Charging pile, protection circuit and control method of charging pile

Abstract

The invention discloses a charging pile, a protection circuit and a control method of the charging pile. The charging pile comprises a power circuit, a control circuit, a switching circuit and a contactor, the output end of the power circuit is connected with the first end of the switching circuit, the second end of the switching circuit is connected with the first end of the contactor, and the second end of the contactor is connected with a load; the control circuit is connected with the control end of the switching circuit; the control circuit is used for controlling the switching circuit to be switched off when the sampling voltage of the output end of the power circuit is larger than the protection voltage. When the sampling voltage of the output end of the power circuit is larger than the protection voltage, it is determined that the charging pile works abnormally, for example, the output side of the charging pile is short-circuited, the control circuit switches connection between the power circuit and the contactor by controlling the switching circuit to be disconnected, circuit protection is conducted in time, and therefore the contactor is prevented from being damaged by large current during short circuit.

Description

Technical Field

[0001] The present application relates to the field of power electronics technology, and in particular to a charging pile, a protection circuit, and a control method for the charging pile. Background Art

[0002] Existing power supply systems usually rely on traditional protection mechanisms to deal with various faults. For example, the power circuit used for power supply shuts down the output based on the short-circuit protection function of the power circuit to protect the power supply system. When the load requires high power, multiple power units need to be used to supply power simultaneously.

[0003] However, when the load input side is short-circuited, the protection of the power unit is delayed and cannot respond to the transient change of the current in time. Especially in the case of a short circuit, the power unit in the circuit may generate excessive short-circuit current due to insufficient response speed, thus causing serious damage to the internal components of the power supply system.

[0004] In this case, the design of traditional protection circuits often cannot effectively prevent damage to internal components of the power supply system, further increasing the risk of failure of the power supply system. Summary of the invention

[0005] In view of this, the present application provides a method that can.

[0006] To solve the above problems, the technical solutions provided by this application are as follows:

[0007] In a first aspect, an embodiment of the present application provides a charging pile, the charging pile comprising: a power circuit, a control circuit, a switch circuit and a contactor;

[0008] The output end of the power circuit is connected to the first end of the switch circuit, the second end of the switch circuit is connected to the first end of the contactor, and the second end of the contactor is used to connect to the load;

[0009] The control circuit is connected to the control end of the switch circuit;

[0010] The control circuit is used to control the switch circuit to be disconnected when the sampling voltage at the output end of the power circuit is greater than the protection voltage.

[0011] In a possible implementation, the control circuit includes a comparator and a drive circuit;

[0012] The first input terminal of the comparator is connected to the sampling voltage, the second input terminal of the comparator is connected to the protection voltage, the output terminal of the comparator is connected to the input terminal of the driving circuit, and the output terminal of the driving circuit is connected to the control terminal of the switch circuit;

[0013] The comparator is used for outputting a first drive signal when the sampling voltage is greater than the protection voltage; the drive circuit is used for controlling the switch circuit to be disconnected when receiving the first drive signal.

[0014] In a possible implementation, the output end of the comparator is connected to the first input end of the comparator through a unidirectional conductive device, so that the output end of the comparator is used to implement positive feedback to the first input end of the comparator, so that the switch circuit remains disconnected.

[0015] In a possible implementation, the control circuit is further configured to control the switch circuit to close when it is detected that the contactor and the load are disconnected.

[0016] In a possible implementation, the control circuit further includes a lock recovery circuit and a controller;

[0017] The output end of the lock recovery circuit is connected to the output end of the comparator;

[0018] After the controller detects that the contactor is disconnected from the load, it controls the lock recovery circuit to output a second drive signal; the drive circuit is used to control the switch circuit to close when receiving the second drive signal.

[0019] In a possible implementation, the switch circuit includes a voltage regulator tube and a first switch tube, and the drive circuit includes a second switch tube;

[0020] The first end of the first switch tube is connected to the positive electrode of the power circuit output terminal and the negative electrode of the voltage regulator tube, and the second end of the first switch tube is connected to the contactor;

[0021] The control end of the second switch tube is connected to the output end of the comparator, the first end of the second switch tube is connected to the negative electrode of the power circuit output end, the second end of the second switch tube is connected to the control end of the first switch tube, and the second end of the second switch tube is connected to the positive electrode of the voltage regulator tube.

