An AC transfer circuit with self-checking function
By designing an AC adapter circuit with self-test function in the charging device, detecting abnormal situations of the neutral wire, ground wire and relay electrical contacts, the problem of not being able to detect safety hazards in the existing technology is solved, and the safety of the charging device is ensured. sex.
Patent Information
- Application Number
- CN202010717091.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2020-07-23
- Publication Date
- 2024-12-27
- Estimated Expiration
- 2040-07-23
AI Technical Summary
The existing charging equipment lacks detection circuits for fire neutral wire short circuits and fire ground wire short circuits, and safety hazards cannot be discovered before formal work, resulting in threats to charging equipment and personal safety.
An AC adapter circuit with self-test function was designed, including a controllable electronic switch for live wire transfer, a controllable electronic switch for neutral wire transfer, a fire neutral wire anti-reverse connection and ground detection circuit, a fire neutral wire short circuit and The detection circuit of the fire-ground wire short circuit, as well as the controllable electronic switch contact adhesion detection circuit for the live wire transfer, adopts sampling voltage divider circuit, one-way conduction device, surge suppression circuit and low-pass filter circuit, detection signal output control circuit and Turn on the control circuit to realize abnormal detection of fire neutral wire, ground wire and relay electrical contacts.
It can detect whether there are abnormal situations such as reverse connection of the fire neutral wire, misconnection of the ground wire, and adhesion of the relay electrical contacts before the charging equipment is officially started, so as to avoid damage to the equipment and personal safety during the use of the charging equipment.
Smart Images
Figure CN111806281B_ABST
Abstract
Description
Technical Field
[0001] The invention relates to an AC transfer circuit, in particular to an AC transfer circuit with a self-checking function. Background Art
[0002] At present, charging equipment used to charge electric vehicles such as new energy vehicles usually does not have detection circuits for short circuits between live and neutral wires and short circuits between live and ground wires, or detection circuits for detecting whether the live and neutral wires are connected reversely and whether the ground wire is connected, or whether the electrical contacts of the relay (contactor) are stuck, etc. Therefore, safety hazards cannot be discovered before the charging equipment officially starts working, causing damage to the charging equipment and even personal safety during the use of the charging equipment. Summary of the invention
[0003] The technical problem to be solved by the present invention is to provide an AC transfer circuit with a self-checking function which can detect potential safety hazards before formal operation.
[0004] In order to solve the above technical problems, the technical solution adopted by the present invention is: an AC transfer circuit with a self-checking function, including: a working power supply, a controllable electronic switch for live wire transfer and a driving circuit thereof, a controllable electronic switch for neutral wire transfer and a driving circuit thereof, and a live and neutral wire reverse connection prevention and grounding detection circuit, a live and neutral wire short circuit and live and ground wire short circuit detection circuit, and a controllable electronic switch contact adhesion detection circuit for live wire transfer, wherein the controllable electronic switch for live wire transfer includes: a live wire input contact and a live wire output contact, and the controllable electronic switch for neutral wire transfer includes: a neutral wire input contact and a neutral wire output contact, and the live wire input contact is connected to the live wire access terminal. , the neutral line input contact is connected to the neutral line access terminal, the live neutral line short circuit and live ground line short circuit detection circuit includes: a live line output terminal connected to the live line output contact, a neutral line output terminal connected to the neutral line output contact, a detection signal output control circuit, a controllable electronic switch for the live line output terminal and its drive circuit, a controllable electronic switch for neutral ground connection and its drive circuit, the live line output terminal is connected to the live line output terminal with one contact of the controllable electronic switch, the live line output terminal is connected to the control terminal of the detection signal output control circuit with another contact of the controllable electronic switch, and the control terminal is provided with a switch for controlling the detection signal output control circuit The on-off control circuit is connected, and the grounding end of the detection signal output control circuit is shared with the grounding output end; the live and neutral line anti-reverse connection and grounding detection circuit, and the controllable electronic switch contact adhesion detection circuit for live wire transfer adopt an abnormality detection circuit with the same structure, and the abnormality detection circuit includes: a sampling voltage divider circuit, a unidirectional conductive device, a surge suppression circuit, a current limiting resistor and a low-pass filter circuit. The input end of the sampling voltage divider circuit serves as the detection end of the abnormality detection circuit, the grounding end of the sampling voltage divider circuit is shared with the working power supply, the output end of the sampling voltage divider circuit is connected to the anode of the unidirectional conductive device, and the cathode of the unidirectional conductive device is connected to the The access end of the surge suppression circuit, the input end of the low-pass filter circuit and one end of the current limiting resistor are connected, the power supply end of the surge suppression circuit is connected to the power supply end of the control circuit for receiving the output signal of the abnormality detection circuit, the grounding end of the surge suppression circuit, the other end of the current limiting resistor, and the grounding end of the low-pass filter circuit are grounded, and the output end of the low-pass filter circuit serves as the signal output end of the abnormality detection circuit; the input end of the sampling voltage divider circuit in the live and neutral line reverse connection protection and grounding detection circuit is connected to the live line access end, and the input end of the sampling voltage divider circuit in the controllable electronic switch contact adhesion detection circuit for live line switching is connected to the live line output end.
