Phase sequence detection circuit and method for three-phase charging pile, and charging pile

Abstract

The present invention provides a phase error detection circuit and method for a three-phase charging pile, and a charging pile. The circuit includes a voltage sampling module connected to an AC power grid for obtaining the voltage difference between the incoming line terminal of the first phase wire and the incoming line terminal of the neutral wire of the charging pile; a first rectification and filtering module, a second rectification and filtering module, and a first switching module, which are respectively connected to the first rectification and filtering module and the second rectification and filtering module; a control module, which is respectively connected to the voltage sampling module and the first switching module, and based on the voltage difference, controls the first switching module to connect the first rectification and filtering module or the second rectification and filtering module. The present invention can prevent the charging pile from being damaged due to phase error, which is beneficial to improving the safety of the charging pile.

Description

Technical Field

[0001] The present invention relates to the technical field of three-phase charging piles, and in particular to a phase error detection circuit and method for a three-phase charging pile, and a charging pile. Background Art

[0002] Electric vehicles are becoming more and more popular in the market, and the use of charging piles has also increased significantly. As a high-voltage device, charging piles have very high safety requirements. In order to improve charging efficiency, three-phase charging piles are becoming more and more widely used.

[0003] The three-phase charging pile includes three phase lines (R line / S line / T line), one neutral line (N line) and one ground line (PE line). The voltage between the phase line and the neutral line (phase voltage) is 230V, the voltage between the phases (line voltage) is 380V, and the PE line is the protective grounding line. In actual applications, customers are likely to make wiring errors, that is, connecting the neutral line to the phase line, which will cause the phase voltage to become the line voltage. That is, the low voltage (230V) becomes a high voltage (380V) due to the wrong connection of the input phase line, which may cause damage to the charging pile, which will cause the charging pile to be destroyed at the beginning of power-on, which will cause a very poor experience for users.

[0004] In order to avoid this problem, there is currently a solution: each phase circuit is designed according to the line voltage, so there will be no safety accidents even if it is connected incorrectly. This solution has high requirements for device design, especially the lightning protection design. Since the lightning protection device is designed according to the line voltage, its clamping position absorption voltage value is high, so in the surge voltage test, its residual voltage value is high, and the design requirements for the subsequent device are high. This solution will cause high cost pressure. Summary of the invention

[0005] In view of this, the present invention provides a phase error detection circuit and method for a three-phase charging pile, and a charging pile, which can prevent the charging pile from being damaged due to phase error, and is beneficial to improving the safety of the charging pile.

[0006] According to one aspect of the present invention, there is provided a phase error detection circuit for a three-phase charging pile, comprising:

[0007] A voltage sampling module is connected to the AC power grid to obtain the voltage difference between the first phase line incoming terminal and the neutral line incoming terminal of the charging pile;

[0008] The first rectifier and filter module, the second rectifier and filter module,

[0009] A first switch module, connected to the first rectifying and filtering module and the second rectifying and filtering module respectively;

[0010] A control module, which is respectively connected to the voltage sampling module and the first switch module, and controls the first switch module to connect the first rectification and filtering module or the second rectification and filtering module based on the voltage difference.

[0011] Optionally, when the voltage difference is equal to a preset line voltage value, the control module controls the first switch module to connect the first rectification and filtering module;

[0012] When the voltage difference is equal to a preset phase voltage value, the control module controls the first switch module to connect the second rectification and filtering module; the preset phase voltage value is less than the preset line voltage value.

[0013] Optionally, the first switch module is a single-pole double-throw switch, which has a common terminal, a first port and a second port; the common terminal is connected to the power grid, the first port is connected to the first rectification and filtering module, and the second port is connected to the second rectification and filtering module.

[0014] Optionally, when the charging pile is powered on, the first switch module connects the common terminal and the first port; when the voltage difference is equal to the preset line voltage value, the control module controls the first switch module to keep connecting the first port and the common terminal; when the voltage difference is equal to the preset phase voltage value, the control module controls the common terminal of the first switch module to switch from connecting the first port to connecting the second port.

