Direct current input type charging pile with current backup protection function
By introducing current backup protection function into the DC input charging pile, the input power is quickly cut off by using the FPGA chip and Hall current sensor, the protection function failure caused by the failure of the converter module is solved, and the safety and conversion efficiency are improved. It is suitable for optical storage DC flexible DC microgrids.
Patent Information
- Application Number
- CN202422240200.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-12
- Publication Date
- 2025-08-19
- Estimated Expiration
- 2034-09-12
AI Technical Summary
The existing DC input charging piles fail when the converter module control chip fails or hardware is damaged, which may lead to accidents such as damage to the electric vehicle circuit or thermal runaway from the battery.
A DC input charging pile with current backup protection function was designed. Through hardware improvement and module combination, including the main control board, DC/DC converter module, input DC contactor, output DC contactor, charging gun, backup protection module, etc., the current is sampled by FPGA chip and Hall current sensor, and the input power is quickly cut off and the DC circuit breaker is used to achieve protection.
In the event of a failure of the DC/DC converter module, the input power is quickly cut off, which improves safety and reduces accidents. It is suitable for optical storage DC flexible DC microgrids, saving costs and improving conversion efficiency, and significantly improving safety and response speed.
Smart Images
Figure CN223237411U_ABST
Abstract
Description
Technical Field
[0001] The utility model provides a DC input type charging pile with a current backup protection function, belonging to the technical field of DC charging piles. Background Art
[0002] Charging piles are mainly used to replenish energy for electric vehicles. The input power supply of charging piles on the market is basically AC power. With the application and promotion of photovoltaic power generation, energy storage technology and photovoltaic-storage-direct-flexible-DC microgrids, DC input charging piles have become an important load in the system; DC input charging piles have certain protection functions, which are mainly achieved by the converter module inside the charging pile by stopping the output voltage; but when the control chip circuit inside the converter module itself fails and short-circuits or the control hardware is damaged, the protection function will fail. In severe cases, it may cause damage to the electric vehicle circuit or lead to accidents such as battery thermal runaway. Utility Model Content
[0003] In order to solve the problem that existing DC input charging piles do not have backup protection, the utility model proposes a DC input charging pile with current backup protection function, the purpose of which is to achieve safety protection for the DC input charging pile through hardware improvements or improvements to the combined connection of hardware modules and / or circuits.
[0004] In order to solve the above technical problems, the technical solution adopted by the utility model is: a DC input charging pile with current backup protection function, including a main control board, a DC / DC converter module, an input DC contactor, an output DC contactor and a charging gun, the input DC contactor is connected to the input end of the DC / DC converter module, the output end of the DC / DC converter module is connected to the output DC contactor, the output DC contactor is connected to the charging gun, a fuse is further connected between the DC / DC converter module and the output DC contactor, and a splitter is connected between the output DC contactor and the charging gun. The main control board is respectively connected to the input DC contactor, the DC / DC converter module, and the output DC contactor to send corresponding control signals. The main control board also collects the output voltage of the DC / DC converter module through the output voltage sampling circuit, and also includes a backup protection module. The backup protection module includes a backup protection board, an electric operating mechanism and an input circuit breaker. The input circuit breaker is connected to the input end of the input DC contactor. The backup protection board collects the input current signal through the input current sampling circuit. The backup protection board is also connected to the electric operating mechanism, and the electric operating mechanism is connected to the input circuit breaker.
[0005] The input current sampling circuit includes an AD sampling chip and a Hall current sensor. Input current terminals are respectively drawn from the input ends of the two input DC contactors. The two input current terminals are respectively connected to the Hall current sensors and then connected to the AD sampling chip.
[0006] The backup protection board uses an FPGA chip as a main chip.
[0007] The DC / DC converter module includes a high-voltage side full-bridge inverter circuit, a transformer T, a low-voltage side full-bridge rectifier circuit and a control module, wherein the high-voltage side full-bridge inverter circuit adopts an NPN transistor with four parallel diodes, and the low-voltage side full-bridge rectifier circuit adopts four diodes. Filter capacitors are provided on both the high-voltage and low-voltage sides of the DC / DC converter module. The control module is used to output a PWM pulse signal to the NPN transistor with four parallel diodes of the high-voltage side full-bridge inverter circuit.
[0008] The main control board is also connected to a card reader, a 4G module and a display screen.
