DC charging pile control system based on SiC device and control method thereof

Abstract

The invention discloses a DC charging pile control system based on a SiC device and a control method thereof. The system comprises a controller, an input rectification and power factor correction (PFC) unit, a high-frequency DC / DC conversion unit, a gate driving and dynamic parameter adjustment module, a multi-level EMI suppression module, a thermal management and temperature prediction module, a safety protection module and a charging control and communication module. The SiC device and the efficient topology are combined with soft switching control, the energy efficiency and the power density of the charging pile are greatly improved, the problem of high switching speed interference is solved through EMI suppression and dynamic parameter adjustment, high-temperature stability is guaranteed by means of junction temperature prediction and mixed heat dissipation, the safety is improved by matching rapid turn-off and multi-dimensional protection, and the energy efficiency and the power density of the charging pile are improved. BMS cooperation and adaptive control are combined to enhance adaptability and intelligence, and efficient, reliable and intelligent operation is achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of direct current charging piles, and in particular to a direct current charging pile control system based on SiC devices and a control method thereof. BACKGROUND

[0002] With the popularity of electric vehicles, there is a rapid increase in demand for fast, efficient and intelligent direct current charging piles. Traditional charging piles based on silicon (Si) power devices have limitations in high frequency, high temperature operation, power density and energy efficiency. SiC devices have lower on-resistance, higher switching frequency, higher voltage resistance and higher temperature working capacity, which can significantly improve the efficiency and power density of charging piles. However, the high switching speed of SiC devices in the prior art causes problems such as electromagnetic interference (EMI), voltage overshoot and rapid rise of device junction temperature. It requires matching driving, topology, protection and thermal management strategies. The existing technology is still not perfect in terms of systematic integration of SiC devices in direct current charging piles, cross-level collaborative control methods, and EMI suppression and thermal management solutions under ultra-high frequency working conditions.

[0003] In summary, the direct current charging pile control system based on SiC devices in the prior art has the following shortcomings: 1. Traditional charging piles based on silicon (Si) power devices have obvious limitations in high frequency, high temperature operation, power density and energy efficiency, and cannot meet the demand for fast charging; 2. Although silicon carbide (SiC) devices have advantages such as low on-resistance and high switching frequency, high switching speed can easily cause problems such as electromagnetic interference (EMI), voltage overshoot and rapid rise of device junction temperature; 3. The EMI suppression and thermal management solutions under ultra-high frequency working conditions lack pertinence and are difficult to match the characteristics of SiC devices. Therefore, the present application proposes a direct current charging pile control system based on SiC devices and a control method thereof. SUMMARY

[0004] Based on the technical problems existing in the background technology, the present application proposes a direct current charging pile control system based on SiC devices and a control method thereof.

[0005] The direct current charging pile control system based on SiC devices proposed by the present application comprises a controller, an input rectification and power factor correction (PFC) unit, a high-frequency DC / DC conversion unit, a gate drive and dynamic parameter adjustment module, a multi-level EMI suppression module, a thermal management and temperature prediction module, a safety protection module, and a charging control and communication module. The input rectification and power factor correction (PFC) unit adopts SiC MOSFET to form an interleaved or three-level Boost structure, realizes high-frequency PFC regulation, improves the input power factor and reduces the input side harmonics. The high-frequency DC / DC conversion unit adopts SiC devices to form an LLC resonance or full-bridge phase shift soft switching topology, realizes high-efficiency isolated high-frequency conversion, the resonance frequency is 100 kHz-500 kHz, soft switching is realized through frequency modulation, and switching loss is reduced; The gate drive and dynamic parameter adjustment module adjusts the gate resistance in real time according to the device temperature, current and dv / dt, realizes overshoot suppression and EMI optimization, and has the advantages of high efficiency, high reliability and low cost. The multi-level EMI suppression module includes a high-precision Hall current sensor, a common mode / differential mode filter, an SiC high-frequency switch optimized wiring, a shielding structure and a variable switch slope control unit. The thermal management and temperature prediction module is based on the SiC device junction temperature model, the radiator thermal resistance model and the fan / liquid cooling control strategy, and realizes active heat dissipation adjustment. The safety protection module includes a short-circuit protection circuit, an overvoltage protection circuit, an over-temperature protection circuit, an over-current protection circuit and a fast shutdown circuit. The charging control and communication module communicates with the vehicle BMS through CAN, Ethernet or PLC, and realizes constant voltage / constant current / impulse charging strategy.

