Description:FORM 2

THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENT RULES, 2003

COMPLETE SPECIFICATION

(See Section 10 and Rule 13)

Title of invention:
A DC-DC CONVERTER FOR OPERATING WITH VARIABLE INPUT AND OUTPUT VOLTAGE RANGE

APPLICANT:
KALYANI POWERTRAIN LIMITED
An Indian entity having address as:
Sr. no. 49, Industry House, Opp. Kalyani Steels Limited, Mundhwa, Pune, 411036, Maharashtra, India.

The following specification describes the invention and the manner in which it is to be performed.

CROSS-REFERENCE TO RELATED APPLICATIONS AND PRIORITY
The present application does not claim priority from any other application.
TECHNICAL FIELD
The present disclosure relates to DC-DC converter. More specifically the present disclosure relates to the DC-DC converter with an improved operating range, enabling variable input voltage range and variable output voltage range.
BACKGROUND
The subject matter discussed in the background section should not be assumed to be prior art merely because of its mention in the background section. Similarly, a problem mentioned in the background section or associated with the subject matter of the background section should not be assumed to have been previously recognized in the prior art. The subject matter in the background section merely represents different approaches, which in and of themselves may also correspond to implementations of the claimed technology.
An electric vehicle industry has seen upward trend in the past few years. The batteries of the electric vehicle are high voltage batteries, which provides several hundred volts of direct current (DC). However, the electric components inside the vehicle vary in their voltage requirements, with most running on a much lower voltage. This includes the radio, dashboard readouts, air conditioning, and in-built computers and displays. A DC-DC converter is a category of power converters, which converts a DC source from one voltage level to another. It can be unidirectional, (transfers power only in one direction), or bidirectional, (transfers power in both directions). Moreover, a DC-DC converter is a critical component in the architecture of the electric vehicle, wherein the DC-DC converter is configured to convert higher DC voltage from the traction of battery pack to the lower DC voltage that is needed to run a vehicle accessories and recharge the auxiliary battery.
Further, the operating voltage of different electronic devices/accessories vary over a wide range, making it necessary to provide desired voltage for each device. It is well known to use buck converter and boost converter to achieve desired voltage. More specifically, the buck/step down converter provides a lower voltage than the original voltage, while the boost/step up converter supplies a higher voltage. However, an implementation of additional converters such as buck/step down converter, boost/step up converter increases the space requirement and cost, which makes designing of DC-DC converter bulky.
Further, the major issue faced by existing DC-DC converter is conversion efficiency of the transformer. When the leakage inductance is used for calculating ZVS range, the primary MOSFETs fails due to increase in the junction temperature. Further, when the leakage inductance is calculated using an average current, it results in an insufficient value of leakage inductance. When the leakage inductance is calculated using peak current instead of the average current, the value of the leakage inductance is excessively high. However, introducing such leakage inductance with higher leakage inductance in the transformer that results in higher core losses and raises the transformer’s operating temperature. In such cases, cooling of the transformer becomes a very difficult task.
Therefore, there is a need for transformer of lower leakage inductance. Therefore, there is an utmost need of DC-DC converter for operating with variable input and output voltage range without use of buck converter or boost converter.
SUMMARY
This summary is provided to introduce concepts related to DC-DC converter for operating with variable input and output voltage range, and also the concepts are further described below in the detailed description. This summary is neither intended to identify essential features of the claimed subject matter nor intended for use in determining or limiting the scope of the claimed subject matter.
In one implementation, a DC-DC converter for operating with variable input and output voltage range, is disclosed. The DC-DC converter comprises of a high voltage battery having variable input DC voltage range between 300V to 800V. Further, the DC-DC converter comprises of switching means comprising a set of primary MOSFETs and a set of secondary MOSFETs. In addition, the DC-DC converter comprises a shim inductor, and a transformer, wherein a primary winding and secondary winding of the transformer are wounded with turns ratio of n:1. The shim inductor is connected in series with the primary winding of the transformer in order to obtain a leakage inductance. The DC-DC converter comprises a low voltage load that is configured to receive an output DC voltage having variable range between 15V-30V.
