Half-bridge three-level bidirectional LLC power module and control method and device thereof

Abstract

The invention belongs to the technical field of power electronics, and particularly relates to a half-bridge three-level bidirectional LLC power module and a control method and device thereof. The method comprises the following steps: controlling the driving signals of a switch tube S1 and an upper switch tube S5 of a leading arm of a full-bridge converter at the low-voltage side of a power module to be the same, and controlling the driving signals of a switch tube S2 and a lower switch tube S8 of a lagging arm of the full-bridge converter to be the same, driving signals of the control switch tube S3 and an upper switch tube S7 of a lagging arm of the full-bridge converter are the same, and driving signals of the control switch tube S4 and an upper switch tube S6 of a leading arm of the full-bridge converter are the same; driving signals of the switch tube S1 and the switch tube S4 are controlled to be complementary, and driving signals of the switch tube S2 and the switch tube S3 are controlled to be complementary; the driving signal of the switch tube S2 lags behind the driving signal of the switch tube S1 by a fixed phase angle. The technical problem of high cost caused by the fact that a control method in the prior art needs to calculate a phase shift angle in real time is solved.

Description

Technical Field

[0001] This invention belongs to the field of power electronics technology, specifically relating to a half-bridge three-level bidirectional LLC power module and its control method and device. Background Technology

[0002] With the rapid development of power electronics technology, especially driven by the demands for high efficiency, high power density, and energy conservation and environmental protection, DC / DC converters are playing an increasingly important role in power systems. Traditional two-level topologies have many limitations when dealing with high-voltage, high-current applications. Compared to two-level topologies, MOSFETs must be selected with higher voltage ratings, and these MOSFETs are not only rare in the market but also expensive, greatly limiting the product's economic viability and market competitiveness.

[0003] A Chinese invention patent application with publication number CN112187054A and publication date of January 5, 2021, discloses a DC transformer. This DC transformer consists of several DC / DC converters connected in series on the high-voltage side and in parallel on the low-voltage side. The high-voltage side of the DC / DC converter includes a front-stage Buck-boost circuit and a rear-stage half-bridge three-level topology. The low-voltage side adopts an H-bridge topology. The intermediate stages employ a high-frequency isolation transformer and an electrically symmetrical bidirectional CLLLC structure design to ensure bidirectional energy flow. The half-bridge three-level topology on the high-voltage side, under the same device voltage withstand conditions, achieves a sub-module input voltage that is twice the conventional voltage, reducing the number of sub-modules by half, thereby significantly reducing the size and cost of the DC transformer.

[0004] Chinese invention patent application CN111697837A, published on September 22, 2020, discloses a DC transformer control method based on a three-level CLLLC resonant converter. This control method mainly targets the LLC circuit topology excluding the front-stage Buck-boost circuit. In this method, the control method for a single power module is as follows: the drive signals of switches S1 and S4 are complementary; the drive signals of S2 and S3 are complementary; S2 lags S1 by a phase shift angle; S5 and S8 are the same and complementary to S6 and S7; S6 and S7 are the same; the rising edge of S5 coincides with the rising edge of S1; and the falling edge of S5 coincides with the falling edge of S2. This control method uses closed-loop phase-shift control to control a single power module. In each control cycle, the phase shift angle needs to be calculated in real time and fed back to the controller. This results in a complex and costly controller; furthermore, feedback loop oscillations may lead to instability. Summary of the Invention

[0005] The purpose of this invention is to provide a half-bridge three-level bidirectional LLC power module and its control method and device, so as to solve the technical problem that the control method in the prior art needs to calculate the phase shift angle in real time, resulting in high cost.