[0006] Preferably, the gate drive and dynamic parameter adjustment module includes an adjustable gate resistance network and a feedback adjustment circuit, which is used for automatically adjusting the switching slope according to the transient current of the SiC device.

[0007] Preferably, the thermal management and temperature prediction module adopts a liquid cooling plate and an intelligent air cooling hybrid structure, and predicts the future ΔT of the SiC device based on the thermal resistance model, to realize pre-cooling control.

[0008] Preferably, the input rectification and power factor correction PFC unit adopts three-phase rectification and interleaved PFC, and each phase PFC adopts two-stage SiC MOSFET interleaving, which reduces current ripple and increases switching frequency to ≥100 kHz.

[0009] The application also provides a SiC device-based direct-current charging pile control method, which includes the following steps: S1: input state detection and PFC soft start: the input voltage, power grid frequency and harmonic condition are detected through voltage division, differential amplifier and high-bandwidth current shunt of the input rectification and power factor correction PFC unit, the interleaved PFC is started, and the control parameters are adaptively adjusted according to the power grid ripple; S2: SiC device high-frequency switch optimization control: the gate drive and dynamic parameter adjustment module collects the gate voltage, drain-source voltage, switching current and dv / dt, di / dt change rate, realizes soft switching operation through gate dynamic resistance adjustment, phase shift adjustment and resonance frequency tracking, and reduces the overshoot and EMI caused by dv / dt; S3: DC / DC stage adaptive energy transmission regulation: the high-frequency DC / DC conversion unit dynamically adjusts the duty ratio and switching frequency according to the vehicle charging demand and bus voltage; S4: multi-level EMI suppression control: the high-precision Hall current sensor of the multi-level EMI suppression module monitors the common-mode current in real time, and adjusts the switching slope, drive voltage, and PWM mode through the digital controller; S5: thermal management strategy execution: the thermal management and temperature prediction module adjusts the cooling system operating parameters in advance according to the junction temperature prediction model, to realize active pre-cooling or limit the switching frequency; S6: safety protection execution: the safety protection module detects abnormalities through the Rogowski coil, resistance voltage division, thermistor, and current sensor, and shuts down the SiC device and restarts the protection logic within 100 ns after detecting abnormalities; S7: charging state regulation and communication: the charging control and communication module interacts with the BMS through CAN, Ethernet, or PLC to exchange power, voltage, and temperature data, and adjusts the constant current stage, voltage rise rate, and cutoff conditions according to the BMS instructions.

[0010] Preferably, in S1, the input state detection uses voltage division and differential amplifier and high-bandwidth current shunt, and the input voltage, grid frequency, and harmonic conditions are obtained by high-speed ADC in a synchronous sampling manner. The controller performs synchronous DFT / Goertzel operation on the data in the sampling window to obtain the fundamental amplitude, phase, and 3, 5, and 7 times high-order harmonic amplitudes in real time, thereby calculating the THD and grid-side equivalent impedance. Based on these detection quantities, the controller adjusts the control parameters using an adaptive strategy during the PFC soft start stage. The adaptive strategy is as follows: when the THD exceeds the preset threshold, gradually increase the gate resistance Rg to reduce the device dv / dt, and reduce the PFC controller bandwidth and / or switching frequency in proportion to reduce EMI; when the grid impedance estimate is too large, automatically reduce the controller bandwidth and limit the transient power output to avoid oscillation.

