to two-phase
conversion on these AC components and performing an arc
23
tangent calculation, a method of performing phase
synchronization calculation on a three-phase to two-phase
conversion result and estimating the rotor position, and
the like. Here, a method of estimating the rotor position
through phase synchronization calculation will be described5
as an example.
[0063] The three-to-two phase converter 43 calculates an
α-axis AC component α and a β-axis AC component β which are
orthogonal biaxial AC components. The three-to-two phase
converter 43 calculates the α-axis AC component α and the10
β-axis AC component β using Formula (18) below, and outputs
the calculated α-axis AC component α and β-axis AC
component β to the phase synchronization calculation unit
44.
[0064] Formula 18:15𝛼
𝛽 = 2
3
1 − 1
2 − 1
2
0 − 3
2
3
2
𝑔𝑟𝑜𝑢𝑝 0,0°
𝑔𝑟𝑜𝑢𝑝 0,120°
𝑔𝑟𝑜𝑢𝑝 0, −120°
･･･(18)
[0065] The phase synchronization calculation unit 44
estimates the rotor position of the rotary machine 1 based
on the α-axis AC component α and the β-axis AC component β20
output from the three-to-two phase converter 43.
Specifically, the phase synchronization calculation unit 44
estimates the rotor position of the rotary machine 1 by
performing phase synchronization calculation on the α-axis
AC component α and the β-axis AC component β.25
[0066] FIG. 11 is a block diagram illustrating a
configuration of the phase synchronization calculation unit
44 illustrated in FIG. 5. The phase synchronization
calculation unit 44 includes a phase error calculation unit
24
441, a proportional integral (PI) controller 442, an
integrator 443, and proportioners 444 and 445.
[0067] The phase error calculation unit 441 receives the
α-axis AC component α and the β-axis AC component β output
from the three-to-two phase converter 43 and the estimated5
rotor position 2θ^ output from the integrator 443. The
phase error calculation unit 441 calculates the phase error
ΔiAC*Δ2θ according to Formula (19) below. The phase error
calculation unit 441 outputs the calculated phase error
ΔiAC*Δ2θ to the PI controller 442.10
[0068] Formula 19:∆𝑖𝐴𝐶 ∗ ∆2𝜃 ∶= 𝛼 sin 2𝜃 − 𝛽 cos 2𝜃 = ∆𝑖𝐴𝐶 sin 2𝜃 − 2𝜃
≅ ∆𝑖𝐴𝐶 2𝜃 − 2𝜃 = ∆𝑖𝐴𝐶 ∗ ∆2𝜃
･･･(19)
[0069] Here, “ΔiAC” in Formula (19) is expressed by
Formula (20) below.
[0070] Formula 20:15∆𝑖𝐴𝐶 = 1
𝐴
𝐿1
𝐿0
･･･(20)
[0071] The PI controller 442 receives input of the phase
error ΔiAC*Δ2θ output from the phase error calculation unit
441. The PI controller 442 outputs the estimated speed 2ω^
such that the phase error ΔiAC*Δ2θ becomes zero.20
[0072] The integrator 443 integrates the estimated speed
2ω^ output from the PI controller 442 and outputs the
integrated value as the estimated rotor position 2θ^. The
estimated rotor position 2θ^ output by the integrator 443
is fed back to the phase error calculation unit 441.25
[0073] In Formula (19) above, when “2θ>2θ^”, the phase
error ΔiAC*Δ2θ is a positive value, and thus the estimated
25
speed 2ω^ and the estimated rotor position 2θ^ are
corrected in an increasing direction. When “2θ<2θ^”, the
phase error ΔiAC*Δ2θ is a negative value, and thus the
estimated speed 2ω^ and the estimated rotor position 2θ^
are corrected in a decreasing direction. Finally, “2θ=2θ^”5
is achieved, and the phase and frequency of the AC
component of the current differential information of the
rotary machine 1 are estimated. In this manner, the phase
synchronization calculation unit 44 takes the form of a
phase locked loop (PLL).10
[0074] The phase synchronization calculation unit 44
inputs the estimated rotor position 2θ^ to the proportioner
444 and multiplies the estimated rotor position 2θ^ by 0.5
to calculate the estimated rotor position θ^. In addition,
the phase synchronization calculation unit 44 inputs the15
estimated speed 2ω^ to the proportioner 445 and multiplies
the estimated speed 2ω^ by 0.5 to calculate the estimated
speed ω^.
