Lightning protection and detection circuit

Abstract

The utility model provides a lightning protection and detection circuit, which comprises a surge absorption circuit and a detection circuit, and is characterized in that the detection circuit is used for detecting whether the surge absorption circuit is in an effective state or not; the detection circuit comprises high-voltage diodes D1, D2 and D3, a relay K1, a current fuse FUSE4, an optocoupler U1, a current-limiting resistor, a high-voltage diode D4 and optocoupler output divider resistors R4 and R5, the high-voltage diodes D1, D2 and D3 are respectively connected to each phase in the surge absorption circuit, the relay K1 is used for carrying out open circuit detection and connection detection, the current-limiting resistor is used for current limiting of the optocoupler U1, the high-voltage diode D4 is used for protecting the optocoupler U1 from reverse voltage withstanding, and the optocoupler output divider resistors R4 and R5 are connected to VCC. And one end, connected with the optocoupler U1, of the resistor F4 is an ADC output detection sampling point.

Description

TECHNICAL FIELD

[0001] The utility model relates to lightning protection and detection circuit. BACKGROUND

[0002] The alternating current charging pile needs to have a surge absorption function for protecting the working circuit of the charging pile, and the three-phase alternating current charging pile generally selects a surge absorption module installed on a DIN track to realize the function requirement, and the surge absorption module installed on the DIN track is generally visually inspected to check the effectiveness of the function, which is not conducive to the realization of online detection of the function by the charging pile, and at the same time, the DIN track module occupies a large space, which is not conducive to circuit integration and reduction of the volume of the entire charging pile.

[0003] The three-phase alternating current charging pile needs to use a surge absorption circuit, in order to avoid the problem of high-temperature combustion after the surge protector fails, a temperature fuse is generally selected to be added in front of the main device MOV to protect it, so as to avoid the problem of high-temperature combustion, and such a modular product is installed on a DIN track, has a large volume, and is visually inspected to check the effectiveness, which is not conducive to the realization of the online detection function. SUMMARY

[0004] The main technical problem to be solved by the utility model is to provide a lightning protection and detection circuit, which can conveniently realize whether the surge absorption circuit is effective.

[0005] In order to solve the above technical problems, the utility model provides a lightning protection and detection circuit, which comprises: a surge absorption circuit and a detection circuit, the detection circuit is used for detecting whether the surge absorption circuit is in an effective state;

[0006] The detection circuit comprises high-voltage diodes D1, D2 and D3 connected to each phase of the surge absorption circuit respectively, a relay K1 used for open circuit detection and on detection, a current fuse FUSE4, an optical coupler U1, a current limiting resistor used for current limiting of the optical coupler U1, a high-voltage diode D4 used for protecting the optical coupler U1 from reverse voltage resistance, and optical coupler output voltage dividing resistors R4 and R5, the resistor R5 is connected to VCC, and one end of the resistor F4 connected to the optical coupler U1 is an ADC output detection sampling point.

[0007] In a preferred embodiment, the surge absorption circuit comprises pressure sensitive resistors MOV1, MOV2, MOV3 and MOV4, wherein MOV4 is connected to a zero line, MOV1, MOV2 and MPV3 are connected to three-phase live lines through current fuses FUSE1, FUSE2 and FUSE3 respectively.

[0008] In a preferred embodiment: the cathode of the high-voltage diode D1 is connected to one end of MOV1 and FUSE1; the cathode of the high-voltage diode D2 is connected to one end of MOV2 and FUSE2; the cathode of the high-voltage diode D3 is connected to one end of MOV3 and FUSE3.

[0009] In a preferred embodiment: one end of MOV1, MOV2, MOV3 and MOV4 is connected and connected to the diode negative of optocoupler U1 through current-limiting resistors R1, R2 and R3, and the diode positive of optocoupler U1 is connected to IN_I N through the high-voltage diode D4.

[0010] In a preferred embodiment: the voltage dividing resistor R5 is connected between the collector of the triode of optocoupler U1 and VCC, and the voltage dividing resistor R4 is connected between the emitter of the triode of optocoupler U1 and GND. BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1 The circuit diagram of the preferred embodiment of the utility model; DETAILED DESCRIPTION

[0012] In order to make the technical scheme and characteristics of the utility model more clear, the utility model will be further described in detail in combination with the drawings and specific examples, and it should be understood that these examples are only used to illustrate the utility model and not used to limit the scope of the utility model, and after reading the utility model, various equivalent forms of the utility model modified by those skilled in the art all fall within the scope defined by the claims attached to the present application.

[0013] REFERENCE Figure 1 The embodiment provides a lightning protection and detection circuit for an alternating current charging pile, which comprises a surge absorption circuit and a detection circuit, and the detection circuit is used for detecting whether the surge absorption circuit is in an effective state.

[0014] The detection circuit comprises high-voltage diodes D1, D2 and D3 connected to each phase in the surge absorption circuit respectively, a relay K1 used for open circuit detection and on detection, a current fuse FUSE4, an optocoupler U1, a current-limiting resistor used for current limiting of the optocoupler U1, a high-voltage diode D4 used for protecting the optocoupler U1 from reverse withstand voltage, and voltage dividing resistors R4 and R5 of an optocoupler output, wherein the resistor R5 is connected to VCC, and one end of the resistor F4 connected to the optocoupler U1 is an ADC output detection sampling point.

