A bidirectional combined wide gain dc-dc converter with bridge-leg multiplexing

Abstract

The application discloses a bidirectional combined wide-gain DC-DC converter with bridge arm multiplexing, and belongs to the technical field of bidirectional DC-DC converters. The converter comprises a DC voltage source V1 and V2, DC side capacitors C1, C2 and C3, power tubes S1, S2, S3, S4, S5, S6, S7, S8, S9 and S10, a magnetizing inductor L, a resonant inductor L, an equivalent leakage inductor L, an input inductor L, a resonant capacitor C, high-frequency transformers T1 and T2. 10 m r S r The converter is composed of a main power circuit LLC / SRC bidirectional converter and a partial power circuit phase-shifted full-bridge / push-pull bidirectional converter, can realize bidirectional energy flow, multiplexes the third bridge arm of the LLC / SRC bidirectional converter and the phase-shifted full-bridge / push-pull bidirectional converter, and adopts a full-wave rectifier circuit at the secondary side of the high-frequency transformers T1 and T2, thereby improving the integration degree of the converter and solving the problem that the lagging bridge arm of the phase-shifted full-bridge converter is difficult to realize zero-voltage turn-on.​​​​

Description

Technical Field

[0001] This invention relates to the field of bidirectional DC-DC converter technology, and in particular to a bidirectional combined wide-gain DC-DC converter with multiplexed bridge arms. Background Technology

[0002] Bidirectional DC-DC converters are crucial bridges supporting the bidirectional flow of energy at the bottom layer of medium- and low-voltage DC distribution networks. Scenarios such as DC interconnection between buses, support and regulation of distributed energy storage, and interactive connections between electric vehicle loads and the grid all rely on bidirectional DC-DC converters. Dual active bridge (DAB) converters, bidirectional LLC resonant converters, and phase-shifted full-bridge / push-pull bidirectional converters are classic circuit structures used in bidirectional DC power conversion scenarios. DABs offer wide voltage regulation capabilities, but their operating efficiency is relatively low due to issues such as soft-switching range, circulating current power loss, and high turn-off current stress. LLC resonant converters offer high operating efficiency, but frequency adjustment is required during voltage regulation, resulting in a limited voltage regulation range. To achieve both high efficiency and a wide voltage regulation range, the IEEE Transactions on Industrial Electronics, Volume 68, Issue 1, 2021, paper titled "Single-Stage DAB-LLC Hybrid Bidirectional Converter With Tight Voltage Regulation Under DCX Operation," reported an LLC-DAB combined converter. The LLC converter operates in open-loop at its resonant point, handling most of the power, while the DAB converter handles a smaller portion. Phase-shifting and PWM control are used to regulate the system's output voltage; however, this converter has low integration. To address this low integration issue, the IEEE Transactions on Power Electronics, Volume 32, Issue 2, 2022, paper titled "An LLC-DAB Bidirectional DCX Converter With Wide Load Range ZVS and Reduced Switch Count," reported a combined DC-DC topology with secondary-side full-bridge multiplexing. By multiplexing the secondary-side H-bridge of the DAB unit with the secondary-side H-bridge of the LLC unit, one H-bridge and its associated drive circuit can be eliminated, thus reducing system development costs. However, this topology has limited application in low-voltage, high-current scenarios. Phase-shifted full-bridge / push-pull bidirectional converters are suitable for low-voltage, high-current applications, but the power transistors in the lagging bridge arm are difficult to turn on at zero voltage. Summary of the Invention

[0003] This invention aims to address the shortcomings of the technology described in the background by proposing a bidirectional combined wide-gain DC-DC converter with bridge arm multiplexing. The main power circuit adopts an LLC / SRC bidirectional converter operating in open loop at the resonant point, while part of the power circuit adopts a phase-shifted full-bridge / push-pull bidirectional converter suitable for low-voltage, high-current applications to regulate the system voltage. By multiplexing the bridge arms, the soft-switching problem of the power transistors of the lagging bridge arms of the phase-shifted full-bridge is solved, and the integration of the converter is improved.

[0004] This invention is achieved using the following technical solution:

[0005] A bidirectional combined wide-gain DC-DC converter with bridge arm multiplexing, the converter comprising: DC voltage source V1, DC voltage source V2, DC-side capacitor C1, DC-side capacitor C2, DC-side capacitor C3, and resonant capacitor C. r Power transistor S1, power transistor S2, power transistor S3, power transistor S4, power transistor S5, power transistor S6, power transistor S7, power transistor S8, power transistor S9, power transistor S 10 Magnetizing inductance L m Resonant inductor L r Equivalent leakage inductance L S The converter consists of an input inductor L, a high-frequency transformer T1, and a high-frequency transformer T2. The converter is composed of a main power circuit LLC / SRC bidirectional converter and a partial power circuit phase-shifted full-bridge / push-pull bidirectional converter. The main power circuit LLC / SRC bidirectional converter is composed of the primary circuit of high-frequency transformer T1, high-frequency transformer T1, and the secondary circuit of high-frequency transformer T1. The partial power circuit phase-shifted full-bridge / push-pull bidirectional converter is composed of the primary circuit of high-frequency transformer T2, high-frequency transformer T2, and the secondary circuit of high-frequency transformer T2. High-frequency transformers T1 and T2... The three bridge arms on the primary side are the first bridge arm, the second bridge arm, and the third bridge arm. The second and third bridge arms form the high-frequency transformer T1 primary-side H-bridge circuit of the main power circuit LLC / SRC bidirectional converter. The first and third bridge arms form the high-frequency transformer T2 primary-side H-bridge circuit of the phase-shifted full-bridge / push-pull bidirectional converter. The main power circuit LLC / SRC bidirectional converter and the phase-shifted full-bridge / push-pull bidirectional converter reuse the third bridge arm. The main power circuit LLC / SRC bidirectional converter and the phase-shifted full-bridge / push-pull bidirectional converter are connected in series for output / input on the V2 side.