[0006] To solve the above technical problems, the present invention provides a control method for a half-bridge three-level bidirectional LLC power module. The method includes: controlling the drive signal of switch S1 to be the same as the drive signal of the upper switch S5 of the leading arm of the full-bridge converter on the low-voltage side of the power module; controlling the drive signal of switch S2 to be the same as the drive signal of the lower switch S8 of the lagging arm of the full-bridge converter; controlling the drive signal of switch S3 to be the same as the drive signal of the upper switch S7 of the lagging arm of the full-bridge converter; controlling the drive signal of switch S4 to be the same as the drive signal of the upper switch S6 of the leading arm of the full-bridge converter; controlling the drive signals of switch S1 and switch S4 to be complementary; controlling the drive signals of switch S2 and switch S3 to be complementary; and controlling the drive signal of switch S2 to lag behind the drive signal of switch S1 by a fixed phase angle.

[0007] The switching transistors S1, S2, S3, and S4 are four switching transistors connected in series from positive to negative on the bridge arm of the half-bridge three-level converter on the high-voltage side of the power module.

[0008] The beneficial effects of the above technical solution are as follows: The technical solution of the control method for a half-bridge three-level bidirectional LLC power module of the present invention belongs to an improved invention. Unlike the closed-loop phase-shift control method in the prior art, which requires calculation of the phase-shift angle, the control method of the present invention directly causes the switching transistor S2 to lag behind the driving signal of the switching transistor S1 by a fixed phase angle. This invention simplifies the control logic, eliminates the need for real-time phase shift angle calculation, and reduces controller costs, making it particularly suitable for low-cost, single-module scenarios (such as charger modules, charging piles, DC power supplies, etc.). This invention solves the technical problem of high costs caused by the need for real-time phase shift angle calculation in existing control methods.

[0009] Furthermore, when energy flows from the high-voltage side to the low-voltage side of the power module, the control method for the power module includes:

[0010] 1) Control switch S2 to turn on at time t0; time t0 is the moment when the junction capacitance C1 of switch S1 has finished discharging;

[0011] 2) Control switch S1 to turn off at time t3; time t3 is the input voltage V of the resonant cavity. AB The moment when the voltage begins to drop from high level;

[0012] 3) Control switch S4 to turn on at time t4; time t4 is the input voltage V of the resonant cavity.AB The moment when the value drops to 0;

[0013] 4) Control switch S2 to turn off at time t5; time t5 is the input voltage V of the resonant cavity. AB The moment when the value stops at 0;

[0014] 5) Control switch S3 to turn on at time t6; time t6 is the time when the junction capacitance C4 of switch S4 has finished discharging;

[0015] 6) Control switch S4 to turn off at time t9; time t9 is the input voltage V of the resonant cavity. AB The moment when the rise begins;

[0016] 7) Control switch S1 at t 10 Available at all times; t 10 The input voltage V of the resonant cavity at time t is AB The moment it rises to the point where it starts at 0.

[0017] Furthermore, the complementary drive signal is a complementary drive signal with a dead zone.

[0018] Furthermore, the fixed phase angle is determined based on the circuit dead time to avoid short circuits.

[0019] The present invention also provides a technical solution for a control device for a half-bridge three-level bidirectional LLC power module: a control device for a half-bridge three-level bidirectional LLC power module, comprising a processor, wherein the processor is used to execute a computer program to implement the steps of the control method for the half-bridge three-level bidirectional LLC power module as described below;

[0020] The control method of the half-bridge three-level bidirectional LLC power module includes: the drive signal of the control switch S1 is the same as that of the upper switch S5 of the leading arm of the full-bridge converter on the low-voltage side of the power module; the drive signal of the control switch S2 is the same as that of the lower switch S8 of the lagging arm of the full-bridge converter; the drive signal of the control switch S3 is the same as that of the upper switch S7 of the lagging arm of the full-bridge converter; and the drive signal of the control switch S4 is the same as that of the upper switch S6 of the leading arm of the full-bridge converter. The drive signals of the control switches S1 and S4 are complementary, and the drive signals of the control switches S2 and S3 are complementary. The drive signal of the control switch S2 lags behind the drive signal of the control switch S1 by a fixed phase angle.

