TAB-Boost converter topology circuit for integrating OBC-LDC

Abstract

The invention discloses a TAB-Boost converter topology circuit for integrating OBC-LDC, which comprises a TAB unit and a Boost unit, the TAB unit adopts three full-bridge structures and is connected with each port through a transformer and an energy storage inductor, the Boost unit is composed of an energy storage inductor Lf and two switch tubes Qb and QDb with complementary signals, the Lf is used for energy storage and current smoothing, the Lf stores energy when a main switch tube of the Qb is switched on, and the QDb is used for switching on the main switch tube of the Qb. Energy is released during turn-off, and the QDb and the Qb are in complementary conduction so as to reduce conduction loss. The TAB unit in the TAB-Boost converter adopts leading edge modulation, the Boost unit adopts trailing edge modulation, the phase difference and the duty ratio are controlled and adjusted through voltage type phase shift, and independent energy regulation and control and wide voltage range output among multiple ports are achieved. According to the invention, the inductance current and device current stress are effectively reduced while the multi-port energy flow flexibility is maintained.

Description

Technical Field

[0001] The present invention belongs to the technical field of switching converters, and in particular relates to a TAB-Boost converter topology circuit for integrating an OBC-LDC. Background Art

[0002] With the rapid development of the electric vehicle industry, the requirements for the size, stability, and charging efficiency of onboard converters are becoming increasingly stringent. The power converters connected to the power battery of an electric vehicle primarily include the power drive converter, the on-board charger (OBC), and the low-voltage, high-current auxiliary power converter (LDC). By integrating multiple traditional independent converters (such as OBCs and LDCs), three-port converters can significantly reduce size, lower costs, and improve conversion efficiency, thus attracting increasing attention from academia and industry.

[0003] Traditional three-port converters such as the TAB converter face some limitations in wide-range output scenarios. The converter's duty cycle or phase shift angle will be constrained. This is because the extreme phase shift angle of the three-port converter leads to increased circulating current losses and severe heat generation, making it often unsuitable for use in electric vehicle applications. Summary of the Invention

[0004] The present invention proposes a TAB-Boost converter topology circuit for integrating OBC-LDC to solve the problems existing in the above-mentioned prior art.

[0005] To achieve the above objectives, the present invention provides a TAB-Boost converter topology circuit for integrating OBC-LDC, comprising:

[0006] The TAB unit includes an A port, a B port, and a C port. Each port includes a full-bridge circuit. The three full-bridge circuits are interconnected through a transformer T and an energy storage inductor.

[0007] The first full-bridge circuit includes a first switch tube Q A1 , the second switch tube Q A2 , the third switch tube Q A3 And the fourth switch tube Q A4 , and the input capacitor C A Connection, input voltage V A Connect the input capacitor C A Both ends;

[0008] The second full-bridge circuit includes a fifth switch tube Q b1 , the sixth switch tube Q b2 , the seventh switch tube Q b3 And the eighth switch tube Qb4 , connect capacitor C B , load resistance R B Connected to capacitor C B Both ends, through the inductor L f Connect with Boost unit;

[0009] The third full-bridge circuit includes the ninth switch tube Q C1 、The tenth switch tube Q C2 、The eleventh switch tube Q C3 and the twelfth switch tube Q C4 , and capacitor C C Connect the load resistor R C Connected to capacitor C C Both ends;

[0010] Boost unit, including the main switch tube Q b 、Inductor L f and synchronous rectifier Q Db , inductance L f Connect on Q b and Q Db Between, used to store energy and smooth current, capacitor C B Connect on Q Db The output terminal and the load resistor R B It is used to stabilize the output voltage.

[0011] Optionally, the voltage waveforms output by the three full-bridge circuits of the TAB unit are symmetrical square waves with the same frequency, and the phase relationship between the symmetrical square waves is adjusted by controlling the switching sequence of the switching tubes, thereby controlling the direction and magnitude of power transmission.

[0012] Optionally, the Boost unit adjusts the main switch tube Q b and synchronous rectifier Q Db duty cycle, widening the output voltage range.

[0013] Optionally, the TAB unit adopts leading-edge modulation, and the Boost unit adopts trailing-edge modulation, forming a dual-edge modulation control method.

