Protection circuit, power supply circuit and charging pile

Abstract

The invention discloses a protection circuit, a power supply circuit and a charging pile. The protection circuit is used for being connected with a power switch module and comprises a main control module, an adhesion detection module and a short circuit detection module. The adhesion detection module is connected with the power switch module and is used for carrying out adhesion detection on the power switch module and outputting an adhesion detection signal; the short circuit detection module is connected with the power switch module and is used for carrying out short circuit detection on the power switch module and outputting a short circuit detection signal; and the main control module is used for controlling the short circuit detection module to be in a forbidden state when the adhesion detection signal is an adhesion signal, and controlling the power switch module to be in a forbidden state when the short circuit detection signal is a short circuit signal. The protection circuit can prevent the relay adhesion situation from harming the short circuit detection, prevents the relay adhesion from causing the burnout of devices in the short circuit detection module, and improves the safety and reliability of the short circuit detection.

Description

Technical Field

[0001] The present invention relates to the technical field of charging piles, and particularly relates to a protection circuit, a power supply circuit and a charging pile. Background Art

[0002] With the popularization of electric vehicles, as an important supporting facility for electric vehicles, the safety and stability of charging piles have attracted much attention.

[0003] Before the charging pile is powered on, if there is a short circuit at the output end of the power relay, when the relay is closed and powered on, a large current may be generated, resulting in equipment damage and even safety accidents. Currently, when detecting the output short circuit situation before the charging pile is powered on, voltage detection or current detection methods are usually used, but the reliability of these detection methods is poor. When there are other faults in the circuit, such as relay adhesion, the existing detection methods may not be able to effectively detect the short circuit situation, and even easily cause other hazards. Summary of the Invention

[0004] Embodiments of the present invention provide a protection circuit, a power supply circuit and a charging pile to solve the problem of poor detection reliability of existing short circuit detection methods.

[0005] Embodiments of the present invention provide a protection circuit for connecting a power switch module, and the protection circuit includes a main control module, an adhesion detection module and a short circuit detection module; The adhesion detection module is connected to the power switch module and is used for performing adhesion detection on the power switch module and outputting an adhesion detection signal; The short circuit detection module is connected to the power switch module and is used for performing short circuit detection on the power switch module and outputting a short circuit detection signal; The main control module is connected to the adhesion detection module and the short circuit detection module, and is further used for connecting the power switch module. When the adhesion detection signal is an adhesion signal, it controls the short circuit detection module to be in a disabled state. When the short circuit detection signal is a short circuit signal, it controls the power switch module to be in a disabled state.

[0006] Preferably, the main control module includes a signal interlock unit and a main control chip; The signal interlock unit is connected to the adhesion detection module, the short circuit detection module and the main control chip, and is used for outputting a first enable signal to the main control chip when the adhesion detection signal is a non-adhesion signal; outputting a first disable signal to the main control chip when the adhesion detection signal is an adhesion signal; outputting a second enable signal to the main control chip when the short circuit detection signal is a non-short circuit signal; outputting a second disable signal to the main control chip when the short circuit detection signal is a short circuit signal; The main control chip is connected to the short - circuit detection module and the power switch module, and is configured to output a first detection control signal to the short - circuit detection module based on the first enable signal, so that the short - circuit detection module is in an available state to perform short - circuit detection on the power switch module; output a second detection control signal to the short - circuit detection module based on the first disable signal, so that the short - circuit detection module is in a disabled state; output a first output control signal to the power switch module based on the second enable signal, so that the power switch module is in an available state; and output a second output control signal to the power switch module based on the second disable signal, so that the power switch module is in a disabled state.

[0007] Preferably, the main control module is further configured to be connected to an alarm module, and when the adhesion detection signal is an adhesion signal or the short - circuit detection signal is a short - circuit signal, send an alarm signal to the alarm module, so that the alarm module performs an alarm operation.

[0008] Preferably, the power switch module includes a power relay; The adhesion detection module is connected to two normally - open contacts of the power relay, and is configured to detect the adhesion detection result on the two normally - open contacts of the power relay. If the adhesion detection result is in an adhesion state, the adhesion detection signal is an adhesion signal; if the adhesion detection result is not in an adhesion state, the adhesion detection signal is a non - adhesion signal.

[0009] Preferably, the relay adhesion detection module includes an optocoupler unit; The light - emitting part of the optocoupler unit is connected to two normally - open contacts of the power relay, and the light - receiving part of the optocoupler unit is connected to the main control module, and is configured to detect the adhesion detection result between the two normally - open contacts of the power relay. If the adhesion detection result is in an adhesion state, the adhesion detection signal is an adhesion signal; if the adhesion detection result is not in an adhesion state, the adhesion detection signal is a non - adhesion signal.

