Title of invention: motor drive device, electric vehicle system
Technical field
[0001]
The present invention relates to a motor drive device for operating a motor (motor), and more particularly to a motor drive device for performing feedback control for adjusting the current energized in the motor to a command current, and an electric vehicle system.
Background technology
[0002]
The current control of the motor drive device can be constructed by feedback control that detects the current energized in the motor and adjusts the detected current to the command current. In general feedback control, proportional control or integral control is performed based on the result of multiplying the difference between the detected current and the command current by the control gain. The time until the current applied to the motor is adjusted to the command current, that is, the control response speed is adjusted by the set value of the control gain.
[0003]
In feedback control, high-speed response of control can be realized by setting a high control gain. However, if a high control gain is set uniformly regardless of the control state, the control may become unstable due to the setting error of the motor parameters and the restrictions of the current and the voltage.
[0004]
From this, a method of switching the control gain of the feedback control according to the control state of the motor has been proposed (see, for example, Patent Document 1). In the control gain switching method according to Patent Document 1, in a motor drive device that performs position control, a motor stop state, acceleration / deceleration state, and constant speed state are determined based on a command signal, and control is performed according to the determined control state. The gain is being switched.
[0005]
The switching method according to Patent Document 1 is applied to a motor drive device that performs position control, but can also be applied to a motor drive device that performs torque control. In this case, the control state is determined and the control gain is switched based on the command torque which is the command signal. For example, the control state is divided into a small torque command state, a medium torque command state, and a large torque command state according to the magnitude of the command torque, and the control gain corresponding to the control state is switched from the magnitude of the command torque.
Prior art literature
Patent documents
[0006]
Patent Document 1: Japanese Unexamined Patent Publication No. 2000-293234
Outline of the invention
Problems to be solved by the invention
[0007]
By the way, in the case of a motor drive device that performs torque control, a high control gain is set in the low torque range, and a low control gain is set in the high torque range in consideration of voltage and current constraints. Here, in a specific situation such as when an abnormality is detected, it is assumed that the command torque is set to 0 Nm at an early stage. In this case, in the switching method described in Patent Document 1, the control gain is set according to the magnitude (target value) of the command torque when the command torque rises, but it is not related to the current torque level when the command torque falls. A high control gain corresponding to 0 Nm is uniformly set. Therefore, there is a possibility that vibration of the motor torque, overshoot, and undershoot may occur during the transient response.
[0008]
The present invention solves the above-mentioned problems, and an object of the present invention is to provide a motor drive device and an electric vehicle system capable of avoiding deterioration of motor torque control stability during transient response.
Means to solve problems
[0009]
The motor drive device according to one aspect of the present invention is a motor drive device that controls the torque of the motor, and includes a power conversion circuit that drives the motor and a controller that controls the power conversion circuit. A command current calculation unit that generates a command current according to the command torque for the motor, a current control unit that performs feedback control for adjusting the current energized in the motor to the command current, and a control gain used for the feedback control. The control gain setting unit has a control gain setting unit that calculates based on the command torque and sets the current control unit, and the control gain setting unit switches the control gain after the absolute value of the command torque decreases. The time until the command torque is increased is controlled to be longer than the time until the control gain is switched.
The invention's effect
[0010]
According to the present invention, the time from the decrease in the absolute value of the command torque to the switching of the control gain is longer than the time from the increase in the absolute value of the command torque to the switching of the control gain. The control gain at the rising edge of the absolute value of can also be applied at the falling edge of the absolute value of the command torque. Therefore, it is possible to realize a stable operation of the motor torque while suppressing vibration of the motor torque, overshoot, undershoot, etc. at the time of transient response.
A brief description of the drawing
[0011]
[Fig. 1] Conceptual waveform diagram of control gain switching operation in a comparative example.
FIG. 2 is a configuration diagram of a motor drive device according to the first embodiment.
FIG. 3 is a block diagram of a current control unit according to the first embodiment.
FIG. 4 is a configuration diagram of a control gain setting unit according to the first embodiment.
FIG. 5 is an operation conceptual diagram of a torque level calculation unit according to the first embodiment.
FIG. 6 is an implementation example of a control gain LUT according to the first embodiment.
FIG. 7 is a flowchart showing the operation of the set time control unit according to the first embodiment.
FIG. 8 is a conceptual waveform diagram of a control gain switching operation according to the first embodiment.
FIG. 9 is a configuration diagram of a motor drive device according to a second embodiment.
FIG. 10 is a block diagram of a current control unit according to a second embodiment.
FIG. 11 is a configuration diagram of a control gain setting unit according to a second embodiment.
FIG. 12 is a conceptual waveform diagram of a control gain switching operation according to a fourth embodiment.
FIG. 13 is a configuration diagram of an electric vehicle system according to a fifth embodiment.
Embodiment for carrying out the invention
[0012]
Before explaining the control gain switching operation according to the present embodiment, the control gain switching operation according to the comparative example will be described. FIG. 1 is a conceptual waveform diagram of a control gain switching operation according to a comparative example.
[0013]
As shown in FIG. 1, in the control gain switching operation according to the comparative example, the control state is determined based on whether or not the command torque τ * crosses the threshold value τ th. When the control state is determined based on the command torque τ *, the control gain ω c is switched at the same time as the state determination. In this case, if it is determined that the command torque τ * exceeds the threshold value τ th, a low control gain ω cL is set as the control gain ω c, and if it is determined that the command torque τ * is below the threshold value τ th, control is performed. A high control gain ω cH is set as the gain ω c.
[0014]
At “t = tr”, when the command torque τ * increases stepwise and changes across the threshold value τ th, the control gain ω c setting is immediately turned off from the high control gain ω cH to the low control gain ω cL. It changes. Therefore, in the rising period of the motor torque τ immediately after the lapse of tr, a low control gain ω cL is set as the control gain ω c.