[0022] In a possible implementation, the driving circuit further includes an isolation circuit;

[0023] The input end of the isolation circuit is connected to the output end of the comparator, and the output end of the isolation circuit is connected to the control end of the second switch tube.

[0024] In a possible implementation, the lock recovery circuit includes a third switch tube;

[0025] The control end of the third switch tube is connected to the output end of the controller, the first end of the third switch tube is connected to the output end of the comparator, and the second end of the third switch tube is grounded.

[0026] In a possible implementation, the charging pile further includes a sampling circuit;

[0027] The sampling end of the sampling circuit is connected to the output end of the power circuit, and the output end of the sampling circuit is connected to the input end of the control circuit; the sampling circuit is used to collect the voltage between the output end of the power circuit and the first end of the switch circuit as the sampling voltage, and send the sampling voltage to the control circuit.

[0028] In a possible implementation manner, the sampling circuit is a current sampling circuit, a voltage sampling circuit, or a temperature sampling circuit.

[0029] In a second aspect, an embodiment of the present application provides a protection circuit, the protection circuit comprising a control circuit and a switch circuit;

[0030] The input end of the control circuit is used to obtain the sampling voltage of the power circuit and the protection voltage of the power circuit, and the output end of the control circuit is connected to the control end of the switch circuit;

[0031] The first end of the switch circuit is connected to the output end of the power circuit, and the second end of the switch circuit is connected to the load;

[0032] The control circuit is used for controlling the switch circuit to be disconnected when the sampling voltage is greater than the protection voltage.

[0033] In a third aspect, an embodiment of the present application provides a method for controlling a charging pile, including:

[0034] Obtaining a sampled voltage of a power circuit in a charging pile and a protection voltage of the power circuit;

[0035] comparing the sampling voltage with the protection voltage;

[0036] When the sampling circuit is greater than the protection circuit, the charging pile is controlled to stop supplying power.

[0037] The embodiment of the present application provides a charging pile, a protection circuit, and a control method for the charging pile. In the charging pile, a control circuit is used to control a switch circuit connected between the power circuit and the contactor according to the output state of the power circuit. When the output of the power circuit is abnormal, the control circuit controls the switch circuit to disconnect and switch the connection between the power circuit and the contactor to avoid damage to the contactor caused by the abnormal output of the power circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 A schematic diagram of the structure of a charging pile provided in an embodiment of the present application;

[0039] Figure 2 A topological structure diagram of a power circuit provided in an embodiment of the present application;

[0040] Figure 3 A schematic diagram of the structure of another charging pile provided in an embodiment of the present application;

[0041] Figure 4 A topological structure diagram of a control circuit provided in an embodiment of the present application;

[0042] Figure 5 A topological schematic diagram of another control circuit provided in an embodiment of the present application;

[0043] Figure 6 A schematic diagram of the structure of another charging pile provided in an embodiment of the present application;

[0044] Figure 7 A schematic diagram of the structure of another charging pile provided in an embodiment of the present application;

[0045] Figure 8 A topological structure diagram of another control circuit provided in an embodiment of the present application;

[0046] Fig. 9 A topological structure diagram of another control circuit provided in an embodiment of the present application;

[0047] Fig.10 A schematic diagram of the structure of a charging pile provided in an embodiment of the present application;

[0048] Fig.11 A schematic diagram of the structure of a protection circuit provided in an embodiment of the present application. DETAILED DESCRIPTION

[0049] As mentioned in the background technology, the current power supply system still has some problems in system protection. Take the charging pile as an example. During the charging process of an electric vehicle, if a short circuit occurs between the positive and negative poles of the charging gun line, the power circuit protection response speed is insufficient, which may cause the short circuit instantaneous energy to be too large, causing the main contacts of the contactor to adhere and be damaged.

[0050] In order to solve the above technical problems, the embodiment of the present application provides a charging pile. The charging pile includes a power circuit, a control circuit, a switch circuit and a contactor; the output end of the power circuit is connected to the first end of the switch circuit, the second end of the switch circuit is connected to the first end of the contactor, and the second end of the contactor is used to connect the load; the control circuit is connected to the control end of the switch circuit. A switch circuit is added between the power circuit and the contactor, and the control circuit is used to control the switch circuit according to the output state of the power circuit. When the sampling voltage at the output end of the power circuit is greater than the protection voltage, it is determined that the charging pile is working abnormally, such as a short circuit on the output side of the charging pile, and the control circuit switches the connection between the power circuit and the contactor by controlling the switch circuit to disconnect, and performs circuit protection in time, thereby avoiding damage to the contactor caused by large current during short circuit. In addition, compared with the method of using a contactor to release short-circuit current in the related art, the embodiment of the present application can directly disconnect the switch circuit, reduce the energy of the power circuit during short circuit, avoid the impact of short-circuit current on the contactor, and further reduce the risk of contactor short circuit adhesion.