[0009] It also includes an electric energy meter, which measures the voltage and current of the input charging gun through an output current sampling circuit and an output voltage sampling circuit respectively.
[0010] The input circuit breaker adopts the GM5-630M model DC circuit breaker, and the electric operating mechanism adopts the CD2-630 model, which can realize the remote control opening and closing function.
[0011] The DC / DC conversion converter module adopts an isolated circuit.
[0012] The control module uses a DSP chip as a main chip.
[0013] The FPGA chip outputs an action signal to the electric operating mechanism through a comparison logic circuit.
[0014] The beneficial effects of the present invention compared to the prior art are:
[0015] 1) This DC input charging pile can be better integrated into the photovoltaic and energy storage direct-flexible DC microgrid, using the DC bus of the DC microgrid itself as the input power supply. Compared with AC input charging piles, there is no input PFC power factor correction circuit, which can save costs and improve conversion efficiency. Because the DC microgrid bus is generally an ungrounded system, the DC input charging pile is safer. In theory, there is no grounding residual current, which can reduce the occurrence of electric shock accidents.
[0016] 2) This charging pile has a current backup protection function. When the protection function of the charging pile DC / DC converter module fails, it can still quickly cut off the input power according to the short-circuit current, which has higher safety.
[0017] 3) The backup protection of this charging pile is implemented through the control of the programmable logic circuit of the FPGA, with a fast response speed and a protection judgment time of no more than 1ms. The input circuit breaker adopts a DC circuit breaker with a stronger arc extinguishing function, which can disconnect the DC input power supply, and the mechanical action time is less than 10ms. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The present invention will be further described below with reference to the accompanying drawings:
[0019] Figure 1 This is the principle diagram of the input type DC charging pile proposed in this utility model;
[0020] Figure 2 This is the schematic diagram of the DC / DC module;
[0021] Figure 3 This is the schematic diagram of the backup protection board;
[0022] Figure 4 This is the logic diagram for backup protection. DETAILED DESCRIPTION
[0023] like Figures 1 to 4 As shown, the utility model provides a DC input charging pile with current backup protection function. The DC input rated voltage is 750V. The main power circuit consists of an input circuit breaker, an input DC contactor, a DC / DC converter module, a fuse, an output DC contactor, a shunt, and a charging gun. The control circuit consists of a main control board, a backup protection board, an electric energy meter, a display, a 4G module, a card reader, a current and voltage sampling circuit, etc. The DC input rated voltage of 750V supplies power to the input circuit breaker. The positive and negative DC power output by the input circuit breaker flows through the input DC contactor respectively and is connected to the positive and negative poles of the DC / DC converter module. The positive pole output of the DC / DC converter module passes through the fuse and the output DC contactor and is connected to the positive pole of the charging gun. The negative pole output of the DC / DC converter module passes through the output DC contactor and the shunt and is connected to the negative pole of the charging gun. The main control board is connected to the card reader, 4G module and display screen respectively, and the main control board is also connected to the positive input DC contactor, DC / DC converter module, and the positive output DC contactor respectively to send corresponding control signals. The main control board also collects the output voltage of the DC / DC converter module through the output voltage sampling circuit; the backup protection board collects the input current of the input circuit breaker through the input current sampling circuit, and the backup protection board is connected to an electric operating mechanism, which is used to remotely open and close the input circuit breaker; the electric energy meter collects the output voltage of the output DC contactor of the output current of the shunt through the output current sampling circuit and the output voltage sampling circuit respectively.
[0024] The DC / DC converter module includes a high-voltage side full-bridge inverter circuit, a transformer T, a low-voltage side full-bridge rectifier circuit and a control module. The high-voltage side full-bridge inverter circuit uses an NPN transistor with four parallel diodes, and the low-voltage side full-bridge rectifier circuit is composed of four diodes. Filter capacitors are provided on both the high-voltage and low-voltage sides of the DC / DC converter module.
[0025] The backup protection board uses an FPGA chip and a 3.3V power supply. The input current sampling circuit includes an AD sampling chip and a Hall current sensor. The electric operating mechanism includes a MOS drive circuit and a 24V power supply. The input current terminals are respectively drawn from the input ends of the two input DC contactors. The two input current terminals are respectively connected to the Hall current sensors and then connected to the AD sampling chip. The AD sampling chip is connected to the FPGA and sends the sampled input current to the backup protection board. The input end of the MOS tube drive circuit is connected to the FPGA, and the output end of the MOS tube drive circuit is connected to the input circuit breaker. The backup protection board controls the action of the MOS tube drive circuit after judging the sampled current, thereby controlling the opening and closing of the input circuit breaker.
