Insulation detection module for charging gun

Abstract

The utility model discloses a charging gun system control circuit comprising a power supply module, a CPU module, a communication module, a charging gun control module and an insulation detection module, and the CPU module is respectively connected with the power supply module, the communication module, the charging gun control module and the insulation detection module. The charging gun control module comprises a direct current contactor, a power controller, a detection module and a gun lock control module, and the detection module comprises a temperature detection module, an auxiliary source detection module, a vehicle-mounted voltage detection module, a CC1 voltage detection module and a return lock feedback detection module. The temperature detection module, the auxiliary source detection module, the vehicle-mounted voltage detection module, the CC1 voltage detection module and the return lock feedback detection module are connected with the CPU module through the CAN module; the charging gun control module provided by the utility model has the advantages of simple and reliable internal circuit, low cost of a micro-control chip of the acquisition control circuit, modular design, reconfigurability, expandability and the like.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the technical field of charging gun, specifically relates to an insulation detection module for charging gun. BACKGROUND

[0002] With the increasing maturity and advancement of new energy automobile technology, the charging gun, a key accessory, plays an important role in the field of automobile charging. It is not only a bridge connecting energy and vehicles, but also an important carrier to promote the concept of green travel. The charging gun system control circuit is a key part of the electric vehicle charging system, which ensures that the electric energy is safely and effectively transmitted from the charging pile to the battery of the electric vehicle.

[0003] At present, the technology of charging gun system control circuit has been relatively mature. These systems usually include core components such as metering chip, rectifier bridge, optocoupler, MCU master chip, etc. However, there are still some problems. The charging gun system works under high current and high voltage, and the insulation monitoring may be short-circuited at high temperature, even causing fire and other serious consequences. SUMMARY

[0004] The utility model aims at providing an insulation detection module for charging gun, which adds an insulation detection circuit to the existing control circuit to solve the above problems.

[0005] To achieve the above purpose, the utility model adopts the following technical scheme:

[0006] An insulation detection module for charging gun, comprising a forward voltage collector, a negative voltage collector, a communication isolation module and a power isolation module.

[0007] The forward voltage collector is composed of a solid-state relay. After the forward voltage input, it enters the solid-state relay input terminal through a resistor. The output terminal of the solid-state relay outputs the forward voltage collection signal, and the control terminal of the solid-state relay is controlled by the switch of the CPU module. The negative voltage collector is composed of a following circuit connected behind the circuit of the forward voltage collector.

[0008] The communication isolation module is connected with the control system of the charging gun. The communication isolation module is realized by using RSM3485CT isolation chip. The output terminal of the RSM3485CT isolation chip is connected with common mode inductor, interference pulse absorption circuit and 485 communication impedance circuit in sequence.

[0009] The power isolation module is connected with a power module. The output terminal of the power isolation module is connected with the voltage feedback circuit through a filter circuit. The control terminal of the power isolation module is connected with the control system of the charging gun.

[0010] The charging gun control module has the advantages of simple internal circuit, reliability, low micro-control chip cost of the acquisition control circuit, modular design, reconfiguration, expansion and the like. BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1 It is the main structure block diagram of the utility model.

[0012] Figure 2 It is the power module circuit diagram.

[0013] Figure 3 It is the circuit diagram of CPU module.

[0014] Figure 4 It is the board temperature sensor circuit diagram.

[0015] Figure 5 It is the wired communication - Ethernet circuit diagram.

[0016] Figure 6 It is the wireless communication - ESP32 circuit diagram.

[0017] Figure 7 It is the direct current contactor circuit diagram.

[0018] Figure 8 It is the power controller circuit diagram.

[0019] Figure 9 It is the CAN communication module circuit diagram.

[0020] Figure 10 It is the temperature detection module circuit diagram.

[0021] Figure 11 It is the auxiliary source detection module circuit diagram.

[0022] Figure 12 It is the auxiliary source switch control module circuit diagram.

[0023] Figure 13 It is the vehicle-mounted voltage detection module circuit diagram.

[0024] Figure 14 It is the CC1 detection module circuit diagram.

[0025] Figure 15 It is the homing lock detection module circuit diagram.

[0026] Figure 16 It is the gun lock control module circuit diagram.

[0027] Figure 17 It is the circuit diagram of communication isolation module and power isolation module.

[0028] Figure 18 It is the insulation detection circuit diagram.

[0029] Figure 19 This is the circuit diagram of the PDU control module.

[0030] Figure 20 This is the circuit diagram for the isolation module.