[0051] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the embodiments of the present application are further described in detail below in combination with the accompanying drawings and specific implementation methods.

[0052] Figure 1 This is a schematic diagram of the structure of a charging pile provided in an embodiment of the present application. Figure 1 As shown, the charging pile includes: a power circuit, a control circuit, a switch circuit and a contactor;

[0053] The output end of the power circuit is connected to the first end of the switch circuit, the second end of the switch circuit is connected to the first end of the contactor, and the second end of the contactor is used to connect to the load;

[0054] The control circuit is connected to the control end of the switch circuit;

[0055] The control circuit is used to control the switch circuit to disconnect when the sampling voltage at the output end of the power circuit is greater than the protection voltage.

[0056] The power circuit is the core part of the charging pile, responsible for converting the mains electricity (AC or DC) into electric energy suitable for charging electric vehicles. The power circuit modulates the input electric energy through a power converter (such as a rectifier or inverter), and outputs the adjusted electric energy to the contactor through a switching circuit.

[0057] In one possible implementation, the power circuit can be as follows Figure 2As shown. The power circuit includes a power distribution unit and n power units. The power distribution unit includes n parallel switch tubes (such as K1, K2 and Kn). Each power unit is connected to the switch tube in the power distribution unit one by one through a diode to achieve parallel output of n power units. The diode is set to achieve unidirectional conduction from the power unit to the switch tube. In different charging scenarios, the power circuit adjusts the number of on and off switches in the power distribution unit to adjust the output power of the power circuit to meet the different power requirements of the load.

[0058] The switch circuit is used to control the electrical connection between the power circuit and the contactor. The switch circuit quickly opens or closes the circuit according to the control from the control circuit to protect the contactor from short circuit or overload.

[0059] In the embodiment of the present application, the switch circuit can be a solid-state relay (SSR) or a metal-oxide-semiconductor field-effect transistor (MOSFET). Among them, the solid-state relay can realize high-frequency switch control and is suitable for fast disconnection of the circuit. The metal-oxide-semiconductor field-effect transistor can also be referred to as a MOS tube. The MOS tube can also be used to quickly shut down the current. At the same time, its driving circuit is also relatively simple, and the on-off control of the MOS tube can be realized by high and low signals.

[0060] The contactor is responsible for safely transmitting the output power of the power circuit to the electric vehicle. The contactor can be an electromagnetic contactor, which can include an armature, a spring, and a contact point. The contact point is closed when the electromagnetic coil is energized, and the spring separates the contact point after the power is removed. The contactor can be selected to meet the high-power application of the charging pile, such as a DC contactor or an AC contactor under the International Electrotechnical Commission (IEC) standard. In the charging pile, the contactor can be connected to the load through the charging gun line.

[0061] The control circuit is used to control the switch circuit according to the output state of the power circuit. When the sampled voltage at the output end of the power circuit is greater than the protection voltage, it is determined that the output state of the power circuit is abnormal, and the control circuit controls the switch circuit to disconnect to cut off the connection between the power circuit and the contactor to avoid damage to the contactor.

[0062] The sampling voltage refers to the current working voltage of the power circuit, and the protection voltage refers to the upper threshold of the working voltage of the power circuit. When the current working voltage of the power circuit exceeds the protection voltage, it indicates that the current working state of the power circuit is abnormal or the output state is abnormal; when the current working voltage of the power circuit is less than or equal to the protection voltage, it indicates that the current working state of the power circuit is normal or the output state is normal. There may be many reasons for the abnormal working state of the power circuit or the abnormal output state, such as a short circuit between the positive and negative poles of the charging gun line, or an abnormal power circuit.

[0063] As an example, when the positive and negative poles of the charging gun line are short-circuited, the current and voltage at the output end of the power circuit increase. When the control circuit determines that the sampled voltage at the output end of the power circuit is greater than the protection voltage, the control circuit controls the switch circuit to disconnect, so as to prevent the main contact point from sticking after the contactor is short-circuited due to a sharp increase in the power circuit output.