[0075] FIG. 12 is a diagram illustrating output of each
unit of the position estimator 4 illustrated in FIG. 5. In20
FIG. 12, the operation condition is the same as that in FIG.
8, and the current differential information is fragmentary.
The first row “rotor position” from the top in FIG. 12
shows the true position of the rotor and the estimated
position output by the phase synchronization calculation25
unit 44. The second to fourth rows from the top in FIG. 12
show the outputs of the current differential information
calculation unit 40. The fifth row from the top in FIG. 12
shows the output of the classifier 41. The sixth row from
the top in FIG. 12 shows the output of the DC component30
remover 42. The seventh row from the top in FIG. 12 shows
the output of the three-to-two phase converter 43. The
eighth row from the top in FIG. 12 shows the number of the
26
voltage vector applied at each time point. In FIG. 12,
similarly to FIG. 8, the voltage vectors of V0 and V7 are
numbered zero for the sake of explanation.
[0076] From FIG. 12, it can be known that the classifier
41 generates six types of signals based on the5
classification illustrated in FIG. 9. In addition, the
output of the DC component remover 42 is an orthogonal-
biaxially expressed AC component having a DC component of
zero and vibrating at a double angle of the rotor position.
The position estimator 4 estimates the rotor position by10
performing phase synchronization calculation on the output
of the three-to-two phase converter 43.
[0077] Returning to FIG. 1, the three-to-two phase
converter 9 of the controller 5 receives input of the
rotary machine currents iu, iv, and iw detected by the15
current detector 2. The three-to-two phase converter 9
converts the rotary machine currents iu, iv, and iw in a
three-phase coordinate system into rotary machine currents
iα and iβ in a stationary two-phase coordinate system. The
three-to-two phase converter 9 outputs the rotary machine20
currents iα and iβ to the rotating coordinate converter 10.
[0078] The rotating coordinate converter 10 receives
input of the rotary machine currents iα and iβ output from
the three-to-two phase converter 9 and the estimated rotor
position θ^ output from the position estimator 4. Using25
the estimated rotor position θ^, the rotating coordinate
converter 10 converts the rotary machine currents iα and iβ
in a stationary two-phase coordinate system into rotary
machine currents id and iq in a rotating coordinate system.
The rotating coordinate converter 10 outputs the rotary30
machine currents id and iq to the current controller 6.
[0079] The current controller 6 receives input of the
rotary machine current commands id* and iq* and the rotary
27
machine currents id and iq. The rotary machine current
command id* is a d-axis drive current command indicating a
d-axis armature current component that minimizes the
magnetic resistance of the rotor of the rotary machine 1.
The rotary machine current iq* is a q-axis drive current5
command indicating a one-axis armature current component
which is a direction orthogonal to the d axis. The current
controller 6 performs current control such that the rotary
machine currents id and iq output from the rotating
coordinate converter 10 comply with the rotary machine10
current commands id* and iq*, and calculates rotary machine
voltage commands vd* and vq* in a rotating coordinate
system. The current control in the current controller 6 is,
for example, PI control. The current controller 6 outputs
the rotary machine voltage commands vd* and vq*, which are15
calculation results, to the rotating coordinate inverse
converter 7.
[0080] The rotating coordinate inverse converter 7
receives input of the rotary machine voltage commands vd*
and vq* and the estimated rotor position θ^. The rotating20
coordinate inverse converter 7 uses the estimated rotor
position θ^ to convert the rotary machine voltage commands
vd* and vq* in a rotating coordinate system calculated by
the current controller 6 into voltage commands vα* and vβ*
in a stationary two-phase coordinate system. The rotating25
coordinate inverse converter 7 outputs the rotary machine
voltage commands vα* and vβ* to the two-to-three phase
converter 8.
[0081] The two-to-three phase converter 8 receives input
of the rotary machine voltage commands vα* and vβ*. The30
two-to-three phase converter 8 converts the rotary machine
voltage commands vα* and vβ* in a stationary two-phase
coordinate system into rotary machine voltage commands vu*,
28
vv*, and vw* in a three-phase coordinate system for driving
the rotary machine 1.