[0026] The Hall current sensor used for current backup protection is CSM500LTB, which is a closed-loop sensor with a linearity of up to 0.1% and a response time of less than 1us.
[0027] The actuator for current backup protection consists of an electric operating mechanism and an input circuit breaker. The input circuit breaker adopts the GM5-630M model DC circuit breaker with a maximum breaking capacity of up to 65kA and a rated impulse voltage of up to 8kV. The electric operating mechanism adopts the CD2-630 model, which can realize remote control opening and closing functions.
[0028] The main chip of the backup protection board uses an FPGA programmable logic controller, model GW1N-1. The device has 1152 logic units and 96kbit user flash memory, and has the advantages of high speed, low cost and small size.
[0029] The AD chip of the backup protection board adopts ZJC2102-14, which has 14-bit accuracy, 600kSPS, and 8-channel sampling, and has high speed and high precision.
[0030] The DC / DC converter module used in the DC input charging pile has a rated input of 750V DC. The module has constant power control and relatively complete protection functions: input over / under voltage protection, output overvoltage protection, over-temperature protection, internal bus fault protection, and output short circuit protection. The circuit topology diagram is shown in Figure 2 .
[0031] The DC / DC converter module adopts an isolated circuit with an input voltage of 750V DC bus. The DSP chip in the control module outputs four PWM1, PWM2, PWM3, and PWM4 pulse signals to the power tubes V1, V2, V3, and V4. The primary and secondary windings of the high-frequency transformer T have magnetic circuit induction functions. The high-frequency pulse electricity of the primary winding will induce a high-frequency voltage in the secondary winding. This voltage passes through the rectifier current composed of fast recovery diodes VD1, VD2, VD3, and VD4, inductor L1, and filter capacitor C2 to output DC voltage U0, thereby charging the DC electric vehicle.
[0032] When the DSP chip of the DC / DC converter module detects a fault in the system such as input overvoltage / undervoltage, output overvoltage, overtemperature, internal bus fault short circuit, output short circuit, etc., it blocks the drive signals PWM1~PWM4 of the power tubes V1~V4, stops the DC output, and achieves the purpose of protecting the charging pile.
[0033] When the DSP system of the DC / DC converter module fails, the short-circuit fault protection will fail. At this time, the current backup protection control board circuit will provide backup protection for the system when a fault occurs, reducing the probability of accidents.
[0034] like Figure 3 Figure 2 shows the backup protection board schematic. The FPGA samples the input current and, through a comparison logic circuit, determines that when the input current exceeds twice the rated input current, the backup protection board immediately outputs a disconnect signal to the electric operating mechanism, which triggers the input circuit breaker to cut off the input power.
[0035] like Figure 4 Figure 2 shows the backup protection logic diagram. When the positive current |I+| exceeds the preset value, the MOS transistor conducts. When the positive current |I+| is less than the preset value and the negative current |I-| is greater than the preset value, the MOS transistor conducts.
[0036] The workflow of this utility model is as follows:
[0037] 1) During normal operation, after the charging gun is connected to the electric vehicle, the main control board receives the charging instruction of swiping the card or scanning the code, and immediately closes the input circuit breaker and the input DC contactor. 750V DC power is input to the DC / DC converter module. The main control board prepares for communication handshake with the electric vehicle before charging through the communication line in the charging gun, and performs a series of operations such as charging circuit insulation detection and electric vehicle BMS charging demand confirmation. After the charging ready conditions are met, the main control board controls the DC / DC converter module to output relevant DC current and DC voltage values for constant power charging. The energy meter can measure the amount of electricity charged by the electric vehicle, and the main control board can charge accordingly. The main control board confirms whether to end charging based on the electric vehicle BMS or the amount of electricity charged. Charging is terminated after the relevant conditions are met, and the charging pile user is prompted to remove the gun and return it to its position, waiting for the next charging.
