High-voltage redundant power conversion circuit based on multi-stage driving and control method

Abstract

The application discloses a high-voltage redundant power conversion circuit based on multi-stage driving and a control method, which comprises an input module, a main power conversion module, an output module, a driving isolation module, an auxiliary power supply, a DSP control module and a signal sampling feedback module, the input module is used for connecting a battery pack, the main power conversion module realizes wide-range voltage rise and fall, electrical isolation and power transmission, the output module is used for connecting a load and providing stable high-voltage direct-current output, and the four MOS tube staggered parallel topology and magnetic integrated coupling fault tolerance are combined to improve the efficiency and power density. The high-voltage redundant power conversion circuit based on multi-stage driving has DC-DC voltage regulation functions in a wide voltage range, and the application range is improved.

Description

Technical Field

[0001] This invention relates to the field of DC / DC power conversion technology, and in particular to a high-voltage redundant power conversion circuit and control method based on multi-stage drive. Background Technology

[0002] Currently, battery packs in industries such as new energy and energy storage are getting larger and larger, resulting in higher and higher voltages for charging (maintenance) equipment, such as 400V, 800V, and 1000V. In addition, for large battery packs with different voltage specifications, charging (maintenance) equipment needs to be equipped with DC / DC rectifier modules with different voltage specifications. A high-power, wide-voltage-range DC / DC rectifier module can meet the needs of most current industry applications and future development trends.

[0003] Current battery charging and discharging (maintenance) equipment all require the use of DC / DC modules. Due to the large number of product models and the inconsistencies in voltage range or specifications between different models, different brands of DC / DC modules are needed. This leads to certain drawbacks in terms of R&D efficiency and supply chain costs. Therefore, a wide-range, high-power, buck-boost DC / DC module is proposed to meet the needs of the new energy and energy storage industries for wide-range, high-power DC / DC modules in battery maintenance, testing and other fields. Summary of the Invention

[0004] To address the aforementioned issues, a high-voltage redundant power conversion circuit and control method based on multi-level drive are provided, aiming to solve the problems existing in the prior art.

[0005] The specific technical solution is as follows:

[0006] The high-voltage redundant power conversion circuit based on multi-level drive includes an input module, a main power conversion module, an output module, a drive isolation module, an auxiliary power supply, a DSP control module, and a signal sampling feedback module.

[0007] The input module is used to connect to the battery pack;

[0008] The main power conversion module enables wide-range voltage boost / pull-down, electrical isolation, and power transfer.

[0009] The output module is used to connect to the load and provide a stable high-voltage DC output;

[0010] The drive isolation module is used to provide switching control for the MOSFETs in the main power conversion module, thereby achieving electrical isolation between the high-voltage side and the low-voltage control circuit.

[0011] The auxiliary power supply is used to provide low-voltage power to the system;

[0012] The DSP control module is the control center of the entire system, assisting in communication and interaction between modules or with external systems, executing advanced topology control strategies, generating PWM signals, and implementing logic control algorithms.

[0013] The signal sampling feedback module is used to collect the current and voltage signals on the input and output sides in real time, and feed the collected signals back to the DSP control module.

[0014] The aforementioned high-voltage redundant power conversion circuit based on multi-level drive also has the following feature: the main power conversion module includes connector U13, resistors R27, R120, R23, R24, R94, R95, capacitors U14, U20, R96, R97, U49, U50, connector U52, MOSFET U57, resistor R118, MOSFET U10, resistor R25, diode D36, diode D10, MOSFET U58, resistor R119, MOSFET U9, resistor R22, inductor L2, MOSFET U59, resistor R121, MOSFET U23, resistor R33, diode D38, diode D39, capacitor U44, resistor R98, capacitor C15, resistor R100, connector U12, and... Connector U25; connector U13 is electrically connected to the drain of MOSFET U10 through resistor R27; resistor R120 is connected in parallel across resistor R27; the drain of MOSFET U10 is connected to the signal sampling feedback circuit as a negative voltage sampling output terminal through resistor R24; the common terminal of connector U13 and resistor R27 is connected to the signal sampling feedback circuit as a positive voltage sampling output terminal through resistor 23; the gate of MOSFET U10 is electrically connected to its source through resistor R25; the drain of MOSFET U10 is electrically connected to the drain of MOSFET U57; the source of MOSFET U10 is electrically connected to the source of MOSFET U57; the gate of MOSFET U57 is electrically connected to its source through resistor R118.

[0015] The common terminal of the connector U13 and the resistor R27 is also electrically connected to the positive output terminal of the auxiliary power supply. The common terminal of the connector U13 and the resistor R27 is sequentially connected to the source of the MOS transistor U9 through the capacitors U14, U20, U49 and U50. The resistor R94 is connected in parallel across the two ends of the capacitor U14, the resistor R95 is connected in parallel across the two ends of the capacitor U20, the resistor R96 is connected in parallel across the two ends of the capacitor U49, and the resistor R97 is connected in parallel across the two ends of the capacitor U50. The common terminal of the capacitors U20 and U49 is connected as an intermediate terminal to the anode of the diode D36. The cathode of the diode D36 is connected to the source of the MOS transistor U10.

[0016] The source of MOS transistor U9 is electrically connected to the connector U52, the source of MOS transistor U9 is electrically connected to the source of MOS transistor U58, the drain of MOS transistor U9 is electrically connected to the drain of MOS transistor U58, the source of MOS transistor U9 is electrically connected to its gate through resistor R119, the source of MOS transistor U58 is electrically connected to its gate through resistor R22, the drain of MOS transistor U9 is electrically connected to the anode of diode D10, and the cathode of diode D10 is electrically connected to the anode of diode D36.

[0017] The source of MOSFET U10 is electrically connected to the drain of MOSFET U59 through inductor L2. The source of MOSFET U59 is electrically connected to the drain of MOSFET U9. The source of MOSFET U59 is also electrically connected to the source of MOSFET U23. The drain of MOSFET U59 is also electrically connected to the drain of MOSFET U23. The gate of MOSFET U59 is electrically connected to its source through resistor R121. The gate of MOSFET U23 is electrically connected to its source through resistor R33.

[0018] The drain of the MOS transistor U23 is electrically connected to the anode of the diode D38, the anode of the diode D38 is also electrically connected to the anode of the diode D39, the cathode of the diode D38 is electrically connected to the cathode of the diode D39, the cathode of the diode D38 is electrically connected to the connector U12 as the positive output terminal, and the source of the MOS transistor U23 is electrically connected to the connector U25 as the negative output terminal.