[0015]
After that, at “t = t f”, when the command torque τ * decreases stepwise and changes across the threshold value τ th, the control gain ω c is immediately set from the low control gain ω cL to the high control gain ω cH. Switch. Therefore, in the falling period of the motor torque τ immediately after the lapse of tr, a high control gain ω cH is set as the control gain ω c.
[0016]
In this way, when the binary command torque τ * goes back and forth in a step-like manner, different control gains are set at the rising edge and the falling edge of the command torque τ * in the control gain switching operation according to the comparative example. In particular, in the operation shown in FIG. 1, a high control gain ω cH is set at the fall of the command torque τ *, so that vibration of the motor torque, undershoot, etc. may occur during the transient response (falling period). There is. Here, an example in which the command torque τ * changes stepwise is shown, but the same problem may occur when the command torque τ * changes abruptly. Therefore, in the control gain switching operation of the present embodiment, the same control gain is set at the rising edge and the falling edge of the command torque τ *.
[0017]
[First Embodiment]
Hereinafter, the motor drive device 200 to which the control gain switching operation according to the present embodiment is applied will be described. FIG. 2 is a configuration diagram of the motor drive device 200 according to the first embodiment.
[0018]
As shown in FIG. 2, the motor drive device 200 according to the present embodiment controls the torque of the AC motor (motor) 201, and includes a power conversion circuit 204 for driving the AC motor 201 and a power conversion circuit 204. It includes a controller 203 to be controlled. The AC motor 201 is provided with a position sensor 202, and the power conversion circuit 204 is provided with a current sensor 205. The AC motor 201 is, for example, a three-phase brushless DC motor. Further, the position sensor 202 is, for example, an encoder or a resolver, and outputs a signal corresponding to the rotation of the rotor.
[0019]
The controller 203 has a basic configuration of vector control, a command torque τ * is input from the outside, and three-phase command voltages V u *, V v *, and V w * are output to the power conversion circuit 204. The power conversion circuit 204 drives the AC motor 201 based on the three-phase command voltages V u *, V v *, and V w * output from the controller 203. The current sensor 205 detects the current energized by the AC motor 201 and feeds back the detected current values ​​I uc, I vc, and I wc to the controller 203.
[0020]
Further, the controller 203 includes a command current calculation unit 206, a control gain setting unit 207, a current control unit 208, a dq / 3-phase conversion unit 209, a 3-phase / dq conversion unit 210, and a rotor position / motor speed. It is provided with a generation unit 211. Each part of the controller 203 is composed of a processor that executes various processes, an integrated circuit, a memory, and the like. The memory is composed of one or a plurality of recording media such as ROM (Read Only Memory) and RAM (Random Access Memory) depending on the intended use. In the following description, it is described that each part of the controller 203 mainly executes various processes, but in reality, the processor executes various processes in cooperation with the memory or the like.
[0021]
The command current calculation unit 206 calculates the d-axis command current I d * and the q-axis command current I q * according to the command torque τ * for the AC motor 201 and outputs them to the current control unit 208. The command current calculation unit 206 is composed of, for example, a look-up table in which a d-axis command current I d * and a q-axis command current I q * are associated with a command torque τ *.
[0022]
The control gain setting unit 207 calculates the control gain ω c used for feedback control based on the command torque τ * and sets it in the current control unit 208. In this case, the control gain setting unit 207 outputs the control gain ω c corresponding to the command torque τ * to the current control unit 208 after a predetermined set time. This control gain ω c is a variable control gain that changes based on the command torque τ *. The detailed configuration of the control gain setting unit 207 will be described later.
[0023]
The current control unit 208 is configured to perform feedback control that adjusts the current energized in the AC motor 201 to the command current. The d-axis command current I d * and q-axis command current I q * are input to the current control unit 208 from the command current calculation unit 206, and the control gain ω c is input from the control gain setting unit 207. Further, the d-axis real current I dc and the q-axis real current I qc are fed back from the current sensor 205 to the current control unit 208 through the three-phase / dq conversion unit 210, and the rotor position / motor speed generation unit is fed from the position sensor 202. The motor speed ω 1 is fed back through 211. The current control unit 208 calculates the d-axis command voltage V d * and the q-axis command voltage V q * based on the inputs from each of these units, and outputs them to the dq / 3 phase conversion unit 209. The detailed configuration of the current control unit 208 will be described later.
[0024]
The dq / 3-phase conversion unit 209 has d-axis command voltages V d * and q input from the current control unit 208 based on the rotor position θ dc input from the rotor position / motor speed generation unit 211. The shaft command voltage V q * is converted into the three-phase command voltage V u *, V v *, and V w *. The AC motor 201 is driven by the three-phase command voltages V u *, V v *, and V w * via the power conversion circuit 204.
[0025]
The three-phase / dq conversion unit 210 has the three-phase actual currents I uc, I vc, and I wc detected by the current sensor 205 based on the rotor position θ dc input from the rotor position / motor speed generation unit 211. Is converted into a d-axis real current I dc and a q-axis real current I qc.
[0026]
The rotor position / motor speed generation unit 211 generates the motor speed ω 1 and the rotor position θ dc from the output signal of the position sensor 202 provided in the AC motor 201.
[0027]
The detailed configuration of the current control unit 208 will be described with reference to FIG. FIG. 3 is a configuration diagram of the current control unit 208 according to the first embodiment.
[0028]
As shown in FIG. 3, the current control unit 208 includes a d-axis current control unit 300 and a q-axis current control unit 301. The d-axis current control unit 300 inputs the d-axis actual current I dc input from the three-phase / dq conversion unit 210 (see FIG. 2) by PI control from the command current calculation unit 206 (see FIG. 2). Control so that it approaches the shaft command current I d *. The q-axis current control unit 301 brings the q-axis actual current I qc input from the 3-phase / dq conversion unit 210 by PI control closer to the q-axis command current I q * input from the command current calculation unit 206. Control.
