Charging pile diode detection circuit

Abstract

The utility model relates to the field of charging pile detection circuits, in particular to a charging pile diode detection circuit which comprises an operational amplifier and a sampling circuit, a first input phase of the operational amplifier is used for being connected with a CP point of a charging pile circuit, and a second input phase of the operational amplifier is connected with a negative voltage source. The input end of the sampling circuit is connected with the output end of the operational amplifier, and the output end of the sampling circuit is connected with a controller. Whether the diode exists or not can be detected, so that charging can be carried out more safely and reliably.

Description

Technical Field

[0001] The present application relates to the field of charging pile detection circuits, and in particular to a charging pile diode detection circuit. Background Art

[0002] During the charging process of electric vehicles, the CP signal (control pilot function signal) plays a vital role. It is responsible for monitoring the interaction between the electric vehicle and the charging pile. The national standard requires that the circuit of the vehicle terminal charging pile CP should be as follows. Figure 1 The CP point of the charging pile circuit is located before the anode of the diode Diode.

[0003] However, in the existing technology, the CP control guide usually uses a signal modulated on the power sine wave, which means that when the charging device is connected to the electric vehicle, it must rely on the detection of the diode Diode to ensure the safety of charging. If the diode Diode is not placed on the CP control guide, the system will not be able to distinguish whether it is an electric vehicle or other load equipment connected, which may lead to serious safety hazards. Therefore, how to effectively detect the existence of the diode Diode has become a technical problem that needs to be solved urgently. In addition, according to the national standard 18487-2023 version, the charging pile needs to detect whether the diode Diode in the CP circuit exists. Utility Model Content

[0004] In order to detect whether a diode exists so that charging can be performed more safely and reliably, the present application provides a charging pile diode detection circuit.

[0005] The present application provides a charging pile diode detection circuit, which adopts the following technical solution:

[0006] A charging pile diode detection circuit includes an operational amplifier and a sampling circuit, wherein the first input phase of the operational amplifier is used to connect to the CP point of the charging pile circuit, the second input phase of the operational amplifier is connected to a negative voltage source, the input end of the sampling circuit is connected to the output end of the operational amplifier, and the output end of the sampling circuit is connected to a controller.

[0007] By adopting the above technical solution, when the charging pile is plugged into the car charging interface, the CP point outputs a PWM waveform as specified in the standard. This design uses an operational amplifier to compare the CP voltage with the negative voltage source voltage. If the vehicle interface has Figure 2 If there is a diode in the circuit, the output end of the sampling circuit outputs a PWM wave, and the microcontroller can detect the PWM wave after voltage division; if there is no diode, the output end of the sampling circuit outputs a constant low level and the PWM wave cannot be detected, so that it is possible to detect whether there is a diode, which can make charging safer and more reliable.

[0008] Preferably, a first diode is connected between the output end of the operational amplifier and the sampling circuit, an anode of the first diode is connected to the output end of the operational amplifier, and a cathode of the first diode is connected to the input end of the sampling circuit.

[0009] By adopting the above technical solution, the first diode can be used as a voltage limiting element to prevent excessive voltage from being input into the operational amplifier, thereby protecting it from damage. When the input voltage exceeds the forward conduction voltage of the first diode, the first diode will begin to conduct, directing the excess voltage to the ground or other appropriate potential to ensure the safety of the operational amplifier; the first diode has unidirectional conductivity, which can ensure that the signal can only flow from one direction to another. By properly configuring the first diode, unwanted reverse current or signal interference can be prevented.

[0010] Preferably, it also includes a first inductor, a first resistor, a first capacitor, a second capacitor and a Zener diode, the first inductor and the first resistor are connected in series with each other, the first inductor and the first resistor are connected between the operational amplifier and the CP point of the charging pile circuit, and the first capacitor and the second capacitor are both connected in parallel with the Zener diode.