[0019] The cathode of the diode D38 is sequentially connected to the source of the MOS transistor U23 through the capacitors U44 and C15. The resistor R98 is connected in parallel across the capacitor U44, and the resistor R100 is connected in parallel across the capacitor C15.

[0020] The aforementioned high-voltage redundant power conversion circuit based on multi-level drive also has the following features: the drive isolation module includes capacitor C64, isolation chip U41, transformer T8, capacitor C63, series diode D26, capacitor C65, resistor R81, diode D27, capacitor C67, and capacitor C66. The ground terminal of isolation chip U41 is electrically connected to the 5V input voltage through capacitor C64. The ground terminal of isolation chip U41 is grounded, and the 5V input voltage is also electrically connected to the input terminal of isolation chip U41. The first isolation terminal of isolation chip U41 is electrically connected to one end of the primary coil of transformer T8, and the second isolation terminal of isolation chip U41 is electrically connected to the other end of the primary coil of transformer T8. The input terminal of isolation chip U41 is also electrically connected to the middle terminal of the primary coil of transformer T8. One end of the secondary coil of transformer T8 is electrically connected to the middle terminal of series diode D26 through capacitor C63. The other end of the secondary coil of transformer T8 is electrically connected to the anode of series diode D26. The cathode of series diode D26 is electrically connected to its anode through capacitor C65. The cathode of series diode D26 is electrically connected to the cathode of diode D27 through resistor R81. The anode of diode D27 is electrically connected to the anode of series diode D26. Capacitor C67 is connected in parallel across resistor R81, and capacitor C66 is connected in parallel across diode D27. The anode and cathode of series diode D26 are used as driving power signals to connect to the driving IC. The common terminal of capacitors C67 and C66 is used as a low-level driving signal output terminal and electrically connected to the gate of the corresponding MOS transistor.

[0021] The aforementioned high-voltage redundant power conversion circuit based on multi-level drive also has the following features: the drive isolation module further includes resistor R82, resistor R80, capacitor C62, driver chip U42, and resistor R83. The power input terminal of driver chip U42 is electrically connected to a 5V power supply. The power input terminal of driver chip U42 is also grounded through capacitor C62. The positive input terminal of driver chip U42 is connected to its negative input terminal sequentially through resistors R80 and R82. The common terminal of resistors R80 and R82 receives a PWM signal. The negative input terminal of driver chip U42 is electrically connected to its ground terminal. The ground terminal of driver chip U42 is grounded. The negative power supply terminal and the positive power supply terminal of driver chip U42 serve as a drive power signal for connecting to the driver IC. The output terminal of driver chip U42 is connected to the gate of the corresponding MOSFET as a high-level drive signal output terminal through resistor R83.

[0022] The aforementioned high-voltage redundant power conversion circuit based on multi-level drive also has the following feature: the signal sampling feedback module includes a current sampling circuit, which includes diode D14, capacitor C34, isolation chip U31, transformer T4, diodes D15 and D16, and capacitor C35. The anode of diode D14 is electrically connected to a 5V power supply, and the cathode of diode D14 is electrically connected to the ground terminal of isolation chip U31 through capacitor C34. The ground terminal of isolation chip U31 is grounded, and the cathode of diode D14 is also electrically connected to the input terminal of isolation chip U31. The first isolation terminal of isolation chip U31 is connected to transformer T4. One end of the primary coil of transformer T4 is electrically connected, the second isolation terminal of the isolation chip U31 is electrically connected to the other end of the primary coil of transformer T4, the input terminal of the isolation chip U31 is electrically connected to the middle terminal of the primary coil of transformer T4, one end of the secondary coil of transformer T4 is electrically connected to the anode of diode D15, the cathode of diode D15 is electrically connected to the cathode of diode D16, the anode of diode D16 is electrically connected to the other end of the secondary coil of transformer T4, the cathode of diode D15 is also electrically connected to the middle terminal of the secondary coil of transformer T4 through capacitor C35, and the cathode of diode D15 serves as the positive power output terminal.

[0023] It also includes capacitor C38, amplifier chip U32, capacitor C36, and capacitor C37. The non-inverting input terminal of amplifier chip U32 is electrically connected to its inverting input terminal through capacitor C38. The non-inverting input terminal of amplifier chip U32 is also electrically connected to the positive output terminal of voltage sampling. The inverting input terminal of amplifier chip U32 is also electrically connected to the negative output terminal of voltage sampling. The first power input terminal of amplifier chip U32 is electrically connected to the cathode of diode D15. The first power input terminal of amplifier chip U32 is electrically connected to the negative output terminal of voltage sampling through capacitor C36. The first ground terminal of amplifier chip U32 is also electrically connected to the negative output terminal of voltage sampling. The second power input terminal of amplifier chip U32 is connected to analog ground through capacitor C37. The two differential output terminals of amplifier chip U32 are connected to the differential processing circuit of the DSP control module.

[0024] The aforementioned high-voltage redundant power conversion circuit based on multi-level drive also has the following feature: the signal sampling feedback module further includes a voltage sampling circuit. This voltage sampling circuit includes diode D33, capacitor C92, isolation chip U55, transformer T10, diodes D34 and D35, and capacitor C93. The anode of diode D33 is electrically connected to a 5V power supply, and the cathode of diode D33 is electrically connected to the ground terminal of isolation chip U55 through capacitor C92. The ground terminal of isolation chip U55 is grounded, and the cathode of diode D33 is also electrically connected to the input terminal of isolation chip U55. The first isolation of isolation chip U55... One end of the isolation chip U55 is electrically connected to one end of the primary coil of the transformer T10. The second isolation end of the isolation chip U55 is electrically connected to the other end of the primary coil of the transformer T10. The input end of the isolation chip U55 is electrically connected to the middle end of the primary coil of the transformer T10. One end of the secondary coil of the transformer T10 is electrically connected to the anode of the diode D34. The cathode of the diode D34 is electrically connected to the cathode of the diode D35. The anode of the diode D35 is electrically connected to the other end of the secondary coil of the transformer T10. The cathode of the diode D34 is also electrically connected to the middle end of the secondary coil of the transformer T10 through the capacitor C93.