[0014] Optionally, the TAB-Boost converter includes three operating modes: simultaneous charging mode, independent OBC mode and independent LDC mode. The power transmission direction and magnitude are controlled by changing the phase shift angle between the ports of the TAB unit and the duty cycle of the Boost unit, and a voltage-type phase shift control method is used to independently regulate the energy between ports.

[0015] Optionally, in simultaneous charging mode, the three ports work simultaneously, the energy of port A flows to port B and port C simultaneously, the phase shift duty ratio of port A and port B is greater than 0, and the phase shift duty ratio of port B and port C is greater than 0.

[0016] Optionally, in independent OBC mode, only port A and port B work, port A transfers energy to port B, the phase shift duty ratio of port A and port B is greater than 0, and the phase shift duty ratio of port B and port C is equal to 0.

[0017] Optionally, in independent LDC mode, only port B and port C work, port B transmits energy to port C, the phase shift duty ratio between port A and port B is equal to 0, and the phase shift duty ratio between port B and port C is greater than 0.

[0018] Compared with the prior art, the present invention has the following advantages and technical effects:

[0019] Compared to existing on-vehicle power converters, this invention integrates both an OBC and an LDC, effectively reducing the number of components, size, and cost while maintaining functionality. Furthermore, even under high-voltage output conditions, this invention maintains a low inductor current, effectively reducing device current stress and enabling a wider and higher output voltage range. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of this application. The exemplary embodiments and descriptions of this application are intended to explain this application and do not constitute an improper limitation on this application. In the accompanying drawings:

[0021] Figure 1 A circuit structure block diagram of an embodiment of the present invention;

[0022] Figure 2 The diagram shows the operating timing of the switching device and the waveform of the inductor current in the simultaneous charging mode according to an embodiment of the present invention;

[0023] Figure 3 The working timing of the switch device and the inductor current waveform in different working modes of the embodiment of the present invention are shown in FIG. 1 , where a is K ab V A >V B Working mode; b is K ab V A ≤V B Working mode;

[0024] Figure 4 This is a control system diagram of a TAB-Boost converter in a simultaneous charging mode according to an embodiment of the present invention;

[0025] Figure 5aThe output voltage and output current of each port of the TAB-Boost converter when the voltage of port B is 380V in the embodiment of the present invention;

[0026] Figure 5b This is a time domain simulation waveform diagram of the inductor current and the switch device control signal when the output voltage of the B port of the TAB-Boost converter according to an embodiment of the present invention is 380V;

[0027] Figure 5c The output voltage and output current of each port of the TAB-Boost converter when the voltage of port B is 500V according to the embodiment of the present invention;

[0028] Figure 5d This is a time domain simulation waveform diagram of the inductor current and the switch device control signal when the output voltage of the B port of the TAB-Boost converter according to an embodiment of the present invention is 700V;

[0029] Figure 5e The output voltage and output current of each port of the TAB-Boost converter when the voltage of port B is 700V according to the embodiment of the present invention;

[0030] Figure 5f This is a time domain simulation waveform diagram of the inductor current and the switch device control signal when the output voltage of the B port of the TAB-Boost converter according to an embodiment of the present invention is 700V;

[0031] Figure 6a The figure is a time domain simulation waveform diagram of the inductor current and the switch device control signal when the output voltage of the B port of the TAB converter is 700V, which is compared with the TAB-Boost converter of the present invention;

[0032] Figure 6b This is a time domain simulation waveform diagram of the output voltage and current of each port of the TAB-Boost converter when the input voltage changes according to an embodiment of the present invention;

[0033] Figure 6c This is a time domain simulation waveform diagram of the output voltage and current of each port of the TAB-Boost converter when the load on port B changes according to an embodiment of the present invention;

[0034] Figure 6d This is a time-domain simulation waveform diagram of the output voltage and current of each port of the TAB-Boost converter when the load on the C port changes according to an embodiment of the present invention. DETAILED DESCRIPTION

[0035] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0036] It should be noted that the steps shown in the flowcharts of the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and that, although a logical order is shown in the flowcharts, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0037] Example 1

[0038] like Figure 1 As shown, this embodiment provides a TAB-Boost converter topology circuit for integrating OBC-LDC, including:

[0039] The TAB unit includes port A, port B, and port C. Each port includes a full-bridge circuit. The three full-bridge circuits are connected to each other through a transformer T and an energy storage inductor. V AB 、V CD and V EF Respectively represent the voltages at the three ports of transformer T;

