AC charging pile CP detection circuit for realizing diode existence detection

Abstract

The utility model discloses an AC charging pile CP detection circuit capable of realizing diode existence detection. The AC charging pile CP detection circuit comprises an isolation boost circuit, an isolation switching circuit, a CP voltage isolation sampling circuit and a diode existence detection and enable circuit. Wherein the isolation booster circuit is used for providing a power supply for the CP detection circuit; the isolation switching circuit is used for being connected to a vehicle CP control guiding circuit in combination with CP voltage output by the MCU. The CP voltage isolation sampling circuit is used for performing isolation sampling on the CP voltage and outputting the CP voltage to an ADC acquisition pin of the MCU; and the diode existence detection and enable circuit at least comprises two optocouplers, and outputs a low level or a high level to the IO detection pin of the MCU control unit of the charging pile through optocoupler isolation output and optocoupler isolation detection enable control. According to the technical scheme provided by the utility model, the circuit is simple and practical, a dual-power isolation module does not need to be additionally arranged, and the stability and reliability of the anti-interference capability of the whole processing circuit are improved.

Description

Technical Field

[0001] The utility model relates to the technical field of AC charging pile CP detection, in particular to an AC charging pile CP detection circuit for realizing diode existence detection. Background Art

[0002] Charging piles are energy supply equipment for electric vehicles. When using AC charging piles for conductive charging of electric vehicles, national standards require diode presence detection. This means that before energy transfer, the power supply equipment must be able to verify that the connected vehicle, not the load, is an electric vehicle by detecting the presence of diode D1 in the control pilot circuit. Existing detection solutions are complex and costly, requiring the addition of dual power isolation modules and lacking robustness and reliability. Utility Model Content

[0003] In order to overcome the shortcomings of the existing technology, an AC charging pile CP detection circuit for realizing diode presence detection is proposed.

[0004] An AC charging pile CP detection circuit for detecting the presence of a diode. The AC charging pile CP detection circuit communicates with the charging pile MCU control unit and includes an isolation boost circuit, an isolation switching circuit, a CP voltage isolation sampling circuit, and a diode presence detection and enabling circuit.

[0005] The isolated boost circuit is used to provide power to the AC charging pile CP detection circuit and includes at least one voltage regulator tube;

[0006] The isolation switching circuit is used to connect to the preset vehicle CP control steering circuit in combination with the CP voltage output by the charging pile MCU control unit, and includes at least one optical isolation switching logic IC;

[0007] The CP voltage isolation sampling circuit is used to isolate and sample the CP voltage and output it to the ADC acquisition pin of the charging pile MCU control unit;

[0008] The diode presence detection and enabling circuit includes at least two optocouplers, and outputs a low level or a high level to the IO detection pin of the charging pile MCU control unit through optocoupler isolation output and optocoupler isolation detection enable control.

[0009] Preferably, the isolated boost circuit further includes a rectifier and filter circuit including an isolated boost IC and an isolation transformer.

[0010] Preferably, the input of the isolated boost circuit is a single power supply voltage of 5V, and the output is positive and negative 12V.

[0011] Preferably, the isolation switching circuit further includes a self-recovery fuse device for overcurrent protection.

[0012] Preferably, the CP voltage isolation sampling circuit includes an isolation amplifier and an RC filter connected to the isolation amplifier; the output of the RC filter is connected to the ADC acquisition pin of the charging pile MCU control unit.

[0013] Preferably, the diode presence detection and enabling circuit includes a current limiting resistor connected to one of the optocouplers, and the current limiting resistor is connected to the output control pin of the charging pile MCU control unit.

[0014] Preferably, the diode presence detection and enabling circuit includes an operational amplifier connected to one of the optocouplers, and the output of the operational amplifier is connected to the IO detection pin of the charging pile MCU control unit.

[0015] Preferably, the diode presence detection and enabling circuit further includes a charging circuit composed of a first resistor, a second diode, and a fourth capacitor, and the charging circuit is used for rectification when the CP voltage is a preset value.

[0016] Preferably, the diode presence detection and enabling circuit further includes a voltage divider circuit composed of a fourth resistor and a fifth resistor.

[0017] Preferably, the diode presence detection and enabling circuit further includes a discharge circuit consisting of a sixth resistor and a fourth capacitor.

