Device for protecting ground wire of single-phase vehicle-mounted charger from being misconnected with power supply live wire

Abstract

The embodiment of the utility model provides a protection device for misconnection of a single-phase vehicle-mounted charger protection ground wire with a power supply live wire, and belongs to the technical field of electrical safety protection. The utility model discloses a protection device for misconnection of a single-phase vehicle-mounted charger protection ground wire with a power supply live wire. The protection device comprises a relay, a relay control circuit, an auxiliary power supply and a safety capacitor, wherein the relay is connected in series between an input protection ground wire and a charger metal casing ground, and is used for controlling connection or disconnection between the input protection ground wire and a charger casing; the safety capacitor is connected between the input live wire and the zero line pair protection ground. According to the scheme of the utility model, the protection when the input protection ground wire of the vehicle-mounted charger is misconnected with the power supply live wire is realized, the isolation and safety of the metal casing of the vehicle-mounted charger and the power supply live wire are ensured, and the safety of other low-voltage power supply control equipment on a vehicle is also ensured; the number of added elements is small, control is easy, and the increased cost is little.

Description

Technical Field

[0001] The utility model relates to the technical field of electrical safety protection, in particular to a protection device for a single-phase vehicle-mounted charger when a protective ground wire is mistakenly connected to a power supply live wire. Background Art

[0002] Currently, for single-phase AC input on-board chargers, when the charger housing is metal, the metal-plastic housing is typically directly connected to the input protective ground. This is a common example of on-board chargers for various construction vehicles, where the charger housing is screwed to the metal frame of the construction vehicle. However, due to improper wiring or improper operation at the construction site, the on-board charger's input protective ground wire can be mistakenly connected to the live power line. This can cause the charger housing to carry high voltage due to the direct connection to the live power line. This situation poses a safety hazard to the metal frame of the construction vehicle due to the direct connection to the live power line. Secondly, the connection of the metal-plastic housing to the live power line can damage other low-voltage control devices on the vehicle. Occasionally, damage to other low-voltage control devices on the vehicle occurs at construction sites due to the inadvertent connection of the vehicle's power protective ground wire to the live power line. Utility Model Content

[0003] The purpose of the embodiments of the utility model is to provide a protection device for a single-phase on-board charger when the protective ground wire is mistakenly connected to the power supply live wire, so as to solve the problem that improper operation or wiring errors may cause the metal casing of the charger to be charged, thereby threatening the safety of people and equipment.

[0004] In order to achieve the above-mentioned objectives, an embodiment of the present invention provides a protection device for a single-phase on-board charger protective ground wire that is mistakenly connected to a power supply live wire. The protection device for a single-phase on-board charger protective ground wire that is mistakenly connected to a power supply live wire comprises: a relay, a relay control circuit, an auxiliary power supply, and a safety capacitor; wherein, the relay is connected in series between the input protective ground wire and the grounding of the charger metal casing to control the connection or disconnection of the input protective ground wire and the charger casing; the safety capacitor is connected between the input live wire and the neutral wire to the protective ground.

[0005] Optionally, the relay is a normally open relay, one terminal of the relay is connected to the input protective ground wire, and the other terminal is connected to the charger casing ground. When the input protective ground wire is mistakenly connected to the power supply live wire, the relay remains in the disconnected state.

[0006] Optionally, the relay control circuit includes: an auxiliary power supply and a control signal generating unit; when it is confirmed that the input protective ground wire is connected correctly and the AC input is normal, the auxiliary power supply provides an operating voltage, and the control signal generating unit drives the relay to close to achieve connectivity between the charger input protective ground wire and the casing ground.

[0007] Optionally, the auxiliary power supply comprises: a filter circuit, a rectifier circuit and a voltage stabilizing circuit; the filter circuit is connected with the rectifier circuit to eliminate high-frequency interference signals in the AC input, and the voltage stabilizing circuit is used to provide a stable auxiliary power supply output to ensure stable operation of the relay control circuit.