[0015] In this embodiment, a three-phase AC charging pile is taken as an example. The surge absorption circuit includes MOV1, MOV2, MOV3 and MOV4. MOV4 is connected to the zero line. MOV1, MOV2 and MPV3 are respectively connected to the three-phase live line through current fuses FUSE1, FUSE2 and FUSE3. If it is a single-phase charging pile, MOV2 and MOV3 and the corresponding current fuses FUSE2 and FUSE3 can be removed.

[0016] The cathode of the high-voltage diode D1 is connected to one end of MOV1 and FUSE1. The cathode of the high-voltage diode D2 is connected to one end of MOV2 and FUSE2. The cathode of the high-voltage diode D3 is connected to one end of MOV3 and FUSE3. One end of MOV1, MOV2, MOV3 and MOV4 is connected and connected to the diode negative of optocoupler U1 through current limiting resistors R1, R2 and R3. The diode positive of optocoupler U1 is connected to N_IN through the high-voltage diode D4.

[0017] The voltage dividing resistor R5 is connected between the collector of the triode of the optocoupler U1 and VCC. The voltage dividing resistor R4 is connected between the emitter of the triode of the optocoupler U1 and GND.

[0018] First, when selecting devices, the current carrying capacity of the GDT should be more than twice the maximum current carrying capacity of the MOV to realize that the bottleneck of the surge absorption circuit is not on the GDT.

[0019] When the relay K1 is not turned on, the circuit is used to detect whether MOV1, 2, 3 is in normal state. When in normal state, the detection ADC voltage should be 0 potential. If a non-zero fixed period pulse potential appears, it means that at least one MOV has been damaged and the surge absorption circuit has failed.

[0020] When the relay K1 is not turned on and the detection is qualified, K1 is turned on for detection. It is detected whether MOV4 and FUSE1, 2, 3 are in normal state. At this time, the normal state of the surge absorption circuit should be that the ADC signal presents a periodic fluctuation signal with a period of 3 times the power frequency. (When the power frequency is 50 Hz, the signal period is 150 Hz. When the power frequency is 60 Hz, the signal frequency is 180 Hz). If there is no periodic fluctuation signal after turning on or a unique pulse signal appears and then returns to 0 potential, it means that MOV4 has been damaged. If a non-3 times power frequency periodic fluctuation signal is received after turning on, it means that at least one of FUSE1, 2, 3 has been blown and the surge absorption circuit has failed.

[0021] In the embodiment, the alternating current charging pile is taken as an example, and actually, the lightning protection and detection circuit is not only suitable for the charging pile, but also can be suitable for other electrical appliances which need lightning protection and detection.

[0022] The above is only one specific embodiment of the present application, but the design concept of the present application is not limited thereto, and any non-substantial modification of the present application using this concept shall be deemed as an infringement of the protection scope of the present application.

Claims

1. A lightning protection and detection circuit, characterized by Comprise: Surge absorption circuit and detection circuit, the detection circuit is used for detecting whether the surge absorption circuit is in the effective state; The detection circuit includes high voltage diode D1, D2, D3 connected to each phase of surge absorption circuit respectively, relay K1 for open circuit detection and on detection, current fuse FUSE4, optocoupler U1, current limiting resistor for limiting the current of optocoupler U1 and high voltage diode D4 for protecting optocoupler U1 from reverse withstand voltage, and optocoupler output voltage dividing resistor R4 and R5, resistor R5 is connected to VCC, and one end of resistor F4 connected to optocoupler U1 is ADC output detection sampling point.

2. The lightning protection and detection circuit for an AC charging pile according to claim 1, characterized in that: The surge absorption circuit includes voltage-dependent resistor MOV1, MOV2, MOV3 and MOV4, wherein MOV4 is connected to the zero line, and MOV1, MOV2 and MPV3 are connected to three-phase live line through current fuse FUSE1, FUSE2 and FUSE3 respectively.

3. The lightning protection and detection circuit for an AC charging pile according to claim 2, characterized in that: The cathode of the high voltage diode D1 is connected to one end of MOV1 and FUSE1; the cathode of the high voltage diode D2 is connected to one end of MOV2 and FUSE2; the cathode of the high voltage diode D3 is connected to one end of MOV3 and FUSE3.

4. The lightning protection and detection circuit for an AC charging pile according to claim 3, characterized in that: One end of the MOV1, MOV2, MOV3 and MOV4 is connected and connected to the diode negative of the optocoupler U1 through the current limiting resistor R1, R2 and R3, and the diode positive of the optocoupler U1 is connected to the IN_IN end through the high voltage diode D4.

5. The lightning protection and detection circuit for an AC charging pile according to claim 4, characterized in that: The voltage dividing resistor R5 is connected between the collector of the triode of the optocoupler U1 and VCC, and the voltage dividing resistor R4 is connected between the emitter of the triode of the optocoupler U1 and GND.

Images