[0025] It also includes resistors R107, R104, R111, R106, R110, and R113, capacitors C94 and C88, isolation amplifier U54, and capacitor C89. The positive output terminal of the main power conversion module is sequentially connected to the input terminal of the isolation amplifier U54 through resistors R107, R104, R111, R106, and R110. The input terminal of the isolation amplifier U54 is connected to its ground terminal through capacitor C94. The isolation amplifier U54 is electrically connected to its ground terminal, and to the negative output terminal of the main power conversion module. The first power input terminal of the isolation amplifier U54 is electrically connected to the negative output terminal of the main power conversion module via capacitor C88. The second power input terminal of the isolation amplifier U54 is electrically connected to analog ground via capacitor C89. The two differential output terminals of the isolation amplifier U54 are electrically connected to the DSP control module.

[0026] The high-voltage redundant power supply conversion control method based on multi-stage drive applies the above circuit to perform the following steps, which include:

[0027] S1. Set reference values, preset two key reference target values: reference input current and reference output voltage;

[0028] S2. Synchronously detect input current and output voltage. In each switching cycle, the following two detections are performed synchronously: single-cycle synchronous detection of input current and single-cycle synchronous detection of output voltage.

[0029] S3. Determine if the input current exceeds the limit. Check if the current input current triggers the input current limiting condition. If the input current reaches or exceeds the set current limit value, switch to the input constant current control mode to limit the input current within the allowable range. Prioritize the current and use the reference input current as the reference for input constant current control. If the input current does not exceed the set current limit value, proceed to S4.

[0030] S4. Determine if the output voltage exceeds the limit. Under the premise of safe input current, further detect and determine whether the current output voltage triggers the output voltage limit condition. If the output voltage has reached or exceeded the set upper limit protection value, switch to the output constant voltage control mode and prioritize stabilizing the output voltage within the safe range. If the output voltage has not exceeded the set upper limit protection value, continue to execute the output constant voltage control mode and adjust according to the output voltage reference, with the output voltage as the main control target.

[0031] S5. Select control mode. Based on the above judgment logic, select and switch to the corresponding control mode.

[0032] S6. PID calculates PWM duty cycle. After selecting the control mode, the system enters the closed-loop regulation loop. The difference between the reference input current or reference output voltage and the sampled input current or output voltage is compared. The difference is input to the PID controller to calculate the required PWM duty cycle D.

[0033] S7. PWM output drives the switching transistor. When the PWM duty cycle D is between 0 and 1.0, the buck switching transistor works and the boost switching transistor is off, and the module is in buck mode. When the PWM duty cycle D is between 1.0 and 2.0, the buck switching transistor is on and the boost switching transistor works, and the module is in boost mode.

[0034] S8. Execute in a loop. The above process constitutes one cycle. Through high-frequency closed-loop adjustment, precise and stable control of input current and output voltage is achieved.

[0035] The aforementioned high-voltage redundant power conversion control circuit based on multi-level drive also has the following characteristics: the control modes in step S6 include input constant current control mode and output constant voltage control mode. When the input current exceeds the limit, it enters the input constant current control mode to prioritize limiting the input current. When the output voltage exceeds the limit, it enters the constant voltage control mode to prioritize stabilizing the output voltage and prevent overvoltage. When the input current and output voltage are normal, it enters the output constant voltage control mode to control the output voltage based on the reference voltage.

[0036] The aforementioned high-voltage redundant power conversion control circuit based on multi-level drive also has the following feature: the control mode in step S6 includes an input constant current control mode and an output constant voltage control mode. The two modes are switched according to whether current limiting or voltage limiting conditions are triggered, with priority given to ensuring that the input current does not exceed the limit.

[0037] In summary, the beneficial effects of this scheme are:

[0038] The high-voltage redundant power conversion circuit based on multi-stage drive provided by this invention improves efficiency and increases power density through a four-MOSFET interleaved parallel topology and magnetically integrated coupling fault tolerance. The multi-stage drive method disperses the voltage stress on the silicon carbide MOSFETs, making the system more stable and reliable. This high-voltage redundant power conversion circuit based on multi-stage drive also features DC / DC voltage regulation over a wide voltage range, improving its applicability. Attached Figure Description

[0039] Figure 1 This is a system block diagram of the high-voltage redundant power conversion circuit based on multi-stage drive according to the present invention.

[0040] Figure 2 This is a schematic diagram of the circuit structure of the main power conversion module of the high-voltage redundant power conversion circuit based on multi-stage drive of the present invention.

[0041] Figure 3 This is a schematic diagram of the circuit structure of the drive isolation module of the high-voltage redundant power conversion circuit based on multi-level drive of the present invention.

[0042] Figure 4 This is a schematic diagram of the current sampling circuit structure of the signal sampling feedback module of the high-voltage redundant power conversion circuit based on multi-stage drive of the present invention.

[0043] Figure 5 This is a schematic diagram of the voltage sampling circuit structure of the signal sampling feedback module of the high-voltage redundant power conversion circuit based on multi-stage drive according to the present invention. Detailed Implementation

[0044] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. 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 of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0045] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0046] The present invention will be further described below with reference to specific embodiments, but these are not intended to limit the scope of the invention.

[0047] Figure 1 This is a system block diagram of the high-voltage redundant power conversion circuit based on multi-stage drive according to the present invention. Figure 2 This is a schematic diagram of the main power conversion module of the high-voltage redundant power conversion circuit based on multi-stage drive of the present invention. Figure 3 This is a schematic diagram of the circuit structure of the drive isolation module of the high-voltage redundant power conversion circuit based on multi-level drive according to the present invention. Figure 4 This is a schematic diagram of the current sampling circuit structure of the signal sampling feedback module of the high-voltage redundant power conversion circuit based on multi-stage drive according to the present invention. Figure 5 This is a schematic diagram of the voltage sampling circuit structure of the signal sampling feedback module of the multi-stage driven high-voltage redundant power conversion circuit of the present invention, as shown below. Figures 1-5 As shown, the high-voltage redundant power conversion circuit and control method based on multi-level drive provided in this embodiment includes an input module, a main power conversion module, an output module, a drive isolation module, an auxiliary power supply, a DSP control module, and a signal sampling feedback module.

[0048] Input module, used to connect to the battery pack;

[0049] The main power conversion module enables wide-range voltage boost / pull-down, electrical isolation, and power transfer.

[0050] The output module is used to connect to the load and provide a stable high-voltage DC output.

[0051] The drive isolation module is used to provide switching control for the MOSFETs in the main power conversion module, thereby achieving electrical isolation between the high-voltage side and the low-voltage control circuit.

[0052] Auxiliary power supply, used to provide low-voltage power to the system;

[0053] The DSP control module serves as the control center of the entire system, assisting in communication and interaction between modules or with external systems, executing advanced topology control strategies, generating PWM signals, and implementing logic control algorithms.