[0008] Optionally, the input end of the auxiliary power supply is connected with an AC input voltage, and the auxiliary power supply output provides a working voltage for the relay control circuit; when the input connection is correct, the auxiliary power supply output provides a normal working voltage, and the relay control circuit causes the relay to be attracted.

[0009] Optionally, when the input protection ground line is misconnected with the power supply live line, the auxiliary power supply cannot be normally started, the relay control circuit cannot work due to lack of power supply, and the relay maintains a disconnected state to ensure that the metal shell of the charger is disconnected with the power supply live line, thereby avoiding electrical safety problems caused by the charged shell.

[0010] Optionally, the charger shell ground is respectively connected in series with a safety capacitor between the input protection ground line and the power supply live line and the input zero line, and the safety capacitor is used to electrically isolate the charger shell ground when the input protection ground line is misconnected with the power supply live line.

[0011] Optionally, the total capacity of the safety capacitor is less than 24nF.

[0012] Optionally, the relay control circuit comprises: an analog control module and a digital control module; the analog control module is used to maintain the relay to be disconnected when the input line is abnormal, and the digital control module is used to control the relay to be attracted through signal judgment when the input line is normal, so as to control the connection and disconnection of the protection ground line.

[0013] Optionally, the relay control circuit comprises a delay circuit; the delay circuit comprises a plurality of resistors, capacitors and transistors, each resistor and capacitor is connected with the base of the transistor, and the transistor is driven to be turned on through a delay voltage signal, so as to delay the relay to be attracted.

[0014] Through the above technical solution, (by connecting a normally open relay on the protection ground line in the charger and effectively controlling the relay, the protection of the input protection ground line of the vehicle charger when the input protection ground line is misconnected with the power supply live line is realized, the metal shell of the vehicle charger is isolated from the power supply live line and is safe, and the safety of other low-voltage power supply control devices on the vehicle is also ensured; the added elements are few, the control is simple, and the cost is little.

[0015] Other features and advantages of the embodiments of the utility model will be described in detail in the following specific embodiment part. BRIEF DESCRIPTION OF DRAWINGS

[0016] The accompanying drawings are included to provide a further understanding of embodiments of the application, and are incorporated in and constitute a part of this specification, illustrate embodiments of the application, and together with the description serve to explain the principles of the application. In the drawings:

[0017] Figure 1 is a principle block diagram of a protection device for protecting a ground wire misconnection power supply live wire of a single-phase vehicle-mounted charger provided by an embodiment of the present application scheme;

[0018] Figure 2 is a circuit diagram of a protection device for protecting a ground wire misconnection power supply live wire of a single-phase alternating current input vehicle-mounted charger corresponding to Figure 1 ;

[0019] Figure 3 is a principle block diagram of a protection device for protecting a ground wire misconnection power supply live wire of a single-phase vehicle-mounted charger provided by another embodiment of the present application scheme;

[0020] Figure 4 is a circuit diagram of another protection device for protecting a ground wire misconnection power supply live wire of a single-phase alternating current input vehicle-mounted charger corresponding to Figure 3 ; DETAILED DESCRIPTION

[0021] The specific embodiments of the present application will be described in detail hereinafter with reference to the drawings. It should be understood that the specific embodiments described herein are merely intended to illustrate and explain the present application, and are not intended to limit the present application.

[0022] In the embodiments of the present application, the orientation words such as "upper", "lower", "left", "right" used without being stated otherwise generally refer to the orientation or position relationship shown in the drawings, or the orientation or position relationship commonly used when the product of the present application is used.

[0023] The terms "first", "second", "third", etc. are only used for distinction and description, and cannot be understood as indicating or implying relative importance.

[0024] The terms "horizontal", "vertical", "suspension", etc. do not mean that the components must be absolutely horizontal, vertical or suspended, but can be slightly inclined. For example, "horizontal" only means that it is more horizontal relative to "vertical", and does not mean that the structure must be completely horizontal, but can be slightly inclined.

