Broken line detection circuit and detection method

Abstract

The invention discloses an open circuit detection circuit and a detection method. The open circuit detection circuit comprises an operational amplifier detection unit, a voltage following unit and an output comparison unit, the operational amplifier detection unit comprises a first operational amplifier and a divider resistor element; the voltage following unit comprises a second operational amplifier, a first unidirectional conductive element is connected between the in-phase input end of the second operational amplifier and the output end of the first operational amplifier, and an energy storage element is connected between the first unidirectional conductive element and the in-phase input end of the second operational amplifier; the operational amplifier detection unit is used for charging the energy storage element until the voltage value at the two ends of the energy storage element is equal to the voltage value of the input signal when the first one-way conductive element is conducted; and the output comparison unit is used for comparing the voltage values at the two ends of the energy storage element with the reference voltage and judging whether the line is broken or not according to whether the voltage value of the input signal jumps from the first voltage to the second voltage or not, so that whether the CP line of the charging pile has a broken line fault or not can be quickly and accurately detected.

Description

Technical Field

[0001] The present application belongs to the technical field of line detection, and specifically relates to a circuit breaker detection circuit and a detection method. Background Art

[0002] With the continuous development of the new energy industry, more and more new energy vehicles are appearing in people's lives. While people enjoy the convenience brought by new energy vehicles, the safety of new energy vehicles has also attracted much attention, and various protection measures have become more perfect. Charging piles, as charging equipment for new energy vehicles, are currently in a rapid growth stage, and their power supply safety has also received attention from everyone. CP signal is a key signal in the AC charging pile of new energy vehicles. The charging pile outputs DC signals or PWM (Pulse Width Modulation) wave signals through the CP line to interact with electric vehicles.

[0003] At present, national standard charging piles and European standard charging piles mainly use PLC modules to realize the charging communication protocol conversion between electric vehicles and charging piles. Since the PLC module communicates with the vehicle first through PLC, and then communicates with the charging pile through CAN communication after conversion, during this conversion process, due to communication delays, once the CP signal is disconnected, it is necessary to go through the above-mentioned communication conversion process again, resulting in the charging pile being unable to promptly know the CP disconnection situation, and unable to disconnect the output within the specified time, and the power supply safety of the charging pile cannot be effectively guaranteed. Summary of the invention

[0004] The present application provides a circuit break detection circuit and a detection method, which can quickly and accurately detect whether a charging pile CP line has a line break fault, thereby improving the power supply safety of the charging pile.

[0005] In order to solve the above technical problems, the present application provides a disconnection detection circuit, which includes an operational amplifier detection unit, a voltage follower unit and an output comparison unit;

[0006] The operational amplifier detection unit includes a first operational amplifier, and a voltage-dividing resistor element connected between a non-inverting input terminal of the first operational amplifier and an input signal;

[0007] The voltage follower unit comprises a second operational amplifier, a first unidirectional conductive element is connected between a non-inverting input terminal of the second operational amplifier and an output terminal of the first operational amplifier, and an energy storage element is connected between the first unidirectional conductive element and the non-inverting input terminal of the second operational amplifier;

[0008] The operational amplifier detection unit is used to charge the energy storage element when the first unidirectional conductive element is turned on, until the voltage value across the energy storage element is equal to the voltage value of the input signal;

[0009] The output comparison unit includes a comparator connected to the output end of the second operational amplifier, and the comparator is used to compare the voltage value across the energy storage element with a reference voltage to determine whether the line is broken based on whether the voltage value of the input signal jumps from a first voltage to a second voltage.

[0010] As a further improvement of the present application, the line break detection circuit further includes an optocoupler isolation unit connected to the output comparison unit;

[0011] The optical coupling isolation unit comprises a photoelectric coupling element, a primary side of the photoelectric coupling element is connected to the output end of the comparator, and a secondary side of the photoelectric coupling element is connected to a load through a contactor;

[0012] The optical coupling isolation unit is used to receive the level signal output by the output comparison unit. When the level signal is at a first level, the photoelectric coupling element is turned on to disconnect the contactor from the load.

[0013] As a further improvement of the present application, the voltage-dividing resistor element includes a first resistor and a second resistor, the first resistor is respectively connected to the input signal and the non-inverting input terminal of the first operational amplifier, one end of the second resistor is connected between the first resistor and the non-inverting input terminal of the first operational amplifier, and the other end of the second resistor is grounded;

[0014] Wherein, the first resistor is smaller than the second resistor.