BRIEF DESCRIPTION OF DRAWINGS
The detailed description is described with reference to the accompanying Figures. In the figures, the same numbers are used throughout the drawings to refer like features and components.
Figure 1 illustrates a block diagram (100) of DC-DC converter for operating with variable input voltage range and output voltage range, in accordance with an embodiment of the present disclosure.
Figure 2 illustrates a schematic diagram (200) of ZVS based phase shift full bridge DC-DC converter for operating with input and output voltage range, in accordance with an embodiment of the present disclosure.
Figure 3 illustrates the designing of the transformer, in accordance with an exemplary embodiment of the present disclosure.
Figure 4A illustrates a waveform representation of a control signal, which are applied to the set of primary MOSFETs of the DC-DC converter, in accordance with the first exemplary embodiment of the present disclosure.
Figure 4B illustrates a waveform representation of a voltage, which is across primary winding of the transformer, in accordance with the first exemplary embodiment of the present disclosure.
Figure 4C illustrates a waveform representation of an output current of the DC-DC converter, in accordance with the first exemplary embodiment of the present disclosure.
Figure 4D illustrates a waveform representation of a Pulse Width Modulation (PWM) control signal, which is applied to the set of secondary MOSFETs of the DC-DC converter, in accordance with the first exemplary embodiment of the present disclosure.
Figure 4E illustrates a waveform representation of an output DC voltage of DC-DC converter, in accordance with the first exemplary embodiment of the present disclosure.
Figure 4F illustrates a waveform representation of a PWM control signal, which is applied to the secondary MOSFET QE of the DC-DC converter, in accordance with the first exemplary embodiment of the present disclosure.
Figure 4G illustrates a waveform representation of a PWM control signal, which is applied to the secondary MOSFET QF of the DC-DC converter, in accordance with the first exemplary embodiment of the present disclosure.
Figure 5 illustrates a schematic diagram of ZVS based phase shift full bridge DC-DC converter for operating with input voltage 740V and output voltage 30V, in accordance with a second exemplary embodiment of the present disclosure.
Figure 6A illustrates a waveform representation of a control signal, which are applied to the set of primary MOSFETs of the DC-DC converter, in accordance with the second exemplary embodiment of the present disclosure.
Figure 6B illustrates a waveform representation of a Pulse Width Modulation (PWM) control signal, which is applied to the set of secondary MOSFETs of the DC-DC converter, in accordance with the second exemplary embodiment of the present disclosure.
Figure 6C illustrates a waveform representation of a PWM control signal, which is applied to the secondary MOSFET QE of the DC-DC converter, in accordance with the second exemplary embodiment of the present disclosure.
Figure 6D illustrates a waveform representation of a PWM control signal, which is applied to the secondary MOSFET QF of the DC-DC converter, in accordance with the second exemplary embodiment of the present disclosure.
Figure 6E illustrates a waveform representation of an output DC voltage of DC-DC converter, in accordance with the second exemplary embodiment of the present disclosure.
Figure 6E illustrates a waveform representation of a voltage, which is across primary winding of the transformer, in accordance with the second exemplary embodiment of the present disclosure.
Figure 6G illustrates a waveform representation of an output current of shim inductor of the DC-DC converter, in accordance with the second exemplary embodiment of the present disclosure.
DETAILED DESCRIPTION
Reference throughout the specification to “various embodiments,” “some embodiments,” “one embodiment,” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment, is included in at least one embodiment. Thus, appearances of the phrases “in various embodiments,” “in some embodiments,” “in one embodiment,” or “in an embodiment”, in places throughout the specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner in one or more embodiments.
The DC-DC converter for operating with variable input voltage range and output voltage range comprises of a switching means comprising a set of primary MOSFETs and a set of secondary MOSFETs. Further, the DC-DC converter comprises of a shim inductor, and a transformer, wherein a primary winding and secondary winding of the transformer are wounded with turns ratio of n:1. The shim inductor is connected in series with the primary winding of the transformer in order to obtain a leakage inductance. The DC-DC converter comprises of a low voltage load that is configured to receive an output voltage having variable range between 15V-30V.