[0010] Preferably, the short - circuit detection module is connected to two normally - open contacts of the power relay, and is configured to detect the short - circuit detection result between the two normally - open contacts of the power relay. If the short - circuit detection result is in a short - circuit state, the short - circuit detection signal is a short - circuit signal; if the short - circuit detection result is not in a short - circuit state, the short - circuit detection signal is a non - short - circuit signal.

[0011] Preferably, the short - circuit detection module includes a pre - detection relay and a signal comparison circuit; The pre-inspection relay is connected to the output ends of the signal comparison circuit and the power switch module, and is also connected to the main control module. It is used to be pulled in under the control of the main control module to connect the signal comparison circuit to the output end of the power switch module, or to be disconnected under the control of the main control module to disconnect the signal comparison circuit from the output end of the power switch module; The signal comparison circuit is connected to the main control module and is used to perform a short-circuit detection on the power switch module when the pre-inspection relay is pulled in, and output a short-circuit detection signal to the main control module.

[0012] Preferably, the signal comparison circuit includes a voltage division unit and an operational amplifier; The voltage division unit is connected to the pre-inspection relay and the operational amplifier, and is used to output a detection voltage signal to the operational amplifier according to the short-circuit detection result between the two normally open contacts of the power relay; The operational amplifier is connected to the main control module and is used to amplify the detection voltage signal to obtain a short-circuit detection signal and output the short-circuit detection signal to the main control module.

[0013] Preferably, the voltage division unit includes a first voltage division resistor, a second voltage division resistor, and a third voltage division resistor; The first voltage division resistor, the second voltage division resistor, and the third voltage division resistor are connected in series between the power supply terminal and the ground; The connection node between the first voltage division resistor and the second voltage division resistor is connected to the output neutral line of the power switch module; The connection node between the second voltage division resistor and the third voltage division resistor is connected to the output live wire of the power switch module and is also connected to the operational amplifier.

[0014] An embodiment of the present invention further provides a power supply circuit, including a power switch module and the protection circuit described in any one of the above; The input end of the power switch module is used to connect to the mains circuit, and the output end of the power switch module is used to connect to the device to be charged; The protection circuit is connected to the output end of the power switch module and is used to perform an adhesion detection and a short-circuit detection on the power switch module, obtain a short-circuit detection signal, and control the power switch module to be in a disabled state when the short-circuit detection signal is a short-circuit signal.

[0015] An embodiment of the present invention further provides a charging pile, including the above power supply circuit, one end of the power supply circuit is used to connect to the mains circuit, and the other end is used to connect to the device to be charged.

[0016] The embodiment of the present invention provides a protection circuit, a power supply circuit and a charging pile. Before the power switch module is closed and power output is carried out, the protection circuit can perform adhesion detection on the power relay in the power switch module, and continue to perform short-circuit detection on the power switch module after detecting that there is no relay adhesion. On the one hand, the protection circuit can detect and eliminate these two fault conditions of relay adhesion and short circuit to ensure the safety of power output. On the other hand, it can also prevent the relay adhesion situation from harming the short-circuit detection, prevent the device in the short-circuit detection module from being burned out due to relay adhesion, and improve the safety and reliability of the short-circuit detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments of the present invention. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0018] Figure 1 is a block diagram structural schematic diagram of the protection circuit in an embodiment of the present invention; Figure 2 is a circuit structural schematic diagram of the power supply circuit in an embodiment of the present invention.

[0019] In the figure: 1, main control module; 11, signal interlock unit; 12, main control chip; 2, adhesion detection module; 3, short-circuit detection module; 31, signal comparison circuit; 311, voltage division unit; 4, power switch module. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0020] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the protection scope of the present invention.

[0021] It should be understood that the present invention can be implemented in different forms and should not be construed as limited to the embodiments presented herein. On the contrary, providing these embodiments will make the disclosure thorough and complete, and will fully convey the scope of the present invention to those skilled in the art. In the drawings, for clarity, the dimensions and relative dimensions of layers and regions may be exaggerated. The same reference numerals denote the same elements throughout the drawings.

[0022] It should be understood that when an element or layer is referred to as being "on", "adjacent to", "connected to" or "coupled to" another element or layer, it can be directly on, adjacent to, connected or coupled to the other element or layer, or there may be intervening elements or layers. In contrast, when an element is referred to as being "directly on", "directly adjacent to", "directly connected to" or "directly coupled to" another element or layer, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc. may be used to describe various elements, components, regions, layers and / or parts, these elements, components, regions, layers and / or parts should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or part from another element, component, region, layer or part. Thus, without departing from the teachings of the present invention, the first element, component, region, layer or part discussed below may be referred to as the second element, component, region, layer or part.