[0015] As a further improvement of the present application, a second unidirectional conductive element is connected between the input signal and the first resistor, and a filter capacitor is arranged in parallel at both ends of the second resistor.

[0016] As a further improvement of the present application, the positive power supply pin of the first operational amplifier is connected to a power supply voltage, the negative power supply pin of the first operational amplifier is grounded, and a third unidirectional conductive element is connected between the output terminal of the first operational amplifier and the inverting input terminal of the first operational amplifier;

[0017] When the voltage value of the non-inverting input terminal of the first operational amplifier is greater than the voltage value of the inverting input terminal of the first operational amplifier, the first unidirectional conductive element is turned on, the second unidirectional conductive element is turned off, and the power supply voltage charges the energy storage element until the voltage value across the energy storage element is equal to the voltage value of the input signal.

[0018] As a further improvement of the present application, a third resistor is arranged in parallel at both ends of the energy storage element, one end of the energy storage element and the third resistor are commonly connected between the first unidirectional conductive element and the in-phase input terminal of the second operational amplifier, and the other end of the energy storage element is commonly connected to the third resistor and then grounded.

[0019] As a further improvement of the present application, a fourth resistor is connected between the inverting input terminal of the first operational amplifier and the output terminal of the second operational amplifier, one end of the fourth resistor is connected to the inverting input terminal of the first operational amplifier and the third unidirectional conductive element, and the other end of the fourth resistor is connected to the inverting input terminal of the second operational amplifier and the output terminal of the second operational amplifier.

[0020] As a further improvement of the present application, the non-inverting input terminal of the comparator is connected to the reference voltage through a fifth resistor, and the inverting input terminal of the comparator is connected to the output terminal of the second operational amplifier through a sixth resistor;

[0021] A seventh resistor and an eighth resistor are further provided between the output end of the comparator and the primary side of the photoelectric coupling element, one end of the seventh resistor is connected to the output end of the comparator, the other end of the seventh resistor is connected to the primary side of the photoelectric coupling element after being connected together with the eighth resistor, and the other end of the eighth resistor is connected to a power supply voltage;

[0022] The first voltage is less than the reference voltage and less than the second voltage.

[0023] As a further improvement of the present application, the line break detection circuit further includes a main control unit for receiving a secondary side output signal of the photoelectric coupling element;

[0024] The main control unit is used to receive the output signal of the secondary side of the photoelectric coupling element. When the photoelectric coupling element is turned on, the secondary side of the photoelectric coupling element sends the output signal to the main control unit, so that the main control unit controls the contactor to disconnect from the load.

[0025] Based on the above disconnection detection circuit, the present application provides a disconnection detection method, which comprises the following steps:

[0026] Get input signal;

[0027] Charging the energy storage element until the voltage value across the energy storage element is equal to the voltage value of the input signal;

[0028] Comparing the voltage value across the energy storage element with a reference voltage;

[0029] When the voltage value across the energy storage element is greater than the reference voltage, the input signal is judged to be in a disconnected state based on the voltage value of the input signal jumping from the first voltage to the second voltage to output the first level; when the voltage value across the energy storage element is less than the reference voltage, the output signal is judged to be in a normally connected state based on the voltage value of the input signal maintaining the first voltage to output the second level.

[0030] The disconnection detection circuit and detection method provided by the present application have the following beneficial effects:

[0031] The present application charges the energy storage element through an operational amplifier detection unit until the voltage value at both ends of the energy storage element is equal to the voltage value of the input signal, collects the voltage value at both ends of the energy storage element through a voltage follower unit, and compares the voltage value at both ends of the energy storage element with a reference voltage through an output comparison unit, and determines whether the input signal is disconnected based on whether the voltage value of the input signal jumps from a first voltage to a second voltage; when the voltage value of the input signal jumps from a first voltage to a second voltage, it is determined that the input signal is disconnected, and the connection with the load is disconnected, and the duration of the entire process from CP disconnection to output disconnection is controlled within the time required by international standards, so as to quickly and accurately detect whether the CP line of the charging pile is disconnected, and effectively ensure the power supply safety of the charging pile. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only part of the embodiments of the present application, rather than all the embodiments. For ordinary technicians in this field, without paying creative work, other drawings obtained based on these drawings all fall within the scope of protection of this application.