[0015] Optionally, the phase error detection circuit further includes a lightning protection sub-circuit, and the lightning protection sub-circuit is respectively connected to the first switch module and the second rectification and filtering module.

[0016] Optionally, the lightning protection sub-circuit includes a plurality of varistors, and the voltage rating of the varistors is the preset phase voltage value.

[0017] Optionally, the first rectification and filtering module is a half-wave rectification circuit, and the second rectification and filtering module is a full-wave rectification circuit.

[0018] Optionally, the first rectification and filtering module includes at least one diode; the second rectification and filtering module includes a rectifier bridge.

[0019] According to another aspect of the present invention, there is provided a charging pile, which includes any of the above phase error detection circuits. The charging pile further includes a second switch module and an auxiliary power supply. The second switch module is connected to the AC power grid and is connected to the control module; the auxiliary power supply is respectively connected to the first rectification and filtering module, the second rectification and filtering module and the control module.

[0020] According to another aspect of the present invention, there is provided a phase error detection method for a three-phase charging pile, which is detected by using any of the above phase error detection circuits. The method includes the steps of:

[0021] Obtain the voltage difference between the incoming line terminal of the first phase line and the incoming line terminal of the neutral line of the charging pile;

[0022] After the charging pile is powered on, control the first switch module to connect the first rectification and filtering module;

[0023] Based on the voltage difference, determine whether there is a phase error in the connection of the charging pile;

[0024] When it is determined that there is a phase error in the connection of the charging pile, the control module controls the first switch module to keep connecting the first rectification and filtering module;

[0025] When it is determined that the wiring phase sequence of the charging pile is correct, the control module controls the first switch module to disconnect from the first rectification and filtering module and switch to connect to the second rectification and filtering module.

[0026] The beneficial effects of the present invention compared with the prior art are as follows:

[0027] The phase error detection circuit, method and charging pile for a three-phase charging pile provided by the present invention perform input phase voltage sampling, obtain the voltage difference between the incoming line terminal of the first phase line and the incoming line terminal of the neutral line of the charging pile, and determine whether there is a phase error in the connection of the charging pile; and when a phase error occurs, control the first switch module not to jump, use the first rectification module to reduce the effective value of the voltage, protect the circuit structure, prevent the problem that the charging pile is damaged due to phase error, and is beneficial to improving the safety of the charging pile. Description of the Drawings

[0028] The drawings here are incorporated into the specification and constitute a part of the specification, showing the embodiments in line with the present invention, and are used together with the specification to explain the principles of the present invention. Obviously, the drawings in the following description are only some embodiments of the present invention, and those of ordinary skill in the art can also obtain other drawings based on these drawings without creative efforts.

[0029] Figure 1 It is a module schematic diagram of a phase error detection circuit for a three-phase charging pile disclosed in an embodiment of the present invention;

[0030] Figure 2 It is a structural schematic diagram of a phase error detection circuit for a three-phase charging pile disclosed in an embodiment of the present invention;

[0031] Figure 3 It is a structural schematic diagram of a voltage sampling module in a phase error detection circuit disclosed in an embodiment of the present invention;

[0032] Figure 4 Schematic diagram of the module structure of the charging pile disclosed in another embodiment of the present invention;

[0033] Figure 5 Schematic flow chart of a phase error detection method for a three-phase charging pile disclosed in another embodiment of the present invention. Detailed implementation manners

[0034] Example embodiments will now be described more fully with reference to the accompanying drawings. However, the example embodiments can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. On the contrary, these embodiments are provided so that this invention will be thorough and complete, and will fully convey the concept of example embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a thorough understanding of the embodiments of the present disclosure. However, those skilled in the art will realize that the technical solutions of the present disclosure can be practiced without one or more of the specific details, or other methods, materials, devices, etc. may be used. In other cases, well-known technical solutions are not shown or described in detail to avoid obscuring aspects of the present disclosure. The same reference numerals in the drawings denote the same or similar structures, and thus their detailed descriptions will be omitted.

[0035] The terms "a", "an", "the", "said" and "at least one" are used to denote the presence of one or more elements / components / etc.; the terms "comprising", "having" and "provided with" are used to mean an open inclusion and mean that there may be additional elements / components / etc. in addition to the listed elements / components / etc.