[0023] Spatial relationship terms such as "under", "below", "beneath", "underneath", "above", "over", etc. are used herein for convenience in describing the relationship of one element or feature shown in the figures to other elements or features. It should be understood that, in addition to the orientation shown in the figures, spatial relationship terms are intended to also include different orientations of the device in use and operation. For example, if the device in the figures is flipped, then an element or feature described as "under" or "beneath" or "underneath" another element or feature will be oriented "over" the other element or feature. Thus, the exemplary terms "under" and "beneath" can include both an upper and a lower orientation. The device may be otherwise oriented (rotated 90 degrees or other orientations) and the spatial descriptors used herein are to be interpreted accordingly.

[0024] The purpose of the terms used herein is only to describe specific embodiments and is not a limitation of the present invention. As used herein, the singular forms "a", "an" and "the" are also intended to include the plural forms unless the context clearly dictates otherwise. It should also be understood that the terms "comprising" and / or "including", when used in this specification, specify the presence of the stated features, integers, steps, operations, elements and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups. As used herein, the term "and / or" includes any and all combinations of the associated listed items.

[0025] To fully understand the present invention, detailed structures and steps will be set forth in the following description in order to explain the technical solutions proposed by the present invention. The preferred embodiments of the present invention are described in detail below. However, in addition to these detailed descriptions, the present invention may have other embodiments.

[0026] An embodiment of the present invention provides a protection circuit, which includes a main control module 1, a sticking detection module 2, and a short - circuit detection module 3. The sticking detection module 2 is used to connect to the power switch module 4, perform sticking detection on the power switch module 4, and output a sticking detection signal check_sta. The short - circuit detection module 3 is used to connect to the power switch module 4, perform short - circuit detection on the power switch module 4, and output a short - circuit detection signal SOP_sta. The main control module 1 is connected to the sticking detection module 2 and the short - circuit detection module 3, and is also used to connect to the power switch module 4. When the sticking detection signal check_sta is a sticking signal, it controls the short - circuit detection module 3 to be in a disabled state. When the short - circuit detection signal SOP_sta is a short - circuit signal, it controls the power switch module 4 to be in a disabled state.

[0027] As an example, the protection circuit includes a main control module 1, a sticking detection module 2, and a short - circuit detection module 3. The sticking detection module 2 is used to connect to the power switch module 4 and perform sticking detection on the power switch module 4. The short - circuit detection module 3 is used to connect to the power switch module 4 and perform short - circuit detection on the power switch module 4. Among them, the power switch module 4 may include a power relay K1 for performing a power output switching function. The power relay K1 can be controlled to be attracted / opened by an MCU to achieve the power output switching function. The MCU may be included in the main control module 1 of the protection circuit, so that the main control module 1 directly controls the power relay K1 while performing circuit safety protection. Or when the MCU is another control chip independent of the main control module 1, the main control module 1 can control to enable or disable the control function of the MCU on the power relay K1 to achieve circuit safety protection.

[0028] The sticking detection module 2 is used to detect whether there is a relay sticking in the power switch module 4 and feedback a corresponding sticking detection signal check_sta to the main control module 1. Specifically, when the relay in the power switch module 4 is in a sticking state, the sticking detection module 2 can detect this sticking state and feedback a sticking signal to the main control module 1. On the contrary, when the relay in the power switch module 4 is in a non - sticking state, the sticking detection module 2 will not detect the sticking state and will feedback a non - sticking signal to the main control module 1. The short - circuit detection module 3 is used to detect whether there is a short - circuit situation in the power switch module 4 and feedback a corresponding short - circuit detection signal SOP_sta to the main control module 1. Specifically, when there is a short - circuit situation in the power switch module 4, the short - circuit detection module 3 can detect this short - circuit state and feedback a short - circuit signal to the main control module 1. On the contrary, when there is no short - circuit situation in the power switch module 4, the short - circuit detection module 3 will not detect the short - circuit state and will feedback a non - short - circuit signal to the main control module 1.

[0029] The main control module 1 is connected to the adhesion detection module 2 and the short - circuit detection module 3. Before the power relay K1 in the power switch module 4 is pulled in, it is used to control the adhesion detection module 2 to perform adhesion detection first. If there is no relay adhesion, it continues to control the short - circuit detection module 3 to perform short - circuit detection. If there is relay adhesion, it does not continue to control the short - circuit detection module 3 to perform short - circuit detection. If a short - circuit situation is detected after the short - circuit detection, it does not control the power relay K1 to be pulled in, or disables the power relay K1 pull - in control function of the MCU that controls the power relay K1 to be pulled in. If no short - circuit situation is detected after the short - circuit detection, it controls the power relay K1 to be normally pulled in.