[0018] The AC charging pile CP detection circuit provided by this utility model implements diode presence detection. It mainly includes isolation boosting, isolation switching, CP voltage isolation sampling, and diode presence detection and enabling components. Through the voltage regulator tube, optocoupler isolation output, optocoupler isolation detection enable control, and detection output signal shaping circuit input to the MCU's IO detection pin, the diode presence can be detected. Compared with the existing technology, it has the following characteristics:

[0019] 1) The circuit is simple and practical. Optocoupler isolation prevents the CP detection circuit and the charging pile MCU control unit from interfering with each other, thereby improving the stability and reliability of the AC charging pile CP detection circuit.

[0020] 2) The power supply is powered by an isolated boost circuit that generates an isolated 12V dual voltage, eliminating the need for an additional dual power isolation module;

[0021] 3) The CP voltage isolation sampling circuit adopts a high-precision linear isolation AD sampling chip. While ensuring the accuracy of the collected voltage, it realizes the electrical isolation between the CP detection circuit and the charging pile MCU control unit, and improves the anti-interference ability, stability and reliability of the entire processing circuit.

[0022] 4) It has 12V CP detection voltage and PWM signal control functions with isolation function. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a block diagram of the principle of the AC charging pile CP detection circuit and the vehicle electrical connection for realizing diode presence detection;

[0024] Figure 2 This is a schematic diagram of an isolated boost circuit in an embodiment of the present utility model;

[0025] Figure 3 This is a schematic diagram of an isolation switching circuit in an embodiment of the present utility model;

[0026] Figure 4 Schematic diagram of the CP voltage isolation sampling circuit in an embodiment of the present utility model;

[0027] Figure 5 This is a schematic diagram of a diode presence detection and enabling circuit in an embodiment of the present utility model. DETAILED DESCRIPTION

[0028] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0029] Provided is an AC charging pile CP detection circuit for implementing diode presence detection, which is used to communicate with the charging pile MCU control unit and includes an isolation boost circuit, an isolation switching circuit, a CP voltage isolation sampling circuit and a diode presence detection and enable circuit; wherein, the isolation boost circuit is used to provide power to the AC charging pile CP detection circuit and includes at least one voltage regulator; the isolation switching circuit is used to connect the CP voltage output by the charging pile MCU control unit to a preset vehicle CP control steering circuit and includes at least one optical isolation switching logic IC; the CP voltage isolation sampling circuit is used to isolate and sample the CP voltage and output it to the ADC acquisition pin of the charging pile MCU control unit; the diode presence detection and enable circuit includes at least two optocouplers, and outputs a low level or a high level to the IO detection pin of the charging pile MCU control unit through the optocoupler isolation output and the optocoupler isolation detection enable control.

[0030] The principle block diagram of the AC charging pile CP detection circuit for realizing diode existence detection and the vehicle electrical connection is as follows: Figure 1 As shown, the input of the isolated boost circuit is a single power supply voltage of 5V, and the output is positive and negative 12V, that is, the isolated boost circuit adopts an isolated positive and negative 12V boost circuit.

[0031] Figure 1 The working principle is as follows: a single power supply voltage of 5V is input to the isolated positive and negative 12V boost circuit, which is converted into the ±12V power supply required by the AC charging pile CP detection circuit through a micro-power isolation power supply dedicated chip, isolation transformer, rectifier circuit, and voltage stabilization circuit; the output ±12V power supply is input to the isolation switching circuit, and the output CP voltage under the control of the AC charging pile controller MCU is connected to the vehicle CP control pilot circuit through resistor R1 to confirm the connection of the charging connection device and judge the rated current parameters.

[0032] In addition, the connection status between the charging pile device and the vehicle is determined by the state of switches S1 and S2 and the voltage divided by resistors R1, R2, and R3, namely the U1 voltage. The U1 voltage is input to the voltage divider, and the isolated sampling circuit inputs it to the ADC pin of the MCU. The voltage value collected by the MCU determines the current connection status: When switch S1 is connected to +12V:

[0033] 1) If U1 = 12V, it means the charging gun is not plugged into the vehicle socket;

[0034] 2) If U1 = 9V, it means R3 is detected and the charging gun is plugged into the vehicle socket;

[0035] 3) If U1 = 6V, it means R2 is detected and the vehicle switch S2 is closed.

[0036] The voltage of U1 is also input to the diode presence detection and enabling circuit. At this time, the presence of diode D is detected by detecting the negative 12V voltage:

[0037] 1) When diode D exists, the positive electrode of diode D is negative and the negative electrode is positive. Due to the unidirectional conductivity of the diode, a current loop cannot be formed. Therefore, regardless of whether R2 and R3 are detected, the voltage of U1 is always 12V.