[0064] In one possible implementation, Figure 1 The charging pile shown also includes a sampling circuit. Figure 3 As shown, Figure 3 A schematic diagram of the structure of another charging pile provided in an embodiment of the present application.

[0065] The sampling end of the sampling circuit is connected to the output end of the power circuit, and the output end of the sampling circuit is connected to the input end of the control circuit; the sampling circuit is used to collect the voltage between the output end of the power circuit and the first end of the switch circuit as a sampling voltage, and send the sampling voltage to the control circuit.

[0066] The sampling circuit is mainly used to monitor the output voltage of the power circuit in real time and pass the voltage signal (i.e., the sampled voltage) to the control circuit. In this configuration, the sampling circuit monitors the working status and voltage level of the power circuit at any time. As an example, the sampling circuit samples the actual voltage or current of the protected device at a certain frequency or time interval, and converts these signals into a format that can be processed by the comparison circuit.

[0067] The sampling circuit provided in the embodiment of the present application may specifically be a voltage sampling circuit, a temperature sampling circuit or a current sampling circuit.

[0068] The voltage sampling circuit is used to detect the operating voltage of the power circuit in real time, and output the operating voltage as a sampling voltage to the control circuit, thereby achieving overvoltage protection.

[0069] The temperature sampling circuit is used to detect the operating temperature of the power circuit in real time, and then convert the temperature signal into a voltage signal and output it to the control circuit. Specifically, a thermistor, thermocouple or digital temperature sensor can be used as the temperature sampling circuit for temperature measurement.

[0070] The current sampling circuit is used to detect the working current of the power circuit in real time, and convert the working current into a working voltage, and output the working voltage as a sampling voltage to the control circuit, thereby realizing overvoltage protection. Specifically, the current sampling circuit can use a Hall sensor or a current identification circuit to convert the current into a measurable voltage signal.

[0071] By using a voltage sampling circuit, a current sampling circuit or a temperature sampling circuit as a sampling circuit, a comprehensive protection function can be achieved to ensure protection in cases of overvoltage, overcurrent and overtemperature, effectively prevent damage to the charging pile, and improve the service life and safety of the device.

[0072] In the charging piles of the above embodiments, the control circuit can control the switch circuit through a comparator and a drive circuit, as shown in FIG. Figure 4 The control circuit includes a comparator U1 and a driving circuit.

[0073] The first input terminal of the comparator U1 is connected to the sampling voltage, the second input terminal of the comparator U1 is connected to the protection voltage, the output terminal of the comparator U1 is connected to the input terminal of the driving circuit, and the output terminal of the driving circuit is connected to the control terminal of the switch circuit;

[0074] The comparator U1 is used for outputting a first driving signal when the sampling voltage is greater than the protection voltage; the driving circuit is used for controlling the switch circuit to be disconnected when receiving the first driving signal.

[0075] In the embodiment of the present application, the comparator U1 determines the working state of the power circuit by comparing the sampling voltage with the protection voltage, and outputs a first drive signal to the drive circuit when the sampling voltage exceeds the protection voltage. After receiving the first drive signal, the drive circuit quickly responds to the first drive signal to drive the switch circuit to disconnect.

[0076] In the embodiment of the present application, when the sampling voltage is less than or equal to the protection voltage, the comparator U1 outputs a second driving signal to the driving circuit, and after receiving the second driving signal, the driving circuit drives the switch circuit to close.

[0077] As an example, the first drive signal and the second drive signal are opposite signals. When the sampling voltage is greater than the protection voltage, the first drive signal output by the comparator U1 is a high-level signal, and the drive circuit responds to the high-level signal to control the switch circuit to be disconnected. When the sampling voltage is less than or equal to the protection voltage, the second drive signal output by the comparator U1 is a low-level signal, and the drive circuit responds to the low-level signal to control the switch circuit to be closed.

[0078] In another possible implementation, the output of the comparator U1 is connected to the first input of the comparator U1 via a unidirectional conductive device, so that the output of the comparator U1 implements positive feedback to the first input of the comparator U1 to keep the switch circuit disconnected.

[0079] The output end of the comparator U1 is connected to the input end of the unidirectional conductive device, and the output end of the unidirectional conductive device is connected to the first input end of the comparator U1.