[0030] In this example, the protection circuit can perform adhesion detection on the relay in the power switch module 4 before the power switch module 4 is closed and power output is carried out, and continue to perform short - circuit detection on the power switch module 4 after detecting that there is no relay adhesion. On the one hand, this protection circuit can detect and eliminate two types of fault situations, namely relay adhesion and short - circuit, to ensure the safety of power output. On the other hand, it can also prevent the relay adhesion situation from causing harm to the short - circuit detection, prevent device burnout and other situations in the short - circuit detection module 3 caused by relay adhesion, and improve the safety and reliability of the short - circuit detection.

[0031] In an embodiment, the main control module 1 includes a signal interlock unit 11 and a main control chip 12. The signal interlock unit 11 is connected to the adhesion detection module 2, the short - circuit detection module 3, and the main control chip 12. It is used to output a first enable signal to the main control chip 12 when the adhesion detection signal check_sta is a non - adhesion signal; output a first disable signal to the main control chip 12 when the adhesion detection signal check_sta is an adhesion signal; output a second enable signal to the main control chip 12 when the short - circuit detection signal SOP_sta is a non - short - circuit signal; output a second disable signal to the main control chip 12 when the short - circuit detection signal SOP_sta is a short - circuit signal. The main control chip 12 is connected to the short - circuit detection module 3 and the power switch module 4. It is used to output a first detection control signal to the short - circuit detection module 3 based on the first enable signal, so that the short - circuit detection module 3 is in an available state to perform short - circuit detection on the power switch module 4; output a second detection control signal to the short - circuit detection module 3 based on the first disable signal, so that the short - circuit detection module 3 is in a disabled state; output a first output control signal to the power switch module 4 based on the second enable signal, so that the power switch module 4 is in an available state; output a second output control signal to the power switch module 4 based on the second disable signal, so that the power switch module 4 is in a disabled state.

[0032] As an example, the main control module 1 includes a signal interlock unit 11 and a main control chip 12. The signal interlock unit 11 is used to control the operation of the main control chip 12 based on the adhesion detection signal check_sta, so that the main control chip 12 controls the short-circuit detection module 3 to be in an available / disabled state.

[0033] Specifically, as an example, when the adhesion detection signal check_sta is a non-adhesion signal, the signal interlock unit 11 outputs a first enable signal to the main control chip 12. Based on this first enable signal, the main control chip 12 can output a first detection control signal to the short-circuit detection module 3, enabling the short-circuit detection module 3 to be in an available state and capable of performing short-circuit detection on the power switch module 4; when the adhesion detection signal check_sta is an adhesion signal, the signal interlock unit 11 outputs a first disable signal to the main control chip 12. Based on this first disable signal, the main control chip 12 can output a second detection control signal to the short-circuit detection module 3, so that the short-circuit detection module 3 is in a disabled state and does not perform short-circuit detection, preventing device burnout and other situations in the short-circuit detection module 3 caused by relay adhesion. Further, the main control chip 12 can also output a second output control signal to the power switch module 4 based on this first disable signal, so that the power switch module 4 is in a disabled state and cannot perform power output.

[0034] After the short-circuit detection module 3 performs short-circuit detection, the signal interlock unit 11 can continue to detect the short-circuit detection signal SOP_sta. When the short-circuit detection signal SOP_sta is a non-short-circuit signal, the signal interlock unit 11 outputs a second enable signal to the main control chip 12. Based on the second enable signal, the main control chip 12 can output a first output control signal to the power switch module 4, so that the power switch module 4 is in an available state and can perform normal power output; when the short-circuit detection signal SOP_sta is a short-circuit signal, the signal interlock unit 11 outputs a second disable signal to the main control chip 12. Based on the second disable signal, the main control chip 12 can output a second output control signal to the power switch module 4, so that the power switch module 4 is in a disabled state and cannot perform power output, ensuring circuit safety.