[0011] Preferably, the specific logic steps of S2 are as follows: S201: The controller collects the real-time changes of gate voltage, drain-source voltage, switching current, main circuit inductance and capacitance voltage and current, dv / dt, and di / dt in real time, and the sampling frequency is ≥5-10 MHz; S202: The controller calculates the optimal gate resistance according to the current switching current and a preset table. The formula used is: where I rises, R needs to be increased g to control dv / dt, T rises, R needs to be moderately increased g to prevent overshoot, according to R gThe controller selects a multi-stage controllable gate resistor array as the optimal gate resistor and verifies dv / dt, where the dv / dt verification constraint is: If the threshold is exceeded, Rg will be automatically increased. S203: The controller obtains this information in real time from the converter topology: And detect the zero-voltage condition, and determine whether the following conditions are met: And I sw The direction is correct, if it satisfies ZVS can be implemented if the conditions are not met. Adjustment Enhanced power transfer makes the inductor current closer to zero voltage when crossing zero. S204: Calculate the equivalent resonant frequency: And calculate the deviation: , where f sw Given the current switching frequency, if Δf > 0 Lower f sw If Δf < 0, increase f sw and keep ; S205: Comprehensive R g Control, phase shift control and f r Tracking, with "soft switching effect E" ss As an evaluation indicator, the formula used is: If E ss Set a threshold and adjust the priority rules accordingly. Specifically: prioritize phase shift correction; if ZVS cannot be achieved, increase the gate impedance; if dv / dt is still high, adjust the switching frequency f. r near.

[0012] Preferably, the specific logical steps of S4 are as follows: S401: Employs a high-precision Hall current sensor, which collects common-mode current in real time based on the Hall effect, providing data support for EMI suppression. V H Hall voltage, K H V is the intrinsic coefficient of the Hall element. H For common-mode current, by measuring V H I can be calculated CM ; S402: Controller Comparison I CM When the threshold is exceeded, the switching speed is controlled by adjusting the gate resistance to reduce dv / dt and di / dt. The switching speed is related to the gate resistance R. g Inversely proportional, R g Increasing the value reduces the switching speed, indirectly suppressing EMI. In engineering, this can be achieved by adjusting the value by I. CM Over-threshold ratio adaptation Rg increment; S403: Adjusting the driving voltage through the power management chip , CM appropriately reduce when large , reduce EMI energy can be reduced while ensuring normal switching of the device; S404: Adjusting PWM parameters according to I CM , EMI strength , I CM can be reduced when too high .

[0013] Preferably, the specific logic steps of S5 are as follows: S501: Based on the SiC device junction temperature prediction model and the heat sink thermal resistance model, input real-time power consumption, environmental temperature parameters to predict the junction temperature, and perform junction temperature preheating calculation, using the formula: , where T j is the junction temperature, , where is the conduction loss, is the switching loss, is the junction shell thermal resistance, T c is the shell temperature; S502: According to the prediction result of T j , adjust the liquid cooling and air cooling parameters, using the formula: , where V f is the cooling liquid flow rate, P d is the power consumption, is the cooling liquid density, c p is the specific heat capacity, and V f is matched by adjusting the water pump speed, and air cooling is adjusted by PWM fan speed; S503: When T j approaches the threshold value, increase the cooling system power to achieve active pre-cooling, and if pre-cooling is ineffective, reduce the switching frequency f s to reduce , control heat production, and if T j exceeds the upper limit of the normal range and cooling adjustment is ineffective, trigger frequency limitation.

[0014] Preferably, the specific logic steps of S6 are as follows: S601: Multi-dimensional anomaly detection: short circuit detection, overvoltage detection, overtemperature detection and overcurrent detection are performed respectively, and the short circuit detection is performed through the Rogowski coil to monitor the current, which meets determine short circuit; overvoltage detection is performed through resistance voltage division to collect voltage, which meets determine overvoltage; overtemperature detection is performed through a thermistor to monitor temperature, Determine over-temperature; over-current detection is monitored by a current sensor, and the following conditions are met Determine over-current; S602: When an abnormality is detected, a 10ns-level high-speed optocoupler and a fast shutdown drive chip are used, and a shutdown signal is transmitted and executed within 30ns; S603: After shutdown, record the fault type and parameters, send an alarm message, and perform a system self-check after troubleshooting, and after the self-check passes and the fault, wait for >=5 minutes, gradually restore the module work and restart the protection logic.