[0036] As Figure 1 and Figure 2 shown, the present invention discloses a phase error detection circuit for a three-phase charging pile. If there is a problem of connecting the neutral line as a phase line during the installation stage of the charging pile, the phase voltage will become the line voltage. After the charging pile starts to be used, this phase error problem may damage the charging pile or the electric vehicle. This application is to avoid the possible damage to the charging pile due to the above phase error problem.

[0037] As Figure 1 shown, in this embodiment, the phase error detection circuit includes a voltage sampling module 11, a first rectification and filtering module 12, a second rectification and filtering module 13, a first switch module 14, and a control module 15.

[0038] Among them, the input end of the voltage sampling module 11 is connected to the AC power grid, and the output end is connected to the control module 15. The control module 15 is also respectively connected to the first switch module 14, the first rectification and filtering module 12, and the second rectification and filtering module 13. The first switch module 14 is respectively connected to the first rectification and filtering module 12 and the second rectification and filtering module 13. The first switch module 14 is also connected to the AC power grid.

[0039] The voltage sampling module 11 is used to obtain the voltage difference between the first phase wire inlet end and the neutral wire inlet end of the charging pile. The above-mentioned first phase wire inlet end can be, for example, the R phase. It should be noted that the object obtained by the voltage sampling module 11 is not the voltage difference between the phase wire and the neutral wire of the power grid. Among them, Figure 2 The voltage sampling module 11 and the control module 15 are not shown.

[0040] The first rectification and filtering module 12 is used to reduce the input voltage value and perform filtering processing, so that the output voltage value after passing through the first rectification and filtering module 12 is less than the input voltage value, thereby facilitating the protection of the auxiliary power supply 17 and the electric vehicle at the rear end of the circuit path and avoiding damage. The second rectification and filtering module 13 is used to rectify and filter the above-mentioned input voltage.

[0041] Optionally, the above-mentioned first rectification and filtering module 12 is a half-wave rectification circuit, and the above-mentioned second rectification and filtering module 13 is a full-wave rectification circuit. The above-mentioned first rectification and filtering module 12 includes at least one diode. The above-mentioned second rectification and filtering module 13 includes a rectifier bridge.

[0042] The control module 15 compares the voltage difference with a preset threshold based on the above-mentioned voltage difference, that is, compares the voltage difference with the preset threshold, so as to control the first switch module 14 to connect the first rectification and filtering module 12 or the second rectification and filtering module 13 according to the comparison result. For example, when the voltage difference is equal to the first preset threshold, the control first switch module 14 only connects the first rectification and filtering module 12. When the voltage difference is equal to the second preset threshold, the control first switch module 14 only connects the second rectification and filtering module 13. That is, after the charging pile is powered on and works, the above-mentioned first switch module 14 only connects one branch of the first rectification and filtering module 12 and the second rectification and filtering module 13 at the same time.

[0043] In this embodiment, in the initial working state after the charging pile is powered on, the first switch module 14 connects the first rectification and filtering module 12. When the charging pile has a wrong phase, the first switch module 14 remains connected to the first rectification and filtering module 12. When the wiring phase sequence of the charging pile is correct, the first switch module 14 disconnects from the first rectification and filtering module 12 and switches to connect to the second rectification and filtering module 13.

[0044] As an alternative embodiment, when the voltage difference is equal to a preset line voltage value, the control module 15 determines that a phase error problem occurs in the charging pile, and controls the first switch module 14 to connect the first rectification and filtering module 12. When the voltage difference is equal to a preset phase voltage value, the control module 15 determines that the wiring phase sequence of the charging pile is correct, controls the first switch module 14 to disconnect from the first rectification and filtering module 12, and the first switch module 14 connects the second rectification and filtering module 13. Wherein, the preset phase voltage value is less than the preset line voltage value.

[0045] In this embodiment, referring to Figure 2 , the first switch module 14 is a signal relay K1, which is a single-pole double-throw switch. The first switch module 14 is provided with a common terminal, a first port and a second port. The common terminal is connected to the power grid, the first port is connected to the first rectification and filtering module 12, and the second port is connected to the second rectification and filtering module 13.