[0029]
The d-axis current control unit 300 includes a subtraction unit 302a, a P (proportional) control unit 303a, an I (integral) control unit 304a, an addition unit 305a, and an addition unit 306a.
[0030]
In the subtraction unit 302a, the d-axis command current I d * input from the command current calculation unit 206 and the d-axis actual current I dc input from the three-phase / dq conversion unit 210 are based on the following equation (1). The d-axis current deviation ΔId is calculated.
ΔI d = I d * -I dc ... (1)
[0031]
The P control unit 303a includes a control gain multiplication unit 307a and a control gain multiplication unit 308a. The variable control gain ω c input from the control gain setting unit 207 (see FIG. 2) is set in the control gain multiplication unit 307a, and the d-axis P control gain K Pd is set in the control gain multiplication unit 308a. In the P control unit 303a, the d-axis P control output V Pd * is calculated from the d-axis current deviation ΔId, the variable control gain ω c, and the d-axis P control gain K Pd based on the following equation (2).
V Pd * = ω c ・ K Pd ・ ΔI d ・ ・ ・ (2)
In the present embodiment, the d-axis current deviation ΔId is multiplied by the variable control gain ω c in the control gain multiplication unit 307a and the d-axis P control gain K Pd which is a constant value in the control gain multiplication unit 308a.
[0032]
The I control unit 304a includes a control gain multiplication unit 309a, a control gain multiplication unit 310a, and an integrator 311a. The variable control gain ω c input from the control gain setting unit 207 is set in the control gain multiplication unit 309a, and the d-axis I control gain KId is set in the control gain multiplication unit 310a. In the I control unit 304a, the d-axis I control output V Id * is calculated from the d-axis current deviation ΔId, the variable control gain ω c, and the d-axis I control gain K Id based on the following equation (3).
V Id * = ω c ・ K Id ・ ∫ΔI dt ・ ・ ・ (3)
In the present embodiment, the d-axis current deviation ΔId is multiplied by the variable control gain ω c in the control gain multiplying unit 309a and the d-axis I control gain K Id which is a constant value in the control gain multiplying unit 310a, and integrated. The integration is performed in the device 311a.
[0033]
In the addition unit 305a, the d-axis P control output VPd * input from the P control unit 303a and the d-axis I control output VId * input from the I control unit 304a are added, and the d-axis PI control output VPId * is added. (= V Pd * + V Id *) is output.
[0034]
In the addition unit 306a, the d-axis PI control output V PId * input from the addition unit 305a and the d-axis non-interference control output V DECd * are added, and the d-axis command voltage V d * (= V PId * + V DECd *). ) Is output. The d-axis non-interference control output V DECd * can be obtained from the calculation of the following equation (4), for example, by the motor speed ω 1, the q-axis inductance L qc, and the q-axis actual current I qc.
V DECd * =-ω 1, L qc, I qc ... (4)
In this embodiment, the q-axis real current I qc is used for the calculation of the equation (4), but instead of the q-axis real current I qc, the q-axis command current I q * or the q-axis I control output V Iq * May be used.
[0035]
The q-axis current control unit 301 includes a subtraction unit 302b, a P control unit 303b, an I control unit 304b, an addition unit 305b, and an addition unit 306b.
[0036]
In the subtraction unit 302b, the q-axis command current I q * input from the command current calculation unit 206 and the q-axis actual current I qc input from the three-phase / dq conversion unit 210 are based on the following equation (5). The q-axis current deviation ΔI q is calculated.
ΔI q = I q * -I qc ... (5)
[0037]
The P control unit 303b includes a control gain multiplication unit 307b and a control gain multiplication unit 308b. The variable control gain ω c input from the control gain setting unit 207 is set in the control gain multiplication unit 307b, and the q-axis P control gain K Pq is set in the control gain multiplication unit 308b. In the P control unit 303b, the q-axis P control output V Pq * is calculated from the q-axis current deviation ΔI q, the variable control gain ω c, and the q-axis P control gain K Pq based on the following equation (6).
V Pq * = ω c ・ K Pq ・ ΔI q ・ ・ ・ (6)
In the present embodiment, the q-axis current deviation ΔI q is multiplied by the variable control gain ω c in the control gain multiplication unit 307b and the q-axis P control gain K Pq which is a constant value in the control gain multiplication unit 308b.
[0038]
The I control unit 304b includes a control gain multiplication unit 309b, a control gain multiplication unit 310b, and an integrator 311b. The variable control gain ω c input from the control gain setting unit 207 is set in the control gain multiplication unit 309b, and the q-axis I control gain K Iq is set in the control gain multiplication unit 310b. In the I control unit 304b, the q-axis I control output V Iq * is calculated from the q-axis current deviation ΔI q, the variable control gain ω c, and the q-axis I control gain K Iq based on the following equation (7).
V IQ * = ω c ・ K Iq ・ ∫ΔI qdt ・ ・ ・ (7)
In the present embodiment, the q-axis current deviation ΔI q is multiplied by the variable control gain ω c in the control gain multiplication unit 309b and the constant value q-axis I control gain K I q in the control gain multiplication unit 310 b, and integrated. The integration is performed in the device 311b.
[0039]
In the addition unit 305b, the q-axis P control output V Pq * input from the P control unit 303b and the q-axis I control output V Iq * input from the I control unit 304b are added, and the q-axis PI control output V PIq * is added. (= V Pq * + V Iq *) is output.
[0040]
In the addition unit 306b, the q-axis PI control output V PIq * input from the addition unit 305b and the q-axis non-interference control output V DECq * are added, and the q-axis command voltage V q * (= V PIq * + V DECq *). ) Is output. The q-axis non-interference control output V DECq * can be obtained from the motor speed ω 1, the d-axis inductance L dc, the d-axis actual current I dc, and the induced voltage constant KEc, for example, from the calculation of the following equation (8). ..