[0015] Compared with the prior art, the beneficial effects of the present application are: 1. The SiC device is used to construct the interleaved PFC and LLC resonant topology, the switching frequency is increased to 100kHz-500kHz, the loss is reduced by combining the soft switching control, the limitation of high frequency of traditional Si device is solved, and the charging pile energy efficiency and power density are greatly improved; 2. Through the multi-level EMI suppression module and dynamic parameter adjustment, the electromagnetic interference problem caused by the high switching speed of SiC is solved, and the electromagnetic compatibility requirement is met; 3. Based on the junction temperature prediction model and the liquid cooling-air cooling mixed structure, active precooling and dynamic heat dissipation adjustment are realized, the problem of rapid rise of SiC device junction temperature is solved, and the stability of the device under high temperature working condition is ensured; 4. Through cooperative communication with BMS and adaptive control strategy, different vehicle charging requirements are adapted, and the problems of compatibility and insufficient intelligence of traditional systems are solved; The present application adopts SiC devices and efficient topology and combines soft switching control, greatly improves the energy efficiency and power density of the charging pile, solves the high switching speed interference problem through EMI suppression and dynamic parameter adjustment, relies on junction temperature prediction and mixed heat dissipation to ensure high temperature stability, and combines fast shutdown and multi-dimensional protection to improve safety, cooperates with BMS and adaptive control to enhance adaptability and intelligence, and realizes efficient and reliable intelligent operation. BRIEF DESCRIPTION OF DRAWINGS

[0016] Fig. 1 A block diagram of a direct current charging pile control system based on SiC devices is provided for the present application; Fig. 2 A flowchart of a direct current charging pile control method based on SiC devices is provided for the present application. DETAILED DESCRIPTION

[0017] The present application will be further described below in conjunction with specific embodiments. EMBODIMENT

[0018] Reference Figs. 1-2The embodiment proposes a DC charging pile control system based on SiC devices, which comprises a controller, an input rectification and power factor correction (PFC) unit, a high-frequency DC / DC conversion unit, a gate drive and dynamic parameter adjustment module, a multi-level EMI suppression module, a thermal management and temperature prediction module, a safety protection module, and a charging control and communication module. The input rectification and PFC unit adopts SiC MOSFET to form an interleaved or three-level Boost structure, realizes high-frequency PFC adjustment, improves the input power factor, and reduces the input side harmonics. The input end of the input rectification and PFC unit adopts three-phase rectification and interleaved PFC, each phase of which adopts two-stage SiC MOSFET interleaving to reduce current ripple and increase switching frequency to ≥100 kHz. The high-frequency DC / DC conversion unit adopts SiC devices to form an LLC resonant or full-bridge phase shift soft switching topology, realizes high-efficiency isolated high-frequency conversion, the resonant frequency is 100 kHz-500 kHz, soft switching is realized through frequency modulation, and switching loss is reduced. The gate drive and dynamic parameter adjustment module adjusts the gate resistance in real time according to the device temperature, current, and dv / dt, realizes overshoot suppression and EMI optimization; the gate drive and dynamic parameter adjustment module comprises an adjustable gate resistance network and a feedback adjustment circuit, which is used to automatically adjust the switching slope according to the transient current of the SiC device. The multi-level EMI suppression module comprises a high-precision Hall current sensor, a common-mode / differential-mode filter, an optimized wiring of SiC high-frequency switches, a shielding structure, and a variable switching slope control unit. The thermal management and temperature prediction module is based on the SiC device junction temperature model, the heat sink thermal resistance model, and the fan / liquid cooling control strategy, and realizes active heat dissipation adjustment. The thermal management and temperature prediction module adopts a hybrid structure of liquid cooling plate and intelligent air cooling, and predicts the future ΔT of the SiC device based on the thermal resistance model, realizes pre-cooling control in advance. The safety protection module comprises a short-circuit protection circuit, an over-voltage protection circuit, an over-temperature protection circuit, an over-current protection circuit, and a fast shutdown circuit. The charging control and communication module communicates with the vehicle BMS through CAN, Ethernet or PLC, and realizes constant voltage / constant current / impulse charging strategy.