[0040] The first full-bridge circuit includes a first switch tube Q A1 , the second switch tube Q A2 , the third switch tube Q A3 And the fourth switch tube Q A4 , and the input capacitor C A Connection, input voltage V A Connect the input capacitor C A Both ends;

[0041] The second full-bridge circuit includes a fifth switch tube Q b1 , the sixth switch tube Q b2 , the seventh switch tube Q b3 And the eighth switch tube Q b4 , connect capacitor C B , load resistance R B Connected to capacitor C B Both ends, through the inductor L f Connect with Boost unit;

[0042] The third full-bridge circuit includes the ninth switch tube Q C1 、The tenth switch tube Q C2 、The eleventh switch tube Q C3 and the twelfth switch tube Q C4 , and capacitor C C Connect the load resistor R C Connected to capacitor C C Both ends;

[0043] Boost unit, including the main switch tube Q b 、Inductor L f and synchronous rectifier Q Db, inductance L f Connect on Q b and Q Db Between, used to store energy and smooth current, capacitor C B Connect on Q Db The output terminal and the load resistor R B It is used to stabilize the output voltage.

[0044] Furthermore, the working process and principle of the TAB-Boost converter are as follows: the TAB-Boost converter controls the direction and size of power transmission by changing the phase shift angle between the ports of the TAB unit and the duty cycle of the Boost unit. The TAB-Boost converter changes the direction of power transmission in combination with actual application conditions, so that it has three main working modes: simultaneous charging mode: the three ports work simultaneously, that is, the energy of port A flows to port B and port C at the same time, and the phase shift duty cycle of port A and port B is D. AB >0, the phase shift duty ratio D of port B and port C BC >0. Independent OBC mode: Only port A and port B work. At this time, only port A transfers energy to port B, while port A does not transfer energy to port C. Therefore, in this working mode, the phase shift duty ratio D of port A and port B is AB >0, and the phase shift duty ratio D of port B and port C BC = 0. Independent LDC mode: Only ports B and C work, that is, port B transmits energy to port C, while port A does not transfer energy. The phase shift duty ratio D between ports A and B is AB =0, and the phase shift duty ratio D of port B and port C BC >0. Since the independent OBC mode and the independent LDC mode are special cases of the simultaneous charging mode, this manual focuses on the operation of the TAB-Boost converter in the simultaneous charging mode. Its timing waveform is as follows: Figure 2 shown.

[0045] When the TAB unit adopts leading-edge modulation and the Boost unit adopts trailing-edge modulation, the working timing of the TAB-Boost converter presents two modes as the relationship between the input and output voltages changes, resulting in two different working timings and inductor current waveforms of the converter, such as Figure 3 When the converter is in K ab V A >V B The working mode of each cycle is divided into three stages. At t0, Q b conduction, Q A2 , Q A3 After the dead time, Q A1 , Q A4 is turned on, so the current flows through QA1 , Q A4 .Q b1 , Q b4 There is no conduction, so v1 = 0, and Q b is turned on, the inductor current flows through Q b Directly to the negative pole of the voltage output of port B, so the inductor does not participate in energy transmission, the inductor current i Lf No change. At time t1, Q b Off, while Q Db conduction, and Q b1 , Q b4 No conduction or Q b1 , Q b4 The inductor L is turned on, but the effective duty cycle of the TAB unit output voltage is lost, so v1 = 0. f Q Db Discharge the load, so i Lf Gradually decreases. At t2, Q b1 , Q b4 The effective duty cycle of the TAB unit is lost and a voltage is generated across v1. b Off, while Q Db conduction, energy storage inductor L f The voltage across the two ends is the voltage difference between the TAB unit output voltage and the load voltage. ab V A >V B , so L f The voltage across the two ends is positive, the inductor is charged, and the inductor current i Lf When the converter is in K ab V A ≤V B The working mode of each cycle is divided into three stages. At t0, Q b1 , Q b4 No conduction or Q b1 , Q b4 However, since the effective duty cycle of the TAB unit output voltage is lost, v1 = 0, and Q b conduction, inductor current i Lf Q b Directly to the negative pole of the voltage output of port B, so the inductor does not participate in energy transmission, i Lf remains unchanged. At time t1, Q b1 , Q b4 The duty cycle of the TAB unit is lost and a voltage is generated across v1. b In the on state, the energy storage inductor L f After Q b Return directly to the negative pole, the voltage across the inductor is equal to v1. fCharging, inductor current i Lf Gradually increases. At t2, Q b Shutdown, Q Db conduction, Q b1 , Q b4 The effective duty cycle loss of the TAB unit ends and a voltage is generated across v1. f The voltage across the two ends is the voltage difference between the TAB unit output voltage and the load voltage. Lf Q Db Instead, it supplies energy to the load and the inductor current decreases.