[0005] As a preferred solution, in the AC transfer circuit with a self-checking function, the live wire output end is connected to the live wire output end through a fuse using a contact of a controllable electronic switch.
[0006] As a preferred solution, in the AC transfer circuit with a self-checking function, the fuse is a resettable fuse.
[0007] As a preferred solution, in the AC transfer circuit with a self-checking function, the detection signal output control circuit includes: a photoelectric isolation device, the output end of the output side of the photoelectric isolation device is connected to the positive electrode of the working power supply through a pull-up resistor, and outputs a signal to the outside through a connecting resistor, and the ground end of the output side of the photoelectric isolation device and the ground end of the input side of the photoelectric isolation device are both grounded with the working power supply; the live wire output end is connected to the control end of the input side of the photoelectric isolation device by the corresponding contact of the controllable electronic switch; the opening control circuit includes: an opening control resistor, one end of the opening control resistor is connected to the control end of the input side of the photoelectric isolation device, and the other end of the opening control resistor is connected to the positive electrode of the working power supply.
[0008] As a preferred solution, in the AC transfer circuit with a self-test function, the specific structure of the sampling voltage divider circuit includes: an access capacitor, an upper voltage divider resistor and a lower voltage divider resistor, one end of the access capacitor serves as the input end of the sampling voltage divider circuit, the other end of the access capacitor is connected to one end of the upper voltage divider resistor, the other end of the upper voltage divider resistor is connected to the lower voltage divider resistor and serves as the output end of the sampling voltage divider circuit, and the other end of the lower voltage divider resistor is grounded.
[0009] As a preferred solution, in the AC transfer circuit with a self-test function, the specific structure of the surge suppression circuit includes: an upper suppression diode and a lower suppression diode, the anode of the upper suppression diode is connected to the cathode of the lower suppression diode and serves as the access end of the surge suppression circuit, the cathode of the upper suppression diode serves as the power supply end of the surge suppression circuit, and the anode of the lower suppression diode serves as the ground end of the surge suppression circuit.
[0010] As a preferred solution, in the AC transfer circuit with a self-test function, the specific structure of the low-pass filter circuit includes: a filter resistor and a filter capacitor, one end of the filter resistor serves as the input end of the low-pass filter circuit, the other end of the filter resistor is connected to the corresponding end of the filter capacitor and serves as the output end of the low-pass filter circuit, and the other end of the filter capacitor is grounded.
[0011] As a preferred solution, in the AC transfer circuit with a self-checking function, the unidirectional conducting device is a diode; the controllable electronic switch for the live wire output terminal and the controllable electronic switch for the neutral wire connection are both relays or contactors.
[0012] As a preferred solution, in the AC transfer circuit with a self-checking function, the controllable electronic switch for live wire transfer and the controllable electronic switch for neutral wire transfer are both relays or contactors.