[0021] The switching transistors S1, S2, S3, and S4 are four switching transistors connected in series from positive to negative on the bridge arm of the half-bridge three-level converter on the high-voltage side of the power module.

[0022] The beneficial effects of the above technical solution are as follows: The technical solution of the control device for a half-bridge three-level bidirectional LLC power module of the present invention belongs to an improved invention. Unlike the closed-loop phase-shift control method in the prior art, which requires calculation of the phase-shift angle, the control method of the present invention directly causes the switching transistor S2 to lag behind the driving signal of the switching transistor S1 by a fixed phase angle. This invention simplifies the control logic, eliminates the need for real-time phase shift angle calculation, and reduces controller costs, making it particularly suitable for low-cost, single-module scenarios (such as charger modules, charging piles, DC power supplies, etc.). This invention solves the technical problem of high costs caused by the need for real-time phase shift angle calculation in existing control methods.

[0023] Furthermore, when energy flows from the high-voltage side to the low-voltage side of the power module, the control method for the power module includes:

[0024] 1) Control switch S2 to turn on at time t0; time t0 is the moment when the junction capacitance C1 of switch S1 has finished discharging;

[0025] 2) Control switch S1 to turn off at time t3; time t3 is the input voltage V of the resonant cavity. AB The moment when the voltage begins to drop from high level;

[0026] 3) Control switch S4 to turn on at time t4; time t4 is the input voltage V of the resonant cavity. AB The moment when the value drops to 0;

[0027] 4) Control switch S2 to turn off at time t5; time t5 is the input voltage V of the resonant cavity. AB The moment when the value stops at 0;

[0028] 5) Control switch S3 to turn on at time t6; time t6 is the time when the junction capacitance C4 of switch S4 has finished discharging;

[0029] 6) Control switch S4 to turn off at time t9; time t9 is the input voltage V of the resonant cavity. AB The moment when the rise begins;

[0030] 7) Control switch S1 at t 10 Available at all times; t 10 The input voltage V of the resonant cavity at time t is AB The moment it rises to the point where it starts at 0.

[0031] Furthermore, the complementary drive signal is a complementary drive signal with a dead zone.

[0032] Furthermore, the fixed phase angle is determined based on the circuit dead time to avoid short circuits.

[0033] The present invention also provides a technical solution for a half-bridge three-level bidirectional LLC power module: a half-bridge three-level bidirectional LLC power module, including a controller, the controller including a processor, characterized in that the processor is used to execute a computer program to implement the steps of the control method of the half-bridge three-level bidirectional LLC power module as described above. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the power module topology in the embodiment of the half-bridge three-level bidirectional LLC power module of the present invention;

[0035] Figure 2 This is a waveform diagram of the power module operation in the embodiment of the half-bridge three-level bidirectional LLC power module of the present invention. Detailed Implementation

[0036] Unlike existing closed-loop phase-shift control methods that require calculating the phase-shift angle, the control method of this invention directly causes the switching transistor S2 to lag behind the driving signal of the switching transistor S1 by a fixed phase angle. This invention simplifies the control logic, eliminates the need for real-time phase shift angle calculation, and reduces controller costs, making it particularly suitable for low-cost, single-module scenarios (such as charger modules, charging piles, DC power supplies, etc.). This invention solves the technical problem of high costs caused by the need for real-time phase shift angle calculation in existing control methods.

[0037] Implementation method of half-bridge three-level bidirectional LLC power module:

[0038] A half-bridge three-level bidirectional LLC power module, the circuit topology of which is as follows: Figure 1 As shown, the circuit includes a front-end BUCK-BOOST circuit and a rear-end LLC circuit, employing a high-frequency transformer for electrical isolation and voltage transformation. The half-bridge three-level LLC circuit not only reduces the voltage stress on the switching transistors to half its original value, but also achieves ZVS (zero-voltage turn-on) for the main switching transistor and ZCS (zero-current turn-off) for the rectifier switching transistors within the coil voltage range. This reduces the overall stress on the switching transistors, improving their lifespan; simultaneously, it also reduces switching losses, increasing overall efficiency.