[0054] The signal sampling feedback module is used to acquire the current and voltage signals on the input and output sides in real time and feed the acquired signals back to the DSP control module.

[0055] In the above embodiment, the main power conversion module includes connector U13, resistors R27, R120, R23, R24, R94, R95, capacitors U14, U20, R96, R97, U49, U50, connector U52, MOSFET U57, resistor R118, MOSFET U10, resistor R25, diode D36, diode D10, MOSFET U58, resistor R119, MOSFET U9, resistor R22, inductor L2, MOSFET U59, resistor R121, MOSFET U23, resistor R33, diode D38, diode D39, capacitor U44, resistor R98, capacitor C15, and resistor R100. Connectors U12 and U25, connector U13 is electrically connected to the drain of MOSFET U10 through resistor R27, resistor R120 is connected in parallel across resistor R27, the drain of MOSFET U10 is connected to the signal sampling feedback circuit as the negative output terminal of voltage sampling through resistor R24, the common terminal of connector U13 and resistor R27 is connected to the signal sampling feedback circuit as the positive output terminal of voltage sampling through resistor 23, the gate of MOSFET U10 is electrically connected to its source through resistor R25, the drain of MOSFET U10 is electrically connected to the drain of MOSFET U57, the source of MOSFET U10 is electrically connected to the source of MOSFET U57, and the gate of MOSFET U57 is electrically connected to its source through resistor R118.

[0056] The common terminal of connector U13 and resistor R27 is also electrically connected to the positive output terminal of the auxiliary power supply. The common terminal of connector U13 and resistor R27 is sequentially connected to the source of MOSFET U9 through capacitors U14, U20, U49 and U50. Resistor R94 is connected in parallel across capacitor U14, resistor R95 is connected in parallel across capacitor U20, resistor R96 is connected in parallel across capacitor U49, and resistor R97 is connected in parallel across capacitor U50. The common terminal of capacitors U20 and U49 is connected as an intermediate terminal to the anode of diode D36. The cathode of diode D36 is connected to the source of MOSFET U10.

[0057] The source of MOSFET U9 is electrically connected to connector U52, the source of MOSFET U9 is electrically connected to the source of MOSFET U58, the drain of MOSFET U9 is electrically connected to the drain of MOSFET U58, the source of MOSFET U9 is electrically connected to its gate through resistor R119, the source of MOSFET U58 is electrically connected to its gate through resistor R22, the drain of MOSFET U9 is electrically connected to the anode of diode D10, and the cathode of diode D10 is electrically connected to the anode of diode D36.

[0058] The source of MOSFET U10 is electrically connected to the drain of MOSFET U59 through inductor L2. The source of MOSFET U59 is electrically connected to the drain of MOSFET U9. The source of MOSFET U59 is also electrically connected to the source of MOSFET U23. The drain of MOSFET U59 is also electrically connected to the drain of MOSFET U23. The gate of MOSFET U59 is electrically connected to its source through resistor R121. The gate of MOSFET U23 is electrically connected to its source through resistor R33.

[0059] The drain of MOSFET U23 is electrically connected to the anode of diode D38. The anode of diode D38 is also electrically connected to the anode of diode D39. The cathode of diode D38 is electrically connected to the cathode of diode D39. The cathode of diode D38 is connected to connector U12 as the positive output terminal. The source of MOSFET U23 is connected to connector U25 as the negative output terminal.

[0060] The cathode of diode D38 is connected to the source of MOSFET U23 in sequence through capacitors U44 and C15. Resistor R98 is connected in parallel across capacitor U44, and resistor R100 is connected in parallel across capacitor C15.

[0061] It should be noted that resistors R94 and R95, capacitors U14 and U20, resistors R96 and R97, capacitor U49 and capacitor C50 constitute a neutral point detection circuit, which is mainly used to detect whether the input side voltage is balanced.

[0062] Resistors R27, R120, R23, and R2 form a sampling shunt circuit, which is used to collect the input current and perform the shunt function.

[0063] MOSFETs U57 and U10 are connected in parallel to form main power transistor 1, MOSFETs U58 and U9 are connected in parallel to form main power transistor 2, and MOSFETs U59 and U23 are connected in parallel to form main power transistor 3. Main power transistors 1 and 2 are both buck switching transistors, with main power transistor 1 being the upper buck transistor, main power transistor 2 being the lower buck transistor, and main power transistor 3 being the boost switching transistor.

[0064] Diode D36 is connected in parallel with diode D40, and diode D10 is connected in parallel with diode D41, together forming a rectifier diode.

[0065] Diodes D38 and D39 are connected in parallel to prevent current backflow when the output current is large;

[0066] Capacitors U44 and U15, resistors R98 and R100 are used for output filtering and voltage division.

[0067] In the above embodiment, the drive isolation module includes capacitor C64, isolation chip U41, transformer T8, capacitor C63, series diode D26, capacitor C65, resistor R81, diode D27, capacitor C67, and capacitor C66. The ground terminal of isolation chip U41 is electrically connected to the 5V input voltage through capacitor C64. The ground terminal of isolation chip U41 is grounded. The 5V input voltage is also electrically connected to the input terminal of isolation chip U41. The first isolation terminal of isolation chip U41 is electrically connected to one end of the primary coil of transformer T8, and the second isolation terminal of isolation chip U41 is electrically connected to the other end of the primary coil of transformer T8. The input terminal of isolation chip U41 is also electrically connected to the middle terminal of the primary coil of transformer T8. One end of the secondary coil is electrically connected to the middle terminal of the series diode D26 through capacitor C63. The other end of the secondary coil of transformer T8 is electrically connected to the anode of the series diode D26. The cathode of the series diode D26 is electrically connected to its anode through capacitor C65. The cathode of the series diode D26 is electrically connected to the cathode of diode D27 through resistor R81. The anode of diode D27 is electrically connected to the anode of the series diode D26. Capacitor C67 is connected in parallel across resistor R81, and capacitor C66 is connected in parallel across diode D27. The anode and cathode of the series diode D26 are used as drive power signals to connect to the driver IC. The common terminal of capacitors C67 and C66 is used as a low-level drive signal output terminal and electrically connected to the gate of the corresponding MOSFET.

[0068] It should be noted that the number of isolation drive modules corresponds one-to-one with the number of MOSFETs.