[0013] The beneficial effect of the present invention is that the abnormality detection circuit of the present invention can detect whether the ground wire is connected, whether the live and neutral wires are reversely connected, whether the electrical contacts of the relay (contactor) that controls whether the live wire is output are adhered, and whether there is a short circuit between the live and neutral wire output terminals, and between the live wire output terminal and the ground terminal. In this way, when any output signal of the above detection circuit is abnormal, the control circuit of the charging device will not open the charging device and give a warning to the user. This can avoid damage to the charging device and even personal safety during the use of the charging device. BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Figure 1 The diagram is a schematic diagram of the electrical principle structure of the AC transfer circuit with a self-checking function of the present invention. DETAILED DESCRIPTION
[0015] The specific implementation scheme of an AC transfer circuit with a self-checking function according to the present invention will be described in detail below with reference to the accompanying drawings.
[0016] like Figure 1As shown, the AC transfer circuit with self-checking function described in the present invention includes: a working power supply (which belongs to the conventional technology in this field and will not be described in detail here), a relay J1 as a controllable electronic switch for live wire transfer and its driving circuit (the driving circuit belongs to the conventional technology in this field and will not be described in detail here), a relay J2 as a controllable electronic switch for neutral wire transfer and its driving circuit (the driving circuit belongs to the conventional technology in this field and will not be described in detail here), and a live and neutral wire reverse connection and grounding detection circuit, a live and neutral wire short circuit and live and ground wire short circuit detection circuit, and a live wire transfer controllable electronic switch contact adhesion detection circuit. The working power supply outputs a +5V voltage as VCC and outputs a +12V voltage to relays J1 and J2. , J3 and J4 and other related devices are powered, the relay J1 includes: a live wire input contact connected to the live wire input terminal AC_L_IN, and a live wire output contact as the live wire input terminal AC_L_OUT, the relay J2 includes: a neutral wire input contact connected to the neutral wire input terminal AC_N_IN, and a neutral wire output contact as the neutral wire output terminal AC_N_OUT; the live-neutral wire short circuit and live-ground wire short circuit detection circuit includes: a live wire output terminal AC_L_OUT, a neutral wire output terminal AC_N_OUT, and a common ground terminal DGND formed by connecting an AC ground wire PE to a ground wire (negative pole) of the working power supply of the detection circuit, a detection signal output control circuit, and a relay as a live wire output terminal with a controllable electronic switch. The electrical appliance J3 and its driving circuit (the driving circuit belongs to the conventional technology in this field and will not be described in detail here), the relay J4 and its driving circuit (the driving circuit belongs to the conventional technology in this field and will not be described in detail here) as a neutral ground connection universal controllable electronic switch, the power supply voltage of the relays J3 and J4 is usually +12V; the two contacts of a group of normally open contacts of the relay J4 are respectively connected to the common ground terminal DGND and the neutral line output terminal AC_N_OUT; the detection signal output control circuit includes: an optical coupler U1 of model EL817S1 as a photoelectric isolation device, the output end of the optical coupler U1 is connected to the positive electrode VCC (usually +5V) of the working power supply through a pull-up resistor RK2, and is connected to the positive electrode VCC (usually +5V) of the working power supply through a connection The resistor RK3 is connected to output the signal to the outside, and the ground terminals of the input and output sides of the optocoupler U1 are connected to the common ground terminal DGND; one contact of a group of normally open contacts of the relay J4 is connected to the control terminal of the input side of the optocoupler U1, i.e., its pin 1, and another contact of a group of normally open contacts of the relay J4 is connected to the live wire output terminal AC_L_OUT through a self-resetting fuse F1; an opening control circuit for controlling the opening of the detection signal output control circuit is provided on the control terminal of the input side of the optocoupler U1, and the opening control circuit includes: an opening control resistor RK1, one end of the opening control resistor RK1 is connected to the control terminal of the input side of the optocoupler U1, i.e., its pin 1, and the other end of the opening control resistor RK1 is connected to the positive electrode VCC of the working power supply;The live and neutral line anti-reverse connection and grounding detection circuit comprises: a sampling voltage divider circuit, a unidirectional conduction device, a surge suppression circuit, a current limiting resistor and a low-pass filter circuit. The specific structure of the sampling voltage divider circuit comprises: connecting a capacitor Y3, an upper voltage divider resistor RD1 and a lower voltage divider resistor RD2, one end of the capacitor Y3 is connected as the input end of the sampling voltage divider circuit, the other end of the capacitor Y3 is connected to one end of the upper voltage divider