[0006] Furthermore, the primary circuit of the main power circuit LLC / SRC bidirectional converter includes a DC voltage source V1, a DC-side capacitor C1, a primary H-bridge circuit of a high-frequency transformer T1, a resonant network, and a primary winding N of the high-frequency transformer T1. p1The primary-side H-bridge circuit of the high-frequency transformer T1 consists of a second bridge arm and a third bridge arm, which are respectively composed of power transistors S3 and S4, and power transistors S5 and S6; the resonant network consists of a magnetizing inductor L. m Resonant inductor L r and resonant capacitor C r Composition; High-frequency transformer T1 primary winding N p1 The same name of the magnetizing inductor L m The upper end and the resonant inductor L r Right end, primary winding N p1 The opposite-named terminal of the magnetizing inductor L m The lower end, the source of power transistor S5 and the drain of power transistor S6, and the resonant inductor L r The left end is connected to the resonant capacitor C. r On the right end, resonant capacitor C r The left end is connected to the source of power transistor S3 and the drain of power transistor S4. The drains of power transistors S3 and S5 are connected to the positive terminals of DC voltage source V1 and DC-side capacitor C1. The sources of power transistors S4 and S6 are connected to the negative terminals of DC voltage source V1 and DC-side capacitor C1.

[0007] Furthermore, the secondary circuit of the main power circuit LLC / SRC bidirectional converter includes the secondary winding N of the high-frequency transformer T1. s1 Secondary winding N s2 The high-frequency transformer T1 consists of a secondary full-wave rectifier circuit, a DC-side capacitor C2, and a DC voltage source V2; the secondary full-wave rectifier circuit of the high-frequency transformer T1 is composed of power transistors S7 and S8; the secondary winding N of the high-frequency transformer T1... s1 The same terminal is connected to the source of power transistor S7. The drain of power transistor S7 is connected to the drain of power transistor S8, the DC voltage source V2, and the positive terminal of DC-side capacitor C2. The negative terminal of DC-side capacitor C2 is connected to the secondary winding N of high-frequency transformer T1. s1 The opposite terminal and secondary winding N s2 The same terminal, secondary winding N s2 The source of the power transistor S8 is connected to the terminal of the transistor with the different name.

[0008] Furthermore, the primary circuit of the phase-shifted full-bridge / push-pull bidirectional converter in the power circuit includes a DC voltage source V1, a DC-side capacitor C1, a primary H-bridge circuit of a high-frequency transformer T2, and an equivalent leakage inductance L of the high-frequency transformer T2. S and the primary winding N of high-frequency transformer T1 p1 The primary-side H-bridge circuit of the high-frequency transformer T2 consists of a first bridge arm and a third bridge arm, wherein the first bridge arm and the third bridge arm are respectively composed of power transistors S1 and S2, and power transistors S5 and S6; the primary winding N of the high-frequency transformer T2 p2 The equivalent leakage inductance L of the high-frequency transformer T2 connected to the opposite nameS On the right end, the equivalent leakage inductance L of the high-frequency transformer T2 S The left end of the power transistor S1 source and power transistor S2 drain are connected. The drain of power transistor S1 is connected to the drain of power transistor S3, the drain of power transistor S5, the DC-side capacitor C1, and the positive terminal of the DC voltage source V1. The primary winding N of the high-frequency transformer T2 is connected to the power transistor S2 source. p2 The corresponding terminals are connected to the source of power transistor S5, the drain of power transistor S6, and the magnetizing inductor L. m The lower end and the primary winding N of the high-frequency transformer T1 p1 The opposite terminal of the power transistor S6 is connected to the drain of the power transistor S2, the drain of the power transistor S4, the DC side capacitor C1, and the negative terminal of the DC voltage source V1.

[0009] Furthermore, the secondary circuit of the phase-shifted full-bridge / push-pull bidirectional converter includes a high-frequency transformer T2 secondary full-wave rectifier circuit, an input inductor L, a DC-side capacitor C3, and a DC voltage source V2; the high-frequency transformer T2 secondary full-wave rectifier circuit consists of power transistor S9 and power transistor S... 10 Composition; secondary winding N of high-frequency transformer T2 s3 The same terminal is connected to the source of power transistor S9, and the drain of power transistor S9 is connected to the source of power transistor S9. 10 The drain and positive terminal of DC-side capacitor C3 are connected to the negative terminal of DC voltage source V2 and the right end of input inductor L. The left end of input inductor L is connected to the secondary winding N of high-frequency transformer T2. s3 The opposite terminal and secondary winding N s4 The same terminal, secondary winding N s4 Equivalent power transistor S 10 Source.