[0082] As described above, the control device 100
according to the first embodiment is the control device 100
that performs drive control of the rotary machine 1 that is5
a multiphase rotary machine, and includes the current
detector 2 that is a current detection unit that detects a
rotary machine current flowing through the rotary machine 1,
the controller 5 that is a drive voltage command
calculation unit that generates a drive voltage command for10
driving the rotary machine 1 based on the rotary machine
current and information on the rotor position of the rotary
machine 1, the voltage applicator 3 that applies a voltage
to the rotary machine 1 based on the drive voltage command
generated, and the position estimator 4 that is a position15
estimation unit that estimates the rotor position based on
the rotary machine current detected by the current detector
2. The position estimator 4 determines the type of the
voltage vector output from the voltage applicator 3 based
on the gate signals Gu, Gv, and Gw of the voltage applicator20
3, calculates current differential information that is a
change amount of the rotary machine current for each type
of the voltage vector determined, generates an AC signal
having a DC component of zero and changing at a double
angle of the rotor position based on the rotary machine25
current change amount that is a calculation result, and
estimates the rotor position based on the AC signal
generated. With such a configuration, even in an
appearance pattern of effective voltage vectors in which
the current differential information is fragmentary, the30
control device 100 can estimate the rotor position with
high accuracy by generating a continuous AC signal having a
DC component of zero and vibrating at a double angle of the
29
rotor position based on the fragmentary current
differential information.
[0083] The position estimator 4 can estimate the rotor
position, for example, by performing phase synchronization
calculation on the AC signal generated as described above.5
In addition, the position estimator 4 generates an AC
signal having a continuous waveform shape based on a
combination of a plurality of pieces of current
differential information including a same waveform shape
among a plurality of pieces of current differential10
information obtained under a plurality of conditions that
differ in at least one of voltage vector or phase. More
specifically, utilizing a feature that two pieces of
current differential information, which are obtained under
a condition that directions of voltage vectors are in an15
opposite-direction relationship and with a same phase, have
a relationship of reverse signs, the position estimator 4
can generate a continuous AC signal by using a value
obtained by multiplying, by minus one, one of the two
pieces of current differential information obtained under a20
condition that directions of voltage vectors are in an
opposite-direction relationship and with a same phase.
[0084] The position estimator 4 can generate a
continuous AC signal utilizing a feature that the phase of
the AC component of the current differential information is25
shifted according to the direction of the voltage vector.
[0085] In addition, as shown in Formulas (10) to (14)
above, the position estimator 4 can calculate the DC
component of the current differential information by taking
the sum of first current differential information, second30
current differential information having a phase difference
of plus 2/3 π from the first current differential
information, and third current differential information
30
having a phase difference of minus 2/3 π from the first
current differential information.
[0086] In addition, the position estimator 4 includes
the phase error calculation unit 441 that calculates a
phase error based on an AC signal having a DC component of5
zero and changing at a double angle of the rotor position,
and based on an estimated position of the rotor position,
the PI controller 442 that is an estimated speed generation
unit that outputs an estimated speed based on the phase
error, and the integrator 443 that outputs a value obtained10
by integrating the estimated speed as the estimated
position.
[0087] Second Embodiment.
The control device 100 according to the second
embodiment has a configuration similar to that in the first15
embodiment. In the second embodiment, the overall
configuration of the control device 100 is similar to the
configuration illustrated in FIG. 1, and the configuration
of the position estimator 4 is similar to the configuration
illustrated in FIG. 5. Therefore, in the second embodiment,20
reference signs identical to those in the first embodiment
will be used for description. However, the second
embodiment is different from the first embodiment in the
processing content performed by the DC component remover 42
illustrated in FIG. 5. Hereinafter, differences from the25
first embodiment will be mainly described.
[0088] In the second embodiment, the DC component
remover 42 calculates the DC component “1/A” using Formulas
(21) to (23) below instead of Formulas (10) to (14) above.