[0069] In the above embodiment, the drive isolation module further includes resistor R82, resistor R80, capacitor C62, driver chip U42, and resistor R83. The power input terminal of driver chip U42 is electrically connected to a 5V power supply. The power input terminal of driver chip U42 is also grounded through capacitor C62. The positive input terminal of driver chip U42 is connected to its negative input terminal through resistors R80 and R82 in sequence. The common terminal of resistors R80 and R82 is used to input a PWM signal. The negative input terminal of driver chip U42 is electrically connected to its ground terminal. The ground terminal of driver chip U42 is grounded. The negative power supply terminal and the positive power supply terminal of driver chip U42 are used as drive power signals to connect to the driver IC. The output terminal of driver chip U42 is connected to the gate of the corresponding MOSFET as a high-level drive signal output terminal through resistor R83.

[0070] In the above embodiment, the signal sampling feedback module includes a current sampling circuit, which includes diode D14, capacitor C34, isolation chip U31, transformer T4, diodes D15 and D16, and capacitor C35. The anode of diode D14 is electrically connected to a 5V power supply, and the cathode of diode D14 is electrically connected to the ground terminal of isolation chip U31 through capacitor C34. The ground terminal of isolation chip U31 is grounded, and the cathode of diode D14 is also electrically connected to the input terminal of isolation chip U31. The first isolation terminal of isolation chip U31 is connected to one end of the primary coil of transformer T4. Electrically connected, the second isolation terminal of isolation chip U31 is electrically connected to the other end of the primary coil of transformer T4, the input terminal of isolation chip U31 is electrically connected to the middle terminal of the primary coil of transformer T4, one end of the secondary coil of transformer T4 is electrically connected to the anode of diode D15, the cathode of diode D15 is electrically connected to the cathode of diode D16, the anode of diode D16 is electrically connected to the other end of the secondary coil of transformer T4, the cathode of diode D15 is also electrically connected to the middle terminal of the secondary coil of transformer T4 through capacitor C35, and the cathode of diode D15 serves as the positive power output terminal;

[0071] It also includes capacitor C38, amplifier chip U32, capacitor C36, and capacitor C37. The non-inverting input terminal of amplifier chip U32 is electrically connected to its inverting input terminal through capacitor C38. The non-inverting input terminal of amplifier chip U32 is also electrically connected to the positive output terminal of voltage sampling. The inverting input terminal of amplifier chip U32 is also electrically connected to the negative output terminal of voltage sampling. The first power input terminal of amplifier chip U32 is electrically connected to the cathode of diode D15. The first power input terminal of amplifier chip U32 is electrically connected to the negative output terminal of voltage sampling through capacitor C36. The first ground terminal of amplifier chip U32 is also electrically connected to the negative output terminal of voltage sampling. The second power input terminal of amplifier chip U32 is connected to analog ground through capacitor C37. The two differential output terminals of amplifier chip U32 are connected to the differential processing circuit of the DSP control module.

[0072] In the above embodiment, the signal sampling feedback module further includes a voltage sampling circuit, which includes diode D33, capacitor C92, isolation chip U55, transformer T10, diodes D34 and D35, and capacitor C93. The anode of diode D33 is electrically connected to a 5V power supply, and the cathode of diode D33 is electrically connected to the ground terminal of isolation chip U55 through capacitor C92. The ground terminal of isolation chip U55 is grounded, and the cathode of diode D33 is also electrically connected to the input terminal of isolation chip U55. The first isolation terminal of isolation chip U55 is connected to transformer T10. One end of the primary coil is electrically connected, the second isolation terminal of the isolation chip U55 is electrically connected to the other end of the primary coil of the transformer T10, the input terminal of the isolation chip U55 is electrically connected to the middle terminal of the primary coil of the transformer T10, one end of the secondary coil of the transformer T10 is electrically connected to the anode of the diode D34, the cathode of the diode D34 is electrically connected to the cathode of the diode D35, the anode of the diode D35 is electrically connected to the other end of the secondary coil of the transformer T10, and the cathode of the diode D34 is also electrically connected to the middle terminal of the secondary coil of the transformer T10 through the capacitor C93.

[0073] It also includes resistors R107, R104, R111, R106, R110, and R113, capacitors C94 and C88, isolation amplifier U54, and capacitor C89. The positive output terminal of the main power conversion module is connected to the input terminal of isolation amplifier U54 through resistors R107, R104, R111, R106, and R110 in sequence. The input terminal of isolation amplifier U54 is connected to its ground terminal through capacitor C94. The shutdown control terminal of isolation amplifier U54 is connected to its ground terminal. The shutdown control terminal of isolation amplifier U54 is connected to the negative output terminal of the main power conversion module. The first power input terminal of isolation amplifier U54 is connected to the negative output terminal of the main power conversion module through capacitor C88. The second power input terminal of isolation amplifier U54 is connected to analog ground through capacitor C89. The two differential output terminals of isolation amplifier U54 are connected to the DSP control module.

[0074] The high-voltage redundant power supply conversion control method based on multi-stage drive applies the above circuit to perform the following steps, which include:

[0075] S1. Set reference values, preset two key reference target values: reference input current and reference output voltage;

[0076] S2. Synchronously detect input current and output voltage. In each switching cycle, the following two detections are performed synchronously: single-cycle synchronous detection of input current and single-cycle synchronous detection of output voltage.

[0077] S3. Determine if the input current exceeds the limit. Check if the current input current triggers the input current limiting condition. If the input current reaches or exceeds the set current limit value, switch to the input constant current control mode to limit the input current within the allowable range. Prioritize the current and use the reference input current as the reference for input constant current control. If the input current does not exceed the set current limit value, proceed to S4.

[0078] S4. Determine if the output voltage exceeds the limit. Under the premise of safe input current, further detect and determine whether the current output voltage triggers the output voltage limit condition. If the output voltage has reached or exceeded the set upper limit protection value, switch to the output constant voltage control mode and prioritize stabilizing the output voltage within the safe range. If the output voltage has not exceeded the set upper limit protection value, continue to execute the output constant voltage control mode and adjust according to the output voltage reference, with the output voltage as the main control target.

[0079] S5. Select control mode. Based on the above judgment logic, select and switch to the corresponding control mode.

[0080] S6. PID calculates PWM duty cycle. After selecting the control mode, the system enters the closed-loop regulation loop. The difference between the reference input current or reference output voltage and the sampled input current or output voltage is compared. The difference is input to the PID controller to calculate the required PWM duty cycle D.

[0081] S7. PWM output drives the switching transistor. When the PWM duty cycle D is between 0 and 1.0, the buck switching transistor works and the boost switching transistor is off, and the module is in buck mode. When the PWM duty cycle D is between 1.0 and 2.0, the buck switching transistor is on and the boost switching transistor works, and the module is in boost mode.