[0038] 2) When diode D does not exist, the voltage of U1 is determined by the state of switches S1 and S2 and the voltage divider formed by resistors R1, R2, and R3. Therefore, the presence of diode D can be determined by the size of the voltage of U1.

[0039] 3) When diode D does not exist and R3 is detected, the voltage of U1 is equal to 9V; when diode D does not exist and R2 is detected, the voltage of U1 is equal to 6V. If both are less than 12V, it can be determined that diode D does not exist.

[0040] Specifically, if Figure 2As shown, the isolated boost circuit also includes a rectifier and filter circuit, including an isolated boost IC and an isolation transformer. In the figure, U1 is the isolated boost IC; T1 is the isolation transformer; D30-D34, C48, and C52 form the rectifier and filter circuit; Q107, R28, R49, R156, R157, R158, C5, and C6 form a high-precision 12V voltage regulator circuit. R28 and R49 are used for current limiting; R156, R157, and R158 form a voltage divider circuit; C5 and C6 provide power filtering; and R7 is a negative voltage load circuit, used to stabilize the -12V output voltage. C53 and C57 are negative 12V voltage filter capacitors, and C46 is a 5V input filter capacitor. CC_POWER is the enable control signal for the isolated boost chip; a high level allows normal operation; a low level disables operation. U2, C767, C188, and C69 form an LDO step-down circuit, which outputs a 5V power supply to other circuits.

[0041] In one implementation, Figure 3 As shown, the isolation switching circuit also includes a resettable fuse for overcurrent protection. In the figure, U3 is the opto-isolator switching logic chip; R183 is the LED current-limiting resistor; TIM9_PWPM1 is the MCU output PWM wave control signal, which controls the CP output voltage to +12V or -12V. R187 is a 1K resistor, which, combined with the vehicle resistor, establishes a connection confirmation level; TVS25 is an overvoltage protection device for preventing external excessive voltage input. F1 is a resettable fuse for overcurrent protection. CP_OUT is the CP output voltage.

[0042] In one implementation, Figure 4 As shown, the CP voltage isolation sampling circuit includes an isolation amplifier and an RC filter connected to the isolation amplifier. The output of the RC filter is connected to the ADC sampling pin of the charging pile's MCU control unit. In the figure, U4 is the isolation amplifier. The measured voltage CP passes through diode M7, which isolates it from the negative 12V voltage. Resistors R162 and R163 divide the voltage and input it to the positive input of the isolation amplifier. C100, C99, and R162 form an RC filter circuit to filter out voltage spikes that could affect voltage sampling accuracy and system reliability. C100, C99, and R163 form a discharge circuit to reduce the impact of voltage level delays, requiring measurement of voltage level changes within 10ms. C118 and C195 are U4's power supply filter capacitors. Rail-to-rail operational amplifier U8B, along with resistors R289, R290, R292, and R291, forms a 1.5x amplifier circuit with differential input and single voltage output. The RC filter formed by R293 and C293 inputs the MCU's ADC sampling pin, where the CP voltage is measured.

[0043] In one implementation, Figure 5As shown, the diode presence detection and enabling circuit includes a current-limiting resistor connected to an optocoupler, and the current-limiting resistor is connected to the output control pin of the charging pile MCU control unit; it also includes an operational amplifier connected to an optocoupler, and the output of the operational amplifier is connected to the IO detection pin of the charging pile MCU control unit; it also includes a charging circuit composed of a first resistor R1, a second diode D2, and a fourth capacitor C4, and the charging circuit is used for rectification when the CP voltage is a preset value; it also includes a voltage divider circuit composed of a fourth resistor R4 and a fifth resistor R5; it also includes a discharge circuit composed of a sixth resistor R6 and a fourth capacitor C4.

[0044] Specifically, U6 is the detection enable isolation control optocoupler; R9 is the current-limiting resistor; and Test_CTL is the output control signal of the AC charging pile MCU unit. A high level enables detection, while a low level disables it. This signal is used to cut off the detection circuit's connection to the CP voltage when not in the detection state. When the CP voltage is higher than -9.1V, Zener diode D1 is blocked, and optocoupler U5 is non-conductive. A +3.3V voltage flows through R1, D2, and R6, dividing the voltage and inputting it to the cathode of operational amplifier U8A. This +3.3V voltage is then divided by R1 and R5 and inputted to the anode of operational amplifier U8A. At this point, the voltage at the cathode of operational amplifier U8A is higher than the voltage at the anode, and the output is low to the MCU's IO detection pin.