[0080] like Figure 5 As shown, Figure 5 In the example, the unidirectional conducting device is a diode D1, the output end of the comparator U1 is connected to the anode of the diode D1, and the cathode of the diode D1 is connected to the first input end of the comparator U1. By connecting the output end of the comparator U1 and the first input end (sampling voltage input end) through the diode D1, the positive feedback of the output end of the comparator U1 to the first input end is realized, thereby forming a "locking" mechanism, so that the comparator U1 continues to output the first drive signal, thereby controlling the switch circuit to remain in the disconnected state.

[0081] As an example, when the sampling voltage (the voltage at the first input terminal) is less than or equal to the protection voltage (the voltage at the second input terminal), the comparator U1 outputs a low-level signal (the output is 0V or close to 0V). At this time, the diode D1 is in a reverse biased state and is not conducting, and the first input terminal of the comparator U1 is still determined by the sampling voltage. When the sampling voltage exceeds the protection voltage due to an instantaneous change in the load (such as a short circuit), the output signal of the comparator U1 immediately becomes a high-level signal (such as close to the power supply voltage). At this time, the diode D1 is in a forward conduction state, and the output voltage of the comparator U1 is fed back to the first input terminal (sampling voltage input terminal). The high-level signal output by the comparator U1 is fed back to the first input terminal of the comparator U1 through the diode D1, so that the sampling voltage maintains a higher output, which in turn causes the comparator U1 to continuously output a high-level signal, thereby causing the drive circuit to continuously control the switch circuit to be in a disconnected state, thereby achieving continuous protection.

[0082] Due to feedback, the comparator U1 is "locked" in the state of outputting a high-level signal. Even if the sampling voltage fluctuates afterwards (such as the sampling voltage is lower than the protection voltage), the comparator will not immediately invert the output signal and will no longer be affected by the sampling voltage.

[0083] In another implementation, if the charging pile further includes a sampling circuit, the first input terminal of the comparator U1 is connected to the output terminal of the sampling circuit.

[0084] As an example, the sampling circuit obtains a voltage signal from the output end of the power circuit and sends it to the first input end of the comparator U1. The protection voltage is loaded to the second input end of the comparator U1. The comparator U1 compares the sampling voltage with the protection voltage. When the sampling voltage is higher than the protection voltage, the output signal of the comparator U1 becomes a high-level signal. The high-level signal output by the comparator U1 is sent to the input end of the driving circuit, and the driving circuit responds quickly and drives the switch circuit to disconnect according to the received high-level signal.

[0085] In a possible implementation, the switch circuit includes a voltage regulator tube and a first switch tube, and the drive circuit includes a second switch tube. Figure 6 shown.

[0086] The first end of the first switch tube is connected to the positive electrode of the power circuit output terminal and the negative electrode of the voltage regulator tube, and the second end of the first switch tube is connected to the contactor S;

[0087] The control end of the second switch tube is connected to the output end of the comparator U1, the first end of the second switch tube is connected to the negative electrode of the power circuit output end, the second end of the second switch tube is connected to the control end of the first switch tube, and the second end of the second switch tube is connected to the positive electrode of the voltage regulator tube.

[0088] In an embodiment of the present application, the control end of the second switch tube is connected to the output end of the comparator U1 to respond to the output signal of the comparator U1, and the second end of the second switch tube is connected to the positive electrode of the voltage regulator tube and the control end of the first switch tube, ensuring that the second switch tube can control the conduction state of the first switch tube and transmit the voltage stabilization effect through the voltage regulator tube.

[0089] In order to improve the electrical isolation performance and safety of the charging pile, the charging pile can also be equipped with an isolation circuit, such as Figure 7 As shown. The driving circuit also includes an isolation circuit;

[0090] The input end of the isolation circuit is connected to the output end of the comparator U1 , and the output end of the isolation circuit is connected to the control end of the second switch tube.

[0091] The charging pile provided in the embodiment of the present application can not only cut off the connection between the power circuit and the contactor when the power circuit output is abnormal, but also restore the connection between the power circuit and the contactor when the abnormality is restored, so that the charging pile can be used to charge the load next time.

[0092] In a possible implementation, when the charging gun line is unplugged, that is, the contactor is disconnected from the load, the control circuit is further used to control the switch circuit to close, so that the load is charged using the output of the power circuit when the contactor is connected to the load next time.