[0089] Formula 21:301
𝐴 = 1
3 𝑔𝑟𝑜𝑢𝑝 2
𝐴 , 0° − 𝑔𝑟𝑜𝑢𝑝 − 1
𝐴 , 0° ･･･(21)
31
[0090] Formula 22:1
𝐴 = 1
3 𝑔𝑟𝑜𝑢𝑝 2
𝐴 , 120° − 𝑔𝑟𝑜𝑢𝑝 − 1
𝐴 , 120° ･･･(22)
[0091] Formula 23:1
𝐴 = 1
3 𝑔𝑟𝑜𝑢𝑝 2
𝐴 , −120° − 𝑔𝑟𝑜𝑢𝑝 − 1
𝐴 , −120° ･･･(23)
[0092] In Formulas (21) to (23), the DC component “1/A”5
is calculated by taking a difference between signals that
are different in DC component and equal in AC component
reference phase among the outputs of the classifier 41.
Here, the three Formulas (21) to (23) are shown, but the DC
component remover 42 only needs to use at least one formula10
that uses the latest effective voltage vector and the
nearest effective voltage vector having a different number
from the latest effective voltage vector. Here, for
example, group (2/A, 0°) is generated based on current
differential information at the time when the effective15
voltage vector V1 or V4 is applied, and group (−1/A, 0°) is
generated based on current differential information at the
time when the effective voltage vector V2 or V3 or V5 or V6
is applied. Therefore, Formula (21) can be said to be a
formula that uses the effective voltage vectors V1 or V4,20
and V2 or V3 or V5 or V6. Similarly, Formula (22) is a
formula that uses the effective voltage vectors V2 or V5,
and V1 or V3 or V4 or V6. Formula (23) is a formula that
uses the effective voltage vectors V3 or V6, and V1 or V2
or V4 or V5.25
[0093] For example, when the latest effective voltage
vector and the nearest effective voltage vector having a
different number from the latest effective voltage vector
are the effective voltage vectors V1 and V2, the
32
calculation is performed using at least one of Formulas
(21) and (22) that use the effective voltage vectors V1 and
V2. Similarly to the first embodiment, when a plurality of
formulas are used, the DC component remover 42 can
calculate the DC component “1/A” by using an average value5
of calculation results of the plurality of formulas. As
described above, in the second embodiment, the processing
of extracting the DC component is different from that in
the first embodiment, and the other processing is similar
to that in the first embodiment. In the second embodiment,10
similarly to the first embodiment, even in an appearance
pattern of effective voltage vectors in which the current
differential information is fragmentary, the control device
100 can estimate the rotor position with high accuracy by
generating a continuous AC signal having a DC component of15
zero and vibrating at a double angle of the rotor position
from the fragmentary current differential information.
[0094] With Formulas (10) to (14) used in the first
embodiment, three signals are required among the outputs of
the classifier 41. On the other hand, with Formulas (21)20
to (23) used in the second embodiment, the DC component
“1/A” can be calculated using two signals among the outputs
of the classifier 41. Therefore, the second embodiment can
obtain the effect of reducing the calculation load as
compared with the first embodiment. Furthermore, while the25
method using Formulas (21) to (23) requires application of
two types of voltage vectors, the method using Formulas
(10) to (14) requires application of two or three types of
voltage vectors. From the viewpoint of position estimation
response, the fewer types of voltage vectors are used for30
calculation produces, the better a responsiveness becomes.
Therefore, in the second embodiment, it is possible to
extract the DC component with high response as compared
33
with the method of the first embodiment.
[0095] Next, a hardware configuration for implementing
each function of the control device 100 according to the
first embodiment and the second embodiment will be
described. Each function as used herein refers to the5
functionality of the current detector 2, the voltage
applicator 3, the position estimator 4, and the controller
5.
[0096] FIG. 13 is a diagram illustrating a first example
of a hardware configuration for implementing the functions10
of the control device 100 according to the first embodiment
and the second embodiment. FIG. 14 is a diagram
illustrating a second example of a hardware configuration
for implementing the functions of the control device 100
according to the first embodiment and the second embodiment.15
In the first example illustrated in FIG. 13, the control
device 100 includes a dedicated processing circuitry 1000,
a current detector 2, and a voltage applicator 3. Here,
the functions of the current detector 2 and the voltage
applicator 3 are implemented by using dedicated hardware,20
and the functions of the position estimator 4 and the
controller 5 are implemented by the dedicated processing
circuitry 1000. In the second example illustrated in FIG.