[0019] The embodiment also proposes a DC charging pile control method based on SiC devices, comprising the following steps: S1: Input state detection and PFC soft start: The input voltage, power grid frequency, and harmonic conditions are detected through voltage division, differential amplifier, and high-bandwidth current shunt of the input rectification and PFC unit, the interleaved PFC is started, and the control parameters are adaptively adjusted according to the power grid ripple. Among them, the input state detection adopts voltage division and differential amplifier and high-bandwidth current shunt, and the input voltage, power grid frequency and harmonic conditions are obtained by high-speed ADC in a synchronous sampling manner. The controller performs synchronous DFT / Goertzel operation on the data in the sampling window to obtain the fundamental amplitude, phase and 3, 5 and 7 times high-order harmonic amplitudes in real time, so as to calculate the THD and the equivalent impedance on the grid side. Based on these detection quantities, the controller adopts an adaptive strategy to adjust the control parameters in the PFC soft start stage. The adaptive strategy is: when the THD exceeds the preset threshold, gradually increase the gate resistance Rg to reduce the dv / dt of the device, and reduce the PFC controller bandwidth and / or switching frequency in proportion to reduce EMI; when the grid impedance estimation value is too large, automatically reduce the controller bandwidth and limit the transient power output to avoid oscillation; S2: SiC device high-frequency switching optimization control: the gate drive and dynamic parameter adjustment module collects the gate voltage, drain-source voltage, switching current and dv / dt, di / dt change rate, realizes soft switching operation through gate dynamic resistance adjustment, phase shift adjustment and resonant frequency tracking, and reduces the overshoot caused by dv / dt and EMI; The specific logic steps are as follows: S201: The controller collects the gate voltage, drain-source voltage, switching current, main circuit inductance and capacitance voltage and current, and the real-time change rate of dv / dt and di / dt in real time, and the sampling frequency is ≥5-10MHz; S202: The controller calculates the optimal gate resistance according to the current switching current and a preset table, and the formula used is: , where I rises, R needs to be increased g to control dv / dt, T rises, R needs to be increased appropriately g to prevent overshoot, according to R g , the controller selects a multi-stage controllable gate resistance array as the optimal gate resistance, and checks dv / dt, wherein the dv / dt checking condition is: , if the threshold is exceeded, Rg is automatically increased; S203: The controller calculates: in real time from the converter topology, and detects the zero voltage condition to determine whether the following conditions are met: , and I sw is in the correct direction, if ZVS can be realized, if adjust to enhance power transmission, so that the inductance current is closer to the zero voltage point when it crosses the zero point; S204: Calculate the equivalent resonant frequency: , and calculate the deviation: , where f sw is the current switching frequency, and if Δf> 0 Lower f sw If Δf < 0, increase f sw and keep ; S205: Comprehensive R g Control, phase shift control and f r Tracking, with "soft switching effect E" ss As an evaluation indicator, the formula used is: If E ss Set a threshold and adjust the priority rules accordingly. Specifically: prioritize phase shift correction; if ZVS cannot be achieved, increase the gate impedance; if dv / dt is still high, adjust the switching frequency f. r near; S3: DC / DC level adaptive energy transfer regulation: The high-frequency DC / DC converter unit dynamically adjusts the duty cycle and switching frequency according to the vehicle charging demand and bus voltage; S4: Multi-level EMI suppression control: The high-precision Hall current sensor of the multi-level EMI suppression module monitors the common-mode current in real time, and adjusts the switching slope, drive voltage and PWM mode through the digital controller; The specific logical steps are as follows: S401: Employs a high-precision Hall current sensor, which collects common-mode current in real time based on the Hall effect, providing data support for EMI suppression. V H Hall voltage, K H V is the intrinsic coefficient of the Hall element. H For common-mode current, by measuring V H I can be calculated CM ; S402: Controller Comparison I CM When the threshold is exceeded, the switching speed is controlled by adjusting the gate resistance to reduce dv / dt and di / dt. The switching speed is related to the gate resistance R. g Inversely proportional, R g Increasing the value reduces the switching speed, indirectly suppressing EMI. In engineering, this can be achieved by adjusting the value by I. CM Over-threshold ratio adaptation R g Increment; S403: Regulates drive voltage via power management chip I CM When it is large, reduce it appropriately. ,reduce It can reduce EMI energy while ensuring normal switching of devices; S404: According to I CM Adjusting PWM parameters and EMI intensity I CM If it is too high, it can be reduced. ; S5: Thermal management strategy execution: The thermal management and temperature prediction module adjusts the cooling system operating parameters in advance according to the junction temperature prediction model to realize active pre-cooling or limit the switching frequency; The specific logic steps are as follows: S501: Based on the SiC device junction temperature prediction model and the heat sink thermal resistance model, input real-time power consumption and environmental temperature parameters to predict the junction temperature, and perform junction temperature preheating calculation, the formula used is: Where T j is the junction temperature, Where P c is the conduction loss, is the switching loss, is the junction-to-case thermal resistance, and T j is the case temperature; S502: According to the T f prediction result, adjust the liquid cooling and air cooling parameters, the formula used is: Where V d is the cooling liquid flow rate, P p is the power consumption, is the cooling liquid density, and c f is the specific heat capacity. Adjust the water pump speed to match V j , and adjust the fan speed through PWM; S503: When T s approaches the threshold value, increase the cooling system power to realize active pre-cooling. If pre-cooling is ineffective, reduce the switching frequency f j to reduce , control heat production, and trigger frequency limitation when T exceeds the upper limit of the normal range and cooling adjustment is ineffective; S6: Safety protection execution: The safety protection module detects abnormalities through the Rogowski coil, resistance voltage division, thermistor, and current sensor. After detecting an abnormality, the SiC device is turned off in 100 ns and the protection logic is restarted; The specific logic steps are as follows: S601: Multi-dimensional abnormality detection: Short circuit detection, overvoltage detection, overtemperature detection, and overcurrent detection are performed respectively. The short circuit detection is performed by monitoring the current through the Rogowski coil, which satisfies to determine short circuit; overvoltage detection is performed by resistance voltage division to collect voltage, which satisfies to determine overvoltage; overtemperature detection is performed by monitoring temperature through the thermistor, to determine overtemperature; overcurrent detection is performed by monitoring through the current sensor, which satisfies to determine overcurrent; S602: When an abnormality is detected, a 10 ns level high-speed optocoupler and a fast turn-off drive chip are used to transmit and execute the turn-off signal within 30 ns; S603: Record fault type and parameters after shutdown, send alarm information, and perform system self-check after troubleshooting, pass the self-check, wait for ≥5 minutes after the fault, and gradually restore the module work restart protection logic; S7: Charging state adjustment and communication: The charging control and communication module interacts with the BMS through CAN, Ethernet or PLC to exchange power, voltage and temperature data, and adjusts the constant current stage, voltage rising rate and cutoff condition according to the BMS instruction; The embodiment adopts SiC devices and high-efficiency topology and combines soft switching control to greatly improve the charging pile energy efficiency and power density, solves the high switching speed interference problem through EMI suppression and dynamic parameter adjustment, guarantees high temperature stability relying on junction temperature prediction and hybrid heat dissipation, improves safety by matching fast turn-off and multi-dimensional protection, enhances adaptability and intelligence by combining BMS cooperation and adaptive control, and realizes efficient and reliable intelligent operation.