[0033] Figure 1 A schematic diagram of the structure of a disconnection detection circuit provided in an embodiment of the present application;

[0034] Figure 2 A schematic diagram of the structure of the disconnection detection circuit provided in the embodiment of the present application Figure 2 ;

[0035] Figure 3 A circuit schematic diagram of an operational amplifier detection unit in a disconnection detection circuit provided in an embodiment of the present application;

[0036] Figure 4 A circuit schematic diagram of an optocoupler isolation unit in a line break detection circuit provided in an embodiment of the present application;

[0037] Figure 5 It is a communication interaction principle diagram of the charging pile provided in the related technology;

[0038] Figure 6 A flow chart of a disconnection detection circuit method provided in an embodiment of the present application;

[0039] Description of reference numerals:

[0040] 10-operational amplifier detection unit; 11-voltage-dividing resistor element; 12-second unidirectional conductive element; 13-third unidirectional conductive element; 20-voltage follower unit; 21-first unidirectional conductive element; 22-energy storage element; 30-output comparison unit; 40-optical coupling isolation unit; 41-photoelectric coupling element. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0042] In order to make the description of the disclosed content more detailed and complete, the following is an illustrative description of the implementation methods and specific examples of the present application; however, this is not the only form of implementing or applying the specific embodiments of the present application. The implementation methods cover the features of multiple specific embodiments and the method steps and their sequences for constructing and operating these specific embodiments. However, other specific embodiments can also be used to achieve the same or equal functions and step sequences. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0043] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein.

[0044] In the description of the embodiments of the present application, unless otherwise specified, " / " means or, for example, A / B can mean A or B; "and / or" in the text is merely a description of the association relationship of associated objects, indicating that three relationships may exist, for example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, in the description of the embodiments of the present application, "multiple" refers to two or more than two, and other quantifiers are similar. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present application, and are not used to limit the present application, and the embodiments of the present application and the features in the embodiments may be combined with each other without conflict.

[0045] Please refer to Figure 1-Figure 6 This application provides a circuit break detection circuit and detection method, which can quickly and accurately detect whether the charging pile CP line has a disconnection fault, thereby improving the power supply safety of the charging pile. Figure 1 , is a structural schematic diagram of a line break detection circuit provided in an embodiment of the present application, wherein the line break detection circuit includes an operational amplifier detection unit 10, a voltage follower unit 20, and an output comparison unit 30.

[0046] As an optional implementation, please refer to Figure 3 , a circuit schematic diagram of an operational amplifier detection unit 10 in a disconnection detection circuit provided in an embodiment of the present application, wherein the operational amplifier detection unit 10 is used to access an input signal VIN, and the operational amplifier detection unit 10 includes a first operational amplifier U1A, and a voltage-dividing resistor element 11 connected between the in-phase input terminal of the first operational amplifier U1A and the input signal. The present application controls the voltage value of the in-phase input terminal of the first operational amplifier U1A by adjusting the resistance value of the voltage-dividing resistor element 11, so that the output terminal of the first operational amplifier U1A outputs a desired voltage signal.

[0047] Furthermore, the above-mentioned voltage follower unit 20 includes a second operational amplifier U1B. In the present application, a first unidirectional conductive element 21 is connected between the same-direction input terminal of the second operational amplifier U1B and the output terminal of the first operational amplifier U1A, and an energy storage element 22 is connected between the first unidirectional conductive element 21 and the same-direction input terminal of the second operational amplifier U1B. The required voltage signal is output through the output terminal of the first operational amplifier U1A. In principle, the voltage value of the voltage signal should be greater than the conduction voltage drop of the first unidirectional conductive element 21, so that the first unidirectional conductive element 21 is turned on, and the energy storage element 22 can also be charged until the voltage value at both ends of the energy storage element 22 is equal to the voltage value of the input signal, and then the voltage value at both ends of the energy storage element 22 is collected through the second operational amplifier U1B.

[0048] Please continue to refer to Figure 1 The present application is also provided with an output comparison unit 30 capable of collecting the voltage value at both ends of the energy storage element 22. The output comparison unit 30 is connected to the output end of the second operational amplifier U1B, and is used to compare the voltage value at both ends of the energy storage element 22 collected by the voltage follower unit 20 with the reference voltage. Since the voltage value at both ends of the energy storage element 22 is equal to the voltage value of the input signal, it is possible to determine whether the voltage value of the input signal jumps from the first voltage to the second voltage.