[0025] In addition, the terms "substantially", "essentially", and the like are intended to convey that the relevant content is not required to be absolute, but can have some deviation. For example, "substantially equal" does not mean only absolute equality, because in actual production and operation, it is difficult to achieve absolute "equality", and generally there is a certain deviation. Therefore, in addition to absolute equality, "substantially equal" also includes the above-mentioned case of having a certain deviation. By way of example, in other cases, unless otherwise specified, the terms "substantially", "essentially" and the like have similar meanings as described above.

[0026] In the description of the utility model, it should be explained that, unless otherwise specified and limited, the terms "setting", "installing", "connecting", "connecting" should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be directly connected, or indirectly connected through an intermediate medium, or it can be connected inside two elements. For ordinary skilled in the art, the specific meaning of the above terms in the utility model can be understood according to the specific circumstances.

[0027] Please refer to Figure 1 The embodiment provides a single-phase vehicle-mounted charger protection ground wire misconnection live wire power supply protection device, which comprises a relay, a relay control circuit, an auxiliary power supply and a safety capacitor; wherein the relay is connected in series between the input protection ground wire and the charger metal shell ground, and is used for controlling the communication or disconnection of the input protection ground wire and the charger shell; the safety capacitor is connected between the input live wire and the zero line to the protection ground.

[0028] Specifically, it comprises: a single-phase vehicle-mounted charger protection ground wire misconnection live wire power supply protection device relay, a relay control circuit, an auxiliary power supply output power supply, a safety Y capacitor between the input live wire and the zero line to the protection ground, a charger metal shell, other filtering, rectification, PFC, DCDC power conversion and detection control processing circuits; Vin _ The L signal is a live wire input, Vin _ The N signal is a zero line input, Vin _ The PE signal is an input protection ground, CASE _ The PE signal is a charger shell ground, CASE _ The PE signal is connected with the charger metal shell.

[0029] Further, the relay is connected in series between the input protection ground Vin PE and the shell ground CASE _ PE, for realizing the communication and disconnection of the input protection ground wire;

[0030] Further, the shell ground CASE PE with the fire line input Vin L between the connection of the total equivalent Y-capacitor C2, the shell ground CASE _ PE with the zero line input Vin _ N between the connection of the total equivalent Y-capacitor C1;

[0031] Further, the fire line input Vin L and zero line input Vin N through other filtering, rectification, PFC, DCDC power conversion and detection control processing circuit power conversion processing to achieve the charger related functions;

[0032] Further, the relay control circuit to achieve the control of the relay attracted or opened in series on the input protection ground of the vehicle power supply; The control of the relay can be analog control or digital control.

[0033] Further, the AC input is filtered, rectified or pre-stabilized as an auxiliary power supply output power supply, the output of the auxiliary power supply output power supply as the power supply of the relay control circuit, and the auxiliary power supply output power supply also serves as a single-phase AC input detection and judgment circuit. When the single-phase AC input wiring is correct, the auxiliary voltage output power supply can have normal output, providing working power for the relay attraction. When the protective ground line is misconnected to the power supply fire line, the auxiliary voltage output power supply cannot work normally and has no output voltage, thereby maintaining the relay open;

[0034] Further, since the protective ground line is not fixedly connected, in order to better realize fault isolation and improve safety performance, it is necessary to ensure that the total capacity of the protective ground line of the AC input part ( Figure 1 The schematic Y-capacitor C1 and C2 capacitors shown in the figure, C1 and C2 are the input Vin N and Vin L line on Vin _ The total equivalent capacitor of PE) cannot be too large, preferably less than 3.5mA of ground leakage current at 465VAC / 50HZ, to ensure the safety of the leakage current to the human body.

[0035] Further, the control protection principle of the utility model is described as follows:

[0036] When the input protective ground of the vehicle charger is connected correctly, and the AC input voltage is normal, the auxiliary power supply will start normally, and the input wiring can be judged to be normal because the auxiliary power supply can work normally. Thereafter, the relay is attracted through the relay control circuit, so that the protective ground CASE _ PE with the power supply protective ground Vin PE is connected normally and enters normal working mode. After that, the relay will not be automatically disconnected when there are other faults or alarms in the charger.