[0020] The above describes only the preferred specific embodiments of the present application, but the protection scope of the present application is not limited thereto, any person skilled in the art can make equivalent replacement or change according to the technical solution and inventive concept of the present application within the technical range disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A DC charging pile control system based on SiC devices, characterized in that, It includes a controller, an input rectification and power factor correction (PFC) unit, a high-frequency DC / DC converter unit, a gate drive and dynamic parameter tuning module, a multi-level EMI suppression module, a thermal management and temperature prediction module, a safety protection module, and a charging control and communication module. The input rectification and power factor correction (PFC) unit uses SiC MOSFETs to form an interleaved or three-level Boost structure to achieve high-frequency PFC regulation, improve the input power factor, and reduce input-side harmonics. The high-frequency DC / DC converter unit uses SiC devices to form an LLC resonant or full-bridge phase-shift soft-switching topology to achieve high-efficiency isolated high-frequency conversion. The resonant frequency is 100kHz-500kHz. Soft switching is achieved through frequency modulation to reduce switching losses. The gate drive and dynamic parameter tuning module adjusts the gate resistance in real time according to the device temperature, current and dv / dt to achieve overshoot suppression and EMI optimization. The multi-level EMI suppression module includes a high-precision Hall current sensor, a common-mode / differential-mode filter, SiC high-frequency switch optimized wiring, a shielding structure, and a variable switch slope control unit. The thermal management and temperature prediction module is based on the SiC device junction temperature model, the heat sink thermal resistance model, and the fan / liquid cooling control strategy to achieve active heat dissipation regulation. The safety protection module includes a short-circuit protection circuit, an overvoltage protection circuit, an overtemperature protection circuit, an overcurrent protection circuit, and a fast shutdown circuit. The charging control and communication module communicates with the vehicle's BMS via CAN, Ethernet, or PLC to implement constant voltage / constant current / pulse charging strategies.