resistor RD1, the other end of the upper voltage divider resistor RD1 is connected to one end of the lower voltage divider resistor RD2 as the output end of the sampling voltage divider circuit, the other end of the lower voltage divider resistor RD2 is connected to the common ground end DGND, and the input end of the sampling voltage divider circuit, i.e., the corresponding end of the capacitor Y3 is connected as the live and neutral line The detection end of the anti-reverse connection and grounding detection circuit; the specific structure of the surge suppression circuit includes: an upper suppression diode D7 and a lower suppression diode D8, the anode of the upper suppression diode D7 is connected to the cathode of the lower suppression diode D8, as the access end of the surge suppression circuit, the cathode of the upper suppression diode D7 is used as the power supply end of the surge suppression circuit, and the anode of the lower suppression diode D8 is used as the grounding end of the surge suppression circuit; the specific structure of the low-pass filter circuit includes: a filter resistor RD4 and a filter capacitor C4, one end of the filter resistor RD4 is used as the input end of the low-pass filter circuit, and the other end of the filter resistor RD4 is connected to the corresponding end of the filter capacitor C4, as the low-pass filter The output end of the surge suppression circuit, the other end of the filter capacitor C4 and the working power supply are grounded; the output end of the sampling voltage divider circuit is connected to the anode of the diode D6 as a unidirectional conductive device, the cathode of the diode D6 is connected to the access end of the surge suppression circuit, the input end of the low-pass filter circuit and one end of the current limiting resistor RD3, the power supply end of the surge suppression circuit is connected to the positive electrode (VCC) of the working power supply, the ground end of the surge suppression circuit, the other end of the current limiting resistor, and the ground end of the low-pass filter circuit are connected to the common ground end DGND, and the output end of the low-pass filter circuit is used as the signal output end of the live and neutral line anti-reverse connection and grounding detection circuit; the controllable electronic switch contact adhesion detection circuit for live wire switching includes: A sampling voltage-dividing circuit, a unidirectional conducting device, a surge suppression circuit, a current-limiting resistor, and a low-pass filtering circuit. The specific structure of the sampling voltage-dividing circuit includes: connecting a capacitor Y1, an upper voltage-dividing resistor RJ1, and a lower voltage-dividing resistor RJ2, one end of the capacitor Y1 is connected as the input end of the sampling voltage-dividing circuit, the other end of the capacitor Y1 is connected to one end of the upper voltage-dividing resistor RJ1, the other end of the upper voltage-dividing resistor RJ1 is connected to one end of the lower voltage-dividing resistor RJ2, and serves as the output end of the sampling voltage-dividing circuit, the other end of the lower voltage-dividing resistor RJ2 is connected to the common ground end DGND, and the input end of the sampling voltage-dividing circuit, i.e., the corresponding end of the capacitor Y1, is used as the detection end of the contact adhesion detection circuit of the controllable electronic switch for live wire switching;The specific structure of the surge suppression circuit includes: an upper suppression diode D4 and a lower suppression diode D5, the anode of the upper suppression diode D4 is connected to the cathode of the lower suppression diode D5, as the access end of the surge suppression circuit, the cathode of the upper suppression diode D4 is used as the power supply end of the surge suppression circuit, and the anode of the lower suppression diode D5 is used as the grounding end of the surge suppression circuit; the specific structure of the low-pass filter circuit includes: a filter resistor RJ4 and a filter capacitor C3, one end of the filter resistor RJ4 is used as the input end of the low-pass filter circuit, and the other end of the filter resistor RJ4 is connected to the corresponding end of the filter capacitor C3, as The output end of the low-pass filter circuit and the other end of the filter capacitor C3 are connected to the working power supply; the output end of the sampling voltage divider circuit is connected to the anode of the diode D3 as a unidirectional conductive device, and the cathode of the diode D3 is connected to the access end of the surge suppression circuit, the input end of the low-pass filter circuit and one end of the current limiting resistor RJ3. The power supply end of the surge suppression circuit is connected to the positive electrode (VCC) of the working power supply, and the ground end of the surge suppression circuit, the other end of the current limiting resistor, and the ground end of the low-pass filter circuit are connected to the common ground end DGND. The output end of the low-pass filter circuit serves as the signal output end of the controllable electronic switch contact adhesion detection circuit for the live wire transfer. ;