[0045] When U6 is on and the CP voltage is below -10V, it exceeds the reverse voltage of the Zener diode. Reverse current flows through Zener diode D1, causing current to flow through the optocoupler U5's LED. Optocoupler CE turns on, grounding the positive terminal of D2 and cutting off D2. At this point, the negative terminal of operational amplifier U8A is grounded via resistor R6, reaching 0V. The positive input voltage is the 1.1V voltage divided by resistors R4 and R5, outputting a high level to the MCU's IO detection pin. R1, D2, and C4 form a charging circuit. When the CP input is a 1kHz square wave, the charging circuit is used for rectification. Combined with the R4 and R5 voltage divider circuit, this eliminates output fluctuations following the input and improves the stability of the detection circuit. R6 and C4 form a discharge circuit to reduce the impact of level delay changes, requiring the ability to measure level changes within 10ms.

[0046] In summary, the AC charging pile CP detection circuit for realizing diode presence detection has the following functions: 1) diode presence detection and isolation function; 2) ±12V voltage boost function; 3) CP voltage detection and isolation function; 4) ±12V PWM wave output and control function.

[0047] The above is an explanation of the AC charging pile CP detection circuit for realizing diode presence detection in the present invention, which is used to help understand the present invention; however, the implementation method of the present invention is not limited to the above-mentioned embodiment. Any changes, modifications, substitutions, combinations, and simplifications made without departing from the principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. An AC charging pile CP detection circuit for realizing diode presence detection, characterized in that: The AC charging pile CP detection circuit communicates with the charging pile MCU control unit and includes an isolation boost circuit, an isolation switching circuit, a CP voltage isolation sampling circuit, and a diode presence detection and enabling circuit; The isolated boost circuit is used to provide power to the AC charging pile CP detection circuit and includes at least one voltage regulator tube; The isolation switching circuit is used to connect to the preset vehicle CP control steering circuit in combination with the CP voltage output by the charging pile MCU control unit, and includes at least one optical isolation switching logic IC; The CP voltage isolation sampling circuit is used to isolate and sample the CP voltage and output it to the ADC acquisition pin of the charging pile MCU control unit; The diode presence detection and enabling circuit includes at least two optocouplers, and outputs a low level or a high level to the IO detection pin of the charging pile MCU control unit through optocoupler isolation output and optocoupler isolation detection enable control.

2. The AC charging pile CP detection circuit for realizing diode presence detection according to claim 1, characterized in that: The isolated boost circuit also includes a rectifier and filter circuit including an isolated boost IC and an isolation transformer.

3. The AC charging pile CP detection circuit for realizing diode presence detection according to claim 2, characterized in that: The input of the isolated boost circuit is a single power supply voltage of 5V, and the output is positive and negative 12V.

4. The AC charging pile CP detection circuit for realizing diode presence detection according to claim 1, characterized in that: The isolation switching circuit also includes a self-recovery fuse device for overcurrent protection.

5. The AC charging pile CP detection circuit for realizing diode presence detection according to claim 1, characterized in that: The CP voltage isolation sampling circuit includes an isolation amplifier and an RC filter connected to the isolation amplifier; the output of the RC filter is connected to the ADC acquisition pin of the charging pile MCU control unit.

6. The AC charging pile CP detection circuit for realizing diode presence detection according to claim 1, characterized in that: The diode presence detection and enabling circuit includes a current limiting resistor connected to the optocoupler, and the current limiting resistor is connected to the output control pin of the charging pile MCU control unit.

7. The AC charging pile CP detection circuit for realizing diode presence detection according to claim 6, characterized in that: The diode presence detection and enabling circuit includes an operational amplifier connected to the optocoupler, and the output of the operational amplifier is connected to the IO detection pin of the charging pile MCU control unit.

8. The AC charging pile CP detection circuit for realizing diode presence detection according to claim 7, characterized in that: The diode presence detection and enabling circuit further includes a charging circuit composed of a first resistor, a second diode, and a fourth capacitor. The charging circuit is used for rectification when the CP voltage is a preset value.

9. The AC charging pile CP detection circuit for realizing diode presence detection according to claim 8, characterized in that: The diode presence detection and enabling circuit further includes a voltage divider circuit composed of a fourth resistor and a fifth resistor.

10. The AC charging pile CP detection circuit for realizing diode presence detection according to claim 9, characterized in that: The diode presence detection and enabling circuit further includes a discharge circuit composed of a sixth resistor and a fourth capacitor.

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