2. The DC charging pile control system based on SiC devices according to claim 1, characterized in that, The gate drive and dynamic parameter tuning module includes an adjustable gate resistor network and a feedback adjustment circuit, which are used to automatically adjust the switching slope according to the transient current of the SiC device.

3. The DC charging pile control system based on SiC devices according to claim 1, characterized in that, The thermal management and temperature prediction module adopts a hybrid structure of liquid cooling plate and intelligent air cooling, and predicts the future ΔT of SiC device based on thermal resistance model to achieve pre-cooling control.

4. The DC charging pile control system based on SiC devices according to claim 1, characterized in that, The input of the input rectification and power factor correction (PFC) unit adopts three-phase rectification and interleaved PFC, wherein each phase PFC uses two-stage SiC MOSFETs interleaved to reduce current ripple and increase the switching frequency to ≥100kHz.

5. A control method for a DC charging pile based on SiC devices, applied to the system described in any one of claims 1-4, characterized in that, Includes the following steps: S1: Input status detection and PFC soft start: The input voltage, grid frequency and harmonic conditions are detected by the voltage divider, differential amplifier and high bandwidth current shunt of the input rectification and power factor correction PFC unit. The interleaved PFC is started and the control parameters are adaptively adjusted according to the grid ripple. S2: Optimized high-frequency switching control of SiC devices: The gate drive and dynamic parameter tuning module collects gate voltage, drain-source voltage, switching current and dv / dt and di / dt rate of change. Soft switching operation is achieved through gate dynamic resistance adjustment, phase shift adjustment and resonant frequency tracking to reduce overshoot and EMI caused by dv / dt. S3: DC / DC level adaptive energy transfer regulation: The high-frequency DC / DC converter unit dynamically adjusts the duty cycle and switching frequency according to the vehicle charging demand and bus voltage; S4: Multi-level EMI suppression control: The high-precision Hall current sensor of the multi-level EMI suppression module monitors the common-mode current in real time, and adjusts the switching slope, drive voltage and PWM mode through the digital controller; S5: Thermal Management Strategy Execution: The thermal management and temperature prediction module adjusts the operating parameters of the cooling system in advance based on the junction temperature prediction model to achieve active precooling or limit the switching frequency. S6: Safety protection execution: The safety protection module detects anomalies using Rogowski coils, resistor voltage dividers, thermistors, and current sensors. Upon detecting an anomaly, it quickly shuts down the SiC device and restarts the protection logic within 100ns. S7: Charging Status Adjustment and Communication: The charging control and communication module uses CAN, Ethernet or PLC to interact with the BMS to exchange power, voltage and temperature data, and adjusts the constant current stage, voltage rise rate and cutoff conditions according to BMS instructions.

6. The DC charging pile control method based on SiC devices according to claim 5, characterized in that, In S1, the input state detection employs a voltage divider, a differential amplifier, and a high-bandwidth current shunt. A high-speed ADC synchronously samples the input voltage, grid frequency, and harmonics. The controller performs synchronous DFT / Goertzel operations on the data within the sampling window to obtain the fundamental amplitude, phase, and amplitudes of the 3rd, 5th, and 7th harmonics in real time, thereby calculating the THD and the grid-side equivalent impedance. Based on these detected quantities, the controller employs an adaptive strategy to adjust control parameters during the PFC soft-start phase. The adaptive strategy is as follows: when the THD exceeds a preset threshold, the gate resistor Rg is gradually increased to reduce the device's dv / dt, and the PFC controller bandwidth and / or switching frequency are proportionally reduced to reduce EMI; when the grid resistance estimate is too high, the controller bandwidth is automatically reduced and transient power output is limited to avoid oscillation.