V DECq * = ω 1, L dc, I dc + ω 1, K Ec ... (8)
In the present embodiment, the d-axis real current I dc is used for the calculation of the equation (8), but instead of the d-axis real current I dc, the d-axis command current I d * or the d-axis I control output V Id * May be used.
[0041]
As described above, the current control unit 208 sets the control gain ω c that changes based on the command torque τ * in the P control units 303a and 303b and the I control units 304a and 304b, and controls according to the control state. It constitutes a motor drive device that can switch the response speed.
[0042]
The detailed configuration of the control gain setting unit 207 will be described with reference to FIGS. 4 to 6. FIG. 4 is a configuration diagram of the control gain setting unit 207 according to the first embodiment. FIG. 5 is an operation conceptual diagram of the torque level calculation unit 401 according to the first embodiment. FIG. 6 is an implementation example of the control gain LUT 402 according to the first embodiment.
[0043]
As shown in FIG. 4, the control gain setting unit 207 includes an absolute value calculation unit 400, a torque level calculation unit 401, a control gain LUT 402, and a set time control unit 403.
[0044]
The absolute value calculation unit 400 outputs the absolute value | τ * | of the input command torque τ *. By this processing, the sign of the command torque τ * is ignored, and the operations during power running and regeneration are treated in the same manner.
[0045]
The torque level calculation unit 401 converts the absolute value | τ * | of the command torque into a predetermined torque level value L τ. Here, the conversion process from the absolute value | τ * | of the command torque to the torque level value will be described. In FIG. 5, in the torque level calculation unit 401, the absolute value | τ * | of the command torque that changes in the range from 0 to | τ 3 | is set to the torque level value L τ in three stages of L τ1, L τ2, and L τ3. An operation example when converting to is shown.
[0046]
As shown in FIG. 5, when the hysteresis characteristic is applied to the torque level calculation unit 401, the operation differs depending on whether the absolute value | τ * | of the command torque increases or decreases. When the absolute value of the command torque | τ * | increases, the torque level value changes from L τ 1 to L τ 2 at | τ 1 | + Δτ 1, and the torque level value changes from L τ 2 to L at | τ 2 | + Δτ 2. It changes to τ3. On the other hand, when the absolute value | τ * | of the command torque decreases, the torque level value changes from L τ 2 to L τ 1 at | τ 1 | −Δτ 1, and the torque level value changes at | τ 2 | −Δτ2. It changes from L τ3 to L τ2.
[0047]
In this way, the torque level calculation unit 401 gives a hysteresis characteristic to the change of the torque level value L τ when the absolute value of the command torque decreases and increases. As a result, frequent changes in the torque level value L τ near the threshold value (| τ 1 |, | τ 2 |) where the torque level value L τ changes are suppressed, and the switching operation of the torque level value L τ is stabilized. can do.
[0048]
The torque level calculation unit 401 of the present embodiment converts the absolute value | τ * | of the command torque into the torque level value L τ of three stages, but the number of stages is less than three stages or the number of stages is more than three stages. You may convert with.
[0049]
Further, the torque level calculation unit 401 of the present embodiment applies the hysteresis characteristic to all threshold values ​​(| τ 1 |, | τ 2 |), that is, changes in the torque level value L τ at all stages. It is not limited to this configuration. The torque level calculation unit 401 may apply the hysteresis characteristic only to the change of the torque level value L τ in some stages, or may not apply the hysteresis characteristic to the change of the torque level value L τ in all stages. ..
[0050]
The control gain LUT 402 is a look-up table in which the control gain ω cpre is stored in association with the torque level value L τ. It should be noted that this control gain ω cpre is a read value of the look-up table and is distinguished from the control gain ω c applied to the current control unit 208.
[0051]
For example, the control gain LUT 402 has the form shown in FIG. 6 when the torque level calculation unit 401 converts the absolute value | τ * | of the command torque into the torque level value L τ in three stages of L τ1, L τ2, and L τ3. It is implemented in. In this way, the control gain setting unit 207 is a finger. The torque level value L τ, which is an argument of the control gain LUT 402, is calculated based on the absolute value | τ * | of the command torque, and the control gain ω cpre is read out from the control gain LUT 402. By using a look-up table to set the control gain, it is possible to read the control gain ω cpre from the torque level L τ by a simple reference process instead of a complicated calculation process.
[0052]
In the present embodiment, the control gain LUT 402 is a look-up table in which only the torque level value L τ is used as an argument, but a more multidimensional look-up table may be provided by adding an argument. As the argument to be added, for example, the motor speed, the carrier frequency, and the like can be considered.
[0053]
The set time control unit 403 controls the time until the control gain ω cpre read from the control gain LUT 402 is set in the current control unit 208 based on the torque level value L τ. When the torque level value L τ increases, the control gain ω cpre is set immediately, and when the torque level value L τ decreases, the control gain ω after the lapse of a predetermined holding time Th after the torque level value L τ decreases. cpre is set. In this way, in the control gain setting unit 207, the time from the decrease of the absolute value | τ * | of the command torque to the switching of the control gain due to the increase / decrease of the torque level value L τ is the absolute value of the command torque | τ. It is controlled so that it is longer than the time from the increase of * | to the switching of the control gain.
[0054]
The control gain switching operation will be described with reference to FIGS. 7 and 8. FIG. 7 is a flowchart showing the operation of the set time control unit 403 according to the first embodiment. FIG. 8 is a conceptual waveform diagram of the control gain switching operation according to the first embodiment. In the flowchart of FIG. 7, it is assumed that the process is performed every time the command torque τ * is input. Further, although an example in which the command torque τ * changes in a step shape will be described here, the same applies to the case where the command torque τ * changes abruptly. Further, FIG. 8 shows a state in which the torque level value changes between the two torque level values ​​L τL and L τH for convenience of explanation, but the actual torque level value changes in a plurality of steps.