[0082] S8. Execute in a loop. The above process constitutes one cycle. Through high-frequency closed-loop adjustment, precise and stable control of input current and output voltage is achieved.

[0083] It should be noted that the reference input current represents the maximum allowable input current value; the reference output voltage represents the desired output voltage value. These two values ​​are the target references for the entire control logic. Among the two reference values, the reference input current has absolute priority and must be ensured to meet the requirements.

[0084] It should also be noted that the input current single-cycle synchronous detection: real-time acquisition and detection of the current input current value; the output voltage single-cycle synchronous detection: real-time acquisition of the current output voltage value. The single-cycle synchronous detection method ensures that the sampling time is aligned with the switching cycle, avoids sampling errors, and provides a data foundation for subsequent precise control.

[0085] In the above embodiments, the control modes in step S6 include an input constant current control mode and an output constant voltage control mode. When the input current exceeds the limit, the input constant current control mode is entered to prioritize limiting the input current. When the output voltage exceeds the limit, the constant voltage control mode is entered to prioritize stabilizing the output voltage and prevent overvoltage. When the input current and output voltage are normal, the output constant voltage control mode is entered to control the output voltage based on the reference voltage.

[0086] In the above embodiments, the control modes in step S6 include input constant current control mode and output constant voltage control mode. The two modes are switched according to whether current limiting or voltage limiting conditions are triggered, with priority given to ensuring that the input current does not exceed the limit.

[0087] It should be noted that the duty cycle D ranges from 0 to 2. When the calculated duty cycle is between 0 and 1, the buck switch is working and the boost switch is off. When the calculated duty cycle is between 1.0 and 2.0, the buck switch is on and the boost switch is working (actual duty cycle minus 1.0).

[0088] The basic timing logic is as follows: when the system is in buck mode (D ≤ 1.0), the buck switch is active, and the boost switch is off. At this time, the upper and lower buck switches are controlled by interleaved parallel connection.

[0089] The upper transistor's conduction period is T: that is, the upper transistor performs PWM modulation with a duty cycle D, and the switching period is T. The lower transistor conducts at 1 / 2T: the lower transistor also performs PWM modulation with a duty cycle D, but its conduction start time is delayed by half a cycle (T / 2) relative to the upper transistor.

[0090] Duty cycle D ≤ 0.5: The upper and lower transistors of the step-down transistor operate in an alternating mode. The operating sequence of this mode is: upper transistor on → upper transistor off → lower transistor on → lower transistor off → upper transistor on again, and so on. The starting moment of the lower transistor's conduction is exactly 1 / 2T of the upper transistor's conduction cycle. Since there is no overlap in conduction, the switching loss and conduction loss are evenly distributed, and the circuit operates in a very stable "alternating" state.

[0091] Duty cycle D > 0.5: There is an overlapping conduction interval between the upper and lower switches of the buck converter. The operating timing of this mode is as follows: the lower switch starts conducting at 1 / 2T after the upper switch has turned on. Since the conduction time of a single switch is T = D * T (greater than T / 2), the lower switch has already turned on before the upper switch turns off, forming an overlapping interval between the upper and lower switches. This overlapping conduction can further reduce the input current ripple, which is very beneficial for high-power applications. The larger the duty cycle, the greater the overlap.

[0092] Capacitors U14 and U20 are connected in series as the upper voltage divider capacitor, which bears the upper tube side bus voltage. Capacitors U49 and U50 are connected in series as the lower voltage divider capacitor, which bears the lower tube bus voltage. The core functions of the voltage divider capacitors are voltage distribution, midpoint potential provision, energy buffering, and balancing.

[0093] In practical applications, it is difficult to keep the voltage of the upper and lower voltage divider capacitors equal at all times. The main reasons include capacitance tolerance, leakage current difference, asymmetrical switching action, PCB layout, asymmetrical parasitic parameters such as lead inductance, and sudden load changes. The risks of voltage imbalance include excessive voltage exceeding the rated voltage of the capacitor, causing the capacitor to break down; uneven stress between the upper and lower switching transistors, causing single transistor overvoltage; long-term imbalance accelerates device aging and reduces system reliability; and fluctuations in the midpoint potential interfere with the sampling signal, affecting control accuracy. This solution has a voltage divider balancing mechanism: by adjusting the distribution of the conduction time of the upper and lower transistors, the charge charging and discharging of the two voltage divider units can achieve dynamic balance. When the voltage of the upper voltage divider capacitor is too high (i.e., the voltage of the upper voltage divider capacitor is higher than that of the lower voltage divider capacitor), the voltage sampling and detection unit uploads the sampled value to the DSP control module. The DSP automatically adjusts the duty cycle of the switching transistor through PID control, either reducing the PWM duty cycle of the upper transistor or increasing the PWM duty cycle of the lower transistor. When the voltage of the two lower voltage divider capacitors is too high (i.e., the voltage of the lower voltage divider capacitor is higher than that of the upper voltage divider capacitor), the voltage sampling and detection unit uploads the sampled value to the DSP control module. The DSP automatically adjusts the duty cycle of the switching transistor through PID control, either reducing the PWM duty cycle of the lower transistor or increasing the PWM duty cycle of the upper transistor.

[0094] The above are merely preferred embodiments of the present invention and are not intended to limit the implementation methods and protection scope of the present invention. Those skilled in the art should recognize that any equivalent substitutions and obvious changes made based on the content of this specification should be included within the protection scope of the present invention.

Claims

1. A high-voltage redundant power conversion circuit based on multi-stage drive, characterized in that: It includes an input module, a main power conversion module, an output module, a drive isolation module, an auxiliary power supply, a DSP control module, and a signal sampling feedback module; The input module is used to connect to the battery pack; The main power conversion module enables wide-range voltage boost / pull-down, electrical isolation, and power transfer. The output module is used to connect to the load and provide a stable high-voltage DC output; The drive isolation module is used to provide switching control for the MOSFETs in the main power conversion module, thereby achieving electrical isolation between the high-voltage side and the low-voltage control circuit. The auxiliary power supply is used to provide low-voltage power to the system; The DSP control module is the control center of the entire system, assisting in communication and interaction between modules or with external systems, executing advanced topology control strategies, generating PWM signals, and implementing logic control algorithms. The signal sampling feedback module is used to collect the current and voltage signals on the input and output sides in real time, and feed the collected signals back to the DSP control module.