14, the control device 100 includes a processor 1001, a
storage device 1002, the current detector 2, and the25
voltage applicator 3. Here, the functions of the current
detector 2 and the voltage applicator 3 are implemented by
using dedicated hardware, and the functions of the position
estimator 4 and the controller 5 are implemented by the
processor 1001 and the storage device 1002. The dedicated30
processing circuitry 1000 and the processor 1001 are also
referred to as a control circuit.
[0097] The dedicated processing circuitry 1000 is a
34
single circuit, a composite circuit, a programmed processor,
a parallel programmed processor, an application specific
integrated circuit (ASIC), a field programmable gate array
(FPGA), or a combination thereof. The control device 100
may collectively implement the above-described functions by5
one piece of dedicated processing circuitry 1000, or may
implement the above-described functions by using a
plurality of pieces of dedicated processing circuitry 1000.
[0098] The processor 1001 can implement each function of
the control device 100 by reading and executing a program10
stored in the storage device 1002. Note that the control
device100 may include a plurality of processors 1001 and a
plurality of storage devices 1002 that cooperate to
implement the above functions.
[0099] In a case where the processor 1001 and the15
storage device 1002 are used, the above functions are
implemented by software, firmware, or a combination thereof.
Software or firmware is described as programs and stored in
the storage device 1002. The processor 1001 reads and
executes the programs stored in the storage device 1002.20
It can also be said that these programs cause a computer to
execute the procedures and methods for executing each
function.
[0100] The processor 1001 is a CPU, and is also called a
processing device, an arithmetic device, a microprocessor,25
a microcomputer, a digital signal processor (DSP), or the
like. Examples of the storage device 1002 include a non-
volatile or volatile semiconductor memory, a magnetic disk,
a flexible disk, an optical disc, a compact disc, a mini
disc, a digital versatile disc (DVD), and the like.30
Examples of non-volatile or volatile semiconductor memories
include a random access memory (RAM), a read only memory
(ROM), a flash memory, an erasable programmable ROM (EPROM),
35
an electrically EPROM (EEPROM, registered trademark), and
the like.
[0101] The configurations described in the above-
mentioned embodiments indicate examples. The embodiments
can be combined with another well-known technique and with5
each other, and some of the configurations can be omitted
or changed in a range not departing from the gist.
[0102] For example, in the first and second embodiments
described above, the rotary machine 1 is a synchronous
reluctance motor, but the type of the rotary machine 1 is10
not limited thereto. The rotary machine 1 may be a motor
having saliency such as an interior permanent magnet
synchronous motor or a surface permanent magnet synchronous
motor (SPMSM).
[0103] In the first and second embodiments, the15
controller 5 of the control device 100 controls the d-axis
current and the q-axis current. However, the controller 5
may be configured to control torque, rotational speed, and
the like.
[0104] In the first and second embodiments, the20
configuration in which the current detector 2 detects the
phase current of the rotary machine 1 has been described,
but the current detector 2 is an example of a current
detection unit and is not limited to the above example.
The current detection unit only needs to be able to detect25
the phase current, and may be a current sensor incorporated
in an inverter (not illustrated) constituting the voltage
applicator 3.
Reference Signs List30
[0105] 1 rotary machine; 2 current detector; 3
voltage applicator; 4 position estimator; 5 controller; 6
current controller; 7 rotating coordinate inverse
36
converter; 8 two-to-three phase converter; 9, 43 three-
to-two phase converter; 10 rotating coordinate converter;
30a transistor; 30b diode; 30A, 30B, 30C leg; 32, 33, 34
connection point; 35a, 35b DC bus; 36 power source; 40
current differential information calculation unit; 415
classifier; 42 DC component remover; 44 phase
synchronization calculation unit; 100 control device; 400
voltage vector determiner; 401 current differential
calculator; 441 phase error calculation unit; 442 PI
controller; 443 integrator; 444, 445 proportioner; 100010
dedicated processing circuitry; 1001 processor; 1002
storage device; UP, UN, VP, VN, WP, WN semiconductor
element.