[0010] Furthermore, in the main power circuit LLC / SRC bidirectional converter, power transistors S3, S6, and S7 have a duty cycle of 0.5 and use the same drive signal; power transistors S4, S5, and S8 have a duty cycle of 0.5 and use the same drive signal; power transistors S3 and S4 are complementary in conduction; power transistors S5 and S6 are complementary in conduction; and power transistors S7 and S8 are complementary in conduction. In the partial power circuit phase-shifted full-bridge / push-pull bidirectional converter, power transistors S1 and S2 have a duty cycle of 0.5; power transistors S9 and S8 have a duty cycle of 0.5. 10 Duty cycle D a When the value is greater than 0.5, power transistors S1 and S2 are complementary conductions, while power transistors S9 and S2 are complementary conductions. 10 The phase shift angles of the drive signals differ by 180 degrees, and the drive signals of power transistors S1 and S6 have a phase shift angle D. b .

[0011] Furthermore, the two operating modes of the bidirectional combined DC-DC converter with bridge arm multiplexing are forward buck mode and reverse boost mode. The main power circuit of the forward buck mode is an LLC converter, the main power circuit of the reverse boost mode is an SRC converter, part of the power circuit of the forward buck mode is a phase-shifted full-bridge converter, and part of the power circuit of the reverse boost mode is a push-pull converter.

[0012] In the forward buck mode, power is transferred from V1 to V2. The main power circuit LLC converter operates as a DC-DC converter at a fixed frequency and duty cycle, bearing the main power. The partial power circuit phase-shifting full-bridge converter adjusts the total gain M1 through the phase shift angles of the first and third arms of the primary side of the high-frequency transformer T2; the total gain M1 is the gain M of the main power circuit LLC converter. LLC The gain M of the phase-shifted full-bridge converter in the partial power circuit PSFB The result of superposition is:

[0013]

[0014] Where, N p1 For the primary winding of high-frequency transformer T1, N s1 For the secondary winding of high-frequency transformer T1, N p2 For the primary winding of high-frequency transformer T2, N s3 For the secondary winding of high-frequency transformer T2, D b The inner phase shift angles of the first and third bridge arms of the phase-shifted full-bridge converter for partial power circuits;

[0015] In the reverse boost mode, power is transferred from V2 to V1. The main power circuit SRC converter operates as a DC-DC converter at a fixed frequency and duty cycle, bearing the majority of the power. The partial power circuit push-pull converter adjusts the total gain M2 through PWM plus phase-shift control; the total gain M2 is the gain M of the main power circuit SRC converter. SRC The gain M of the phase-shifted full-bridge converter in the partial power circuit CFPP The result of superposition is:

[0016]

[0017] Among them, L S The equivalent leakage inductance of high-frequency transformer T2 is given by D, where L is the input inductance and D is the equivalent leakage inductance of high-frequency transformer T2. a For the power transistors S9 and S in the push-pull converter of the partial power circuit 10 Duty cycle.

[0018] The present invention has the following beneficial technical effects:

[0019] (1) The present invention proposes a bidirectional combined wide-gain DC-DC converter with multiplexed bridge arms. The main power circuit adopts LLC / SRC bidirectional converter, and some power circuits adopt phase-shifted full-bridge / push-pull bidirectional converter, which can realize bidirectional energy flow.

[0020] (2) The present invention proposes a bidirectional combined wide-gain DC-DC converter with multiplexed bridge arms. The main power circuit LLC / SRC bidirectional converter and the partial power circuit phase-shifted full-bridge / push-pull bidirectional converter are multiplexed by the third bridge arm composed of power transistor S5 and power transistor S6. The secondary side of the high-frequency transformers T1 and T2 adopts a full-wave rectifier circuit, which improves the integration of the converter.

[0021] (3) The present invention proposes a bidirectional combined wide-gain DC-DC converter with multiplexed bridge arms. The third bridge arm of the converter is the lagging bridge arm of the phase-shifted full-bridge converter of part of the power circuit. With the help of the LLC converter of the main power circuit, the problem that the lagging bridge arm of the phase-shifted full-bridge converter is difficult to achieve zero-voltage turn-on is solved. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of a bidirectional combined wide-gain DC-DC converter with multiplexed bridge arms proposed in this invention.

[0023] Figure 2 The main waveform diagram of the forward buck mode of a bidirectional combined wide-gain DC-DC converter with bridge arm multiplexing proposed in this invention is shown.

[0024] Figure 3 This is a schematic diagram of mode 1 of a bidirectional combined wide-gain DC-DC converter with multiplexed bridge arms proposed in this invention, in the forward buck mode.

[0025] Figure 4 This is a schematic diagram of mode 2 of a bidirectional combined wide-gain DC-DC converter with multiplexed bridge arms proposed in this invention, in the forward buck mode.

[0026] Figure 5 This is a schematic diagram of mode 3 of a bidirectional combined wide-gain DC-DC converter with bridge arm multiplexing proposed in this invention, in the forward buck mode.

[0027] Figure 6 This is a schematic diagram of mode 4 of a bidirectional combined wide-gain DC-DC converter with multiplexed bridge arms proposed in this invention, in the forward buck mode.