[0046] In the initial working state after the charging pile is powered on, the first switch module 14 connects the common terminal and the first port. When the voltage difference is equal to the preset line voltage value, the control module 15 controls the first switch module 14 to keep connecting the first port and the common terminal. When the voltage difference is equal to the preset phase voltage value, the connection between the common terminal and the first port of the first switch module 14 is disconnected, and the control module 15 controls the common terminal of the first switch module 14 to switch from connecting the first port to connecting the second port.

[0047] Exemplarily, the preset phase voltage value can be 230Vac. The preset line voltage value can be 380Vac. The present application is not limited thereto.

[0048] As Figure 1 and Figure 2 shown, in this embodiment, the phase error detection circuit further includes a lightning protection sub-circuit 16. The lightning protection sub-circuit 16 is respectively connected to the first switch module 14 and the second rectification and filtering module 13. The lightning protection sub-circuit 16 includes a plurality of varistors. The voltage rating of the varistors is the preset phase voltage value. The lightning protection sub-circuit 16 can be connected to the first phase wire inlet end through the first switch module 14, and the input end of the lightning protection sub-circuit 16 is also connected to the neutral wire inlet end. The preset phase voltage value is less than the line voltage.

[0049] In the prior art, if a conventional lightning protection device is used in the lightning protection sub-circuit 16, when the user connects the N wire as the phase wire (such as the S phase), the varistor VAR1 will be instantly broken down or even catch fire, resulting in an accident. To avoid the potential safety hazards caused by wrong phase connection, in the prior art, when the lightning protection sub-circuit 16 is designed according to the line voltage, the rated voltage value of the varistor needs to be set as the line voltage (usually 380 Vac). Then, in the surge test, the residual voltage of VAR1 is relatively high, that is, the input voltage of the auxiliary power supply 17 will be relatively high (possibly increased to 700 V or even higher), which will have a great impact on the design of the subsequent auxiliary power supply 17, that is, a high-voltage design is required. If the auxiliary power supply 17 adopts a high-voltage design, the design cost of the auxiliary power supply 17 is relatively high and the volume is relatively large.

[0050] In this embodiment, through the setting of the above-mentioned wrong phase detection circuit, the charging pile does not need to consider designing the circuit according to the line voltage to avoid the hidden danger of wrong phase connection. Therefore, a varistor with a rated voltage value of the preset phase voltage value (such as 230 Vac) can be adopted in the lightning protection sub-circuit 16, which is beneficial to the subsequent realization of the low-voltage design of the auxiliary power supply 17.

[0051] Reference Figure 2 , the first switch module 14 has ports 1, 2, 3, 4, and 5. Among them, port 3 is the common terminal. Port 5 is the above-mentioned first port. Port 4 is the above-mentioned second disconnection. Ports 1 and 2 are used to connect to the power supply to supply power to the first switch module 14. The first rectifier filter module 12 includes a diode D1 and an electrolytic capacitor EC1. The second rectifier filter module 13 includes a rectifier bridge DB1 and an electrolytic capacitor EC1. That is to say, the first rectifier filter module 12 and the second rectifier filter module 13 share the electrolytic capacitor EC1. The positive pole of the diode D1 is connected to port 5 of the first switch module 14, and the negative pole of the diode D1 is connected to the positive pole of the electrolytic capacitor EC1. The diode D1 can adopt a conventional low-current diode.

[0052] The lightning protection sub-circuit 16 is respectively connected to port 4 of the first switch module 14 and the rectifier bridge DB1 of the second rectifier filter module 13. Specifically, the lightning protection sub-circuit 16 includes a varistor VAR1, a varistor VAR2, a varistor VAR3, and a discharge tube Z1. The discharge tube Z1 is grounded.