[0017] The working principle of the present invention is as follows: after power-on, the working power supply is always in working state. When the live and neutral wires are reversely connected or the ground wire is not connected, the live and neutral wire reverse connection prevention and grounding detection circuit outputs a low level as an abnormal signal; only when the live and neutral wires are correctly connected and the ground wire is connected, the live and neutral wire reverse connection prevention and grounding detection circuit outputs a high level as a normal signal. When the normally open electrical contact group of the relay J1 is adhered, the live wire switching controllable electronic switch contact adhesion detection circuit outputs a high level as an abnormal signal; otherwise, the live wire switching controllable electronic switch contact adhesion detection circuit outputs a low level as a normal signal. Under normal circumstances, due to the existence of the opening control circuit, the detection signal output control circuit outputs a low level; during detection, the control circuit responsible for receiving the output signal of the above detection circuit gives a drive signal to relays J3 and J4, and relays J3 and J4 are energized to open their respective normally open contacts, so that the neutral line output terminal AC_N_OUT is connected to the common ground terminal DGND. At this time, whether the live line output terminal AC_L_OUT is short-circuited with the common ground terminal DGND or the live line output terminal AC_L_OUT is short-circuited with the neutral line output terminal AC_N_OUT, the control terminal (pin 1) on the input side of the optocoupler U1 becomes a low level, so that the output side of the optocoupler U1 is turned off, and the detection signal output control circuit outputs a high level as a short-circuit output signal. At this time, the control circuit will not open the charging device and give the user a warning (which can be a sound and light alarm alone or a sound and light alarm at the same time).
[0018] In summary, the above is only a preferred embodiment of the present invention and is not intended to limit the scope of the present invention. All equivalent changes and modifications made to the shape, structure, characteristics and spirit described in the scope of the claims of the present invention should be included in the scope of the claims of the present invention.
Claims
1. An AC transfer circuit with a self-checking function, comprising: Working power supply, controllable electronic switch for live wire transfer and its driving circuit, controllable electronic switch for neutral wire transfer and its driving circuit, the controllable electronic switch for live wire transfer includes: live wire input contact and live wire output contact, the controllable electronic switch for neutral wire transfer includes: neutral wire input contact and neutral wire output contact, the live wire input contact is connected to the live wire access terminal, the neutral wire input contact is connected to the neutral wire access terminal, characterized in that the AC transfer circuit with self-checking function also includes: live and neutral wire reverse connection and grounding detection circuit, live and neutral wire short circuit and live and ground wire short circuit detection circuit, live wire transfer controllable electronic switch contact sticky The detection circuit for short circuit between live and neutral wires and short circuit between live and ground wires comprises: a live wire output terminal connected to the live wire output contact, a neutral wire output terminal connected to the neutral wire output contact, a detection signal output control circuit, a controllable electronic switch for the live wire output terminal and a driving circuit thereof, a controllable electronic switch for neutral and ground wire connection and a driving circuit thereof, the live wire output terminal is connected to the live wire output terminal with one contact of the controllable electronic switch, the live wire output terminal is connected to the control terminal of the detection signal output control circuit with another contact of the controllable electronic switch, and the control terminal is provided with an opening control circuit for controlling the opening of the detection signal output control circuit , the grounding end of the detection signal output control circuit is shared with the grounding output end; the live and neutral line anti-reverse connection and grounding detection circuit, and the controllable electronic switch contact adhesion detection circuit for live line transfer adopt an abnormality detection circuit with the same structure, and the abnormality detection circuit includes: a sampling voltage divider circuit, a unidirectional conductive device, a surge suppression circuit, a current limiting resistor and a low-pass filter circuit. The input end of the sampling voltage divider circuit serves as the detection end of the abnormality detection circuit, the grounding end of the sampling voltage divider circuit is shared with the working power supply, the output end of the sampling voltage divider circuit is connected to the anode of the unidirectional conductive device, and the cathode of the unidirectional conductive device is connected to the surge suppression circuit. The access end of the control circuit, the input end of the low-pass filter circuit and one end of the current limiting resistor are connected, the power end of the surge suppression circuit is connected to the power end of the control circuit for receiving the output signal of the abnormality detection circuit, the ground end of the surge suppression circuit, the other end of the current limiting resistor and the ground end of the low-pass filter circuit are grounded, and the output end of the low-pass filter circuit serves as the signal output end of the abnormality detection circuit; the input end of the sampling voltage divider circuit in the live and neutral line reverse connection protection and grounding detection circuit is connected to the live wire access end, and the input end of the sampling voltage divider circuit in the controllable electronic switch contact adhesion detection circuit for live wire switching is connected to the live wire output end.