[0046] Further, Figure 4 The following figure shows the control system diagram of the TAB-Boost converter in simultaneous charging mode. To achieve independent energy regulation between multiple ports, the system adopts a voltage-type phase-shift control strategy. This method uses the output voltage of each port as the control object, and adjusts the phase difference between the full bridge and the duty cycle of the Boost unit through a voltage closed loop, thereby accurately controlling the energy flow and power level. In the specific implementation, the B port and the C port are set with independent voltage reference values ​​(v B_ref 、v C_ref ), real-time acquisition of output voltage v B (t) and v C (t) and compared with the reference value. The generated voltage error is adjusted by the voltage loop and output as a control variable, and is also limited at the same time. These control variables are used to adjust the phase shift angle between port A and ports B and C, thereby effectively controlling the direction and amplitude of power transmission from port A to ports B and C. To further expand the output voltage adjustment range of port B, the Boost unit adopts voltage loop control and introduces duty cycle limiting to ensure the stability of the output voltage. b and Q Db The control signal is calculated by the duty cycle DQ b The control signal of the switch tube at port A is generated by the sawtooth wave and the value range through the comparator. Similarly, the D AB and D BC The values ​​are converted into their respective ranges and then compared with the sawtooth wave through the comparator to generate the control signals for the switch tubes at ports B and C.

[0047] The method of the present invention was subjected to time domain simulation analysis using PSIM simulation software, and the results are as follows.

[0048] Figure 5a When the voltage of port B of the TAB-Boost converter is 380V, the output voltage and output current of each port are: Figure 5b This is a time domain simulation waveform diagram of the inductor current and the switch device control signal when the output voltage of the B port of the TAB-Boost converter according to an embodiment of the present invention is 380V. Figure 5c When the voltage at port B of the TAB-Boost converter of the embodiment of the present invention is 500V, the output voltage and output current of each port are as follows: Figure 5d This is a time domain simulation waveform diagram of the inductor current and the switch device control signal when the output voltage of the B port of the TAB-Boost converter according to an embodiment of the present invention is 700V. Figure 5e The output voltage and output current of each port when the voltage of port B of the TAB-Boost converter in the embodiment of the present invention is 700V are shown in FIG. Figure 5f The following is a time domain simulation waveform diagram of the inductor current and the switch device control signal when the output voltage of the B port of the TAB-Boost converter of the embodiment of the present invention is 700 V. As can be seen from the above figures, the output voltage range of the B port of the TAB-Boost converter is 380 V to 700 V. Figure 5a 、 Figure 5b 、 Figure 5c 、 Figure 5d 、 Figure 5e and Figure 5f The common simulation condition is the input voltage V A =400V, voltage reference value v C_ref =14V, inductor L A =2μH、L B =30μH、L C =0.8μH、L f =200μH, transformer ratio n A :n B :n C =25:25:1, capacitor C A =1000μF, C A =220μF, C C =2000μF, load resistance R C =0.5Ω. Figure 5a 、 Figure 5b Voltage reference value v B_ref =380V, load resistance R B =48.5Ω. Figure 5c 、 Figure 5d Voltage reference value v B_ref =500V, load resistance R B =84Ω. Figure 5e 、 Figure 5f Voltage reference value v B_ref =700V, load resistance R B =164.6Ω.