[0055]
First, the operation flow at the start of rising of the absolute value | τ * | of the command torque of "t = tr" will be described. The absolute value | τ * | of the command torque is converted into the torque level value L τ, and the set time control unit 403 (see FIG. 4) determines whether or not the torque level value L τ has increased (step S1). The increase in the torque level value L τ is determined, for example, by whether or not the absolute value | τ * | of the command torque exceeds the threshold value τ th. At "t = tr", the absolute value | τ * | of the command torque increases stepwise and changes over the threshold value τ th. Therefore, it is determined that the torque level value L τ has increased from the torque level value L τ L to the torque level value L τH.
[0056]
When the set time control unit 403 determines that the torque level value L τ has increased (YES in step S1), the set time control unit 403 inputs “1” to the permission signal Sp (step S5). “Sp = 1” means that “the control gain ω cpre read from the control gain LUT 402 (see FIG. 4) can be immediately set in the current control unit 208 as the control gain ω c”. The set time control unit 403 sets the control gain ω cpre read from the control gain LUT 402 as the control gain ω c (step S6). Here, the control gain ω cL corresponding to the torque level value L τH is immediately set in the current control unit 208. Then, the set time control unit 403 resets the time counting time to “0” (step S7). At the start of rising of the absolute value | τ * | of the command torque, the processes of steps S1 and S5-S7 are performed.
[0057]
Next, the operation flow while the absolute value | τ * | of the command torque is maintained at a constant value immediately after the lapse of tr will be described. The set time control unit 403 determines whether or not the torque level value L τ has increased (step S1) and whether or not the torque level value L τ has decreased (step S2). The decrease in the torque level value L τ is determined, for example, by whether or not the absolute value | τ * | of the command torque is below the threshold value τ th. Immediately after the lapse of tr, the absolute value | τ * | of the command torque does not change across the threshold value τ th. Therefore, it is determined that the torque level value L τ does not increase or decrease from the torque level value L τH.
[0058]
When the set time control unit 403 determines that the torque level value L τ has not increased or decreased (NO in steps S1 and S2), the set time control unit 403 determines whether or not “1” is input to the permission signal Sp (NO). Step S3). When "1" is input to the permission signal Sp (YES in step S3), the set time control unit 403 sets the control gain ω cpre read from the control gain LUT 402 as the control gain ω c (step S11). .. Here, the control gain ω cL corresponding to the torque level value L τH is set in the current control unit 208. Then, the set time control unit 403 resets the time counting time to “0” (step S12). Immediately after the lapse of tr, the processes of steps S1-S3, S11, and S12 are performed while the absolute value | τ * | of the command torque is maintained at a constant value.
[0059]
Next, the operation flow at the start of the fall of the absolute value | τ * | of the command torque of "t = t f" will be described. The set time control unit 403 determines whether or not the torque level value L τ has increased (step S1) and whether or not the torque level value L τ has decreased (step S2). At "t = t f", the absolute value | τ * | of the command torque decreases stepwise and changes over the threshold value τ th. Therefore, it is determined that the torque level value L τ has decreased from the torque level value L τH to the torque level value L τ L.
[0060]
When the set time control unit 403 determines that the torque level value L τ has decreased (NO in step S1 and YES in step S2), "0" is input to the permission signal Sp (step S8).
“Sp = 0” means that “a state in which the previously set value of the control gain ω c is maintained”.
The set time control unit 403 holds the previously set value of the control gain ω c (step S9). Here, the torque level value is L τL, but the control gain ω cL, which is the previously set value, is set in the current control unit 208 for the control gain ω c. Then, the set time control unit 403 resets the time counting time to “0” (step S10). At the start of the fall of the absolute value | τ * | of the command torque, the processes of steps S1, S2, and S8-S10 are performed.
[0061]
Next, the operation flow while the absolute value | τ * | of the command torque is maintained at a constant value immediately after the elapse of t f will be described. The set time control unit 403 determines whether or not the torque level value L τ has increased (step S1) and whether or not the torque level value L τ has decreased (step S2). Immediately after the elapse of t f, the absolute value | τ * | of the command torque does not change across the threshold value τ th. Therefore, it is determined that the torque level value L τ does not increase or decrease from the torque level value L τL.
[0062]
When the set time control unit 403 determines that the torque level value L τ has not increased or decreased (NO in steps S1 and S2), the set time control unit 403 determines whether or not “1” is input to the permission signal Sp (NO). Step S3). Since "0" is input to the permission signal Sp at "t = t f" (NO in step S3), the set time control unit 403 determines whether or not the time counting time is the predetermined holding time Th (NO). Step S4). If the predetermined holding time Th has not elapsed immediately after the elapse of t f (NO in step S4), the set time control unit 403 holds the previously set value of the control gain ω c (step S16). Here, the torque level value is L τL, but the control gain ω cL, which is the previously set value, is set in the current control unit 208 for the control gain ω c. Then, the set time control unit 403 measures the time (step S17).
[0063]
The set time control unit 403 repeats the processes of steps S1-S4, S16, and S17 until the predetermined holding time Th elapses immediately after the elapse of t f. That is, the setting of the control gain ω cL is continued until the predetermined holding time Th, which is the falling period of the motor torque, elapses. By holding the control gain ω c until the holding time Th elapses, it is possible to avoid immediate switching of the control gain ω c at the fall of the absolute value | τ * | of the command torque.