Referring to figure 1, a block diagram (100) of DC-DC converter for operating with variable input and output voltage range, in accordance with an embodiment of the present disclosure is illustrated.
The block diagram (100) of DC-DC converter comprises of the high voltage battery (101), one or more Electromagnetic interference (hereinafter referred as “EMI”) filters (102), the primary metal oxide semiconductor field effect transistors (MOSFETs) (103), a shim inductor (104), a transformer (105), a pair of secondary metal oxide semiconductor field effect transistors (MOSFETs) (106), an output filter (107), a low voltage load (108), a control circuit (109), a power supply (110).
In one embodiment, the high voltage battery (101) has a voltage rating between the range of 300V to 800V, depending on the battery pack. The high voltage battery is an energy storing component. The high voltage battery (101) is configured to provide an input DC voltage. Further, DC-DC converter comprises of one or more EMI filters (102) for eliminating high frequency noises from the input DC voltage. The DC-DC converter comprises of primary MOSFETs (103) and a pair of secondary MOSFETs (106). The “ON” and “OFF” time of the primary MOSFETs (103) and the pair of the secondary MOSFETs (106) are controlled by a control circuit (109). The control circuit (109) is controlled by the power supply (110).
In one embodiment, the power supply is 24V DC. The primary MOSFETs (103) are configured to form the H-bridge at the input side of the DC-DC converter. The primary MOSFETs (103) are triggered by a zero-voltage-switching (hereinafter referred as “ZVS”) topology. The ZVS topology is used to reduce the switching losses. In one exemplary embodiment, the primary MOSFETs (103) are high voltage and low current devices. The H-bridge of the primary MOSFETs are configured to convert the input DC voltage into a high frequency AC voltage, whereas high frequency AC voltage is fed into the transformer (105). The transformer (105) is a high frequency transformer. The high frequency transformer (105) is configured to step down high frequency AC voltage into a low AC voltage. The transformer is comprising of a primary winding and secondary winding are wounded with turns ratio of n:1. The primary winding of the transformer (105) is in series with a shim inductor (104) in order to achieve a required leakage inductance. The shim inductor is having variable inductance 0 to 42 uH, depending on the input DC voltage. The shim inductor is connected in series with the transformer in order to increase the collective leakage inductance. The shim inductor degrades the power density of the DC-DC converter. The primary current is reduced with correct position of the shim inductor and clamping diodes that results in reduced conduction losses of switches and increase in efficiency. In one exemplary embodiment, the shim inductor is made up of alloy powder core with a diameter of 46mm. The shim inductor connected in series with the transformer compensates the temperature of the MOSFETs and obtain the ZVS range. The DC-DC converter provides operation efficiency of 94% and relatively stable at 200kHz. The low AC voltage is fed to the set of secondary MOSFETs (106). The set of secondary MOSFETs (106) are used to rectify low AC voltage and obtain an output DC voltage. The output filter (107) comprises an inductor and a capacitor. The output filter (107) is configured to filter out the ripple from the output DC voltage, which is obtained from the pair of secondary MOSFETs. The low voltage load is configured to receive the output DC voltage having variable range between 15V-30V, depending on the voltage requirement of the load.
Referring to Fig. 2, a schematic diagram (200) of ZVS based phase shift full bridge DC-DC converter for operating with input voltage range and output voltage range, in accordance with an embodiment of the present disclosure is illustrated. The schematic diagram (200) depicts a plurality of circuit components including the high voltage battery (101), the set of primary MOSFETs Q1-Q4 (103), the set of secondary MOSFETs QE-QF (106), the shim inductor Ls (104), the transformer (105), inductor L, capacitor C and resistor R. The core of the transformer T1 (105) comprises of the primary winding and the secondary winding. The turns ratio of the primary winding and the secondary winding of the transformer is n:1.