[0011] By adopting the above technical solution, by introducing the first inductor, the first resistor, the capacitor and other components, the noise and interference signals from the charging pile circuit can be effectively filtered out, and only low-frequency signals are allowed to pass, thereby improving the stability and reliability of the signal; the addition of the voltage regulator provides an overvoltage protection function for the circuit. When an abnormally high voltage appears in the circuit, the voltage regulator can absorb the excess voltage to prevent it from damaging other circuit components, thereby improving the safety and durability of the entire circuit.

[0012] Preferably, the first resistor is connected in parallel with a second diode.

[0013] By adopting the above technical solution, when the second diode and the first resistor are connected in parallel, they can withstand a larger current and play a shunt role. When the current in the circuit is too large, the diode can share part of the current, thereby protecting the resistor and other circuit components from damage by the excessive current.

[0014] Preferably, it also includes a second resistor, a third resistor and a fourth resistor, one end of the second resistor is connected to the first input of the operational amplifier, the other end of the second resistor is connected to the first resistor, one end of the third resistor is connected to the second input of the operational amplifier, the other end of the third resistor is connected to a negative voltage source, one end of the fourth resistor is connected between the third resistor and the second input of the operational amplifier, and the other end of the fourth resistor is grounded.

[0015] By adopting the above technical solution, the fourth resistor is a balancing resistor for eliminating zero drift. In addition, the combination of the third resistor and the fourth resistor may be used for voltage division of the input signal to ensure that the input of the operational amplifier is within its linear operating range to avoid saturation or distortion; the second resistor can protect the safety of the operational amplifier.

[0016] Preferably, a third capacitor and a fourth capacitor are also included, one end of the third capacitor is connected to the positive power supply of the operational amplifier, and the other end of the third capacitor is grounded, one end of the fourth capacitor is connected to the negative power supply of the operational amplifier, and the other end of the fourth capacitor is grounded.

[0017] By adopting the above technical solution, the capacitor has the function of filtering noise. Connecting a capacitor to the power line and grounding it can effectively filter out high-frequency noise or stray signals that may exist in the power supply, ensuring the purity of the power supply of the operational amplifier. This helps to improve the signal-to-noise ratio of the operational amplifier output and make the circuit more stable and reliable.

[0018] Preferably, the sampling circuit includes a fifth resistor, a sixth resistor and a fifth capacitor, one end of the fifth resistor is connected to the cathode of the first diode, the other end of the fifth resistor is connected to the controller, one end of the sixth resistor is connected to the other end of the fifth resistor, the other end of the sixth resistor is grounded, and the fifth capacitor is connected in parallel with the sixth resistor.

[0019] By adopting the above technical solution, the amplified signal output from the operational amplifier is divided by the fifth resistor and the sixth resistor, and the fifth capacitor is used to filter out the clutter coupled into the circuit.

[0020] Preferably, it also includes a third diode and a fourth diode, the cathode of the third diode is connected to one end of the fifth resistor, the anode of the third diode is grounded, the anode of the fourth diode is connected to one end of the fifth resistor, and the cathode of the fourth diode is connected to a 3.3V voltage.

[0021] By adopting the above technical solution, the third diode and the fourth diode constitute a clamping diode, so that the sampling signal obtained after voltage division is clamped within a certain range.

[0022] In summary, the present application includes at least one of the following beneficial technical effects:

[0023] 1. When the charging pile is plugged into the car charging port, the CP point outputs a PWM waveform as specified in the standard. This design uses an operational amplifier to compare the CP voltage with the negative voltage source voltage. If the vehicle interface has Figure 2If the diode exists, the output end of the sampling circuit outputs a PWM wave, and the single-chip microcomputer can detect the PWM wave after voltage division; if there is no diode, the output end of the sampling circuit outputs a constant low level, and the PWM wave cannot be detected, so that the presence of the diode can be detected, so that charging can be more safe and reliable;