[0035] As another example, the adhesion signal can be a low-level signal, and the non-adhesion signal can be a high-level signal; the short-circuit signal can be a low-level signal, and the non-short-circuit signal can be a high-level signal; the master control chip 12 controls the short-circuit detection module 3 to be in an available state, and the first enable signal for short-circuit detection can be a high-level signal; the first disable signal for the master control chip 12 to control the short-circuit detection module 3 to be in a disabled state is a low-level signal; the second enable signal for the master control chip 12 to control the power switch module 4 to be in an available state can be a high-level signal; the second disable signal for the master control chip 12 to control the power switch module 4 to be in a disabled state can be a low-level signal. At this time, the interlock unit can be a logic control module, which is used to interlock the adhesion detection signal check_sta and the signal output by the master control chip 12 for controlling the short-circuit detection module 3 (to be at the same level), and interlock the short-circuit detection signal SOP_sta and the signal output by the master control chip 12 for controlling the power switch module 4 (to be at the same level), so that when the adhesion detection signal check_sta is a low-level signal, the master control chip 12 outputs the first disable signal which is also a low-level signal; when the adhesion detection signal check_sta is a high-level signal, the master control chip 12 outputs the first enable signal which is also a high-level signal to control the short-circuit detection module 3 to perform short-circuit detection; when the short-circuit detection signal SOP_sta is a low-level signal, the master control chip 12 outputs the second disable signal which is also a low-level signal; when the short-circuit detection signal SOP_sta is a high-level signal, the master control chip 12 outputs the second enable signal which is also a high-level signal to control the power relay K1 in the power switch module 4 to be attracted and perform power output.

[0036] In one embodiment, the master control module 1 is further configured to connect to an alarm module, and when the adhesion detection signal check_sta is an adhesion signal or the short-circuit detection signal SOP_sta is a short-circuit signal, send an alarm signal to the alarm module to cause the alarm module to perform an alarm operation.

[0037] As an example, the master control module 1 is further configured to connect to an alarm module, and receive the adhesion detection signal check_sta output by the adhesion detection module 2 and the short-circuit detection signal SOP_sta output by the short-circuit detection module 3. When the adhesion detection signal check_sta is an adhesion signal, or the short-circuit detection signal SOP_sta is a short-circuit signal, the master control module 1 can send an alarm signal to the alarm module to cause the alarm module to perform an alarm operation.

[0038] In one embodiment, the power switch module 4 includes a power relay K1; the adhesion detection module 2 is connected to two normally open contacts of the power relay K1 and is used to detect the adhesion detection result between the two normally open contacts of the power relay K1. If the adhesion detection result is in an adhered state, the adhesion detection signal check_sta is an adhesion signal; if the adhesion detection result is not in an adhered state, the adhesion detection signal check_sta is a non-adhesion signal.

[0039] As an example, the power switch module 4 includes a power relay K1. The power relay K1 includes a first magnetic core and two first normally open contacts provided on the neutral line and the live line. The magnetic attraction can attract and close the normally open contacts under the control of the main control module 1, making the circuit conduct and enabling power output. The adhesion detection module 2 is connected to two normally open contacts of the power relay K1 and is used to detect the adhesion detection result on the two normally open contacts of the power relay K1. If the adhesion detection result is in an adhered state, the adhesion detection signal check_sta is an adhesion signal; if the adhesion detection result is not in an adhered state, the adhesion detection signal check_sta is a non-adhesion signal.

[0040] In one embodiment, the relay adhesion detection module 2 includes an optocoupler unit U1; the light-emitting part of the optocoupler unit U1 is connected to two normally open contacts of the power relay K1, and the light-receiving part of the optocoupler unit U1 is connected to the main control module 1 and is used to detect the adhesion detection result between the two normally open contacts of the power relay K1. If the adhesion detection result is in an adhered state, the adhesion detection signal check_sta is an adhesion signal; if the adhesion detection result is not in an adhered state, the adhesion detection signal check_sta is a non-adhesion signal.

[0041] As an example, the relay adhesion detection module 2 includes an optocoupler unit U1. The light-emitting part of the optocoupler unit U1 is connected to two normally open contacts of the power relay K1, and the light-receiving part of the optocoupler unit U1 is connected to the main control module 1 and is used to detect the adhesion detection result on the two normally open contacts of the power relay K1. If the two normally open contacts of the power relay K1 are in an adhered state, the light-emitting part of the optocoupler unit U1 will conduct and emit light, causing the light-receiving part to conduct accordingly. At this time, the output adhesion detection signal check_sta is an adhesion signal; if the two normally open contacts of the power relay K1 are not in an adhered state, the light-emitting part of the optocoupler unit U1 will not conduct and emit light, and the light-receiving part is in a cut-off state. At this time, the output adhesion detection signal check_sta is a non-adhesion signal.

[0042] In one embodiment, the short - circuit detection module 3 is connected to two normally - open contacts of the power relay K1, and is used to detect the short - circuit detection result between the two normally - open contacts of the power relay K1. If the short - circuit detection result is in a short - circuit state, the short - circuit detection signal SOP_sta is a short - circuit signal; if the short - circuit detection result is not in a short - circuit state, the short - circuit detection signal SOP_sta is a non - short - circuit signal.