[0038] 2) Charging Pile Backup Protection: This function circuit consists of an input current sampling circuit, a backup protection board, an electric operating mechanism, and an input circuit breaker. The backup protection board samples the input current via an FPGA and, through a comparison logic circuit, immediately outputs a disconnect signal to the electric operating mechanism when the input current exceeds twice the rated input current. The electric operating mechanism triggers the input circuit breaker to cut off the input power. This function can be used as backup protection in the event of a short circuit on the charging gun output side or a faulty short circuit caused by internal control failure of the charging pile's DC / DC converter module.
[0039] Regarding the specific structure of the present invention, it should be noted that the connection relationship between the various component modules adopted in the present invention is definite and feasible. Except for the special instructions in the embodiments, the specific connection relationship can bring about corresponding technical effects and solve the technical problems raised by the present invention without relying on the execution of the corresponding software program. The components, modules, models of specific components appearing in the present invention, the connection methods between each other, and the conventional usage methods and expected technical effects brought about by the above-mentioned technical features, except for the specific instructions, all belong to the disclosed contents in patents, journal articles, technical manuals, technical dictionaries, and textbooks that can be obtained by technical personnel in this field before the application date, or belong to the existing technologies such as conventional technology and common knowledge in this field, and there is no need to elaborate, so that the technical solution provided in this case is clear, complete, and feasible, and the corresponding physical products can be reproduced or obtained based on this technical means.
[0040] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention.
Claims
1. A DC input charging pile with current backup protection, comprising a main control board, a DC / DC converter module, an input DC contactor, an output DC contactor, and a charging gun, wherein the input DC contactor is connected to the input end of the DC / DC converter module, the output end of the DC / DC converter module is connected to the output DC contactor, and the output DC contactor is connected to the charging gun. A fuse is further connected between the DC / DC converter module and the output DC contactor, and a shunt is connected between the output DC contactor and the charging gun. The main control board is respectively connected to the input DC contactor, the DC / DC converter module, and the output DC contactor, and sends corresponding control signals. The main control board also collects the output voltage of the DC / DC converter module through an output voltage sampling circuit. The main control board is characterized in that: It also includes a backup protection module, which includes a backup protection board, an electric operating mechanism and an input circuit breaker. The input circuit breaker is connected to the input end of the input DC contactor. The backup protection board collects the input current signal through the input current sampling circuit. The backup protection board is also connected to the electric operating mechanism, and the electric operating mechanism is connected to the input circuit breaker.
2. The DC input charging pile with current backup protection function according to claim 1, characterized in that: The input current sampling circuit includes an AD sampling chip and a Hall current sensor. Input current terminals are respectively drawn from the input ends of the two input DC contactors. The two input current terminals are respectively connected to the Hall current sensors and then connected to the AD sampling chip.
3. The DC input charging pile with current backup protection function according to claim 1, characterized in that: The backup protection board uses an FPGA chip as a main chip.
4. The DC input charging pile with current backup protection function according to claim 1, characterized in that: The DC / DC converter module includes a high-voltage side full-bridge inverter circuit, a transformer T, a low-voltage side full-bridge rectifier circuit and a control module, wherein the high-voltage side full-bridge inverter circuit adopts an NPN transistor with four parallel diodes, and the low-voltage side full-bridge rectifier circuit adopts four diodes. Filter capacitors are provided on both the high-voltage and low-voltage sides of the DC / DC converter module. The control module is used to output a PWM pulse signal to the NPN transistor with four parallel diodes of the high-voltage side full-bridge inverter circuit.
5. A DC input charging pile with current backup protection function according to any one of claims 1 to 4, characterized in that: The main control board is also connected to a card reader, a 4G module and a display screen.
6. The DC input charging pile with current backup protection function according to claim 5, characterized in that: It also includes an electric energy meter, which measures the voltage and current of the input charging gun through an output current sampling circuit and an output voltage sampling circuit respectively.
7. The DC input charging pile with current backup protection function according to claim 1, characterized in that: The input circuit breaker adopts the GM5-630M model DC circuit breaker, and the electric operating mechanism adopts the CD2-630 model, which can realize the remote control opening and closing function.
8. The DC input charging pile with current backup protection function according to claim 4, characterized in that: The DC / DC converter module adopts an isolated circuit.
9. The DC input charging pile with current backup protection function according to claim 4, characterized in that: The control module uses a DSP chip as a main chip.
10. The DC input charging pile with current backup protection function according to claim 3, characterized in that: The FPGA chip outputs an action signal to the electric operating mechanism through a comparison logic circuit.