[0024] 2. The first diode can be used as a voltage-limiting element to prevent excessive voltage from being input into the operational amplifier, thereby protecting it from damage. When the input voltage exceeds the forward conduction voltage of the first diode, the first diode will begin to conduct, directing the excess voltage to the ground or other appropriate potential to ensure the safety of the operational amplifier; the first diode has unidirectional conductivity, which can ensure that the signal can only flow from one direction to another. By properly configuring the first diode, unwanted reverse current or signal interference can be prevented;

[0025] 3. By introducing the first inductor, the first resistor, the capacitor and other components, the noise and interference signals from the charging pile circuit can be effectively filtered out, and only low-frequency signals are allowed to pass, thereby improving the stability and reliability of the signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a circuit that the existing Chinese standard requires the vehicle to be connected to the charging pile CP.

[0027] Figure 2 It is a circuit diagram of the charging pile diode detection circuit of Example 1.

[0028] Figure 3 It is a circuit diagram of the charging pile diode detection circuit of Example 2.

[0029] Figure 4 This is a circuit diagram of the charging pile diode detection circuit of Example 3. DETAILED DESCRIPTION

[0030] The present application is further described in detail below in conjunction with all the accompanying drawings.

[0031] Embodiment 1 discloses a charging pile diode detection circuit. Figure 1 , Figure 2A charging pile diode detection circuit includes an operational amplifier and a sampling circuit. The first input phase of the operational amplifier is negative, and the second input phase of the operational amplifier is positive. The first input phase of the operational amplifier is connected to a second resistor R2. The other end of the second resistor is connected to the CP point of the charging pile circuit through the CP negative OUT interface. The second input phase of the operational amplifier is connected to a negative voltage source. The negative voltage source voltage is negative 12V and it is a negative voltage of the CP generating circuit, specifically a negative 12V voltage of a PWM signal of a charging pile CP product. The input end of the sampling circuit is connected to the output end of the operational amplifier, and the output end of the sampling circuit is connected to a controller, so that the controller determines whether there is a diode at the vehicle end by detecting whether there is a continuous high-level frequency of 1khz PWM waveform. The controller adopts a single-chip microcomputer chip. The controller can be connected to an alarm or a display screen to prompt whether there is a continuous high-level frequency of 1khz PWM waveform.

[0032] It also includes a third capacitor C3, a fourth capacitor C4, a third resistor R3 and a fourth resistor R4, the second input phase of the operational amplifier is connected to the third resistor, the other end of the third resistor is connected to a negative 12V power supply, one end of the fourth resistor is connected between the third resistor and the second input phase of the operational amplifier, and the other end of the fourth resistor is grounded. Figure 2 The comparison voltage is generated by the negative 12V voltage of the PWM signal of the charging pile CP product through resistors R3 and R4 to ground. The comparison voltage = -12V*R1 / (R1+R2), which is required to be greater than -12V*3 / 4, that is, R1 / (R1+R2)>3 / 4.

[0033] In addition, one end of the third capacitor is connected to the positive power supply 12V of the operational amplifier, and the other end of the third capacitor is grounded. One end of the fourth capacitor is connected to the negative power supply 12V of the operational amplifier, and the other end of the fourth capacitor is grounded.

[0034] The sampling circuit includes a voltage divider sampling circuit including a third diode D3, a fourth diode D4, a fifth resistor R5, a sixth resistor R6 and a fifth capacitor C5, one end of the fifth resistor is connected to the cathode of the first diode, the other end of the fifth resistor is connected to the controller through the Check_diode_exsitt output interface, one end of the sixth resistor is connected to the other end of the fifth resistor, the other end of the sixth resistor is grounded, the fifth resistor and the sixth resistor divide the signal output by the operational amplifier, one end of the fifth capacitor is connected to the other end of the fifth resistor, and the other end of the fifth capacitor is grounded, thereby filtering out the clutter coupled into the circuit, the cathode of the third diode is connected to one end of the fifth resistor, the positive pole of the third diode is grounded, the anode of the fourth diode is connected to one end of the fifth resistor, the cathode of the fourth diode is connected to a positive 3.3V voltage, which can be provided by a switching power supply, and the third diode and the fourth diode constitute a clamping diode, so that the sampling signal obtained after voltage division is clamped within a certain range to protect the controller.