[0043] As an example, the short - circuit detection module 3 is connected to two normally - open contacts of the power relay K1, and is used to detect the short - circuit detection result between the two normally - open contacts of the power relay K1. If the short - circuit detection result is in a short - circuit state, the short - circuit detection signal SOP_sta is a short - circuit signal; if the short - circuit detection result is not in a short - circuit state, the short - circuit detection signal SOP_sta is a non - short - circuit signal. Further, the short - circuit state may include the state where the live wire is short - circuited to the ground, the neutral wire is short - circuited to the ground, or the live wire and the neutral wire are short - circuited. When any of the above short - circuit states occurs, the short - circuit detection signal SOP_sta is a short - circuit signal.

[0044] In one embodiment, the short - circuit detection module 3 includes a pre - inspection relay K2 and a signal comparison circuit 31; the pre - inspection relay K2 is connected to the output end of the signal comparison circuit 31 and the power switch module 4, and is also connected to the main control module 1, and is used to be energized under the control of the main control module 1 to connect the signal comparison circuit 31 to the output end of the power switch module 4, or to be disconnected under the control of the main control module 1 to disconnect the signal comparison circuit 31 from the output end of the power switch module 4; the signal comparison circuit 31 is connected to the main control module 1, and is used to perform short - circuit detection on the power switch module 4 when the pre - inspection relay K2 is energized, and output a short - circuit detection signal SOP_sta to the main control module 1.

[0045] As an example, the short - circuit detection module 3 includes a pre - inspection relay K2 and a signal comparison circuit 31. The pre - inspection relay K2 may include a second magnetic core and two second normally - open contacts provided on the live wire and the neutral wire connected to the output end of the power switch module 4. The pre - inspection relay K2 is connected to the main control module 1, and is used to be briefly energized and then disconnected (the energization time is less than or equal to 200 ms) under the control of the main control module 1 when there is no relay adhesion in the power switch module 4, so that the signal comparison circuit 31 is briefly connected to the output end of the power switch module 4 to perform short - circuit detection on the neutral wire and the live wire at the output end of the power switch module 4, and output a short - circuit detection signal SOP_sta to the main control module 1.

[0046] In one embodiment, the signal comparison circuit 31 includes a voltage dividing unit 311 and an operational amplifier U2; the voltage dividing unit 311 is connected to the pre-inspection relay K2 and the operational amplifier U2, and is configured to output a detection voltage signal to the operational amplifier U2 according to the short-circuit detection result between the two normally open contacts of the power relay K1; the operational amplifier U2 is connected to the main control module 1, and is configured to obtain a short-circuit detection signal SOP_sta after amplifying the detection voltage signal, and output the short-circuit detection signal SOP_sta to the main control module 1.

[0047] As an example, the signal comparison circuit 31 includes a voltage dividing unit 311 and an operational amplifier U2. The voltage dividing unit 311 is connected to the pre-inspection relay K2 and the operational amplifier U2, and is configured to output a corresponding detection voltage signal to the operational amplifier U2 according to the short-circuit state of the live wire and the neutral wire connected to the output end of the power switch module 4 at the moment when the pre-inspection relay K2 is briefly closed; the operational amplifier U2 is connected to the main control module 1, and is configured to obtain a short-circuit detection signal SOP_sta that can be normally processed and received by the main control chip 12 in the main control module 1 after amplifying the detection voltage signal, and output the short-circuit detection signal SOP_sta to the main control module 1.

[0048] In one embodiment, the voltage dividing unit 311 includes a first voltage dividing resistor R1, a second voltage dividing resistor R2, and a third voltage dividing resistor R3; the first voltage dividing resistor R1, the second voltage dividing resistor R2, and the third voltage dividing resistor R3 are connected in series between the power supply terminal and the ground; the connection node between the first voltage dividing resistor R1 and the second voltage dividing resistor R2 is connected to the neutral wire of the output end of the power switch module 4; the connection node between the second voltage dividing resistor R2 and the third voltage dividing resistor R3 is connected to the live wire of the output end of the power switch module 4, and is also connected to the operational amplifier U2.