[0037] When the on-board charger's input protective earth connection is connected to the live power line, the charger's original live and neutral wires are inevitably connected to the neutral and protective earth wires of the input power supply. Consequently, there is no actual input voltage between the charger's original live wire (L) and neutral wire (N). The charger will not receive AC input, nor will it be able to provide the necessary rectified DC voltage to the charger's internal auxiliary power supply. Consequently, the auxiliary power supply cannot start and operate properly. Consequently, the relay control circuit cannot function properly due to the lack of power supply, and the relay remains disconnected. Consequently, the charger's internal protective earth and housing remain disconnected from the live power line. This ensures that the charger's housing is not charged and prevents any abnormal damage to the charger's internal circuitry. Once the on-board power input cable is correctly reconnected, the charger will resume normal operation.

[0038] Furthermore, since the protective ground wire is not a fixed connection method, in order to better achieve fault isolation and improve safety performance, it is necessary to ensure that the safety capacitor capacity of the AC input part to the protective ground wire is not too large. It is best to ensure that the ground leakage current is less than 3.5mA when the AC input is 465VAC / 50HZ. That is, all the safety Y capacitors of the AC input to the protective ground ( Figure 2 The C1 and C2 shown in the figure are safety Y capacitors. C1 and C2 are the input voltage of the charger. _ N and Vin v L line to the chassis protection CASE _ The sum of the total equivalent capacitance of PE, that is, the total capacitance, should not exceed 24nF to ensure that the leakage current safety requirements for the protective earth are met when the AC input is 465VAC / 50HZ.

[0039] Furthermore, the live wire input Vin L and neutral line input Vin N is processed by other filtering, rectification, PFC, DCDC power conversion and detection control processing circuits to realize the relevant functions of the charger.

[0040] Example 1:

[0041] like Figure 3 , as a specific implementation method, it is suitable for normal single-phase 220VAC / 50HZ AC input.

[0042] The entire circuit includes relays, relay control circuits, auxiliary power output, safety Y capacitors between the input live and neutral wires and the protective ground, and other filtering, rectification, PFC, DCDC power conversion, and detection control processing circuits.

[0043] Specifically, Vin _ L signal is the hot input, Vin _ N signal is the zero input, Vin _ PE signal is the input protection ground, CASE PE signal is the charger case ground, CASE PE signal is connected with the charger case;

[0044] Specifically, the case ground CASE _ PE and the hot input Vin _ L are connected with the total equivalent safety Y capacitor C2, the case ground CASE PE and the zero input Vin N are connected with the total equivalent safety Y capacitor C1;

[0045] Specifically, one end of the normally open relay K1 is connected with the input protection ground Vin PE, the other end of the normally open relay K1 is connected with the input charger case protection ground CASE _ PE, the case protection ground CASE _ PE;

[0046] Specifically, the hot input Vin L and the zero input Vin N are processed by other filtering, rectification, PFC, DCDC power conversion and detection control processing circuits to realize the related functions of the charger;

[0047] The AC input is filtered, rectified or pre-stabilized as an auxiliary power supply output power supply input, and the output of the auxiliary power supply output power supply is used as the power supply of the relay control circuit;

[0048] Specifically, one end of the normally open relay K1 control line package is connected with the anode of diode VDl and the collector of NPN transistor VTl, the other end of the normally open relay K1 control line package is connected with the cathode of diode VDl and the positive terminal VCC of the power supply, the base of NPN transistor VTl is connected with one end of resistor R1, one end of resistor R2 and one end of capacitor C3, the other end of resistor R2, the other end of capacitor C3 and the emitter of NPN transistor VTl are connected to the working ground GND _ D, the other end of resistor R1 is connected with the positive terminal VCC of the power supply, VCC signal is the output positive terminal of one way of the auxiliary power supply output power supply, GND v D signal is the output negative terminal of one way of the auxiliary power supply output power supply, and this part of the circuit constitutes the relay control circuit.