The equation of turns ratio for Phase Shift Full Bridge (PSFB) topology is,
Ns/Np=Vo/(Vin*Dmax)
Here, Secondary turns, Ns= 1 is constant
Output voltage, Vo is maintained constant
Duty cycle, Dmax is kept constant
Thus, equation becomes,
Vin?Np
Hence, the input voltage of the transformer T (105) is varied by changing turns of the primary winding. Therefore, input voltage and output voltage ranges of the DC-DC converter are affected by changing in turns ratio of primary and secondary winding.
Now referring to Figure 3, the design of the transformer T is illustrated, in accordance with an exemplary embodiment of the present disclosure. In the exemplary embodiment, the transformer T comprises of E55 double stack bobbin. The transformer comprises of a E-core transformer, which forms a closed magnetic flux path. The primary winding and the secondary winding in the transformer are placed around the central leg of the core. The turns ratio of the primary winding and the secondary winding of the transformer is n:1. The transformer is designed with lower leakage inductance.
Now referring back to Figure 2, the transformer T (105) of lower leakage inductance and the shim inductor Ls (104) are used to reduce loss of the transformer T (105). In one exemplary embodiment, the material of the core of transformer is SIFERRIT, N87 grade. Further, the material of the primary winding and the secondary winding of transformer is copper.
In one embodiment, turns in primary winding is 14 and turns in secondary windings is 1. Results of the test that are conducted by maintaining low load and varying the input voltage range for transformer having turns ratio of 14:1 as shown in Table 1.
Sr. No. Load
(A) V_in
(V) I_in
(A) V_out
(V) I_out
(A)
1 10 50 0.12 3.53 1.3
2 100 0.28 7.8 2.92
3 150 0.41 11.81 4.46
4 200 0.53 15.65 5.9
5 250 0.67 19.81 7.51
6 300 0.83 24.04 9.12
7 350 0.84 26.07 9.92
8 400 0.75 26.06 9.97
9 450 0.68 26.06 9.96
10 500 0.63 26.07 9.93
11 550 0.61 26.06 9.94
12 600 0.56 26.07 9.96
13 650 0.54 26.07 10.01
Table 1: Test conducted by keeping low load and varying the input voltage range.
Further, results of the test conducted by maintaining full load and varying the input voltage range for transformer, having turns ratio of 14:1 as shown in the Table 2.
Sr. No. Load
(A) V_in
(V) I_in
(A) V_out
(V) I_out
(A)
1 140 620 6.1 27.76 132.1
2 140 630 6.1 27.91 132.9
3 140 640 6.05 27.99 133.3
4 140 650 5.96 27.99 133.2
5 140 668 5.78 27.99 133.3
6 140 690 5.64 27.99 133.4
7 140 714 5.47 27.99 133.3
8 140 731 5.35 27.99 133.3
9 140 750 5.2 27.99 133.2
Table 2: Test conducted by keeping full load and varying voltage range.
Thus, results are obtained for minimum load to full load for the transformer of 14:1 turns ratio, which is found to be satisfactory for the input DC voltage range of 620V to 750V
In another embodiment, turns in primary winding is 11 and turns in secondary winding is 1. Results of the test that are conducted by maintaining minimum load and varying the input DC voltage range for transformer, having turns ratio of 11:1 as shown in Table 3.
Sr. No. Load
(A) V_in
(V) I_in
(A) V_out
(V) I_out
(A)
1 10 50 0.14 3.688 1.37
2 100 0.26 7.63 2.87
3 150 0.41 11.81 4.48
4 200 0.56 16.01 6.1
5 250 0.69 19.96 7.62
6 300 0.83 24.03 9.21
7 350 0.85 26.11 10.02
8 400 0.76 26.11 10.02
9 450 0.69 26.11 10.03
10 500 0.63 26.11 10.03
11 550 0.59 26.11 10.03
12 600 0.56 26.11 10.04
13 650 0.54 26.11 10.04
14 700 0.52 26.11 10.04
15 750 0.5 26.11 10.04
Table 3: Test conducted by keeping low load and varying the input voltage range.