[0093] When the user pulls out the charging gun, the control circuit can detect the disconnection state of the contactor and the load through a sensor or other detection mechanism. When the contactor is disconnected from the load, the short circuit on the output side of the charging pile disappears and the power circuit stops outputting. The control circuit controls the switch circuit to close, so that the power circuit remains in a ready state and reconnects with the contactor. The next time the charging pile is used for charging, the contactor is reconnected to the load. At this time, the switch circuit is in a closed state, and the power circuit can immediately power the load through the contactor, thereby achieving a fast and safe charging process and optimizing user experience and system efficiency.

[0094] In another possible implementation, Figure 8 As shown, the control circuit also includes a lock recovery circuit and a controller (the controller is not shown in the figure).

[0095] The output end of the lock recovery circuit is connected to the output end of the comparator U1;

[0096] After the controller detects that the contactor is disconnected from the load, it controls the lock recovery circuit to output a second drive signal; the drive circuit is used to control the switch circuit to close when receiving the second drive signal.

[0097] The controller can detect the connection status between the contactor and the load through a sensor or other detection mechanism. When it is detected that the contactor is disconnected from the load (for example, when the user pulls out the charging gun), the controller will trigger the lock recovery circuit to output a second drive signal, and use the second drive signal to eliminate the lock state of the output end of the comparator U1 to the first input end, so that the comparator U1 can resume normal working state. At the same time, after receiving the second drive signal, the drive circuit will control the switch circuit to close. At this time, the contactor is disconnected from the load, and the power circuit is restored to the contactor through the switch circuit, ready to supply power for the next charge.

[0098] As an example, when the sampling voltage is greater than the protection voltage, the comparator U1 outputs a high-level signal (the first drive signal is a high-level signal), and the output end of the comparator U1 is connected to the sampling voltage input end (the first input end), so that the comparator U1 is locked and outputs a high-level signal. The drive circuit responds to the high-level signal to control the switch circuit to disconnect. When the controller detects that the contactor is disconnected from the load, it controls the lock recovery circuit to output a low-level signal (the second drive signal is a low-level signal), so that the sampling voltage input end (the first input end) of the comparator U1 is set to a low level, and the output end of the comparator U1 is unlocked from the sampling voltage input end. The drive circuit responds to the low-level signal to control the switch circuit to close, and the charging pile enters the ready state.

[0099] In another possible implementation, Fig. 9 As shown, the lock recovery circuit includes a third switch tube;

[0100] The control end of the third switch tube is connected to the output end of the controller, the first end of the third switch tube is connected to the output end of the comparator U1, and the second end of the third switch tube is grounded.

[0101] The controller is connected to the control end of the third switch tube. When the controller detects that the contactor is disconnected from the load, it inputs a recovery signal to the third switch tube, causing the third switch tube to output a second drive signal, thereby eliminating the lock of the first input end of the comparator U1 and causing the drive circuit to control the switch circuit to close.

[0102] In order to more clearly describe the structure of the charging pile provided in the present application, a detailed embodiment is provided below in combination with the above embodiments. Fig.10 shown. Fig.10 Taking the first switch tube Q1 as a P-type MOS tube, the second switch tube Q2 as an N-type MOS tube, the third switch tube Q3 as an N-type MOS tube, and the sampling circuit as a high-speed Hall current sensor as an example, it should be noted that if the second switch tube Q2 is an N-type MOS tube, a NOT gate circuit is also connected between the isolation circuit and the comparator U1.

[0103] like Fig.10 As shown, the high-speed Hall current sensor is arranged at the positive output of the power circuit to collect the sampled voltage at the output end of the power circuit, and the output end of the high-speed Hall current sensor is connected to the first input end of the comparator U1 through the first resistor R1.

[0104] The second input terminal of the comparator U1 is connected to the protection voltage of the power circuit, the output terminal of the comparator U1 is connected to the input terminal of the NOT gate circuit U2 through the second resistor R2 and the third resistor R3 connected in series, and the output terminal of the comparator U1 is connected to the first input terminal of the comparator U1 through the second resistor R2, the fourth resistor R4 and the diode D1 connected in series, so as to realize the unidirectional conduction from the output terminal of the comparator U1 to the first input terminal. When the comparator U1 outputs a high-level signal, the first input terminal of the comparator U1 is locked to a high level, so that the comparator U1 continuously outputs a high-level signal. The output terminal of the comparator U1 is connected to the drain of the third switch tube Q3 through the second resistor R2.