37
We Claim:
[Claim 1] A control device (100) that performs drive
control of a multiphase rotary machine (1), the control
device (100) comprising:
a current detection unit (2) to detect a rotary5
machine current flowing through the rotary machine (1);
a drive voltage command calculation unit (5) to
generate a drive voltage command for driving the rotary
machine (1) based on the rotary machine current and an
estimated value of a rotor position of the rotary machine10
(1);
a voltage applicator (3) to apply a voltage to the
rotary machine (1) based on the drive voltage command
generated; and
a position estimation unit (4) to estimate the rotor15
position based on the rotary machine current, wherein
the position estimation unit (4) determines a type of
a voltage vector output from the voltage applicator (3)
based on a gate signal of the voltage applicator (3),
calculates a change amount of the rotator current for each20
type of the voltage vector determined, generates an AC
signal having a DC component of zero and changing at a
double angle of the rotor position based on a rotary
machine current change amount that is a calculation result,
and estimates the rotor position based on the AC signal.25
[Claim 2] The control device (100) according to claim 1,
wherein
the position estimation unit (4) estimates the rotor
position by performing phase synchronization calculation on
the AC signal.30
[Claim 3] The control device (100) according to claim 1 or
2, wherein
38
the position estimation unit (4) generates the AC
signal having a continuous waveform shape based on a
combination of a plurality of the rotary machine current
change amounts including a same waveform shape among a
plurality of the rotary machine current change amounts5
obtained under a plurality of conditions that differ in at
least one of voltage vector or phase.
[Claim 4] The control device (100) according to claim 3,
wherein
utilizing a feature that the two rotary machine10
current change amounts obtained under a condition that
directions of voltage vectors are in an opposite-direction
relationship and with a same phase have a relationship of
reverse signs, the position estimation unit (4) generates
the AC signal by using a value obtained by multiplying, by15
minus one, one of the two rotary machine current change
amounts obtained under a condition that directions of
voltage vectors are in an opposite-direction relationship
and with a same phase.
[Claim 5] The control device (100) according to claim 3 or20
4, wherein
the position estimation unit (4) generates the AC
signal utilizing a feature that a phase of an AC component
of the rotary machine current change amount is shifted
according to a direction of a voltage vector.25
[Claim 6] The control device (100) according to any one of
claims 3 to 5, wherein
the position estimation unit (4) calculates a DC
component of the rotary machine current change amount,
calculates an AC component of the rotary machine current30
change amount by subtracting the DC component calculated
from the rotary machine current change amount, and
39
generates the AC signal based on the AC component.
[Claim 7] The control device (100) according to claim 6,
wherein
the position estimation unit (4) calculates the DC
component by taking a sum of a first rotary machine current5
change amount, a second rotary machine current change
amount having a phase difference of plus 2/3 π from the
first rotary machine current change amount, and a third
rotary machine current change amount having a phase
difference of minus 2/3 π from the first rotary machine10
current change amount, among the rotary machine current
change amounts.
[Claim 8] The control device (100) according to claim 6,
wherein
the position estimation unit (4) calculates the DC15
component by taking a difference between the two rotary
machine current change amounts that are equal in phase of
the AC component and different in magnitude of the DC
component, among the rotary machine current change amounts.
[Claim 9] The control device (100) according to any one of20
claims 1 to 8, wherein
the position estimation unit (4) includes:
a phase error calculation unit (441) to calculate a
phase error based on an AC signal having a DC component of
zero and changing at a double angle of the rotor position,25
and based on an estimated position of the rotor position;
an estimated speed generation unit (442) to output an
estimated speed based on the phase error; and
an integrator (443) to output a value obtained by
integrating the estimated speed as the estimated position.30
[Claim 10] A drive control method for a multiphase
40
rotary machine (1), the drive control method comprising:
a step of detecting a rotary machine current flowing
through the rotary machine (1);
a step of generating a drive voltage command for
driving the rotary machine (1) based on the rotary machine5
current and an estimated value of a rotor position of the
rotary machine (1);
a step of applying a voltage to the rotary machine (1)
based on the drive voltage command generated; and
a step of estimating the rotor position based on the10
rotary machine current, wherein
in the step of estimating the rotor position, a type
of a voltage vector output from a voltage applicator (3)
that applies a voltage to the rotary machine (1) is
determined based on a gate signal of the voltage applicator15
(3), a change amount of the rotator current is calculated
for each type of the voltage vector determined, an AC
signal having a DC component of zero and changing at a
double angle of the rotor position is generated based on a
rotary machine current change amount that is a calculation20
result, and the rotor position is estimated based on the AC
signal.