[0049] Figure 6a 、 Figure 5f The time domain simulation waveforms of the inductor current and switch device control signal at port B of the TAB converter and TAB-Boost converter are respectively. Figure 6b 、 Figure 6c 、 Figure 6d The time domain simulation waveforms of the output voltage and output current of the TAB-Boost converter correspond to changes in input voltage or load. Figure 6a and Figure 5f , under the condition of outputting the same high voltage, the energy storage inductor current at the B port of the TAB converter is much larger than the energy storage inductor current at the B port of the TAB-Boost converter. Therefore, the wide voltage regulation capability demonstrated by the TAB converter is difficult to achieve in practical applications due to the excessively large inductor current. In contrast, the TAB-Boost converter can maintain a lower inductor current even under high voltage working conditions, effectively reducing the device current stress, making it feasible to achieve a wider and higher output voltage range in practice. Figure 6b 、 Figure 6c and Figure 6d It can be seen that when an input or load transient disturbance occurs during the simulation circuit model, the PI controller recalculates the correct phase shift angle and duty cycle, restoring the converter's output voltages at ports B and C to 500V and 14V, respectively. This verifies the TAB-Boost converter's excellent dynamic response capability. Figure 6a and Figure 5f The simulation condition is the input voltage V A =400V, voltage reference value v B_ref =700V,v C_ref =14V, inductor L A =2μH、L B =30μH、L C =0.8μH、L f =200μH, transformer ratio n A :n B :n C =25:25:1, capacitor C A =1000μF, C A =220μF, C C =2000μF, load resistance R B =164.6Ω、R C =0.5Ω.

[0050] The above are merely preferred embodiments of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A TAB-Boost converter topology circuit for integrating OBC-LDC, characterized in that: include: The TAB unit includes an A port, a B port, and a C port. Each port includes a full-bridge circuit. The three full-bridge circuits are interconnected through a transformer T and an energy storage inductor. The first full-bridge circuit includes a first switch tube Q A1 , the second switch tube Q A2 , the third switch tube Q A3 And the fourth switch tube Q A4 , and the input capacitor C A Connection, input voltage V A Connect the input capacitor C A Both ends; The second full-bridge circuit includes a fifth switch tube Q b1 , the sixth switch tube Q b2 , the seventh switch tube Q b3 And the eighth switch tube Q b4 , connect capacitor C B , load resistance R B Connected to capacitor C B Both ends, through the inductor L f Connect with Boost unit; The third full-bridge circuit includes the ninth switch tube Q C1 、The tenth switch tube Q C2 、The eleventh switch tube Q C3 and the twelfth switch tube Q C4 , and capacitor C C Connect the load resistor R C Connected to capacitor C C Both ends; Boost unit, including the main switch tube Q b 、Inductor L f and synchronous rectifier Q Db , inductance L f Connect on Q b and Q Db Between, used to store energy and smooth current, capacitor C B Connect on Q Db The output terminal and the load resistor R B It is used to stabilize the output voltage.

2. The circuit according to claim 1, characterized in that The voltage waveforms output by the three full-bridge circuits of the TAB unit are symmetrical square waves with the same frequency. The phase relationship between the symmetrical square waves is adjusted by controlling the switching sequence of the switching tubes, thereby controlling the direction and magnitude of power transmission.

3. The circuit according to claim 1, wherein: The Boost unit adjusts the main switch tube Q b and synchronous rectifier Q Db duty cycle, widening the output voltage range.

4. The circuit according to claim 1, wherein: The TAB unit adopts leading edge modulation, and the Boost unit adopts trailing edge modulation, forming a dual-edge modulation control method.

5. The circuit according to claim 1, wherein: The TAB-Boost converter includes three operating modes: simultaneous charging mode, independent OBC mode, and independent LDC mode. The power transmission direction and magnitude are controlled by changing the phase shift angle between the ports of the TAB unit and the duty cycle of the Boost unit. A voltage-type phase shift control method is used to independently regulate the energy between the ports.

6. The circuit according to claim 5, characterized in that In simultaneous charging mode, the three ports work simultaneously, and the energy of port A flows to port B and port C simultaneously. The phase shift duty ratio of port A and port B is greater than 0, and the phase shift duty ratio of port B and port C is greater than 0.

7. The circuit according to claim 5, characterized in that In independent OBC mode, only port A and port B work, port A transfers energy to port B, the phase shift duty cycle of port A and port B is greater than 0, and the phase shift duty cycle of port B and port C is equal to 0.

8. The circuit according to claim 5, characterized in that In independent LDC mode, only ports B and C work, port B transmits energy to port C, the phase shift duty ratio between port A and port B is equal to 0, and the phase shift duty ratio between port B and port C is greater than 0.

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