[0035] Example 1 The implementation principle of a charging pile diode detection circuit is: CP minus OUT corresponds to Figure 1CP point in, when the charging pile is in standby, the CP voltage is positive 12V plus or minus 0.8V according to the national standard, then the comparison voltage at the positive end of the comparator is less than the CP voltage at the negative end of the comparator, so the comparator outputs negative 12V. Because there is a diode in the detection circuit, the Check_diode_exsitt interface outputs 0V; when the charging pile is plugged into the car charging interface, the output is a PWM waveform as specified in the national standard, with a PWM high point voltage of positive 12V, a low point voltage of negative 12V, and a frequency of 1kHz. If there is a diode at the vehicle end, the CP is divided by the vehicle end diode and R3_vehicle to cause the CP signal to be a PWM signal of positive 9V plus or minus 0.8V to negative 12V plus or minus 0.8V. Compared with the comparison voltage at the comparator end, the positive end voltage is greater than the negative end voltage or less than the negative end voltage, so the output is a PWM signal of positive or negative 12V, then Check_diode _exsit interface outputs square wave signal; if there is no diode on the vehicle side, then after CP is divided by R3_vehicle, CP outputs positive and negative 9V PWM signal, then the positive end of the comparator is smaller than the negative end, and outputs negative 12V, so Check_diode_exsit interface outputs constant 0V; therefore, by detecting whether there is a continuous high-level waveform with a frequency of 1khz, it is judged whether there is a diode on the vehicle side; before charging, in accordance with the national standard requirements, s2_vehicle on the vehicle side is closed, and the positive and negative 12V PWM signals are divided after being connected in parallel by R2_vehicle and R3_vehicle. When a diode exists, CP outputs positive 6V, positive and negative 0.8V and negative 12V PWM signals, and Check_diode_exsit interface outputs 1kHz waveform; if there is no diode on the vehicle side, it outputs 0V; the presence of a diode is detected by detecting whether there is a continuous 1kHz waveform.

[0036] Embodiment 2 discloses a charging pile diode detection circuit. Figure 2 , Figure 3 The difference between Example 2 and Example 1 is that a first inductor L1, a first resistor R1, a first capacitor C1, a second capacitor C2 and a Zener diode TS2 are arranged between the operational amplifier U1A and the CP negative OUT interface, the other end of the second resistor is connected to the first resistor, the other end of the first resistor is connected to the first inductor, the other end of the first inductor is connected to the CP negative OUT interface, one end of the Zener diode is connected between the first inductor and the CP negative OUT interface, and the other end of the Zener diode is grounded, one end of the first capacitor is connected between the first inductor and the CP negative OUT interface, the other end of the first capacitor is grounded, the second capacitor is between the first inductor and the first resistor, and the other end of the second capacitor is grounded, the first resistor is connected in parallel with a second diode D2, the anode of the second diode is connected to the first inductor, and the cathode of the second diode is connected to the second resistor.

[0037] Embodiment 2 The implementation principle of a charging pile diode detection circuit is as follows: by introducing the first inductor, the first resistor, the capacitor and other components, the noise and interference signals from the charging pile circuit can be effectively filtered out, and only low-frequency signals are allowed to pass, thereby improving the stability and reliability of the signal; the addition of the voltage regulator provides an overvoltage protection function for the circuit. When an abnormally high voltage appears in the circuit, the voltage regulator can absorb the excess voltage to prevent it from damaging other circuit components, thereby improving the safety and durability of the entire circuit.

[0038] Embodiment 3 discloses a charging pile diode detection circuit. Figure 2 , Figure 4 The difference between Example 3 and Example 1 is that the first input phase of the operational amplifier is a positive phase, and the second input phase is a negative phase.