2. The AC transfer circuit with self-checking function according to claim 1, characterized in that: The live wire output end is connected to the live wire output end through a fuse using a contact of a controllable electronic switch.
3. The AC transfer circuit with self-checking function according to claim 2, characterized in that: The fuse is a resettable fuse.
4. The AC transfer circuit with self-checking function according to claim 1, characterized in that: The detection signal output control circuit includes: a photoelectric isolation device, the output end of the output side of the photoelectric isolation device is connected to the positive electrode of the working power supply through a pull-up resistor, and outputs a signal to the outside through a connecting resistor, and the ground end of the output side of the photoelectric isolation device and the ground end of the input side of the photoelectric isolation device are both grounded with the working power supply; the live wire output end is connected to the control end of the input side of the photoelectric isolation device through the corresponding contact of the controllable electronic switch; the opening control circuit includes: an opening control resistor, one end of the opening control resistor is connected to the control end of the input side of the photoelectric isolation device, and the other end of the opening control resistor is connected to the positive electrode of the working power supply.
5. The AC transfer circuit with self-checking function according to claim 1, characterized in that: The specific structure of the sampling voltage divider circuit includes: an access capacitor, an upper voltage divider resistor and a lower voltage divider resistor, one end of the access capacitor serves as the input end of the sampling voltage divider circuit, the other end of the access capacitor is connected to one end of the upper voltage divider resistor, the other end of the upper voltage divider resistor is connected to the lower voltage divider resistor and serves as the output end of the sampling voltage divider circuit, and the other end of the lower voltage divider resistor is grounded.
6. The AC transfer circuit with self-checking function according to claim 1, characterized in that: The specific structure of the surge suppression circuit includes: an upper suppression diode and a lower suppression diode, the anode of the upper suppression diode is connected to the cathode of the lower suppression diode and serves as the access end of the surge suppression circuit, the cathode of the upper suppression diode serves as the power supply end of the surge suppression circuit, and the anode of the lower suppression diode serves as the grounding end of the surge suppression circuit.
7. The AC transfer circuit with self-checking function according to claim 1, characterized in that: The specific structure of the low-pass filter circuit includes: a filter resistor and a filter capacitor, one end of the filter resistor serves as the input end of the low-pass filter circuit, the other end of the filter resistor is connected to the corresponding end of the filter capacitor and serves as the output end of the low-pass filter circuit, and the other end of the filter capacitor is grounded.
8. The AC transfer circuit with self-checking function according to any one of claims 1 to 7, characterized in that: The one-way conducting device is a diode; the controllable electronic switch used at the live wire output end and the controllable electronic switch used for neutral wire connection are both relays or contactors.
9. The AC transfer circuit with self-checking function according to any one of claims 1 to 7, characterized in that: The controllable electronic switch for live wire switching and the controllable electronic switch for neutral wire switching are both relays or contactors.