[0039] like Figure 1As shown, the front-end buck-boost circuit includes a three-level buck-boost topology composed of switching transistors SZ1 to SZ4, which are connected in series. Capacitor CBB1 and inductors LBB1 and LBB2 of the boost circuit are connected in parallel across SZ2 and SZ3, with an operating voltage of Vin / 2. A bypass switch PL1 is also connected in parallel across SZ2 and SZ3. Buck output capacitor Cd1 is connected in parallel across SZ1 and SZ2 of the upper bridge arm, and buck output capacitor Cd2 is connected in parallel across SZ3 and SZ4 of the lower bridge arm. The connection point of Cd1 and Cd2 is connected to the connection between SZ2 and SZ3, and also to the primary input terminal of the transformer in the LLC circuit.

[0040] like Figure 1 As shown, the subsequent LLC circuit includes a high-voltage side circuit, a transformer, and a low-voltage side circuit connected in sequence. The high-voltage side circuit includes a half-bridge three-level converter, which consists of switches S1, S2, S3, and S4 connected in series. Switches S2 and S3 are connected in parallel with a flying capacitor Css and a clamping diode unit. The clamping diode unit consists of two non-inverting diodes Dd1 and Dd2 connected in series.

[0041] The primary and secondary sides of the transformer are respectively equipped with LC resonant networks. Lr1 and Cr1 form the LC resonant network of the primary side of the transformer, and Lr2 and Cr2 form the LC resonant network of the secondary side of the transformer. Lm is the magnetizing inductance of the transformer.

[0042] The low-voltage side circuit includes a full-bridge converter, which includes switching transistors S5, S6, S7, and S8, and a low-voltage side bus capacitor Co. Switches S5 and S6, and S7 and S8 are connected in series and then in parallel, and are also connected in parallel with the low-voltage side bus capacitor Co.

[0043] One input terminal of the primary side of the transformer is connected to the connection point between switching transistors S2 and S3, and the other input terminal of the primary side is connected to the connection point between non-inverting diodes Dd1 and Dd2, and also connected to the connection point between Cd1 and Cd2 of the preceding buck-boost circuit; one input terminal of the secondary side of the transformer is connected to the connection point between switching transistors S5 and S6, and the other input terminal of the secondary side is connected to the connection point between switching transistors S7 and S8.

[0044] The power module also includes a control device for controlling the switching transistors in the power module. The control device includes a processor that executes a computer program to implement the steps of a control method for a half-bridge three-level bidirectional LLC power module.

[0045] The control method of the half-bridge three-level bidirectional LLC power module includes: during normal operation, S1 and S5 are the same drive signal, S2 and S8 are the same drive signal, S3 and S7 are the same drive signal, and S4 and S6 are the same drive signal; S1 and S4 are complementary drive signals (with dead time), S2 and S3 are complementary drive signals (with dead time), and S2 lags behind S1 by one phase. (i.e., fixed phase angle). The direction of energy flow is determined by the external circuit, and the module operates in an open-loop fixed-frequency mode. The fixed phase angle is a fixed phase angle that meets the dead time requirements of the circuit and can avoid short circuits.

[0046] When energy flows from the high-voltage side to the low-voltage side of the circuit, its control principle is as follows: Figure 2 As shown, i S For the low-voltage side resonant current, i LC For the low-voltage side excitation current, i S5 i S6 i S7 i S8 The currents flowing through the corresponding IGBTs (S5, S6, S7, S8) on the low-voltage side are as follows:

[0047] [t0~t1]: At time t0, S2 is turned on, and S1 leads S2 by a fixed phase angle. The junction capacitance of S1 has completely discharged at time t0. Before it turns on, because the primary current freewheels through the body diodes of S1 and S2, S1 and S2 turn on with zero voltage. The input voltage V of the resonant cavity... AB When the voltage is high, the resonant current i through Lr1 and Cr1... p With a near-sinusoidal rate of change gradually increasing, i Lm As i increases linearly, p with i Lm The difference is transmitted to the secondary side through the high-frequency isolation transformer; at this time, the voltage across Lm is clamped by the output voltage and does not participate in the resonance of Lr1 and Cr1.