[0039] Embodiment 3 The implementation principle of a charging pile diode detection circuit is as follows: when the charging pile gun end is inserted into the vehicle, according to the national standard, CP outputs a 1kHz PWM wave with a frequency of positive and negative 12V. If there is a diode at the vehicle end, CP divides the voltage through the vehicle end diode and R3_vehicle, resulting in a CP signal of positive 9V positive and negative 0.8V to negative 12V positive and negative 0.8V PWM signal. Compared with the comparison voltage at the comparator end, the positive end voltage is greater than the negative end voltage and less than the negative end voltage, so the output is a PWM signal of positive and negative 12V, and the Check_cp_exsit interface outputs a square wave signal; if there is no diode at the vehicle end, CP outputs a PWM signal of positive and negative 9V after being divided by R3_vehicle, then the positive end of the comparator is greater than the negative end, and the output is positive 12V, so Check_cp_exsit outputs a constant high level; therefore, it is determined whether there is a diode at the vehicle end by detecting whether there is a continuous high-level waveform with a frequency of 1khz.

[0040] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A charging pile diode detection circuit, characterized in that: It includes an operational amplifier and a sampling circuit, wherein the first input phase of the operational amplifier is used to connect to the CP point of the charging pile circuit, the second input phase of the operational amplifier is connected to a negative voltage source, the input end of the sampling circuit is connected to the output end of the operational amplifier, and the output end of the sampling circuit is connected to a controller.

2. A charging pile diode detection circuit according to claim 1, characterized in that: A first diode is connected between the output end of the operational amplifier and the sampling circuit, an anode of the first diode is connected to the output end of the operational amplifier, and a cathode of the first diode is connected to the input end of the sampling circuit.

3. A charging pile diode detection circuit according to claim 1, characterized in that: It also includes a first inductor, a first resistor, a first capacitor, a second capacitor and a Zener diode. The first inductor and the first resistor are connected in series with each other. The first inductor and the first resistor are connected between the operational amplifier and the CP point of the charging pile circuit. The first capacitor and the second capacitor are both connected in parallel with the Zener diode.

4. A charging pile diode detection circuit according to claim 3, characterized in that: The first resistor is connected in parallel with a second diode.

5. A charging pile diode detection circuit according to claim 1, characterized in that: It also includes a second resistor, a third resistor and a fourth resistor, one end of the second resistor is connected to the first input of the operational amplifier, the other end of the second resistor is connected to the first resistor, one end of the third resistor is connected to the second input of the operational amplifier, the other end of the third resistor is connected to a negative voltage source, one end of the fourth resistor is connected between the third resistor and the second input of the operational amplifier, and the other end of the fourth resistor is grounded.

6. A charging pile diode detection circuit according to claim 1, characterized in that: It also includes a third capacitor and a fourth capacitor, one end of the third capacitor is connected to the positive power supply of the operational amplifier, and the other end of the third capacitor is grounded, one end of the fourth capacitor is connected to the negative power supply of the operational amplifier, and the other end of the fourth capacitor is grounded.

7. A charging pile diode detection circuit according to claim 2, characterized in that: The sampling circuit includes a fifth resistor, a sixth resistor and a fifth capacitor, one end of the fifth resistor is connected to the cathode of the first diode, the other end of the fifth resistor is connected to the controller, one end of the sixth resistor is connected to the other end of the fifth resistor, the other end of the sixth resistor is grounded, and the fifth capacitor is connected in parallel with the sixth resistor.

8. A charging pile diode detection circuit according to claim 7, characterized in that: It also includes a third diode and a fourth diode, wherein the cathode of the third diode is connected to one end of the fifth resistor, the anode of the third diode is grounded, the anode of the fourth diode is connected to one end of the fifth resistor, and the cathode of the fourth diode is connected to a 3.3V voltage.

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