[0028] Figure 7 The main waveform diagram of the reverse boost mode of a bidirectional combined wide-gain DC-DC converter with bridge arm multiplexing proposed in this invention is shown.

[0029] Figure 8This is a schematic diagram of mode 1 of a bidirectional combined wide-gain DC-DC converter with multiplexed bridge arms proposed in this invention, in reverse boost mode.

[0030] Figure 9 This is a schematic diagram of mode 2 of a bidirectional combined wide-gain DC-DC converter with multiplexed bridge arms proposed in this invention, in reverse boost mode.

[0031] Figure 10 This is a schematic diagram of mode 3 of a bidirectional combined wide-gain DC-DC converter with bridge arm multiplexing proposed in this invention in reverse boost mode.

[0032] Figure 11 This is a schematic diagram of mode 4 of a bidirectional combined wide-gain DC-DC converter with bridge arm multiplexing proposed in this invention in reverse boost mode.

[0033] Figure 12 This is a schematic diagram of mode 5 of a bidirectional combined wide-gain DC-DC converter with bridge arm multiplexing proposed in this invention in reverse boost mode.

[0034] Figure 13 This is a schematic diagram of mode 6 of a bidirectional combined wide-gain DC-DC converter with bridge arm multiplexing proposed in this invention, in reverse boost mode.

[0035] Figure 14 The simulation waveform diagram shows the forward buck mode of a bidirectional combined wide-gain DC-DC converter with multiplexed bridge arms proposed in this invention.

[0036] Figure 15 The simulation waveform diagram shows the reverse boost mode of a bidirectional combined wide-gain DC-DC converter with multiplexed bridge arms proposed in this invention. Specific implementation methods

[0037] The following will describe in detail some details of the technical solutions in the embodiments of the present invention with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] A bidirectional combined wide-gain DC-DC converter with bridge arm multiplexing, such as Figure 1 As shown, the converter includes: DC voltage source V1, DC voltage source V2, DC-side capacitor C1, DC-side capacitor C2, DC-side capacitor C3, and resonant capacitor C. r Power transistor S1, power transistor S2, power transistor S3, power transistor S4, power transistor S5, power transistor S6, power transistor S7, power transistor S8, power transistor S9, power transistor S10 Magnetizing inductance L m Resonant inductor L r Equivalent leakage inductance L S The converter consists of an input inductor L, a high-frequency transformer T1, and a high-frequency transformer T2. The converter is composed of a main power circuit LLC / SRC bidirectional converter and a partial power circuit phase-shifted full-bridge / push-pull bidirectional converter. The main power circuit LLC / SRC bidirectional converter is composed of the primary circuit of high-frequency transformer T1, high-frequency transformer T1, and the secondary circuit of high-frequency transformer T1. The partial power circuit phase-shifted full-bridge / push-pull bidirectional converter is composed of the primary circuit of high-frequency transformer T2, high-frequency transformer T2, and the secondary circuit of high-frequency transformer T2. High-frequency transformers T1 and T2... The three bridge arms on the primary side are the first bridge arm, the second bridge arm, and the third bridge arm. The second and third bridge arms form the high-frequency transformer T1 primary-side H-bridge circuit of the main power circuit LLC / SRC bidirectional converter. The first and third bridge arms form the high-frequency transformer T2 primary-side H-bridge circuit of the phase-shifted full-bridge / push-pull bidirectional converter. The main power circuit LLC / SRC bidirectional converter and the phase-shifted full-bridge / push-pull bidirectional converter reuse the third bridge arm. The main power circuit LLC / SRC bidirectional converter and the phase-shifted full-bridge / push-pull bidirectional converter are connected in series for output / input on the V2 side.

[0039] Furthermore, the primary circuit of the main power circuit LLC / SRC bidirectional converter includes a DC voltage source V1, a DC-side capacitor C1, a primary H-bridge circuit of a high-frequency transformer T1, a resonant network, and a primary winding N of the high-frequency transformer T1. p1 The primary-side H-bridge circuit of the high-frequency transformer T1 consists of a second bridge arm and a third bridge arm, which are respectively composed of power transistors S3 and S4, and power transistors S5 and S6; the resonant network consists of a magnetizing inductor L. m Resonant inductor L r and resonant capacitor C r Composition; High-frequency transformer T1 primary winding N p1 The same name of the magnetizing inductor L m The upper end and the resonant inductor L r Right end, primary winding N p1 The opposite-named terminal of the magnetizing inductor L m The lower end, the source of power transistor S5 and the drain of power transistor S6, and the resonant inductor L r The left end is connected to the resonant capacitor C. r On the right end, resonant capacitor C r The left end is connected to the source of power transistor S3 and the drain of power transistor S4. The drains of power transistors S3 and S5 are connected to the positive terminals of DC voltage source V1 and DC-side capacitor C1. The sources of power transistors S4 and S6 are connected to the negative terminals of DC voltage source V1 and DC-side capacitor C1.