Further, results of the test that are conducted by maintaining full load and varying the input DC voltage range for transformer, having turns ratio of 11:1 as shown in Table 4.
Sr. No. Load
(A) V_in
(V) I_in
(A) V_out
(V) I_out
(A)
1 140 500 8.25 27.93 141.4
2 140 510 8.09 27.93 141.3
3 140 520 7.93 27.93 141
4 140 530 7.77 27.92 140.9
5 140 550 7.51 27.92 142.3
6 140 600 6.9 27.92 142.2
7 140 620 6.71 27.91 142.5
8 140 640 6.58 28.06 143.3
9 140 660 6.38 28.05 141.2
10 140 680 6.2 28.05 142.2
11 140 700 5.85 28.04 138.5
12 140 740 5.73 27.93 141.9
Table 4: Test conducted by keeping full load and varying voltage range.
Thus, results are obtained for minimum load to full load with transformer of 11:1 turns ratio, which are found to be satisfactory for input voltage range of 500V to 740V.
The transformer T1(105) is centre tap transformer, wherein the secondary winding of the transformer T1 (105) is divided into two parts. It is assumed that the core of the transformer T1 (105) operates in symmetrical condition. Therefore, both cross sectional area of outer side of transformer T1 (105) is same and it is half of the centre side of transformer.
Now referring to Table 5, electrical values of variable input voltage range and output range of the different DC-DC converter are depicted.
Input Voltage Range 300V-410V 400-800 V 620V-750V 520V-740V
Output Voltage range 22V-30 V 24-28 V 22V-30 V 22V-30 V
Leakage inductance of transformer 9uH 4uH 4uH 3.5uH
Shim inductor Not required 26uH 42uH 28uH
Table 5: Electrical values of variable input voltage range and output range of the different DC-DC converter
It can be noted that, the aforementioned comparison table 5 clearly shows that the transformer is having lower leakage inductance, therefore, loss of the transformer is minimized. Further, the shim inductor is used to achieve leakage inductance in the DC-DC converter.
The working operation of the circuit configuration (200) is as follows:
At step 1, the control circuit is configured to turn “ON” a first pair Q1-Q2 of the set of primary MOSFETs and turn “OFF” a second pair Q3-Q4 of the set of primary MOSFETs, wherein the primary current flows from the primary winding of the transformer T1. The transformer T1 delivers the power from the primary winding to the secondary winding due to the mutual inductance.
At step 2, the control circuit is configured to turn off the primary MOSFET Q2 of the first pair Q1-Q2 of the set of primary MOSFETs, the primary current flows through the output capacitance Coss of the primary MOSFET Q3, which comes on second pair Q3-Q4 of the primary MOSFETs and discharge it. Therefore, no power transferred from the primary winding to the secondary winding of the transformer T1.
At step 3, the magnetizing current flows through the body diode of the set of primary MOSFET Q3, which comes on second pair of the set of primary MOSFETs that is turned “ON” with zero voltage across it.
At step 4, the control circuit is configured to turn “OFF” the primary MOSFET Q1 of the first pair Q1-Q2, which comes on set of primary MOSFETs and the magnetizing current finds it path through primary MOSFET Q4 of the second pair Q3-Q4, of the set of primary MOSFETs, discharging its Coss.
At step 5, the control circuit is configured to turn “ON” the primary MOSFET Q4 of the second pair Q3-Q4, of the set of primary MOSFETs with ZVS, the power transfer from the primary winding to the secondary winding is resumed. At the end of this time interval the primary MOSFET Q3 of the second pair Q3-Q4, of the set of primary MOSFETs is turned “OFF” and the sequence is repeated.
The set of secondary MOSFETs QE, QF are controlled by the control circuit. The control circuit provides PWM signal to a gate of the set of the secondary MOSFETs. The set of secondary MOSFETs QE, QF are configured to rectify low AC voltage and obtain the output DC voltage. The output filter contains an inductor Lout and a capacitor Cout. The output filter is configured to filter out the ripple from the output DC voltage that is obtained from the pair of secondary MOSFETs QE, QF. The low voltage load is configured to receive the output DC voltage having variable range between 15V-30V, depending on the voltage requirement of the load.