[0064]
When the predetermined holding time Th has elapsed immediately after the elapse of t f (YES in step S4), the set time control unit 403 inputs “1” to the permission signal Sp (step S13). The set time control unit 403 sets the control gain ω cpre read from the control gain LUT 402 as the control gain ω c (step S14). Here, the control gain ω cH corresponding to the torque level value L τL is set in the current control unit 208. Then, the set time control unit 403 resets the time counting time to “0” (step S15). Immediately after the elapse of t f, the processes of steps S1-S4 and S13-S17 are performed while the absolute value | τ * | of the command torque is maintained at a constant value.
[0065]
In this way, at the rising edge when the absolute value | τ * | of the command torque increases, the control gain ω cpre calculated from the control gain LUT 402 is immediately set in the current control unit 208. Further, at the falling edge where the absolute value | τ * | of the command torque decreases, the control gain ω cpre calculated from the control gain LUT 402 is set in the current control unit 208 with a delay of a predetermined holding time Th. As a result, the same control gain ω c can be set for the current control unit 208 at the rising edge and the falling edge of the absolute value | τ * | of the command torque.
[0066]
The predetermined holding time Th is the time estimated by the controller 203 as the transition time from the transient response state to the steady state. Since it is difficult to detect the motor torque and observe the state, for example, the d-axis real current I dc and the q-axis real current I qc are the d-axis command current I d * and the q-axis command current I q *, respectively. The time until reaching 90% may be obtained from the following equation (9) and set as the holding time Th.
Th = 2.197 / ω c ... (9)
[0067]
The holding time Th may be set to the time required for the motor torque τ to be adjusted to the command torque τ *, and is not limited to the time obtained by the equation (9). The holding time Th is at least the control gain ω after the absolute value of the command torque | τ * | decreases, rather than the time from the increase of the absolute value | τ * | of the command torque to the switching of the control gain ω c. It suffices if the time is set so that the time until c is switched becomes long. For example, the transition time set as the holding time Th is not limited to the time from the transient response state to the complete transition to the steady state, but may be the time considered to be the transition from the transient response state to the steady state. Therefore, the steady state is a state in which the change in the motor torque τ can be regarded as substantially constant, and may include a state in which the change in the motor torque τ can be regarded as being substantially constant. Therefore, the holding time Th may be set to be slightly shorter than the time obtained by the equation (9), or may be set to be slightly longer.
[0068]
Further, in the present embodiment, the control gain setting unit 207 (setting time control unit 403) measures the transition time of the motor torque from the transient response state to the steady state, and the previous control gain ω c is measured until after the transition time elapses. The configuration is such that the set value is retained, but the configuration is not limited to this configuration. When the absolute value | τ * | of the command torque changes over a predetermined threshold value and the absolute value | τ * | of the command torque decreases, the control gain setting unit 207 changes the motor torque from the transient response state. The configuration may be such that the previously set value of the control gain ω c is maintained until the transition to the steady state.
[0069] For example, the control gain setting unit 207 counts the transition time of the motor torque from the transient response state to the steady state at predetermined intervals, and holds the previously set value of the control gain ω c until the count value after the transition time elapses. It may be configured. As a result, the holding time Th can be set longer than in the case of measuring the transition time. For example, when the transition time is 3.1 msec and the count is performed every 0.5 msec, the holding time Th can be extended to 3.5 msec.
[0070]
As described above, in the first embodiment, the time from the decrease of the absolute value | τ * | of the command torque to the switching of the control gain ω c increases the absolute value | τ * | of the command torque. It becomes longer than the time until the control gain ω c is switched from. Therefore, the control gain ω c at the rising edge of the absolute value | τ * | of the command torque can be applied also at the falling edge of the absolute value | τ * | of the command torque. Therefore, when the absolute value | τ * | of the command torque changes suddenly, stable operation can be realized in which vibration of the motor torque, overshoot, undershoot, etc. at the time of transient response are suppressed. Further, in the present embodiment, since the control gain ω c that directly specifies the response time is switched, the switching operation according to the present embodiment can be applied regardless of the type of the motor.
[0071]
[Second embodiment]
Subsequently, the motor drive device 200 according to the second embodiment will be described with reference to FIGS. 9 to 11. FIG. 9 is a configuration diagram of the motor drive device 200 according to the second embodiment. FIG. 10 is a block diagram of the current control unit 901 according to the second embodiment. FIG. 11 is a configuration diagram of the control gain setting unit 900 according to the second embodiment. The motor drive device 200 according to the second embodiment is a current control unit based on the d-axis P control gain K Pd, the d-axis I control gain K Id, the q-axis P control gain K Pq, and the q-axis I control gain K Iq. It differs from the first embodiment in that the control response speed of the 901 is adjusted. Therefore, the description of the configuration similar to that of the first embodiment will be omitted.
[0072]
As shown in FIG. 9, instead of the control gain ω c, the current control unit 901 has a d-axis P control gain K Pd, a d-axis I control gain K Id, and a q-axis P control gain K Pq from the control gain setting unit 900. , Q-axis I control gain K Iq is input. As is clear from the above equations (2), (3), (6), and (7), the control response speed of the current control unit 208 is the d-axis P control gain K Pd and the d-axis I control gain. It can also be adjusted by K Id, q-axis P control gain K Pq, and q-axis I control gain K Iq. These control gains K Pd, K Id, K Pq, and K Iq are switched based on, for example, a motor parameter having a current dependence.
[0073]
As shown in FIG. 10, the current control unit 901 has a control gain ω c which is a constant value in the control gain multiplication unit 1000a and 1001a, and a d-axis P control gain K Pd which is a variable value in the control gain multiplication unit 1002a. The d-axis I control gain KId, which is a variable value, is set in the gain multiplication unit 1003a. Further, the current control unit 901 has a control gain ω c which is a constant value in the control gain multiplication unit 1000b and 1001b, the q-axis P control gain K Pq which is a variable value in the control gain multiplication unit 1002b, and the control gain multiplication unit 1003b. The q-axis I control gain KIq, which is a variable value, is set. As described above, the current control unit 901 constitutes a motor drive device capable of switching the control response speed by setting the variable control gains K Pd, K Id, K Pq, and K Iq.