[0031] Figure 21 This is a circuit diagram for the PDU power output drive. Detailed Implementation

[0032] like Figure 1 As shown, the charging gun system control circuit provided in this embodiment includes a power supply module, a CPU module, a communication module, a charging gun control module, and an insulation detection module. The power supply module provides operating voltage to the other modules, and the CPU module is connected to the communication module, the charging gun control module, and the insulation detection module.

[0033] The power module includes a DC 12V three-wire input circuit, a 5V regulated power supply circuit, and a 3.3V regulated power supply circuit connected in sequence; such as Figure 2 As shown, the DC 12V three-wire input circuit includes a positive (+12V), a negative (-12V), and an additional signal line (PE). A fuse F1 is connected after the positive (+12V) for overcurrent protection; then a varistor U1 is connected for overvoltage protection; then a pair of ferrite beads (L1 and L4) are connected to suppress high-speed pulses; and finally, a diode D1 is connected to prevent reverse connection. These four protection circuits ensure a stable input power supply. The power supply is then connected to a high-power MOSFET Q1, which controls the voltage. The gate of the high-power MOSFET Q1 is connected to a reference voltage, which is adjusted by two adjustable voltage reference devices U2 and U3 to ensure that the MOSFET Q1 is not affected by external interference fluctuations. The maximum output current of the high-power MOSFET Q1 can reach 10A, ensuring a stable current supply to the subsequent circuits. Both the 5V and 3.3V regulated power supply circuits use voltage regulator chips.

[0034] The CPU module is implemented using an ARM Cortex-M4 microcontroller, such as Figure 3 As shown, this embodiment specifically uses the STM32F413ZHT6 as the CPU main control chip. The STM32F413ZHT6 is an ARM Cortex-M4 microcontroller that integrates a DSP and an FPU. The MCU is equipped with 1.5MB of Flash memory, providing ample space for code and data storage. The maximum CPU frequency can reach 100 MHz, and it provides rich communication interfaces, including multiple USARTs, I2C, SPI, etc., facilitating communication with other devices. The PB1 pin of the CPU main control chip is connected to a temperature sensor RT1, such as... Figure 4As shown, it is used for temperature detection of the PCB circuit board.

[0035] The communication module is used to establish communication with a remote or mobile device. In this embodiment, the communication module includes a wired network communication module and a wireless network communication module. The wired network communication module uses the U9 Ethernet communication chip, such as... Figure 5 As shown, this embodiment uses the W5500 chip with SPI communication. The W5500 chip integrates a full hardware TCP / IP protocol stack, Ethernet data link layer (MAC) and physical layer (PHY), and supports high-speed standard 4-wire SPI interface for communication with the host. In this embodiment, an RJ45 connector is used to connect the W5500 chip to achieve communication with the host.

[0036] The wireless communication module is implemented using an ESP32 module. The ESP32 module supports both Bluetooth and WiFi communication, enabling easy connection to wireless networks and other Bluetooth devices for remote control and data transmission. Figure 6 As shown.

[0037] The charging gun control module is used to control the charging gun's charging and power-off. In this embodiment, it includes a DC contactor, a power controller, a detection module, and a gun lock control module. The number of charging gun control modules in this embodiment is determined according to the number of guns in the charging pile, and each charging gun is connected to a charging gun control module.

[0038] The DC contactor includes a positive optocoupler, a negative optocoupler, and a relay. Both the positive and negative optocouplers are connected to the relay. The circuit is as follows: Figure 7 As shown, isolation is achieved through an optocoupler, which also provides good electrical insulation and anti-interference capabilities. The connection and disconnection of the positive and negative optocouplers are controlled by a relay. This embodiment has two charging guns, each of which is connected to a DC contactor.

[0039] The power controller consists of four optocouplers and two relays, and the circuit is as follows: Figure 8 As shown, two relays constitute an energy distribution controller for overload protection, short circuit protection, undervoltage protection, overvoltage protection, and temperature protection. When overload, short circuit, undervoltage, overvoltage, or overtemperature occurs in the circuit, the relays can quickly cut off the power supply to protect electrical equipment and personnel safety. Four optocouplers constitute the feedback circuit of the charging gun power distributor, allowing energy to be mutually distributed when the two charging guns are idle. Dynamic energy distribution between the two charging guns improves overall efficiency and meets the charging needs of different electric vehicles, thereby optimizing power distribution and ensuring that each charging gun can provide appropriate charging power according to the specific needs of the connected electric vehicle.