[0048] [t1~t2]: At time t1, i p Start in reverse, i p The rate of change continues to gradually increase at a near-sinusoidal rate, i Lm It continues to increase linearly until time t2.

[0049] [t2~t3]: At time t2, the resonant current i p and excitation current i Lm When the inductance is equal to that of Lr1, the current is no longer transmitted to the secondary side through the high-frequency isolation transformer. Lm is not clamped by the secondary side voltage and participates in the resonance of Lr1 and Cr1. Since the inductance of Lm is much greater than that of Lr1, its resonance period is much greater than that of Lr1 and Cr1. At this time, the resonant current can be considered to be approximately constant.

[0050] [t3~t4]: At time t3, S1 is turned off, i p C1 is charged, and C4 is discharged through Css. After the junction capacitance is charged and discharged, the voltage across S4 is clamped by the diode, creating conditions for zero-voltage turn-on of S4.

[0051] [t4~t5]: During this stage, the resonant current circulates through Lr1, Cr1, D5, and S2, and the input voltage of the resonant cavity is 0. p Approximately unchanged.

[0052] [t5~t6]: At time t5, S2 is turned off, i p C2 is charged, and C3 is discharged through Css. After the junction capacitance is charged and discharged, the voltage across S3 is clamped by the diode, creating conditions for zero-voltage turn-on of S3.

[0053] [t6~t7]: At time t6, S3 is activated, i p Since the body diodes S3 and S4 provide freewheeling, S3 and S4 are turned on at zero voltage. The input voltage VAB of the resonant cavity is low, and the resonant current i flows through Lr1 and Cr1. p With a near-sinusoidal rate of change gradually decreasing, i Lm As i increases linearly, p with i Lm The difference is transmitted to the secondary side through the high-frequency isolation transformer; at this time, the voltage across Lm is clamped by the output voltage and does not participate in the resonance of Lr1 and Cr1.

[0054] [t7~t8]: At time t7, i p Start in reverse, i p The rate of change continues to gradually decrease at a near-sinusoidal rate, i Lm It continues to decrease linearly until time t8.

[0055] [t8~t9]: At time t8, the resonant current i p and excitation current i Lm When the inductance is equal to that of Lr1, the current is no longer transmitted to the secondary side through the high-frequency isolation transformer. Lm is not clamped by the secondary side voltage and participates in the resonance of Lr1 and Cr1. Since the inductance of Lm is much greater than that of Lr1, its resonance period is much greater than that of Lr1 and Cr1. At this time, the resonant current can be considered to be approximately constant.

[0056] [t9~t 10 At time t9, S4 is turned off, i p C4 is charged, and C1 is discharged through Css. After the junction capacitance is charged and discharged, the voltage across S1 is clamped by the diode, creating conditions for zero-voltage turn-on of S1.

[0057] [t10 ~t 11 During this stage, the resonant current circulates through Lr1, Cr1, D6, and S3, and the input voltage of the resonant cavity is 0. p Approximately unchanged.

[0058] [t 11 ~t 12 ]:t 11 At that moment, S3 is turned off, i p C3 is charged, and C2 is discharged through Css. After the junction capacitance is charged and discharged, the voltage across S2 is clamped by the diode, creating conditions for zero-voltage turn-on of S2.