[0053] The first terminal of the varistor VAR1 is respectively connected to the first terminal of the fuse F1 and port 4 of the first switch module 14. The second terminal of the varistor VAR1 is respectively connected to the neutral wire incoming terminal and port 3 of the rectifier bridge DB1. The first terminal of the varistor VAR2 is respectively connected to the fuse F1 and port 4 of the first switch module 14. The second terminal of the varistor VAR2 is respectively connected to the second terminal of the varistor VAR3 and the discharge tube Z1. The first terminal of the varistor VAR3 is respectively connected to the second terminal of the varistor VAR1, the neutral wire incoming terminal and port 3 of the rectifier bridge DB1. The second terminal of the fuse F1 is connected to port 2 of the rectifier bridge DB1. Port 4 of the rectifier bridge DB1 is connected to the positive electrode of the electrolytic capacitor EC1. Port 1 of the rectifier bridge DB1 is connected to the negative electrode of the electrolytic capacitor EC1.

[0054] As Figure 3 shown, in this embodiment, the voltage sampling module 11 is a differential sampling circuit. The above voltage sampling module 11 includes a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, and an amplifier U1. The input terminal of the second resistor R2 is connected to the neutral wire incoming terminal of the charging pile. The input terminal of the third resistor R3 is connected to the first phase wire incoming terminal of the charging pile. The connection relationship between the various components in the voltage sampling module 11 can be referred to Figure 3 shown, and this embodiment will not be elaborated here. Figure 2 and Figure 3 in which InputN is the neutral wire incoming terminal and InputR is the first phase wire incoming terminal.

[0055] In this embodiment, the voltage sampling module 11 samples the voltage difference between one phase wire and the neutral wire in the three phases. However, in other embodiments, it is also possible to sample each phase voltage, that is, the voltage between R / N, S / N, and T / N. In this case, a differential sampling circuit is provided for each of the three phase wires. This application does not limit this.

[0056] The phase sequence error detection circuit disclosed in this application can better identify the misconnection of the neutral wire, and will not cause safety accidents. At the same time, the circuit has a small volume and low cost.

[0057] As an optional embodiment, the above phase sequence error detection circuit may further include a second switch module. The above second switch module is connected to the above AC power grid and is connected to the above control module 15. The output terminal of the second switch module is connected to the vehicle charging terminal.

[0058] If the wiring phase sequence is correct, the control module 15 controls the second switch module to close, and the electric vehicle charges normally.

[0059] If a phase - error problem occurs, the input is the line voltage. The control module 15 controls the first switch module 14 to remain connected to the first rectification and filtering module 12, that is, the first switch module 14 does not jump. At the same time, the control module 15 controls the second switch module not to close and remain open. And it prompts the customer of the phase error, which will not affect the rear - end vehicle. This can protect the charging pile and avoid damage.

[0060] As Figure 4 shown, another embodiment of the present invention discloses a charging pile. The charging pile includes the phase - error detection circuit disclosed in any of the above - mentioned embodiments, as well as an auxiliary power supply 17 and a second switch module 18. The second switch module 18 is connected to the above - mentioned AC power grid and is connected to the control module 15. The auxiliary power supply 17 is respectively connected to the first rectification and filtering module 12, the second rectification and filtering module 13, and the control module 15. The auxiliary power supply 17 is used for transforming the input voltage to provide a working power supply for the control module 15. The output end of the second switch module 18 is connected to the vehicle charging end.

[0061] The second switch module 18 is a three - phase power circuit relay and adopts a three - phase input and three - phase output mode. Therefore, the second switch module 18 is respectively connected to the R line, S line, and T line of the AC power grid. The lightning protection sub - circuit 16 is arranged at the front end of the auxiliary power supply 17 and can protect the circuit from withstanding surge voltage.

[0062] In the prior art, in order to avoid potential safety hazards caused by phase error, each phase circuit is designed according to the line voltage, and its clamping absorption voltage value is relatively high. Therefore, in the surge voltage experiment, its residual voltage value is relatively high, that is, the input voltage of the auxiliary power supply 17 will be relatively high (it may be increased to 700V or even higher), which requires higher design requirements for the subsequent - stage devices.