[0040] Furthermore, the secondary circuit of the main power circuit LLC / SRC bidirectional converter includes the secondary winding N of the high-frequency transformer T1. s1 Secondary winding N s2 The high-frequency transformer T1 consists of a secondary full-wave rectifier circuit, a DC-side capacitor C2, and a DC voltage source V2; the secondary full-wave rectifier circuit of the high-frequency transformer T1 is composed of power transistors S7 and S8; the secondary winding N of the high-frequency transformer T1... s1 The same terminal is connected to the source of power transistor S7. The drain of power transistor S7 is connected to the drain of power transistor S8, the DC voltage source V2, and the positive terminal of DC-side capacitor C2. The negative terminal of DC-side capacitor C2 is connected to the secondary winding N of high-frequency transformer T1. s1 The opposite-named terminal and secondary winding N s2 The same terminal, secondary winding N s2 The source of the power transistor S8 is connected to the terminal of the transistor with the opposite name.

[0041] Furthermore, the primary circuit of the phase-shifted full-bridge / push-pull bidirectional converter in the power circuit includes a DC voltage source V1, a DC-side capacitor C1, a primary H-bridge circuit of a high-frequency transformer T2, and an equivalent leakage inductance L of the high-frequency transformer T2. S and the primary winding N of high-frequency transformer T1 p1 The primary-side H-bridge circuit of the high-frequency transformer T2 consists of a first bridge arm and a third bridge arm, wherein the first bridge arm and the third bridge arm are respectively composed of power transistors S1 and S2, and power transistors S5 and S6; the primary winding N of the high-frequency transformer T2 p2 The equivalent leakage inductance L of the high-frequency transformer T2 connected to the opposite name S On the right end, the equivalent leakage inductance L of the high-frequency transformer T2 S The left end of the power transistor S1 source and power transistor S2 drain are connected. The drain of power transistor S1 is connected to the drain of power transistor S3, the drain of power transistor S5, the DC-side capacitor C1, and the positive terminal of the DC voltage source V1. The primary winding N of the high-frequency transformer T2 is connected to the power transistor S2 source. p2 The corresponding terminals are connected to the source of power transistor S5, the drain of power transistor S6, and the magnetizing inductor L. m The lower end and the primary winding N of the high-frequency transformer T1 p1 The opposite terminal of the power transistor S6 is connected to the drain of the power transistor S2, the drain of the power transistor S4, the DC side capacitor C1, and the negative terminal of the DC voltage source V1.

[0042] Furthermore, the secondary circuit of the phase-shifted full-bridge / push-pull bidirectional converter includes a high-frequency transformer T2 secondary full-wave rectifier circuit, an input inductor L, a DC-side capacitor C3, and a DC voltage source V2; the high-frequency transformer T2 secondary full-wave rectifier circuit consists of power transistor S9 and power transistor S... 10 Composition; secondary winding N of high-frequency transformer T2 s3 The same terminal is connected to the source of power transistor S9, and the drain of power transistor S9 is connected to the source of power transistor S9. 10The drain and positive terminal of DC-side capacitor C3 are connected to the negative terminal of DC voltage source V2 and the right end of input inductor L. The left end of input inductor L is connected to the secondary winding N of high-frequency transformer T2. s3 The opposite terminal and secondary winding N s4 The same terminal, secondary winding N s4 Equivalent power transistor S 10 Source.

[0043] Furthermore, in the main power circuit LLC / SRC bidirectional converter, power transistors S3, S6, and S7 have a duty cycle of 0.5 and use the same drive signal; power transistors S4, S5, and S8 have a duty cycle of 0.5 and use the same drive signal; power transistors S3 and S4 are complementary in conduction; power transistors S5 and S6 are complementary in conduction; and power transistors S7 and S8 are complementary in conduction. In the partial power circuit phase-shifted full-bridge / push-pull bidirectional converter, power transistors S1 and S2 have a duty cycle of 0.5; power transistors S9 and S8 have a duty cycle of 0.5. 10 Duty cycle D a When the value is greater than 0.5, power transistors S1 and S2 are complementary conductions, while power transistors S9 and S2 are complementary conductions. 10 The phase shift angles of the drive signals differ by 180 degrees, and the drive signals of power transistors S1 and S6 have a phase shift angle D. b .

[0044] Furthermore, the two operating modes of the bidirectional combined DC-DC converter with bridge arm multiplexing are forward buck mode and reverse boost mode. The main power circuit of the forward buck mode is an LLC converter, the main power circuit of the reverse boost mode is an SRC converter, part of the power circuit of the forward buck mode is a phase-shifted full-bridge converter, and part of the power circuit of the reverse boost mode is a push-pull converter.

[0045] In the forward buck mode, power is transferred from V1 to V2. The main power circuit LLC converter operates as a DC-DC converter at a fixed frequency and duty cycle, bearing the main power. The partial power circuit phase-shifting full-bridge converter adjusts the total gain M1 through the phase shift angles of the first and third arms of the primary side of the high-frequency transformer T2; the total gain M1 is the gain M of the main power circuit LLC converter. LLC The gain M of the phase-shifted full-bridge converter in the partial power circuit PSFB The result of superposition is:

[0046]

[0047] Where, N p1 For the primary winding of high-frequency transformer T1, N s1 For the secondary winding of high-frequency transformer T1, N p2For the primary winding of high-frequency transformer T2, N s3 For the secondary winding of high-frequency transformer T2, D b The inner phase shift angles of the first and third bridge arms of the phase-shifted full-bridge converter for partial power circuits;

[0048] Combination Figures 2-6 The working principle of the forward buck mode of the bidirectional combined DC-DC converter with bridge arm multiplexing of the present invention is described in detail. Figure 2 It is known that the converter can be divided into two symmetrical stages within one cycle. Since the circuit of the converter is symmetrical in the first half cycle and the second half cycle, only the operating mode of the first half cycle is analyzed. The half-cycle operating mode is divided into two modes, namely mode 1 [t0~t1] and mode 2 [t1~t2].