[0059] Implementation method of control method for half-bridge three-level bidirectional LLC power module:

[0060] A control method for a half-bridge three-level bidirectional LLC power module includes: controlling the drive signal of switch S1 to be the same as that of the upper switch S5 of the leading arm of the full-bridge converter on the low-voltage side of the power module; controlling the drive signal of switch S2 to be the same as that of the lower switch S8 of the lagging arm of the full-bridge converter; controlling the drive signal of switch S3 to be the same as that of the upper switch S7 of the lagging arm of the full-bridge converter; and controlling the drive signal of switch S4 to be the same as that of the upper switch S6 of the leading arm of the full-bridge converter. The drive signals of switches S1 and S4 are complementary, and the drive signals of switches S2 and S3 are complementary. The drive signal of switch S2 lags behind the drive signal of switch S1 by a fixed phase angle. Switches S1, S2, S3, and S4 are four switches connected in series from positive to negative on the bridge arm of the half-bridge three-level converter on the high-voltage side of the power module. The specific control method of the half-bridge three-level bidirectional LLC power module has been described in sufficient detail in the above implementation of the half-bridge three-level bidirectional LLC power module, and will not be repeated here.

[0061] Implementation method of control device for half-bridge three-level bidirectional LLC power module:

[0062] A control device for a half-bridge three-level bidirectional LLC power module includes a processor for executing a computer program to implement the steps of the control method for the half-bridge three-level bidirectional LLC power module as described above. The specific control method for the half-bridge three-level bidirectional LLC power module has been described in sufficient detail in the above embodiments and will not be repeated here.

[0063] Specifically, a processor can be a CPU, or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor can be a microprocessor or any conventional processor. A processor can also be a processor that supports the Advanced Reduced Instruction Set Machine (ARM) architecture.

[0064] This invention has the following characteristics:

[0065] This invention simplifies the control logic (fixed phase). This invention sacrifices some performance in exchange for reduced costs and improved reliability, meeting the requirements of industrial-grade single modules. It also boasts advantages such as no debugging required and strong anti-interference capabilities.

[0066] (1) Simplified drive design: fixed phase relationship (S2 lags S1 fixed) No need to calculate the phase shift angle in real time, reducing the complexity of the controller.

[0067] (2) Cost optimization: Open-loop fixed frequency eliminates the need for current / voltage sampling circuits, saving on sensor and ADC costs.

[0068] (3) Improved reliability: No closed-loop control algorithm, avoiding stability risks caused by feedback loop oscillation.

[0069] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still make modifications to the technical solutions described in the foregoing embodiments without creative effort, or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A control method for a half-bridge three-level bidirectional LLC power module, characterized in that, The method includes: controlling switch S1 to have the same drive signal as the upper switch S5 of the leading arm of the full-bridge converter on the low-voltage side of the power module; controlling switch S2 to have the same drive signal as the lower switch S8 of the lagging arm of the full-bridge converter; controlling switch S3 to have the same drive signal as the upper switch S7 of the lagging arm of the full-bridge converter; and controlling switch S4 to have the same drive signal as the upper switch S6 of the leading arm of the full-bridge converter. The drive signals of switch S1 and switch S4 are complementary, and the drive signals of switch S2 and switch S3 are complementary. The drive signal of switch S2 lags behind the drive signal of switch S1 by a fixed phase angle. The switching transistors S1, S2, S3, and S4 are four switching transistors connected in series from positive to negative on the bridge arm of the half-bridge three-level converter on the high-voltage side of the power module.