[0049] As an example, the voltage dividing unit 311 includes a first voltage dividing resistor R1, a second voltage dividing resistor R2, and a third voltage dividing resistor R3; the first voltage dividing resistor R1, the second voltage dividing resistor R2, and the third voltage dividing resistor R3 are connected in series between the power supply terminal VCC (5V low voltage source) and the ground; the connection node between the first voltage dividing resistor R1 and the second voltage dividing resistor R2 is connected to the output neutral line of the output terminal of the power switch module 4; the connection node between the second voltage dividing resistor R2 and the third voltage dividing resistor R3 is connected to the output live wire of the output terminal of the power switch module 4 and is also connected to the comparison operational amplifier U2. When the live wire is short-circuited to the ground, the third voltage dividing resistor R3 is short-circuited, and at this time, the voltage value obtained by the operational amplifier U2 is 0; when the neutral line is short-circuited to the ground, both the second voltage dividing resistor R2 and the third voltage dividing resistor R3 are short-circuited, and at this time, the voltage value obtained by the operational amplifier U2 is also 0; when the live wire and the neutral line are short-circuited, the second voltage dividing resistor R2 is short-circuited, and at this time, only the first voltage dividing resistor R1 and the third voltage dividing resistor R3 divide the voltage provided by the power supply terminal VCC, and the voltage value obtained by the operational amplifier U2 is the voltage across the third voltage dividing resistor R3; when there is no short-circuit state at the output terminal of the power switch module 4, at this time, the first voltage dividing resistor R1, the second voltage dividing resistor R2, and the third voltage dividing resistor R3 divide the voltage provided by the power supply terminal VCC, and the voltage value obtained by the operational amplifier U2 is the voltage across the third voltage dividing resistor R3.

[0050] The embodiment of the present invention further provides a power supply circuit, including a power switch module 4 and the above protection circuit; the input end of the power switch module 4 is used to connect to the mains circuit, and the output end of the power switch module 4 is used to connect to the device to be charged; the protection circuit is connected to the output end of the power switch module 4 and is used to perform adhesion detection and short-circuit detection on the power switch module 4, obtain the short-circuit detection signal SOP_sta, and control the power switch module 4 to be in a disabled state when the short-circuit detection signal SOP_sta is a short-circuit signal.

[0051] As an example, the power supply circuit includes a power switch module 4 and the above-mentioned protection circuit; the input end of the power switch module 4 is used to connect to the mains circuit, and the output end of the power switch module 4 is used to connect to the device to be charged, which can be a vehicle to be charged or a portable energy storage device to be charged, etc.; the protection circuit is connected to the output end of the power switch module 4 and is used to perform adhesion detection and short-circuit detection on the power switch module 4, obtain a short-circuit detection signal SOP_sta, and control the power switch module 4 to be in a disabled state when the short-circuit detection signal SOP_sta is a short-circuit signal. In this example, the protection circuit in the power supply circuit can perform adhesion detection on the power relay in the power switch module 4 before the power switch module 4 closes and outputs power, and continue to perform short-circuit detection on the power switch module 4 after detecting that there is no relay adhesion. On the one hand, this protection circuit can detect and eliminate these two fault conditions of relay adhesion and short circuit to ensure the safety of power output. On the other hand, it can also prevent the relay adhesion situation from causing harm to the short-circuit detection, prevent the device in the short-circuit detection module 3 from being burned out due to relay adhesion, etc., and improve the safety and reliability of the short-circuit detection.

[0052] An embodiment of the present invention further provides a charging pile, including the above-mentioned power supply circuit, one end of the power supply circuit is used to connect to the mains circuit, and the other end is used to connect to the device to be charged. In this example, the protection circuit in the charging pile can perform adhesion detection on the power relay in the power switch module 4 before the power switch module 4 closes and outputs power to the device to be charged, and continue to perform short-circuit detection on the power switch module 4 after detecting that there is no relay adhesion. On the one hand, this protection circuit can detect and eliminate these two fault conditions of relay adhesion and short circuit to ensure the safety of power output. On the other hand, it can also prevent the relay adhesion situation from causing harm to the short-circuit detection, prevent the device in the short-circuit detection module 3 from being burned out due to relay adhesion, etc., and improve the safety and reliability of the short-circuit detection.

[0053] The above-described embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included in the protection scope of the present invention.

Claims

1. A protection circuit, characterized in that: Used to connect the power switch module, the protection circuit includes a main control module, an adhesion detection module and a short circuit detection module; The adhesion detection module is connected to the power switch module and is used to perform adhesion detection on the power switch module and output an adhesion detection signal; The short-circuit detection module is connected to the power switch module and is used to perform short-circuit detection on the power switch module and output a short-circuit detection signal; The main control module is connected to the adhesion detection module and the short circuit detection module, and is also used to connect the power switch module. When the adhesion detection signal is a adhesion signal, the short circuit detection module is controlled to be in a disabled state. When the short circuit detection signal is a short circuit signal, the power switch module is controlled to be in a disabled state.