2. The high-voltage redundant power conversion circuit based on multi-stage drive according to claim 1, characterized in that: The main power conversion module includes connector U13, resistors R27, R120, R23, R24, R94, R95, capacitors U14, U20, R96, R97, U49, U50, connector U52, MOSFET U57, resistor R118, MOSFET U10, resistor R25, diode D36, diode D10, MOSFET U58, resistor R119, MOSFET U9, resistor R22, inductor L2, MOSFET U59, resistor R121, MOSFET U23, resistor R33, diode D38, diode D39, capacitor U44, resistor R98, capacitor C15, resistor R100, connector U12, and connector U25. Connector U13... The drain of the MOS transistor U10 is electrically connected to the resistor R27. The resistor R120 is connected in parallel across the resistor R27. The drain of the MOS transistor U10 is connected to the signal sampling feedback circuit as a negative voltage sampling output terminal via the resistor R24. The common terminal of the connector U13 and the resistor R27 is connected to the signal sampling feedback circuit as a positive voltage sampling output terminal via the resistor 23. The gate of the MOS transistor U10 is electrically connected to its source via the resistor R25. The drain of the MOS transistor U10 is electrically connected to the drain of the MOS transistor U57. The source of the MOS transistor U10 is electrically connected to the source of the MOS transistor U57. The gate of the MOS transistor U57 is electrically connected to its source via the resistor R118. The common terminal of the connector U13 and the resistor R27 is also electrically connected to the positive output terminal of the auxiliary power supply. The common terminal of the connector U13 and the resistor R27 is sequentially connected to the source of the MOS transistor U9 through the capacitors U14, U20, U49 and U50. The resistor R94 is connected in parallel across the two ends of the capacitor U14, the resistor R95 is connected in parallel across the two ends of the capacitor U20, the resistor R96 is connected in parallel across the two ends of the capacitor U49, and the resistor R97 is connected in parallel across the two ends of the capacitor U50. The common terminal of the capacitors U20 and U49 is connected as an intermediate terminal to the anode of the diode D36. The cathode of the diode D36 is connected to the source of the MOS transistor U10. The source of MOS transistor U9 is electrically connected to the connector U52, the source of MOS transistor U9 is electrically connected to the source of MOS transistor U58, the drain of MOS transistor U9 is electrically connected to the drain of MOS transistor U58, the source of MOS transistor U9 is electrically connected to its gate through resistor R119, the source of MOS transistor U58 is electrically connected to its gate through resistor R22, the drain of MOS transistor U9 is electrically connected to the anode of diode D10, and the cathode of diode D10 is electrically connected to the anode of diode D36. The source of MOSFET U10 is electrically connected to the drain of MOSFET U59 through inductor L2. The source of MOSFET U59 is electrically connected to the drain of MOSFET U9. The source of MOSFET U59 is also electrically connected to the source of MOSFET U23. The drain of MOSFET U59 is also electrically connected to the drain of MOSFET U23. The gate of MOSFET U59 is electrically connected to its source through resistor R121. The gate of MOSFET U23 is electrically connected to its source through resistor R33. The drain of the MOS transistor U23 is electrically connected to the anode of the diode D38, the anode of the diode D38 is also electrically connected to the anode of the diode D39, the cathode of the diode D38 is electrically connected to the cathode of the diode D39, the cathode of the diode D38 is electrically connected to the connector U12 as the positive output terminal, and the source of the MOS transistor U23 is electrically connected to the connector U25 as the negative output terminal. The cathode of the diode D38 is sequentially connected to the source of the MOS transistor U23 through the capacitors U44 and C15. The resistor R98 is connected in parallel across the capacitor U44, and the resistor R100 is connected in parallel across the capacitor C15.

3. The high-voltage redundant power conversion circuit based on multi-stage drive according to claim 2, characterized in that: The drive isolation module includes capacitor C64, isolation chip U41, transformer T8, capacitor C63, series diode D26, capacitor C65, resistor R81, diode D27, capacitor C67, and capacitor C66. The ground terminal of isolation chip U41 is electrically connected to the 5V input voltage through capacitor C64. The ground terminal of isolation chip U41 is grounded, and the 5V input voltage is also electrically connected to the input terminal of isolation chip U41. The first isolation terminal of isolation chip U41 is electrically connected to one end of the primary coil of transformer T8, and the second isolation terminal of isolation chip U41 is electrically connected to the other end of the primary coil of transformer T8. The input terminal of isolation chip U41 is also electrically connected to the middle terminal of the primary coil of transformer T8. One end of the secondary coil of transformer T8 is connected to... The capacitor C63 is electrically connected to the middle terminal of the series diode D26. The other end of the secondary coil of the transformer T8 is electrically connected to the anode of the series diode D26. The cathode of the series diode D26 is electrically connected to its anode through the capacitor C65. The cathode of the series diode D26 is electrically connected to the cathode of the diode D27 through the resistor R81. The anode of the diode D27 is electrically connected to the anode of the series diode D26. The capacitor C67 is connected in parallel across the resistor R81. The capacitor C66 is connected in parallel across the diode D27. The anode and cathode of the series diode D26 are used as driving power signals to connect to the driving IC. The common terminal of the capacitors C67 and C66 is used as a low-level driving signal output terminal and is electrically connected to the gate of the corresponding MOS transistor.

4. The high-voltage redundant power conversion circuit based on multi-stage drive according to claim 3, characterized in that: The drive isolation module also includes resistors R82 and R80, capacitor C62, driver chip U42, and resistor R83. The power input terminal of driver chip U42 is electrically connected to a 5V power supply. The power input terminal of driver chip U42 is also grounded through capacitor C62. The positive input terminal of driver chip U42 is connected to its negative input terminal through resistors R80 and R82 in sequence. The common terminal of resistors R80 and R82 is used to input a PWM signal. The negative input terminal of driver chip U42 is electrically connected to its ground terminal. The ground terminal of driver chip U42 is grounded. The negative power supply terminal and the positive power supply terminal of driver chip U42 are used as drive power signals to connect to the driver IC. The output terminal of driver chip U42 is connected to the gate of the corresponding MOSFET as a high-level drive signal output terminal through resistor R83.