[0105] The gate of the third switch tube Q3 is connected to the output end of the controller through the fifth resistor R5 to receive the recovery signal sent by the controller. The source of the third switch tube Q3 is grounded, and a sixth resistor R6 is also connected between the gate and source of the third switch tube Q3.

[0106] The output end of the NOT gate circuit U2 is connected to the gate of the second switch tube Q2 through the isolation circuit U3, the source of the second switch tube Q2 is connected to the negative output of the power circuit, the drain of the second switch tube Q2 is connected to the positive electrode of the voltage regulator tube Z1 through the seventh resistor R7 and the eighth resistor R8 connected in series, the drain of the second switch tube Q2 is connected to the gate of the first switch tube Q1 through the seventh resistor R7, and the ninth resistor R9 is also connected between the source and the gate of the second switch tube Q2.

[0107] The source of the first switch tube Q1 is connected to the cathode of the voltage regulator tube Z1 and the output anode of the power circuit, and the drain of the first switch tube Q1 is connected to the contactor S+. The contactor S is arranged at the output anode and cathode of the power circuit. The contactor S is connected to the load through a gun line.

[0108] The working process of the charging pile is specifically as follows: under normal conditions, the controller inputs a recovery signal to the third switch tube as a low-level signal. At this time, the low-level signal is converted into a high-level signal through the NOT gate circuit U2, and the gate of the second switch tube Q2 receives the high-level signal, the second switch tube Q2 is turned on, the voltage regulator Z1 is turned on and clamped, and the gate of the first switch tube Q1 receives a low-level signal, and the first switch tube Q1 remains turned on.

[0109] When the user uses the charging pile to charge the electric vehicle, the contactor connects to the electric vehicle through the gun line, and the power circuit outputs current. At this time, the sampling voltage collected by the high-speed Hall current sensor is less than or equal to the protection voltage, the comparator U1 outputs a low-level signal, and the power circuit continues to output to charge the vehicle.

[0110] When a short circuit occurs between the positive and negative poles of the gun line, the output current of the power circuit surges. The sampling voltage collected by the high-speed Hall current sensor is greater than the protection voltage, and the comparator U1 outputs a high-level signal. The high-level signal is converted into a low-level signal through the NOT gate circuit U2, and the gate of the second switch tube Q2 is in a disconnected state after receiving the low-level signal. At this time, the voltage regulator tube Z1 is no longer turned on, and the first switch tube Q1 is in a disconnected state, cutting off the connection between the power circuit and the contactor. In addition, the positive feedback of the diode D1 locks the first input terminal of the comparator U1 to a high level, so that the comparator U1 continues to output a high-level signal, and the first switch tube Q1 remains in a disconnected state.

[0111] When the controller detects that the gun line is unplugged, it sets the recovery signal to a high level within a preset time (such as 1 second), and then sets the recovery signal to a low level. The third switch tube Q3 is turned on under the action of the high level signal, and the drain of the third switch tube Q3 outputs a low level signal to eliminate the high level lock of the first input terminal of the comparator U1. The drain of the third switch tube Q3 outputs a low level signal that is converted into a high level signal through the NOT gate circuit U2. The second switch tube Q2 and the first switch tube Q1 are turned on, and the charging pile enters the ready state.

[0112] On the basis of the above embodiments, the present application further provides a control method for a charging pile, which specifically includes:

[0113] Obtaining a sampled voltage of a power circuit in a charging pile and a protection voltage of the power circuit;

[0114] comparing the sampling voltage with the protection voltage;

[0115] When the sampling circuit is greater than the protection circuit, the charging pile is controlled to stop supplying power.

[0116] Through the control method provided in the embodiment of the present application, the sampled voltage of the power circuit is collected, and the protection voltage of the power circuit and the sampled voltage are compared to determine whether there is an abnormality at the current output of the power circuit. When the sampled voltage is greater than the protection voltage, the charging pile is controlled to stop supplying power, that is, the connection between the output of the power circuit and the electrical equipment is cut off to achieve protection of the charging pile.

[0117] The present application also provides a protection circuit. Fig.11 As shown, the protection circuit includes a control circuit and a switch circuit;

[0118] The input end of the control circuit is used to obtain the sampling voltage of the power circuit and the protection voltage of the power circuit, and the output end of the control circuit is connected to the control end of the switch circuit;

[0119] A first end of the switch circuit is connected to an output end of the power circuit, and a second end of the switch circuit is connected to a load;

[0120] The control circuit is used to control the switch circuit to disconnect when the sampling voltage is greater than the protection voltage.