2. The protection circuit according to claim 1, characterized in that: The main control module includes a signal interlocking unit and a main control chip; The signal interlocking unit is connected to the adhesion detection module, the short circuit detection module and the main control chip, and is used to output a first enable signal to the main control chip when the adhesion detection signal is a non-adhesion signal; output a first disable signal to the main control chip when the adhesion detection signal is a adhesion signal; output a second enable signal to the main control chip when the short circuit detection signal is a non-short circuit signal; output a second disable signal to the main control chip when the short circuit detection signal is a short circuit signal; The main control chip is connected to the short-circuit detection module and the power switch module, and is used to output a first detection control signal to the short-circuit detection module based on the first enable signal, so that the short-circuit detection module is in an available state and performs short-circuit detection on the power switch module; based on the first disable signal, output a second detection control signal to the short-circuit detection module, so that the short-circuit detection module is in a disabled state; Based on the second enable signal, a first output control signal is output to the power switch module to put the power switch module in an available state; based on the second disable signal, a second output control signal is output to the power switch module to put the power switch module in a disabled state.

3. The protection circuit according to claim 1, characterized in that: The main control module is also used to connect to the alarm module, and when the adhesion detection signal is an adhesion signal or the short circuit detection signal is a short circuit signal, send an alarm signal to the alarm module so that the alarm module performs an alarm operation.

4. The protection circuit according to claim 1, characterized in that: The power switch module includes a power relay; The adhesion detection module is connected to the two normally open contacts of the power relay, and is used to detect the adhesion detection result on the two normally open contacts of the power relay. If the adhesion detection result is in a adhesion state, the adhesion detection signal is a adhesion signal; if the adhesion detection result is not in a adhesion state, the adhesion detection signal is a non-adhesion signal.

5. The protection circuit according to claim 4, characterized in that: The relay adhesion detection module includes an optical coupling unit; The light-emitting part of the optocoupler unit is connected to the two normally open contacts of the power relay, and the light-receiving part of the optocoupler unit is connected to the main control module, and is used to detect the adhesion detection result between the two normally open contacts of the power relay. If the adhesion detection result is in an adhesion state, the adhesion detection signal is a adhesion signal; if the adhesion detection result is not in an adhesion state, the adhesion detection signal is a non-adhesion signal.

6. The protection circuit according to claim 4, characterized in that: The short-circuit detection module is connected to the two normally open contacts of the power relay and is used to detect a short-circuit detection result between the two normally open contacts of the power relay. If the short-circuit detection result is a short-circuit state, the short-circuit detection signal is a short-circuit signal. If the short-circuit detection result is not in a short-circuit state, the short-circuit detection signal is a non-short-circuit signal.

7. The protection circuit according to claim 6, characterized in that: The short circuit detection module includes a pre-detection relay and a signal comparison circuit; The pre-check relay is connected to the signal comparison circuit and the output end of the power switch module, and is also connected to the main control module, and is used to be attracted under the control of the main control module to connect the signal comparison circuit to the output end of the power switch module, or to be disconnected under the control of the main control module to disconnect the signal comparison circuit from the output end of the power switch module; The signal comparison circuit is connected to the main control module, and is used to perform short-circuit detection on the power switch module when the pre-detection relay is energized, and output a short-circuit detection signal to the main control module.

8. The protection circuit according to claim 7, characterized in that: The signal comparison circuit includes a voltage dividing unit and an operational amplifier; The voltage dividing unit is connected to the pre-detection relay and the operational amplifier, and is used to output a detection voltage signal to the operational amplifier according to a short circuit detection result between two normally open contacts of the power relay; The operational amplifier is connected to the main control module, and is used for obtaining a short-circuit detection signal after amplifying the detection voltage signal, and outputting the short-circuit detection signal to the main control module.

9. The protection circuit according to claim 8, characterized in that: The voltage dividing unit includes a first voltage dividing resistor, a second voltage dividing resistor and a third voltage dividing resistor; The first voltage-dividing resistor, the second voltage-dividing resistor and the third voltage-dividing resistor are connected in series between the power supply terminal and the ground; A connection node between the first voltage-dividing resistor and the second voltage-dividing resistor is connected to an output neutral line of a terminal of the power switch module; The connection node between the second voltage-dividing resistor and the third voltage-dividing resistor is connected to the output live wire of the end of the power switch module and is also connected to the operational amplifier.

10. A power supply circuit, characterized in that: Comprising a power switch module and a protection circuit according to any one of claims 1 to 9; The input end of the power switch module is used to connect to the mains circuit, and the output end of the power switch module is used to connect to the device to be charged; The protection circuit is connected to the output end of the power switch module, and is used to perform adhesion detection and short circuit detection on the power switch module, obtain a short circuit detection signal, and control the power switch module to be in a disabled state when the short circuit detection signal is a short circuit signal.

11. A charging pile, characterized in that: It comprises the power supply circuit as claimed in claim 10, wherein one end of the power supply circuit is used to connect to a mains circuit, and the other end of the power supply circuit is used to connect to a device to be charged.

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