In first exemplary embodiment, the DC-DC converter as shown in figure 2 comprises input voltage of 650V, the input capacitance Cin = 20uF, shim inductance Ls= 80 uH, Lout= 2uH, Cout=5500uF, R1=0.12 ohm, in transformer T1: primary winding resistance Rp=0.11 ohm, secondary winding resistance Rs=0.11m ohm, tertiary winding resistance Rt= 0.11m ohm, primary leakage inductance Lp= 1uH, secondary leakage inductance Ls= 1uH, tertiary leakage inductance Lt= 1uH, magnetizing inductance of the transformer Lm=1mH, no. of turns of the primary winding Np=10, no. of turns of the secondary winding Ns=1, no. of turns of tertiary winding Nt=1 and an output voltage Vo= 15V.
Referring to Fig. 4A-4G, a waveform representation of various parameters of the DC-DC converter having the input voltage of 650V and output voltage of 15V are illustrated.
Now referring to Figure 4A, a waveform representation of a control signal applied to the primary MOSFETs of the DC-DC converter is illustrated.
Now referring to Figure 4B, a waveform representation of voltage across primary winding of the transformer, is illustrated in accordance with the first exemplary embodiment of the present disclosure.
Now referring to Figure 4C, a waveform representation of an output current of the DC-DC converter, is illustrated in accordance with the first exemplary embodiment of the present disclosure.
Now referring to Figure 4D, a waveform representation of a Pulse Width Modulation (PWM) control signal applied to the set of the secondary MOSFETs of the DC-DC converter, is illustrated in accordance with the first exemplary embodiment of the present disclosure.
Now referring to Figure 4E, a waveform representation of an output DC voltage of DC-DC converter, is illustrated in accordance with the first exemplary embodiment of the present disclosure.
Now referring to Figure 4F, a waveform representation of a PWM control signal applied to the secondary MOSFET QE of the DC-DC converter, is illustrated in accordance with the first exemplary embodiment of the present disclosure.
Now referring to Figure 4G a waveform representation of a PWM control signal applied to the secondary MOSFET QF of the DC-DC converter, is illustrated in accordance with the first exemplary embodiment of the present disclosure.
In second exemplary embodiment, the DC-DC converter as shown in figure 5 comprises the input voltage of 740V, the input capacitance Cin= 110 uF, a shim inductance 28 uH, Lout=1.6 uH, Cout=1100 uF, magnetizing inductance of the transformer Lm=1.2mH, no. of turns of the primary winding Np=11, no. of turns of the secondary winding Ns=1 and an output voltage Vo=28.8V.
Further, the Dc-Dc converter in accordance with the second embodiment of the present disclosure comprises an output power 4000W max, output current 4000/28.8=148A, allowable output voltage transient 2V, Full load efficiency =95%, inductor (Lout) switching frequency is 200kHz typical.
Referring to Fig. 6A-6G, a waveform representation of various parameters of the DC-DC converter having the input voltage of 740V and output voltage of 28.8V are illustrated.
Now referring to Figure 6A, a waveform representation of a control signal, which are applied to the set of primary MOSFETs of the DC-DC converter, is illustrated in accordance with the second exemplary embodiment of the present disclosure.
Now referring to Figure 6B, a waveform representation of a Pulse Width Modulation (PWM) control signal, which is applied to the set of secondary MOSFETs of the DC-DC converter, is illustrated in accordance with the second exemplary embodiment of the present disclosure.
Now referring to Figure 6C, a waveform representation of a PWM control signal, which is applied to the secondary MOSFET QE of the DC-DC converter, is illustrated in accordance with the second exemplary embodiment of the present disclosure.
Now referring to Figure 6D, a waveform representation of a PWM control signal, which is applied to the secondary MOSFET QF of the DC-DC converter, is illustrated in accordance with the second exemplary embodiment of the present disclosure.