[0074]
As shown in FIG. 11, the control gain setting unit 900 is associated with the d-axis command current I d * and the q-axis command current I q *, and has a d-axis P control gain K Pdpre and a d-axis I control gain K Idpre. It has a control gain LUT1100 in which the q-axis P control gain K Pqpre and the q-axis I control gain K Iqpre are stored. The control gain setting unit 900 reads out the control gains K Pdpre, K Idpre, K Pqpre, and K Iqpre from the control gain LUT1100 with the d-axis command current I d * and the q-axis command current I q * as arguments of the control gain LUT1100. There is. By using a look-up table to set the control gain, the control gains K Pdpre, K Idpre, from the d-axis command current I d * and the q-axis command current I q * can be used by simple reference processing instead of complicated calculation processing. It is possible to read K Pqpre and KIqpre. The d-axis command current I d * and the q-axis command current I q * are calculated by the command current calculation unit 206 (see FIG. 9) based on the command torque τ *. Therefore, in the present embodiment, the control gain is switched based on the command torque τ *.
[0075]
For the control gain switching operation in the present embodiment, in the flowchart shown in FIG. 7, “K Pdpre is set to K Pd, K Idpre is set to K Id, and K Pq pre is set to K Pq” in steps S6, S11, and S14. , K Iq is set to K Iqpre ", and in steps S9 and S16, the process of" holding the previously set values ​​of K Pd, K Id, K Pq, and K I q "is performed. Other than that, the setting of the holding time Th and the like are the same as those in the first embodiment.
[0076]
As described above, also in the second embodiment, stable operation of the motor torque at the time of transient response can be realized, which is effective for, for example, a motor in which the motor constant changes according to the current. The motor constant is a parameter determined based on the use of the motor, and is, for example, a resistance value, an inductance, an induced voltage constant, or the like of the motor.
[0077]
[Third embodiment]
As the third embodiment, a configuration in which the first embodiment and the second embodiment are combined may be used. That is, the control gain ω c is switched based on the command torque τ *, and the d-axis P control gain K Pd and the d-axis I control gain K Id and q are based on the d-axis command current I d * and the q-axis command current I q *. The axis P control gain K Pq and the q axis I control gain K Iq may be switched in combination. This makes it possible to perform more accurate current control. Also in the third embodiment, stable operation of the motor torque at the time of transient response can be realized.
[0078]
[Fourth Embodiment]
The control gain setting unit of each of the above embodiments measures the transition time (holding time Th) until the motor torque transitions from the transient response state to the steady state, and the previously set value of the control gain until the transition time elapses. However, the configuration is not limited to this configuration. It is also possible to switch the control gain by filtering. In this case, as in each of the above embodiments, the time from when the absolute value | τ * | of the command torque decreases until the control gain ω c is switched is after the absolute value | τ * | of the command torque increases. Although it is not longer than the time until the control gain ω c is switched, it is possible to avoid the immediate switching of the control gain ω c at the falling edge of the absolute value | τ * | of the command torque. Hereinafter, the motor drive device according to the fourth embodiment will be described with reference to FIG. 12. FIG. 12 is a conceptual waveform diagram of the control gain switching operation according to the fourth embodiment. The motor drive device according to the fourth embodiment is different from the first embodiment in that the set time of the control gain ω c is controlled by the filter processing. Therefore, the description of the configuration similar to that of the first embodiment will be omitted.
[0079]
As shown in FIG. 12, the control gain setting unit brings the behavior of the command torque τ * closer to the behavior of the motor torque (actual torque) τ by filtering the command torque τ *, and makes the command torque τ * the motor torque ( The behavior of the actual torque) τ is simulated. Then, the control gain setting unit calculates the control gain ω c based on the command torque τ * a after the filter processing and sets it in the current control unit. In this case, the control gain ω cL is set as the control gain ω c when the absolute value | τ * a | of the command torque exceeds the threshold value τ th, and the absolute value | τ * a | of the command torque sets the threshold value τ th. When the value falls below the limit, the control gain ω cH is set as the control gain ω c. Even with such a configuration, it is possible to suppress the immediate switching of the control gain ω c when the absolute value | τ * | of the command torque falls, and it is possible to realize a stable operation of the motor torque during a transient response. The filter processing is realized, for example, by replacing a part of the control gain setting unit 207 shown in FIG. 4 with a low-pass filter.
[0080] [0080]
[Fifth Embodiment]
Next, the electric vehicle system according to the fifth embodiment will be described with reference to FIG. FIG. 13 is a configuration diagram of an electric vehicle system according to a fifth embodiment. Here, an example of an electric vehicle system equipped with a motor drive device according to any one of the first embodiment, the second embodiment, the third embodiment, and the fourth embodiment will be described.
[0081]
As shown in FIG. 13, in the electric vehicle system 1200, a pair of axles 1201 and 1204 are pivotally supported on the vehicle body. Wheels 1202 and 1203 are fixed to both ends of one axle 1201, and wheels 1205 and 1206 are fixed to both ends of the other axle 1204. An AC motor 201 is connected to one of the axles 1201, and the rotational power of the AC motor 201 is transmitted to the wheels 1202 and 1203 via the axle 1201. The motor drive device 200 uses the drive battery 1207 as a power source, receives the command torque τ * generated by the host system, and drives the AC motor 201.