[0121] It should be noted that the various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same and similar parts between the various embodiments can be referred to each other. For the method disclosed in the embodiment, since it corresponds to the product embodiment disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the description of the product embodiment part.

[0122] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A charging pile, characterized in that: include: Power circuits, control circuits, switching circuits and contactors; The output end of the power circuit is connected to the first end of the switch circuit, the second end of the switch circuit is connected to the first end of the contactor, and the second end of the contactor is used to connect to the load; The control circuit is connected to the control end of the switch circuit; The control circuit is used to control the switch circuit to be disconnected when the sampling voltage at the output end of the power circuit is greater than the protection voltage.

2. The charging pile according to claim 1, characterized in that: The control circuit includes a comparator and a driving circuit; The first input terminal of the comparator is connected to the sampling voltage, the second input terminal of the comparator is connected to the protection voltage, the output terminal of the comparator is connected to the input terminal of the driving circuit, and the output terminal of the driving circuit is connected to the control terminal of the switch circuit; The comparator is used for outputting a first drive signal when the sampling voltage is greater than the protection voltage; the drive circuit is used for controlling the switch circuit to be disconnected when receiving the first drive signal.

3. The charging pile according to claim 2, characterized in that: The output end of the comparator is connected to the first input end of the comparator through a unidirectional conductive device, so that the output end of the comparator is used to realize positive feedback to the first input end of the comparator, so that the switch circuit remains disconnected.

4. The charging pile according to claim 1, characterized in that: The control circuit is further used to control the switch circuit to close when it is detected that the connection between the contactor and the load is disconnected.

5. The charging pile according to claim 3, characterized in that: The control circuit also includes a lock recovery circuit and a controller; The output end of the lock recovery circuit is connected to the output end of the comparator; After the controller detects that the contactor is disconnected from the load, it controls the lock recovery circuit to output a second drive signal; the drive circuit is used to control the switch circuit to close when receiving the second drive signal.

6. The charging pile according to claim 2, characterized in that: The switch circuit includes a voltage regulator tube and a first switch tube, and the drive circuit includes a second switch tube; The first end of the first switch tube is connected to the positive electrode of the power circuit output terminal and the negative electrode of the voltage regulator tube, and the second end of the first switch tube is connected to the contactor; The control end of the second switch tube is connected to the output end of the comparator, the first end of the second switch tube is connected to the negative electrode of the power circuit output end, the second end of the second switch tube is connected to the control end of the first switch tube, and the second end of the second switch tube is connected to the positive electrode of the voltage regulator tube.

7. The charging pile according to claim 6, characterized in that: The driving circuit also includes an isolation circuit; The input end of the isolation circuit is connected to the output end of the comparator, and the output end of the isolation circuit is connected to the control end of the second switch tube.

8. The charging pile according to claim 5, characterized in that: The lock recovery circuit includes a third switch tube; The control end of the third switch tube is connected to the output end of the controller, the first end of the third switch tube is connected to the output end of the comparator, and the second end of the third switch tube is grounded.

9. The charging pile according to claim 1, characterized in that: The charging pile also includes a sampling circuit; The sampling end of the sampling circuit is connected to the output end of the power circuit, and the output end of the sampling circuit is connected to the input end of the control circuit; the sampling circuit is used to collect the voltage between the output end of the power circuit and the first end of the switch circuit as the sampling voltage, and send the sampling voltage to the control circuit.

10. The charging pile according to claim 9, characterized in that: The sampling circuit is a current sampling circuit, a voltage sampling circuit or a temperature sampling circuit.

11. A protection circuit, characterized in that: Including control circuit and switch circuit; The input end of the control circuit is used to obtain the sampling voltage of the power circuit and the protection voltage of the power circuit, and the output end of the control circuit is connected to the control end of the switch circuit; The first end of the switch circuit is connected to the output end of the power circuit, and the second end of the switch circuit is connected to the load; The control circuit is used for controlling the switch circuit to be disconnected when the sampling voltage is greater than the protection voltage.

12. A method for controlling a charging pile, characterized in that: include: Obtaining a sampled voltage of a power circuit in a charging pile and a protection voltage of the power circuit; comparing the sampling voltage with the protection voltage; When the sampling circuit is greater than the protection circuit, the charging pile is controlled to stop supplying power.

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