2. The control method for the half-bridge three-level bidirectional LLC power module according to claim 1, characterized in that, When energy flows from the high-voltage side to the low-voltage side of the power module, the control method of the power module includes: 1) Control switch S2 to turn on at time t0; time t0 is the time when the junction capacitance C1 of switch S1 has finished discharging; 2) Control switch S1 to turn off at time t3; time t3 is the input voltage V of the resonant cavity. AB The moment when the voltage begins to drop from high level; 3) Control switch S4 to turn on at time t4; time t4 is the input voltage V of the resonant cavity. AB The moment when it drops back to its initial value of 0; 4) Control switch S2 to turn off at time t5; time t5 is the input voltage V of the resonant cavity. AB The moment when the value stops at 0; 5) Control switch S3 to turn on at time t6; time t6 is the time when the junction capacitance C4 of switch S4 has finished discharging; 6) Control switch S4 to turn off at time t9; time t9 is the input voltage V of the resonant cavity. AB The moment when the rise begins; 7) Control switch S1 at t 10 Available at all times; t 10 The input voltage V of the resonant cavity at time t is AB The moment it rises to the point where it starts at 0.

3. The control method for the half-bridge three-level bidirectional LLC power module according to claim 1, characterized in that, The complementary drive signal is a complementary drive signal with a dead zone.

4. The control method for the half-bridge three-level bidirectional LLC power module according to any one of claims 1 to 3, characterized in that, The fixed phase angle is determined based on the circuit dead time to avoid short circuits.

5. A control device for a half-bridge three-level bidirectional LLC power module, comprising a processor, characterized in that, The processor is used to execute a computer program to implement the steps of the control method for the half-bridge three-level bidirectional LLC power module as described below. The control method of the half-bridge three-level bidirectional LLC power module includes: the drive signal of the control switch S1 is the same as that of the upper switch S5 of the leading arm of the full-bridge converter on the low-voltage side of the power module; the drive signal of the control switch S2 is the same as that of the lower switch S8 of the lagging arm of the full-bridge converter; the drive signal of the control switch S3 is the same as that of the upper switch S7 of the lagging arm of the full-bridge converter; and the drive signal of the control switch S4 is the same as that of the upper switch S6 of the leading arm of the full-bridge converter. The drive signals of the control switches S1 and S4 are complementary, and the drive signals of the control switches S2 and S3 are complementary. The drive signal of the control switch S2 lags behind the drive signal of the control switch S1 by a fixed phase angle. The switching transistors S1, S2, S3, and S4 are four switching transistors connected in series from positive to negative on the bridge arm of the half-bridge three-level converter on the high-voltage side of the power module.

6. The control device for the half-bridge three-level bidirectional LLC power module according to claim 1, characterized in that, When energy flows from the high-voltage side to the low-voltage side of the power module, the control method of the power module includes: 1) Control switch S2 to turn on at time t0; time t0 is the time when the junction capacitance C1 of switch S1 has finished discharging; 2) Control switch S1 to turn off at time t3; time t3 is the input voltage V of the resonant cavity. AB The moment when the voltage begins to fall from a high level; 3) Control switch S4 to turn on at time t4; time t4 is the input voltage V of the resonant cavity. AB The moment when it drops back to its initial value of 0; 4) Control switch S2 to turn off at time t5; time t5 is the input voltage V of the resonant cavity. AB The moment when the value stops at 0; 5) Control switch S3 to turn on at time t6; time t6 is the time when the junction capacitance C4 of switch S4 has finished discharging; 6) Control switch S4 to turn off at time t9; time t9 is the input voltage V of the resonant cavity. AB The moment when the rise begins; 7) Control switch S1 at t 10 Available at all times; t 10 The input voltage V of the resonant cavity at time t is AB The moment it rises to the point where it starts at 0.

7. The control device for the half-bridge three-level bidirectional LLC power module according to claim 1, characterized in that, The complementary drive signal is a complementary drive signal with a dead zone.

8. The control device for the half-bridge three-level bidirectional LLC power module according to any one of claims 1 to 3, characterized in that, The fixed phase angle is determined based on the circuit dead time to avoid short circuits.

9. A half-bridge three-level bidirectional LLC power module, comprising a controller, the controller including a processor, characterized in that, The processor is used to execute a computer program to implement the steps of the control method for the half-bridge three-level bidirectional LLC power module as described in any one of claims 1 to 4.

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