[0049] The principles of this embodiment are specifically explained as follows:

[0050] When the input protection ground of the on-board charger is connected correctly, and the AC input voltage is normal, the auxiliary power supply will start normally, the auxiliary power supply output power supply will have normal power supply VCC output, the auxiliary power supply can work normally and output VCC can judge that the input wiring is normal, so the VCC signal is used as the control signal of the relay control circuit, the VCC signal is delayed through resistor R1, resistor R2 and capacitor C3, then drives transistor VTl to turn on, thereby attracting relay K1, thereby disconnecting the input protection ground Vin of the on-board charger from the power supply ground CASE _ PE and the protection ground Vin of the power supply _ PE is normally connected, and enters the normal working mode. Thereafter, the relay is no longer actively disconnected in the event of other faults or alarms of the charger.

[0051] When the input protection ground Vin of the on-board charger is connected to the power supply ground CASE PE, the original input live line and zero line of the on-board charger are necessarily connected to the zero line and protection ground line of the power supply in this case, so that there is no AC input voltage between the original input live line L and zero line N of the on-board charger, there is no AC input in the internal of the charger, and the necessary AC rectified DC voltage cannot be provided for the auxiliary power supply of the charger, so the auxiliary power supply cannot start and work normally, and the control circuit of the relay cannot work normally due to no normal power supply, and the relay continues to maintain the disconnected state. Therefore, the protection ground and the case of the charger are disconnected from the power supply live line in this case. This ensures that the on-board charger case is not electrified, and will not cause abnormal damage to the internal circuit of the charger. After the input line of the on-board power supply is connected correctly, the charger can work normally.

[0052] Embodiment Two:

[0053] As Figure 3 shown in the control circuit and principle, the specific scheme is not repeated, and the difference is that the relay in the scheme Figure 1 is only used to control the communication or disconnection between the metal case ground (CASE Figure 3 PE) of the charger and the input protection ground line (Vin PE).

[0054] In this technical scheme, since the charger case is not directly connected to the safety equivalent total capacitance (C1, C2) between the input live line (Vin _ L) and the zero line (Vin _ N), compared with Figure 2 , there is no additional special requirement for the safety Y capacitor of the input end of the on-board charger. At the same time, the requirements of the on-board power supply input safety capacitor leakage current to the ground or the specific needs of the customer for this index still need to be met. ​

[0055] Specifically, Figure 3 In the scheme, the control principle of the relay is as follows:

[0056] When the input protective ground (Vin _ PE) is connected correctly and the AC input is normal, the auxiliary power supply will start normally and provide the working voltage of the relay control circuit, the relay control circuit drives the relay to attract, so that the metal shell of the charger (CASE PE) is connected with the input protective ground (Vin PE), and enters the normal working mode.

[0057] When the input protective ground (Vin PE) is connected with the power supply live line (Vin L) by mistake, the original input live line and zero line of the charger are connected with the zero line and protective ground of the power supply, there is no actual AC input voltage in the charger, the auxiliary power supply cannot start normally, the relay control circuit lacks the necessary working voltage, and the relay maintains the open state, thereby ensuring that the charger shell is disconnected from the input live line and avoiding safety problems caused by the charged shell.

[0058] Through this design, the connection or disconnection between the relay control shell and the input protective ground is realized by the relay, and the relay is controlled by the auxiliary power supply. Figure 3 In the scheme, the shell itself is not directly connected with the input part of the regulatory equivalent total capacitance C1 and C2, so it is not necessary to increase other requirements for the regulatory Y capacitor, but it is still necessary to ensure that the leakage current of the AC input to the protective ground meets the safety standards, such as the leakage current to the ground should be less than 3.5mA under the condition of AC 465VAC / 50Hz.

[0059] The beneficial effects of the present scheme are that the protection function is realized when the input protective ground of the vehicle charger is connected with the power supply live line by mistake, the circuit design is simplified, the additional requirements for the regulatory capacitor are reduced, the metal shell of the vehicle charger is isolated from the power supply live line, the system safety is improved, and the implementation cost is low.