Now referring to Figure 6E, a waveform representation of an output DC voltage of DC-DC converter, is illustrated in accordance with the second exemplary embodiment of the present disclosure.
Now referring to Figure 6F, a waveform representation of a voltage, which is across primary winding of the transformer, is illustrated in accordance with the second exemplary embodiment of the present disclosure.
Now referring to Figure 6G, a waveform representation of an output current of shim inductor of the DC-DC converter, is illustrated in accordance with the second exemplary embodiment of the present disclosure.
Further, the aforementioned illustrated embodiments offer the following advantages over the conventional DC-DC converter, which include but not limited to:
• Some embodiments of the present disclosure provide DC-DC converter operating with variable input and output voltage range without the use of buck converter or boost converter.
• Some embodiments of the present disclosure provide DC-DC converter operating with variable input voltage ranges from 520V-740V and the output voltage ranges from 15V - 30V.
• Some embodiments of the present disclosure help to design optimized DC-DC converter for electric vehicle.
• Some embodiments of the present disclosure provide the DC-DC converter which is compact in size.
• Some embodiments of the present disclosure provide the DC-DC converter which is less bulky. Further, components of DC-DC converter have better space utilization.
• Some embodiments of the present disclosure comprise isolation transformers, which is having the output voltage floating with respect to the input voltage, which is useful for powering loads that have a different common (ground) polarity or other compatibility issue.
• In some embodiments of the present disclosure comprise isolation transformer, which provides protection from the input voltage such as spikes with the thousand Volt range.
• In some embodiments of the present disclosure do not comprise isolation transformer, wherein such DC-DC converter uses an inductance, wherein the inductance does not isolate the input to output and share a common negative ground.
Although implementations of the DC-DC converter for operating with variable input and output voltage range have been described in language specific to structural features and/or methods, it is to be understood that the appended claims are not necessarily limited to the specific features or methods described. Rather, the specific features and methods are disclosed as examples of implementations of the DC-DC converter for operating with variable input and output voltage range.
, Claims:WE CLAIM:
1. A DC - DC converter for operating with variable input and output voltage range, characterized in that, the DC-DC converter comprising:
a switching means comprising of a set of primary MOSFETs Q1 to Q4 and a set of secondary MOSFETs QE and QF;
a transformer comprising of a primary winding and secondary winding with turns ratio of n:1, wherein a shim inductor is connected in series with the primary winding of the transformer in order to obtain a leakage inductance; and
a low voltage load configured to receive an output DC voltage having a variable range between 15V-30V.
2. The DC-DC converter as claimed in claim 1, comprising of a high voltage battery having a variable input DC voltage range between 300V to 800V, depending on the battery pack.
3. The DC-DC converter as claimed in claim 1, wherein the shim inductor has a variable inductance between 0 to 42 uH, depending on the input DC voltage.
4. The DC-DC converter as claimed in claim 1, wherein the DC-DC converter comprises of one or more EMI filters for eliminating high frequency noises from the input DC voltage.
5. The DC-DC converter as claimed in claim 1, wherein the set of primary MOSFETs Q1 to Q4 are configured to convert the input DC voltage to a high AC voltage.
6. The DC-DC converter as claimed in claim 1, wherein the set of secondary MOSFETs QE and QF are configured to receive and rectify the low AC voltage in order to obtain an output DC voltage.
7. The DC-DC converter as claimed in claim 1, wherein an output filter is configured to filter out ripple from the output DC voltage obtained from the set of secondary MOSFETs Q3 and Q4.
8. The DC-DC converter as claimed in claim 1, wherein “ON” and “OFF” time of the set of primary MOSFETs Q1 to Q4 and the set of secondary MOSFETs QE and QF are controlled by a control circuit.
9. The DC-DC converter as claimed in claim 8, wherein the control circuit is powered by 24V DC supply.
10. The DC-DC converter as claimed in claim 1, wherein the low voltage load is configured to receive an output DC voltage having variable range between 15V-30V, depending upon voltage requirement of the load.
Dated this 25th Day of November 2022

Deepak Pawar
Agent for the Applicant
IN/PA-2052