[0063] In this embodiment, through the setting of the above - mentioned phase - error detection circuit, the charging pile does not need to consider designing the circuit according to the line voltage to avoid the hidden danger of phase error. Therefore, a varistor with a voltage rating of the preset phase voltage value (such as 230Vac) can be used in the lightning protection sub - circuit 16. So, the residual voltage of the varistor after the surge experiment can be reduced, which is beneficial to reducing the input voltage of the auxiliary power supply 17. Therefore, compared with the prior art, the auxiliary power supply 17 in this embodiment can adopt a low - voltage design and set a relatively small input voltage upper limit value, such as 550V. That is, it is a low - voltage auxiliary power supply 17, which can better save volume and cost.

[0064] After the charging pile disclosed in this embodiment is powered on, the first switch module 14 is controlled to connect to the first rectification and filtering module 12, and a low-voltage power supply required for the operation of the charging pile is generated through the auxiliary power supply 17. Then, the control module 15 performs phase error judgment through the voltage sampling module 11. If the wiring phase sequence is correct, the first switch module 14 disconnects from the first rectification and filtering module 12 and switches to connect to the second rectification and filtering module 13. In this way, the input will become the phase voltage, and the lightning protection sub-circuit 16 is arranged at the front end of the auxiliary power supply 17, which can protect the circuit from surge voltage. The control module 15 controls the second switch module 18 to close, and the electric vehicle charges normally.

[0065] If a phase error problem occurs, then the input is the line voltage. The control module 15 controls the first switch module 14 to remain connected to the first rectification and filtering module 12, that is, the first switch module 14 will not jump. At the same time, the control module 15 controls the second switch module 18 not to close and remains open. And it prompts the customer of the phase error. It will not affect the vehicle at the back end.

[0066] In this embodiment, the voltage sampling module 11 samples the voltage difference between one phase line and the neutral line among the three phases. However, in other embodiments, it is also possible to sample each phase voltage, that is, the voltages between R / N, S / N, and T / N. In this case, a differential sampling circuit is provided for each of the three phase lines. This application does not limit this.

[0067] An embodiment of the present invention also discloses a phase error detection method. This phase error detection method uses the phase error detection circuit disclosed in any of the above embodiments for detection. The detailed structural features and advantages of the phase error detection circuit can be referred to the description of the above embodiments, and will not be elaborated here.

[0068] As Figure 5 shown, this detection method includes the steps:

[0069] S110, obtain the voltage difference between the incoming line end of the first phase line and the incoming line end of the neutral line of the charging pile. For example, the voltage difference between the R phase and the N line can be sampled through the differential sampling module.

[0070] S120, after the charging pile is powered on, control the first switch module to connect to the first rectification and filtering module. That is, after the charging pile is powered on, the first switch module is defaultly connected to the first rectification and filtering module.

[0071] S130. Based on the above voltage difference, determine whether there is a wrong phase connection in the above charging pile. In this embodiment, when the above voltage difference is equal to the preset line voltage value, it is determined that there is a wrong phase connection in the charging pile, and the first switch module is controlled to connect the first rectification and filtering module. When the above voltage difference is equal to the preset phase voltage value, it is determined that the wiring phase sequence of the charging pile is correct, the first switch module is controlled to disconnect from the first rectification and filtering module, and the first switch module is controlled to connect the second rectification and filtering module. Among them, the preset phase voltage value is less than the preset line voltage value.

[0072] When it is determined that there is a wrong phase connection in the above charging pile, step S140 is executed: control the first switch module to remain connected to the first rectification and filtering module.

[0073] When it is determined that the wiring phase sequence of the above charging pile is correct, step S150 is executed: control the first switch module to disconnect from the first rectification and filtering module and switch to connect to the second rectification and filtering module.

[0074] In summary, the wrong phase detection circuit and method for a three-phase charging pile, and the charging pile of the present invention at least have the following advantages:

[0075] The wrong phase detection circuit and method for a three-phase charging pile, and the charging pile disclosed in this embodiment sample the input phase voltage, obtain the voltage difference between the first phase line inlet end and the neutral line inlet end of the charging pile, and determine whether there is a wrong phase connection in the charging pile; and when a wrong phase occurs, control the first switch module not to jump, use the first rectification module to reduce the effective value of the voltage, protect the circuit structure, and prevent the charging pile from being damaged due to wrong phase, which is beneficial to improving the safety of the charging pile. When the wiring phase sequence is correct, control the first switch module to jump, connect the lightning protection circuit and the full-wave rectification circuit, which is beneficial to the subsequent auxiliary power supply to adopt a low-voltage design, and is beneficial to reducing the circuit cost and volume.