[0060] As Figure 4 , as a specific embodiment, it is applicable to normal single-phase 220VAC / 50Hz AC input.

[0061] The overall circuit includes a relay, a relay control circuit, an auxiliary power supply output power supply, an input live line and zero line to a protective ground regulatory Y capacitor, and other filtering, rectification, PFC, DCDC power conversion and detection control processing circuits.

[0062] Specifically, the Vin _ L signal is the live line input, the Vin _ N signal is the zero line input, and the Yin _PE signal is input protection ground, CASE _ PE signal is charger case ground, CASE _ PE signal is connected with charger case;

[0063] Specifically, one end of the normally open relay K1 is connected with input protection ground Vin _ PE, the other end of the normally open relay K1 is connected with charger case protection ground CASE _ PE;

[0064] Firewire input Vin L and zero line input Vin N through other filtering, rectification, PFC, DCDC power conversion and detection control processing circuit, complete the power conversion processing of charger, so as to realize the related function of charger;

[0065] AC input after filtering, rectification or pre-stabilization as auxiliary power supply output power supply input, auxiliary power supply output power supply output as the power supply of relay control circuit;

[0066] Specifically, one end of the normally open relay K1 control coil is connected with the anode of diode VDl and the collector of NPN triode VTl, the other end of the normally open relay K1 control coil is connected with the cathode of diode VDl and the positive end VCC of power supply, the base of NPN triode VTl is connected with one end of resistor R1, one end of resistor R2 and one end of capacitor C3, the other end of resistor R2, the other end of capacitor C3 and the emitter of NPN triode VTl are connected to working ground GND D, the other end of resistor R1 is connected with the positive end VCC of power supply, VCC signal is a positive output end of one way of auxiliary power supply output power supply, GND D signal is a negative output end of one way of auxiliary power supply output power supply, this part of circuit constitutes relay control circuit.

[0067] The principle of this embodiment is specifically explained as follows:

[0068] When the input protection ground connection of vehicle charger is connected correctly, and the AC input voltage is normal, the auxiliary power supply will start normally, and the auxiliary power supply output power supply will have normal power supply VCC output. The normal working and output VCC signal of auxiliary power supply can judge that the input connection is correct, and then VCC signal is used as the control signal of relay control circuit. VCC signal drives triode VTl to conduct after delay through resistor R1, resistor R2 and capacitor C3, so as to attract relay K1, and connect the protection ground CASE _ PE with input protection ground Vin _PE is normally connected, and the charger enters normal working mode. After that, when other faults or alarms occur in the charger, the relay will not be disconnected.

[0069] When the input protection Vin of the on-board charger is connected to the protective earth _ When PE is connected to the live wire of the power supply, the original input live wire and zero wire of the on-board charger are necessarily connected to the zero wire and protective earth wire of the power supply. Thus, there is no AC input voltage between the original input live wire L and zero wire N of the on-board charger, and there is no AC input in the charger. The charger cannot provide the necessary AC rectified DC voltage for the auxiliary power supply, and the auxiliary power supply cannot start and work normally. Thus, the relay control circuit cannot work normally due to lack of normal power supply, and the relay K1 continues to maintain the open state, ensuring that the protective earth and the charger case are disconnected from the live wire of the power supply. In this case, the on-board charger case is ensured to be not electrified, and the internal circuit of the charger is not damaged. After the input line of the on-board power supply is connected correctly, the charger can work normally.

[0070] The optional implementation manners of the embodiments of the present application are described in detail above in combination with the drawings, but the embodiments of the present application are not limited to the specific details in the above implementation manners. Within the technical concept range of the embodiments of the present application, the technical solutions of the embodiments of the present application can be subjected to various simple modifications, and these simple modifications all belong to the protection range of the embodiments of the present application.

[0071] In addition, it should be noted that each specific technical feature described in the above specific implementation manners can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, the various possible combination manners are not described again in the embodiments of the present application.