7. The DC charging pile control method based on SiC devices according to claim 5, characterized in that, The specific logical steps of S2 are as follows: S201: The controller collects the gate voltage, drain-source voltage, switching current, main circuit inductor and capacitor voltage and current, as well as the real-time rate of change of dv / dt and di / dt in real time, and the sampling frequency is ≥5-10MHz. S202: The controller calculates the optimal gate resistance based on the current switching current and a preset table. The formula used is: As I increases, R needs to be increased. g To control dv / dt and increase T, R needs to be increased appropriately. g To prevent overshoot, according to R g The controller selects a multi-stage controllable gate resistor array as the optimal gate resistor and verifies dv / dt, where the dv / dt verification constraint is: If the threshold is exceeded, Rg will be automatically increased. S203: The controller obtains this information in real time from the converter topology: And detect the zero-voltage condition, and determine whether the following conditions are met: And I sw The direction is correct, if it satisfies ZVS can be implemented if the conditions are not met. Adjustment Enhanced power transfer makes the inductor current closer to zero voltage when crossing zero. S204: Calculate the equivalent resonant frequency: And calculate the deviation: , where f sw Given the current switching frequency, if Δf > 0 Lower f sw If Δf < 0, increase f sw and keep ; S205: Comprehensive R g Control, phase shift control and f r Tracking, with "soft switching effect E" ss As an evaluation indicator, the formula used is: If E ss Set a threshold and adjust the priority rules accordingly. Specifically: prioritize phase shift correction; if ZVS cannot be achieved, increase the gate impedance; if dv / dt is still high, adjust the switching frequency f. r near.

8. A method for a DC charging pile based on SiC devices according to claim 5, characterized in that, The specific logical steps of S4 are as follows: S401: Employs a high-precision Hall current sensor, which collects common-mode current in real time based on the Hall effect, providing data support for EMI suppression. V H Hall voltage, K H V is the intrinsic coefficient of the Hall element. H For common-mode current, by measuring V H I can be calculated CM ; S402: Controller Comparison I CM When the threshold is exceeded, the switching speed is controlled by adjusting the gate resistance to reduce dv / dt and di / dt. The switching speed is related to the gate resistance R. g Inversely proportional, R g Increasing the value reduces the switching speed, indirectly suppressing EMI. In engineering, this can be achieved by adjusting the value by I. CM Over-threshold ratio adaptation R g Increment; S403: Regulates drive voltage via power management chip I CM When it is large, reduce it appropriately. ,reduce It can reduce EMI energy while ensuring normal switching of devices; S404: According to I CM Adjusting PWM parameters and EMI intensity I CM If it is too high, it can be reduced. .

9. A method for a DC charging pile based on SiC devices according to claim 5, characterized in that, The specific logical steps of S5 are as follows: S501: Based on the SiC device junction temperature prediction model and heat sink thermal resistance model, it predicts the junction temperature by inputting real-time power consumption and ambient temperature parameters, and performs junction temperature preheating calculations. The formula used is: T j For the junction temperature, ,in For conduction loss, For switching losses, For the junction thermal resistance, T c The shell temperature; S502: According to T j Based on the predicted results, the liquid cooling and air cooling parameters are adjusted using the following formula: V f P is the coolant flow rate. d For power consumption, c is the density of the coolant. p To determine the specific heat capacity, the pump speed is adjusted to match V. f Air cooling uses PWM to adjust the fan speed; S503: When T j When the threshold value is approached, the cooling system power is increased to achieve active precooling; if precooling is ineffective, the switching frequency f is reduced. s In order to reduce Control heat production, and T j Frequency limit is triggered when the frequency exceeds the upper limit of the normal range and cooling adjustment is ineffective.

10. A method for a DC charging pile based on SiC devices according to claim 5, characterized in that, The specific logical steps of S6 are as follows: S601: Multi-dimensional anomaly detection: Performs short-circuit detection, overvoltage detection, overtemperature detection, and overcurrent detection respectively. During short-circuit detection, the current is monitored via a Rogowski coil, meeting the following requirements: Short circuit detection; overvoltage detection uses a resistor divider to collect the voltage, which meets the requirements. Overvoltage and overtemperature detection are performed by monitoring temperature using a thermistor. Over-temperature detection; over-current detection is performed via a current sensor, and the following conditions are met. Determine if there is an overcurrent. S602: When an anomaly is detected, the 10ns-level high-speed optocoupler and fast shutdown driver chip transmit and execute the shutdown signal within 30ns. S603: After shutdown, record the fault type and parameters, send alarm information, and perform system self-test after the fault is cleared. If the self-test passes and the fault is cleared, wait for ≥5 minutes before gradually restoring the module's operation and restarting the protection logic.

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