[0040] The detection module includes a CAN communication module, a temperature detection module, an auxiliary power source detection module, and an auxiliary power source switch control module. The CAN communication module is used to establish communication between the vehicle and the charging pile, and is specifically implemented using a CTM1051A module. The circuit is as follows: Figure 9 As shown, pins 3 and 4 of the CTM1051A module U18 are connected to the CPU module, and pins 6 and 7 are connected to the vehicle via a filter circuit. A local area network (LAN) for the charging gun is established via CAN communication, enabling the transmission of detection data from each detection module to the CPU module. The temperature detection module is used to detect the charging gun temperature, preventing damage caused by high temperatures during use. Figure 10 As shown, the temperature detection module in this embodiment includes two sets of temperature sensors (LT1 and LT2), which are connected to the ADC unit of the CPU module through voltage followers.

[0041] To ensure stable operation of the charging station under various conditions, including power outages or main power failures, the auxiliary power supply can continue to power the charging station via backup batteries or generators. The auxiliary power supply detection module detects the operating voltage of the auxiliary power supply, typically 12V or 24V, and controls the switching circuit based on the detected voltage. Figure 11 As shown, the auxiliary power supply detection module of this application includes diode reverse connection protection input terminals (D50 and D54), linear regulator U12, operational amplifier circuit U11, and optocoupler OC9. The voltage of the auxiliary power supply is input to the linear regulator through the diode reverse connection protection input terminals, and then amplified by the operational amplifier circuit. The voltage output of the operational amplifier controls the conduction or disconnection of the optocoupler. When the voltage of the auxiliary power supply is 12V, the output of the operational amplifier circuit is a high level of 5V, the optocoupler is turned on, and pin 4 of the optocoupler is at a low level. In this case, L_ASS_TEST is detected as low. Conversely, if there is no voltage input from the auxiliary power supply, pin 4 of the optocoupler is at a high level, and L_ASS_TEST is detected as high.

[0042] The auxiliary power supply switch control module is used to determine whether to start power supply based on the result of the auxiliary power supply detection module, such as... Figure 12 As shown, it includes a transistor Q6 and a power relay K4. The base of transistor Q6 is connected to the CPU module, and the collector is connected to the power relay K4. The CPU module turns on transistor Q6 by inputting a high level, which in turn activates the power relay K4. In this embodiment, a diode D52 is connected in parallel between the transistor and the power relay to eliminate the reverse electromotive force of the relay. The power relay is connected to the auxiliary power supply, thereby enabling the start-up of the auxiliary power supply and providing 12V power to the vehicle.

[0043] The PDU control module incorporates a BDR6122H chip to control the auxiliary power supply's PDU; for example... Figure 19As shown, an isolation module is connected before the input of the BDR6122H chip, such as... Figure 20 and 21 As shown, when K1+_con1 is high, K1+_con2 is low, relay OC5 is on, and relay OC7 is off. K1+_IN1 outputs high, K1+_IN2 outputs low, K1+_REL- is high (12V), and K1+_REL+ is low, turning on the magnetic latching relay REL1. When K1+_con1 is low, K1+_con2 is high, relay OC5 is off, and relay OC7 is on. K1+_IN1 outputs low, K1+_IN2 outputs high, K1+_REL- is low (12V), and K1+_REL+ is high, turning off the magnetic latching relay REL1.

[0044] The on-board voltage detection module is used to detect whether any additional voltage is entering during the charging process, such as... Figure 13 As shown, this application is constructed using a transistor Q31 and a relay OC38. The base of the transistor Q31 is connected to the vehicle interface, and the relay OC38 is connected to the collector and the CPU module. When the vehicle interface is energized, the relay OC38 is activated.

[0045] The CC1 voltage detection module is suitable for detecting the insertion / removal status of the plug-in / removal gun. This embodiment adds isolation processing, using an isolation power supply U37 to separate the supply voltage and the detection voltage to achieve plug-in / removal status detection. Figure 14 As shown, the isolation power supply U37 outputs L_CC1_12V, D55 is a power indicator, and L_CC1_12V powers the operational amplifier U41. Resistors R134 and R133 provide a reference voltage of approximately 9.1K / 29.1K*12V=3.7V. When no gun is inserted, VREF=9V, relay OC10 and U41 output a high level, L_CC1_TEST1 detects a high level, and the CPU module detects that no gun is inserted. Conversely, when a gun is inserted, CC1 is connected to the 500R resistor at the vehicle end to ground. At this time, VREF=3.1V, relay OC10 and U41 output a low level, L_CC1_TEST1 outputs a low level, and the system detects that a gun is inserted.