[0082]
The motor drive device 200 of the electric vehicle system 1200 generally has a certain gradient in setting the command torque τ *. However, the motor drive device 200 may set the command torque τ * to 0 Nm in steps when an abnormality is detected, and may return the command torque τ * to the original set value in steps after recovery. Further, even when the vehicle slips, the motor drive device 200 may sharply change the command torque τ *. In these cases, in the electric vehicle system 1200 according to the present embodiment, the motor drive device 200 switches to an appropriate control gain according to the operating conditions, and the vibration of the motor torque, overshoot, undershoot, etc. generated during the transient response are generated. Can be suppressed.
[0083]
Although this embodiment relates to an electric vehicle, the same effect can be obtained by applying the motor drive device 200 to home appliances, railways, and the like. In short, the technique of the present disclosure can be similarly applied as long as it is provided with a motor drive device having a feedback type current control.
[0084]
The technique of the present disclosure is not limited to the above-described embodiment, and includes various modifications. For example, the above-described embodiment has been described in detail in order to explain the technique of the present disclosure in an easy-to-understand manner, and is not necessarily limited to the one including all the configurations described. Further, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Further, it is also possible to add / delete / replace a part of the configuration of each embodiment with another configuration.
[0085]
Further, each of the above configurations, functions, processing units, processing means, etc. may be realized by hardware by designing a part or all of them by, for example, an integrated circuit. Further, each of the above configurations, functions, and the like may be realized by software by the processor interpreting and executing a program that realizes each function. Information such as programs, tables, and files that realize each function can be recorded in a memory, a hard disk, a storage device such as an SSD (Solid State Drive), or a recording medium such as an IC card, an SD card, or a DVD.
[0086]
In addition, the control lines and information lines are shown in the drawings as necessary for explanation, and not all control lines and information lines are necessarily shown. Actually almost all You may think that all the configurations are interconnected.
Description of the sign
[0087]
200 Motor drive device
201 AC motor (motor)
203 controller
204 Power conversion circuit
206 Command current calculation unit
207 Control gain setting unit
208 Current control unit
401 Torque level calculation unit
402 Control gain LUT
403 Set time control unit
900 Control gain setting unit
901 Current control unit
1100 Control gain LUT
1200 electric vehicle system
1201 axle
1202 wheels
1203 wheels
1204 axle
1205 wheels
1206 wheels
1207 drive battery
The scope of the claims
[Claim 1]
It is a motor drive device that controls the torque of the motor.
The power conversion circuit that drives the motor and
Equipped with a controller to control the power conversion circuit
The controller is
A command current calculation unit that generates a command current according to the command torque for the motor,
A current control unit that performs feedback control to adjust the current energized to the motor to the command current,
It has a control gain setting unit that calculates the control gain used for the feedback control based on the command torque and sets it in the current control unit.
In the control gain setting unit, the time from the decrease of the absolute value of the command torque to the switching of the control gain is longer than the time from the increase of the absolute value of the command torque to the switching of the control gain. A motor drive device characterized by being controlled so as to be.
[Claim 2]
The motor drive device according to claim 1, wherein the absolute value of the command torque changes in a stepwise manner.
[Claim 3]
In the control gain setting unit, the time from when the absolute value of the command torque changes over a predetermined threshold value and when the absolute value of the command torque decreases until the control gain is switched is the time of the command torque. The motor drive device according to claim 1, wherein the motor drive device is controlled so as to be longer than the time from the increase in the absolute value to the switching of the control gain.
[Claim 4]
When the absolute value of the command torque changes over a predetermined threshold value and the absolute value of the command torque decreases, the control gain setting unit waits until the motor torque shifts from the transient response state to the steady state. The motor drive device according to claim 1, wherein the previously set value of the control gain is held.
[Claim 5]
When the absolute value of the command torque changes over a predetermined threshold value and the absolute value of the command torque decreases, the control gain setting unit determines the transition time of the motor torque from the transient response state to the steady state. 4. The motor drive device according to claim 4, wherein the previously set value of the control gain is held until after the transition time has elapsed.
[Claim 6]
When the absolute value of the command torque changes over a predetermined threshold value and the absolute value of the command torque decreases, the control gain setting unit determines the transition time of the motor torque from the transient response state to the steady state. 4. The motor drive device according to claim 4, wherein the motor drive device is counted at predetermined intervals, and the previously set value of the control gain is held up to the count value after the transition time has elapsed.
[Claim 7]
The control gain setting unit calculates a torque level value from the absolute value of the command torque, imparts a hysteresis characteristic to the change when the torque level value decreases and increases, and controls the control after the torque level value decreases. The motor drive device according to claim 1, wherein the time until the gain is switched is controlled to be longer than the time from the increase of the torque level value to the switching of the control gain.
[Claim 8]
The control gain setting unit has a look-up table in which the control gain is stored, calculates an argument of the look-up table based on the absolute value of the command torque, and reads the control gain from the lookup table. The motor driving device according to claim 1, wherein the motor driving device is characterized by the above.
[Claim 9]
The control gain setting unit has a look-up table in which the control gain is stored, and uses the command current as an argument of the look-up table to read the control gain from the look-up table. The motor drive device according to claim 1.
[Claim 10]
It is a motor drive device that controls the torque of the motor.
The power conversion circuit that drives the motor and
Equipped with a controller to control the power conversion circuit
The controller is
A command current calculation unit that generates a command current according to the command torque for the motor,
A current control unit that performs feedback control to adjust the current energized to the motor to the command current,
It has a control gain setting unit that calculates the control gain used for the feedback control based on the command torque and sets it in the current control unit.
The control gain setting unit is characterized in that the behavior of the command torque is brought closer to the behavior of the motor torque by the filter processing for the command torque, and the switching of the control gain is controlled based on the command torque after the filter processing. Motor drive device.
[Claim 11]
The motor drive device according to any one of claims 1 to 10.
The motor driven by the motor drive device and
With the axle connected to the motor,
The wheels fixed to the axle and
A drive battery that serves as a power source for the motor drive device is provided.
An electric vehicle system characterized by that.