[0072] Those skilled in the art can understand that all or part of the steps of the methods in the above embodiments can be completed by a program instructing related hardware. The program is stored in a storage medium and includes a plurality of instructions for causing a single-chip microcomputer, chip or processor to execute all or part of the steps of the methods described in the various embodiments of the present application. The foregoing storage medium includes a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk and various program code storage media.

[0073] In addition, various different implementation manners of the embodiments of the present application can also be combined in any manner, as long as they do not deviate from the technical concept of the embodiments of the present application, and they should be considered as disclosed contents of the embodiments of the present application.

Claims

1. A single-phase on-board charger protection device for protecting the ground wire from being mistakenly supplied with power from the live wire, characterized in that, The single-phase on-vehicle charger protection device for protecting the ground wire from being connected to the live wire comprises: a relay, a relay control circuit, an auxiliary power supply and a safety capacitor, wherein the relay is connected in series between the input protection ground wire and the charger metal shell ground, for controlling the connection or disconnection of the input protection ground wire and the charger shell; the safety capacitor is connected between the input live wire and the protection ground.

2. The single phase on-board charger protection device that protects ground miswired to hot power in claim 1, wherein, The relay is a normally open relay, one terminal of the relay is connected to the input protection ground wire, and the other terminal is connected to the charger shell ground. When the input protection ground wire is connected to the live wire by mistake, the relay remains in the open state.

3. The single phase on-board charger protection device that protects ground miswired to hot power in claim 1, wherein, The relay control circuit comprises: an auxiliary power supply and a control signal generation unit; When it is confirmed that the input protection ground wire is connected correctly and the AC input is normal, the auxiliary power supply provides working voltage, and the control signal generation unit drives the relay to be attracted, so as to realize the connection of the charger input protection ground wire and the shell ground.

4. The single phase on-board charger protection device that protects against misapplication of the protective ground to the hot line of claim 3, wherein, The auxiliary power supply comprises: a filter circuit, a rectifier circuit and a voltage stabilizing circuit; The filter circuit is connected with the rectifier circuit to eliminate high-frequency interference signals in the AC input, and the voltage stabilizing circuit is used to provide stable auxiliary power supply output, so as to ensure the stable operation of the relay control circuit.

5. The single phase on-board charger protection device that protects ground miswired to hot power in claim 4, wherein, The input end of the auxiliary power supply is connected with the AC input voltage, and the auxiliary power supply output provides working voltage for the relay control circuit. When the input is connected correctly, the auxiliary power supply outputs normal working voltage, and the relay control circuit causes the relay to be attracted.

6. The single phase on-board charger protection device that protects ground miswired hot of claim 4, wherein, When the input protection ground wire is connected to the live wire by mistake, the auxiliary power supply cannot be started normally, the relay control circuit cannot work due to lack of power supply, and the relay remains in the open state, so as to ensure that the metal shell of the charger is disconnected from the live wire, and to avoid electrical safety problems caused by the charged shell.

7. The single phase on-board charger protection device that protects ground miswired hot of claim 1, wherein, Safety capacitors are connected in series between the charger shell ground and the live wire input and the zero line input, respectively, for electrically isolating the shell ground when the input protection ground wire is connected to the live wire by mistake.

8. The single phase on-board charger protection device that protects against misapplication of the protective ground to the hot line of claim 7, wherein, The total capacity of the safety capacitor is less than 24nF.

9. The single phase on-board charger protection device that protects ground miswired hot of claim 1, wherein, The relay control circuit comprises: an analog control module and a digital control module; The analog control module is used to maintain the relay in the open state when the input line is abnormal, and the digital control module is used to realize the attraction of the relay through signal judgment when the input line is normal, so as to control the connection and disconnection of the protection ground wire.

10. The single phase on-board charger protection device that protects ground miswired hot of claim 1, wherein, The relay control circuit comprises a delay circuit; The delay circuit comprises a plurality of resistors, capacitors and transistors, each resistor and capacitor is connected with the base of the transistor, and the transistor is driven to be conductive through the delay voltage signal, so as to delay the attraction of the relay.

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