[0049] 1. The circuit topology for mode 1 [t0~t1] is as follows: Figure 3 As shown

[0050] The power transistors S4, S5, and S8 of the LLC converter in the main power circuit are turned on, and the voltage v between points B and C is... BC -V1, flowing through the magnetizing inductor L m current i Lm Greater than the resonant inductance L r current i Lr The difference between them flows out of the primary winding N of the high-frequency transformer T1. p1 The same terminal, the secondary winding N of the high-frequency transformer T1. s2 The voltage is clamped at -V C2 Therefore, the primary winding N of the high-frequency transformer T1 p1 The voltage is:

[0051]

[0052] Among them, v C2 This is the voltage across capacitor C2 on the DC side.

[0053] The power transistors S1, S5, S9, and S1 in the phase-shifted full-bridge converter of the partial power circuit 10 When the circuit is on, the voltage v between points A and C is... AC v is 0 C3 The voltage is maintained by the discharge of C3, v C3 This is the voltage across capacitor C3 on the DC side.

[0054] 2. The circuit topology for mode 2 [t1~t2] is as follows: Figure 4 As shown

[0055] The power transistors S3, S6, and S7 of the LLC converter in the main power circuit are turned on, and the voltage v between points B and C is... BC For V1, i LrGreater than i Lm Their difference flows into the primary winding N of the high-frequency transformer T1. p1 The same terminal, the secondary winding N of the high-frequency transformer T1. s1 The voltage is clamped at v C2 Therefore, the primary winding N of the high-frequency transformer T1 p1 The voltage is:

[0056]

[0057] The power transistors S1, S6, and S7 of the phase-shifted full-bridge converter in the partial power circuit 10 When the circuit is on, the voltage v between points A and C is... AC It is V1.

[0058] In the reverse boost mode, power is transferred from V2 to V1. The main power circuit SRC converter operates as a DC-DC converter at a fixed frequency and duty cycle, bearing the majority of the power. The partial power circuit push-pull converter adjusts the total gain M2 through PWM plus phase-shift control; the total gain M2 is the gain M of the main power circuit SRC converter. SRC The gain M of the phase-shifted full-bridge converter in the partial power circuit CFPP The result of superposition is:

[0059]

[0060] Among them, L S The equivalent leakage inductance of high-frequency transformer T2 is given by D, where L is the input inductance and D is the equivalent leakage inductance of high-frequency transformer T2. a For the power transistors S9 and S in the push-pull converter of the partial power circuit 10 Duty cycle.

[0061] Combination Figures 7-13 The working principle of the reverse boost mode of the bidirectional combined DC-DC converter with bridge arm multiplexing of the present invention is described in detail. Figure 7 It is known that the converter can be divided into two symmetrical stages within one cycle. Since the circuits of the first half cycle and the second half cycle of the converter are symmetrical, only the operating mode of the first half cycle is analyzed. The operating mode of the half cycle is divided into three modes: mode 1 [t0~t1], mode 2 [t1~t2] and mode 3 [t2~t3].

[0062] 1. The circuit topology for mode 1 [t0~t1] is as follows: Figure 8 As shown

[0063] The power transistors S4, S5, and S8 of the SRC converter in the main power circuit are turned on, and the secondary winding N of the high-frequency transformer T1 is turned on. s2 The voltage is clamped at -V C2 i Lr Greater than iLm Their difference flows into the primary winding N of the high-frequency transformer T1. p1 The same name terminal.

[0064] The power transistors S2, S5, S9, and S in the push-pull converter of the partial power circuit 10 When the circuit is turned on, the voltage across the input inductor is V1, and the equivalent leakage inductance L of the high-frequency transformer T2 is... S Discharging first and then energizing results in a current mismatch across the high-frequency transformer T2, therefore v C2 Energy is not transferred from the side to the V1 side.

[0065] 2. The circuit topology for mode 2 [t1~t2] is as follows: Figure 9 As shown

[0066] The mode 2 and mode 1 analyses of the main power circuit SRC converter are consistent. In the partial power circuit push-pull converter, power transistors S1, S5, and S9 are turned on. Because power transistor S... 10 Since current flows through the body diode, the voltage across the input inductor is V1, and the equivalent leakage inductance L flows through the high-frequency transformer T2. S current i LS Unchanged, v C2 Energy is not transferred from the side to the V1 side.

[0067] 3. The circuit topology for mode 3 [t2~t3] is as follows: Figure 10 As shown

[0068] The power transistors S3, S6, and S7 of the SRC converter in the main power circuit are turned on, and the secondary winding N of the high-frequency transformer T1 is turned on. s2 The voltage is clamped at v C2 i Lm Greater than i Lr The difference between them flows out of the primary winding N of the high-frequency transformer T1. p1 The same name terminal.