[0076] On the other hand, the varistors in the lightning protection circuit in the circuit disclosed in the present invention all adopt the phase voltage specification. Compared with the varistors adopting the line voltage specification, the cost is lower, and it can better suppress the high voltage generated by the surge lightning strike experiment, which is beneficial to reducing the circuit cost.

[0077] The above content is a further detailed description of the present invention in combination with specific preferred embodiments. It cannot be determined that the specific implementation of the present invention is only limited to these descriptions. For those of ordinary skill in the technical field to which the present invention belongs, without departing from the concept of the present invention, several simple deductions or substitutions can be made, and all should be regarded as belonging to the protection scope of the present invention.

Claims

1. A phase error detection circuit for a three-phase charging pile, characterized in that, Comprising: A voltage sampling module, connected to the AC power grid, for obtaining the voltage difference between the incoming line end of the first phase wire and the incoming line end of the neutral wire of the charging pile; A first rectification and filtering module, a second rectification and filtering module; A first switching module, respectively connected to the first rectification and filtering module and the second rectification and filtering module; A control module, respectively connected to the voltage sampling module and the first switching module, and based on the voltage difference, controlling the first switching module to connect the first rectification and filtering module or the second rectification and filtering module; when the voltage difference is equal to a preset line voltage value, the control module controls the first switching module to connect the first rectification and filtering module; when the voltage difference is equal to a preset phase voltage value, the control module controls the first switching module to connect the second rectification and filtering module; the preset phase voltage value is less than the preset line voltage value.

2. The phase error detection circuit according to claim 1, wherein The first switching module is a single-pole double-throw switch, provided with a common terminal, a first port and a second port; the common terminal is connected to the power grid, the first port is connected to the first rectification and filtering module, and the second port is connected to the second rectification and filtering module.

3. The phase error detection circuit according to claim 2, wherein When the charging pile is powered on, the first switching module connects the common terminal and the first port; when the voltage difference is equal to the preset line voltage value, the control module controls the first switching module to keep connecting the first port and the common terminal; when the voltage difference is equal to the preset phase voltage value, the control module controls the common terminal of the first switching module to switch from connecting the first port to connecting the second port.

4. The phase error detection circuit according to claim 1, wherein The phase error detection circuit further includes a lightning protection sub-circuit, and the lightning protection sub-circuit is respectively connected to the first switching module and the second rectification and filtering module.

5. The phase error detection circuit according to claim 4, characterized in that The lightning protection sub-circuit includes a plurality of varistors, and the voltage rating of the varistors is the preset phase voltage value.

6. The out-of-phase detection circuit according to claim 1, wherein The first rectification and filtering module is a half-wave rectification circuit, and the second rectification and filtering module is a full-wave rectification circuit.

7. The phase error detection circuit according to claim 1, wherein The first rectification and filtering module includes at least one diode; the second rectification and filtering module includes a rectifier bridge.

8. A charging pile, characterized in that, Comprising the phase error detection circuit according to any one of claims 1-7, the charging pile further includes a second switching module and an auxiliary power supply, the second switching module is connected to the AC power grid and is connected to the control module; the auxiliary power supply is respectively connected to the first rectification and filtering module, the second rectification and filtering module and the control module.

9. A phase error detection method, characterized in that, Using the phase error detection circuit according to any one of claims 1-7 for detection, the method includes the steps: Obtaining the voltage difference between the incoming line end of the first phase wire and the incoming line end of the neutral wire of the charging pile; After the charging pile is powered on, controlling the first switching module to connect the first rectification and filtering module; Based on the voltage difference, determining whether there is a phase error in the connection of the charging pile; When it is determined that there is a phase error in the connection of the charging pile, the control module controls the first switching module to keep connecting the first rectification and filtering module; When it is determined that the wiring phase sequence of the charging pile is correct, the control module controls the first switching module to disconnect from the first rectification and filtering module and switch to communicate with the second rectification and filtering module.

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