5. The high-voltage redundant power conversion circuit based on multi-stage drive according to claim 3, characterized in that: The signal sampling feedback module includes a current sampling circuit, which comprises a diode D14, a capacitor C34, an isolation chip U31, a transformer T4, diodes D15 and D16, and a capacitor C35. The anode of diode D14 is electrically connected to a 5V power supply, and the cathode of diode D14 is electrically connected to the ground terminal of the isolation chip U31 through the capacitor C34. The ground terminal of the isolation chip U31 is grounded, and the cathode of diode D14 is also electrically connected to the input terminal of the isolation chip U31. The first isolation terminal of the isolation chip U31 is electrically connected to one end of the primary coil of the transformer T4. The second isolation terminal of the isolation chip U31 is electrically connected to the other end of the primary coil of the transformer T4. The input terminal of the isolation chip U31 is electrically connected to the middle terminal of the primary coil of the transformer T4. One end of the secondary coil of the transformer T4 is electrically connected to the anode of the diode D15. The cathode of the diode D15 is electrically connected to the cathode of the diode D16. The anode of the diode D16 is electrically connected to the other end of the secondary coil of the transformer T4. The cathode of the diode D15 is also electrically connected to the middle terminal of the secondary coil of the transformer T4 through the capacitor C35. The cathode of the diode D15 serves as the positive power output terminal. It also includes capacitor C38, amplifier chip U32, capacitor C36, and capacitor C37. The non-inverting input terminal of amplifier chip U32 is electrically connected to its inverting input terminal through capacitor C38. The non-inverting input terminal of amplifier chip U32 is also electrically connected to the positive output terminal of voltage sampling. The inverting input terminal of amplifier chip U32 is also electrically connected to the negative output terminal of voltage sampling. The first power input terminal of amplifier chip U32 is electrically connected to the cathode of diode D15. The first power input terminal of amplifier chip U32 is electrically connected to the negative output terminal of voltage sampling through capacitor C36. The first ground terminal of amplifier chip U32 is also electrically connected to the negative output terminal of voltage sampling. The second power input terminal of amplifier chip U32 is connected to analog ground through capacitor C37. The two differential output terminals of amplifier chip U32 are connected to the differential processing circuit of the DSP control module.

6. The high-voltage redundant power conversion circuit based on multi-stage drive according to claim 3, characterized in that: The signal sampling feedback module further includes a voltage sampling circuit, which comprises diode D33, capacitor C92, isolation chip U55, transformer T10, diodes D34 and D35, and capacitor C93. The anode of diode D33 is electrically connected to a 5V power supply, and the cathode of diode D33 is electrically connected to the ground terminal of isolation chip U55 through capacitor C92. The ground terminal of isolation chip U55 is grounded, and the cathode of diode D33 is also electrically connected to the input terminal of isolation chip U55. The first isolation terminal of isolation chip U55 is connected to the primary coil of transformer T10. One end of the isolation chip U55 is electrically connected to the primary coil of the transformer T10, the second isolation terminal of the isolation chip U55 is electrically connected to the other end of the primary coil of the transformer T10, the input terminal of the isolation chip U55 is electrically connected to the middle terminal of the primary coil of the transformer T10, one end of the secondary coil of the transformer T10 is electrically connected to the anode of the diode D34, the cathode of the diode D34 is electrically connected to the cathode of the diode D35, the anode of the diode D35 is electrically connected to the other end of the secondary coil of the transformer T10, and the cathode of the diode D34 is also electrically connected to the middle terminal of the secondary coil of the transformer T10 through the capacitor C93. It also includes resistors R107, R104, R111, R106, R110, and R113, capacitors C94 and C88, isolation amplifier U54, and capacitor C89. The positive output terminal of the main power conversion module is sequentially connected to the input terminal of the isolation amplifier U54 through resistors R107, R104, R111, R106, and R110. The input terminal of the isolation amplifier U54 is connected to its ground terminal through capacitor C94. The isolation amplifier U54 is electrically connected to its ground terminal, and to the negative output terminal of the main power conversion module. The first power input terminal of the isolation amplifier U54 is electrically connected to the negative output terminal of the main power conversion module via capacitor C88. The second power input terminal of the isolation amplifier U54 is electrically connected to analog ground via capacitor C89. The two differential output terminals of the isolation amplifier U54 are electrically connected to the DSP control module.

7. A high-voltage redundant power supply conversion control method based on multi-stage drive, comprising the following steps using the control circuit described in any one of claims 1-6, characterized in that: The following steps include S1. Set reference values, preset two key reference target values: reference input current and reference output voltage; S2. Synchronously detect input current and output voltage. In each switching cycle, the following two detections are performed synchronously: single-cycle synchronous detection of input current and single-cycle synchronous detection of output voltage. S3. Determine if the input current exceeds the limit. Check if the current input current triggers the input current limiting condition. If the input current reaches or exceeds the set current limit value, switch to the input constant current control mode to limit the input current within the allowable range. Prioritize the current and use the reference input current as the reference for input constant current control. If the input current does not exceed the set current limit value, proceed to S4. S4. Determine if the output voltage exceeds the limit. Under the premise of safe input current, further detect and determine whether the current output voltage triggers the output voltage limit condition. If the output voltage has reached or exceeded the set upper limit protection value, switch to the output constant voltage control mode and prioritize stabilizing the output voltage within the safe range. If the output voltage has not exceeded the set upper limit protection value, continue to execute the output constant voltage control mode and adjust according to the output voltage reference, with the output voltage as the main control target. S5. Select control mode. Based on the above judgment logic, select and switch to the corresponding control mode. S6. PID calculates PWM duty cycle. After selecting the control mode, the system enters the closed-loop regulation loop. The difference between the reference input current or reference output voltage and the sampled input current or output voltage is compared. The difference is input to the PID controller to calculate the required PWM duty cycle D. S7. PWM output drives the switching transistor. When the PWM duty cycle D is between 0 and 1.0, the buck switching transistor works and the boost switching transistor is off, and the module is in buck mode. When the PWM duty cycle D is between 1.0 and 2.0, the buck switching transistor is on and the boost switching transistor works, and the module is in boost mode. S8. Execute in a loop. The above process constitutes one cycle. Through high-frequency closed-loop adjustment, precise and stable control of input current and output voltage is achieved.

8. The high-voltage redundant power supply conversion control method based on multi-level drive according to claim 5, characterized in that: The control modes in step S6 include input constant current control mode and output constant voltage control mode. When the input current exceeds the limit, the input constant current control mode is entered to prioritize limiting the input current. When the output voltage exceeds the limit, the constant voltage control mode is entered to prioritize stabilizing the output voltage and prevent overvoltage. When the input current and output voltage are normal, the output constant voltage control mode is entered to control the output voltage based on the reference voltage.

9. The high-voltage redundant power supply conversion control method based on multi-stage drive according to claim 5, characterized in that: The control modes in step S6 include input constant current control mode and output constant voltage control mode. The two modes are switched according to whether current limiting or voltage limiting conditions are triggered, with priority given to ensuring that the input current does not exceed the limit.

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