[0069] In the push-pull converter of the partial power circuit, power transistors S1, S6, and S9 are turned on, and power transistor S... 10 The current in the body diode is zero, therefore v C2 Side, equivalent leakage inductance L of high-frequency transformer T2 S Together with the input inductor L, it transfers energy to the V1 side.

[0070] In this embodiment, Figure 14 and Figure 15 The simulation waveforms of the bidirectional combined wide-gain DC-DC converter with bridge arm multiplexing according to the present invention are shown in the forward buck mode and the reverse boost mode, respectively. The simulation parameters are shown in Table 1.

[0071] Table 1 Simulation parameters under the two modes

[0072]

[0073] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A bidirectional combined wide-gain DC-DC converter with bridge arm multiplexing, characterized in that, The converter includes: DC voltage source V1, DC voltage source V2, DC-side capacitor C1, DC-side capacitor C2, DC-side capacitor C3, and resonant capacitor C. r Power transistor S1, power transistor S2, power transistor S3, power transistor S4, power transistor S5, power transistor S6, power transistor S7, power transistor S8, power transistor S9, power transistor S 10 Magnetizing inductance L m Resonant inductor L r Equivalent leakage inductance L S The converter consists of an input inductor L, a high-frequency transformer T1, and a high-frequency transformer T2. The converter is composed of a main power circuit LLC / SRC bidirectional converter and a partial power circuit phase-shifted full-bridge / push-pull bidirectional converter. The main power circuit LLC / SRC bidirectional converter is composed of the primary circuit of high-frequency transformer T1, high-frequency transformer T1, and the secondary circuit of high-frequency transformer T1. The partial power circuit phase-shifted full-bridge / push-pull bidirectional converter is composed of the primary circuit of high-frequency transformer T2, high-frequency transformer T2, and the secondary circuit of high-frequency transformer T2. High-frequency transformers T1 and T2... The three bridge arms on the primary side are the first bridge arm, the second bridge arm, and the third bridge arm. The second and third bridge arms form the high-frequency transformer T1 primary-side H-bridge circuit of the main power circuit LLC / SRC bidirectional converter. The first and third bridge arms form the high-frequency transformer T2 primary-side H-bridge circuit of the phase-shifted full-bridge / push-pull bidirectional converter. The main power circuit LLC / SRC bidirectional converter and the phase-shifted full-bridge / push-pull bidirectional converter reuse the third bridge arm. The main power circuit LLC / SRC bidirectional converter and the phase-shifted full-bridge / push-pull bidirectional converter are connected in series for output / input on the V2 side.

2. The bidirectional combined wide-gain DC-DC converter with bridge arm multiplexing according to claim 1, characterized in that, The primary circuit of the main power circuit LLC / SRC bidirectional converter includes a DC voltage source V1, a DC-side capacitor C1, a primary H-bridge circuit of a high-frequency transformer T1, a resonant network, and a primary winding N of the high-frequency transformer T1. p1 The primary-side H-bridge circuit of the high-frequency transformer T1 consists of a second bridge arm and a third bridge arm, which are respectively composed of power transistors S3 and S4, and power transistors S5 and S6; the resonant network consists of a magnetizing inductor L. m Resonant inductor L r and resonant capacitor C r Composition; High-frequency transformer T1 primary winding N p1 The same name of the magnetizing inductor L m The upper end and the resonant inductor L r Right end, primary winding N p1 The excitation inductor L with different names is connected to the excitation inductor. m The lower end, the source of power transistor S5 and the drain of power transistor S6, and the resonant inductor L r The left end is connected to the resonant capacitor C. r On the right end, resonant capacitor C r The left end is connected to the source of power transistor S3 and the drain of power transistor S4. The drains of power transistors S3 and S5 are connected to the positive terminals of DC voltage source V1 and DC-side capacitor C1. The sources of power transistors S4 and S6 are connected to the negative terminals of DC voltage source V1 and DC-side capacitor C1.

3. The bidirectional combined wide-gain DC-DC converter with bridge arm multiplexing according to claim 1, characterized in that, The main power circuit LLC / SRC bidirectional converter secondary circuit includes the secondary winding N of the high-frequency transformer T1. s1 Secondary winding N s2 The high-frequency transformer T1 consists of a secondary full-wave rectifier circuit, a DC-side capacitor C2, and a DC voltage source V2; the secondary full-wave rectifier circuit of the high-frequency transformer T1 is composed of power transistors S7 and S8; the secondary winding N of the high-frequency transformer T1... s1 The same terminal is connected to the source of power transistor S7. The drain of power transistor S7 is connected to the drain of power transistor S8, the DC voltage source V2, and the positive terminal of DC-side capacitor C2. The negative terminal of DC-side capacitor C2 is connected to the secondary winding N of high-frequency transformer T1. s1 The opposite terminal and secondary winding N s2 The same terminal, secondary winding N s2 The source of the power transistor S8 is connected to the terminal of the transistor with the opposite name.