[0046] The return-to-position feedback detection module is used to detect whether the charging gun has been placed in its correct position, such as... Figure 15 As shown, a return lock switch composed of relay OC12 is used. When the charging gun is returned to its position, the return lock is closed, the relay is turned on, the relay output is low level, and the CPU module detects that the charging gun has been placed in its position.

[0047] The gun lock control circuit incorporates the BDR6122T chip U16 and an H-bridge motor forward and reverse rotation circuit, such as Figure 16As shown, this controls the locking and unlocking of the gun lock. L_LOCK_CON1 and L_LOCK_CON2 are the output control ports. Both ports cannot be high at the same time. If they are both high, it may burn out the BDR6122T chip. Transistors Q7 and Q8 prevent the two ports from being high at the same time. L_IN1 and L_IN2 are high and low level inputs, and L_EL+ and L_EL- are high and low level outputs to control the gun lock.

[0048] The insulation detection module is used for insulation detection under high voltage and high current conditions, such as... Figure 17 As shown, it includes a communication isolation module and a power isolation module. The communication isolation module uses an RSM3485CT isolation chip U27 for connection to the CPU module. The output terminals (pins 8-10) of the RSM3485CT isolation chip U27 are sequentially connected to a common-mode inductor FL3, an interference pulse absorption circuit, and a 485 communication impedance circuit. The common-mode inductor FL3 filters out common-mode interference signals. The interference pulse absorption circuit is composed of diodes D92, D90, D93, D91, and D94, which absorb external interference pulses. The 485 communication impedance circuit inputs and outputs to the insulation detection interface for communication.

[0049] The power isolation module is connected to the power module. The 12V power supply is connected to the input terminal (pin 2) of the isolation module U48 through resistor R501. The output terminal (pins 1 and 3) of the isolation module U48 is connected to the voltage feedback circuit through the filter circuit and outputs a 5V voltage. The control terminal (pin 7) of the isolation module U48 is connected to the CPU module. The control signal (IMD_POW) controls the power-on and power-off functions of U48.

[0050] The insulation detection circuit described in this embodiment includes a positive voltage acquisition unit and a negative voltage acquisition unit. The positive voltage acquisition unit is composed of a solid-state relay D1. After the positive voltage (BAT2+) is input, it enters the input terminal (pin 8) of the solid-state relay D1 through resistors (R4, R12). The output terminals (5, 6, 7) of the solid-state relay D1 output positive voltage acquisition signals (AIN12 and AIN13). The control terminal (pin 1) of the solid-state relay D1 is controlled by the PB11 switch of the CPU module. Pins (2, 3) of the solid-state relay D1 are selected and shorted by resistors (R5, R6) to realize a resistor balance bridge. The negative voltage acquisition unit refers to the circuit after which a voltage follower and voltage inversion circuit U1 is connected to the circuit of the positive voltage acquisition unit to realize the voltage inversion and following functions.

[0051] This embodiment also includes other control modules of existing charging guns, such as serial port screen control module, light control module, card swiping module, etc. These modules are all existing and have not been substantially improved, so they will not be described in detail in this embodiment.

[0052] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any modifications and substitutions based on the technical solutions and utility model concepts provided by the present utility model should be covered within the protection scope of the present utility model.

Claims

1. An insulation detection module for a charging gun, characterized in that: It includes a positive voltage acquisition unit, a negative voltage acquisition unit, a communication isolation module, and a power isolation module; The positive voltage acquisition unit is composed of a solid-state relay. After the positive voltage is input, it passes through a resistor to the input terminal of the solid-state relay. The output terminal of the solid-state relay outputs a positive voltage acquisition signal. The control terminal of the solid-state relay is controlled by the switch of the CPU module. The negative voltage acquisition unit is composed of a follower and voltage inversion circuit connected after the circuit of the positive voltage acquisition unit. The communication isolation module is connected to the control system of the charging gun. The communication isolation module is implemented using an RSM3485CT isolation chip. The output terminal of the RSM3485CT isolation chip is connected in sequence to a common mode inductor, an interference pulse absorption circuit, and a 485 communication impedance circuit. The power isolation module is connected to a power module. The output of the power isolation module is connected to a voltage feedback circuit through a filter circuit. The control terminal of the power isolation module is connected to the control system of the charging gun.

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