4. A bidirectional combined wide-gain DC-DC converter with bridge arm multiplexing according to claim 1, characterized in that, The primary circuit of the phase-shifted full-bridge / push-pull bidirectional converter in the power circuit section includes a DC voltage source V1, a DC-side capacitor C1, a high-frequency transformer T2, a primary H-bridge circuit, and an equivalent leakage inductance L of the high-frequency transformer T2. S and the primary winding N of high-frequency transformer T1 p1 The primary-side H-bridge circuit of the high-frequency transformer T2 consists of a first bridge arm and a third bridge arm, wherein the first bridge arm and the third bridge arm are respectively composed of power transistors S1 and S2, and power transistors S5 and S6; the primary winding N of the high-frequency transformer T2 p2 The equivalent leakage inductance L of the high-frequency transformer T2 connected to the opposite name S On the right end, the equivalent leakage inductance L of the high-frequency transformer T2 S The left end of the power transistor S1 source and power transistor S2 drain are connected. The drain of power transistor S1 is connected to the drain of power transistor S3, the drain of power transistor S5, the DC-side capacitor C1, and the positive terminal of the DC voltage source V1. The primary winding N of the high-frequency transformer T2 is connected to the power transistor S3 source and power transistor S2 drain. p2 The corresponding terminals are connected to the source of power transistor S5, the drain of power transistor S6, and the magnetizing inductor L. m The lower end and the primary winding N of the high-frequency transformer T1 p1 The opposite terminal of the power transistor S6 is connected to the drain of the power transistor S2, the drain of the power transistor S4, the DC side capacitor C1, and the negative terminal of the DC voltage source V1.

5. A bidirectional combined wide-gain DC-DC converter with bridge arm multiplexing according to claim 1, characterized in that, The secondary circuit of the phase-shifted full-bridge / push-pull bidirectional converter includes a high-frequency transformer T2 secondary full-wave rectifier circuit, an input inductor L, a DC-side capacitor C3, and a DC voltage source V2; the high-frequency transformer T2 secondary full-wave rectifier circuit consists of power transistor S9 and power transistor S... 10 Composition; secondary winding N of high-frequency transformer T2 s3 The same terminal is connected to the source of power transistor S9, and the drain of power transistor S9 is connected to the source of power transistor S9. 10 The drain and positive terminal of DC-side capacitor C3 are connected to the negative terminal of DC voltage source V2 and the right end of input inductor L. The left end of input inductor L is connected to the secondary winding N of high-frequency transformer T2. s3 The opposite terminal and secondary winding N s4 The same terminal, secondary winding N s4 Equivalent power transistor S 10 Source.

6. A bidirectional combined wide-gain DC-DC converter with bridge arm multiplexing according to claim 1, characterized in that, In the main power circuit LLC / SRC bidirectional converter, power transistors S3, S6, and S7 have a duty cycle of 0.5 and use the same drive signal; power transistors S4, S5, and S8 have a duty cycle of 0.5 and use the same drive signal. Power transistors S3 and S4 are complementary in conduction; power transistors S5 and S6 are complementary in conduction; and power transistors S7 and S8 are complementary in conduction. In the partial power circuit phase-shifted full-bridge / push-pull bidirectional converter, power transistors S1 and S2 have a duty cycle of 0.5; power transistors S9 and S8 have a duty cycle of 0.

5. 10 Duty cycle D a When the value is greater than 0.5, power transistors S1 and S2 are complementary conductions, while power transistors S9 and S2 are complementary conductions. 10 The phase shift angles of the drive signals differ by 180 degrees, and the drive signals of power transistors S1 and S6 have a phase shift angle D. b .

7. A bidirectional combined wide-gain DC-DC converter with bridge arm multiplexing according to claim 1, characterized in that, The two operating modes of the bidirectional combined DC-DC converter with bridge arm multiplexing are forward buck mode and reverse boost mode. The main power circuit of the forward buck mode is an LLC converter, the main power circuit of the reverse boost mode is an SRC converter, part of the power circuit of the forward buck mode is a phase-shifted full-bridge converter, and part of the power circuit of the reverse boost mode is a push-pull converter. In the forward buck mode, power is transferred from V1 to V2. The main power circuit LLC converter operates as a DC-DC converter at a fixed frequency and duty cycle, bearing the main power. The partial power circuit phase-shifting full-bridge converter adjusts the total gain M1 through the phase shift angles of the first and third arms of the primary side of the high-frequency transformer T2; the total gain M1 is the gain M of the main power circuit LLC converter. LLC The gain M of the phase-shifted full-bridge converter in the partial power circuit PSFB The result of superposition is: Where, N p1 For the primary winding of high-frequency transformer T1, N s1 For the secondary winding of high-frequency transformer T1, N p2 For the primary winding of high-frequency transformer T2, N s3 For the secondary winding of high-frequency transformer T2, D b The inner phase shift angles of the first and third bridge arms of the phase-shifted full-bridge converter for partial power circuits; In the reverse boost mode, power is transferred from V2 to V1. The main power circuit SRC converter operates as a DC-DC converter at a fixed frequency and duty cycle, bearing the majority of the power. The partial power circuit push-pull converter adjusts the total gain M2 through PWM plus phase-shift control; the total gain M2 is the gain M of the main power circuit SRC converter. SRC The gain M of the phase-shifted full-bridge converter in the partial power circuit CFPP The result of superposition is: Among them, L S The equivalent leakage inductance of high-frequency transformer T2 is given by D, where L is the input inductance and D is the equivalent leakage inductance of high-frequency transformer T2. a For the power transistors S9 and S in the push-pull converter of the partial power circuit 10 Duty cycle.

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