[0049] In an optional application embodiment, the above-mentioned input signal can be set to a CP signal (Control Pilot function). The CP signal is a key signal in the AC charging pile of new energy vehicles. The charging pile outputs a DC signal or a PWM (Pulse Width Modulation) wave signal through the CP line to interact and communicate with the electric vehicle. At the same time, the charging pile performs voltage detection on the CP line and determines the current connection status between the charging pile and the electric vehicle based on the detected CP voltage result.

[0050] When the charging pile is charging normally, the CP signal output through the CP line is a voltage signal with an amplitude of 6V. When the CP line of the charging pile is broken during the charging process, the CP signal will jump to a 12V voltage signal. Therefore, it is possible to determine whether the CP line is broken by detecting whether the voltage value of the CP signal jumps from 6V to 12V.

[0051] Taking the CP signal as an example, at this time, the above-mentioned first voltage corresponds to a 6V voltage, and the second voltage corresponds to a 12V voltage. When the disconnection detection circuit provided in the present application is applied to the disconnection detection of the CP line, it is necessary to connect the operational amplifier detection unit 10 to the CP signal, and charge the energy storage element 22 through the operational amplifier detection unit 10 until the voltage value at both ends of the energy storage element 22 is equal to the voltage value of the CP signal, and then collect the voltage value at both ends of the energy storage element 22 through the second operational amplifier U1B.

[0052] Furthermore, the output comparison unit 30 compares the voltage value across the energy storage element 22 obtained by the second operational amplifier U1B with a reference voltage. The reference voltage should be greater than the first voltage and less than the second voltage. Taking the first voltage as 6V and the second voltage as 12V as an example, the reference voltage should be between 6V and 12V.

[0053] Exemplarily, the reference voltage can be set to 7.5V, and the voltage value across the energy storage element 22 is compared with 7.5V through the comparator U2A. When the voltage value across the energy storage element 22 is less than 7.5V, the voltage value of the CP signal is judged to be the first voltage 6V, and the CP line is not broken at present. When the voltage value across the energy storage element 22 is greater than 7.5V, it is judged that the CP line is broken, and the voltage value of the CP signal jumps from the first voltage 6V to the second voltage 12V.

[0054] The present application realizes rapid detection of whether a CP disconnection occurs by causing a change in the voltage value at both ends of the energy storage element 22 due to a jump from the first voltage to the second voltage. Of course, the disconnection detection circuit provided by the present application can also be applied to other situations where the first voltage jumps to the second voltage due to a disconnection. The jump from the first voltage of 6V to the second voltage of 12V mentioned in the above charging pile technical field is only an optional implementation provided by the present application and does not constitute any limitation on the implementation scenario of the present application.

[0055] For details, please continue to refer to Figure 3 The above-mentioned voltage-dividing resistor element 11 includes a first resistor R1 and a second resistor R2. It can be observed that the first resistor R1 is connected to the input signal and the non-inverting input terminal of the first operational amplifier U1A respectively, one end of the second resistor R2 is connected between the first resistor R1 and the non-inverting input terminal of the first operational amplifier U1A, and the other end of the second resistor R2 is grounded.

[0056] In the embodiment of the present application, the first resistor R1 and the second resistor R2 constitute a voltage-dividing resistor, and the voltage value of the input signal is divided by setting the resistance value of the first resistor R1 to be smaller than the resistance value of the second resistor R2. Preferably, the resistance value of the first resistor R1 should be set much smaller than the resistance value of the second resistor R2. The voltage is divided by the first resistor R1 and the second resistor R2 so that the output voltage of the first operational amplifier U1A is consistent with the power supply voltage VCC connected to the positive power pin of the first operational amplifier U1A.

[0057] As an optional implementation, the present application connects a second unidirectional conductive element 12 between the input signal and the first resistor R1. When the input signal is a PWM wave signal, since the PWM wave signal has positive and negative voltages, the second unidirectional conductive element 12 can be used to clamp the negative voltage of the PWM wave signal to remove the negative voltage.

[0058] For example, the second unidirectional conductive element 12 can be configured as a diode, corresponding to the attached Figure 3 The diode D1 in the circuit has an anode connected to the input signal and a cathode connected to the first resistor R1, so that the diode D1 clamps the negative voltage of the PWM wave signal and removes the negative voltage therein.

[0059] Furthermore, in the present application, a filter capacitor C1 is connected in parallel at both ends of the second resistor R2, and the noise in the input signal is filtered out by the filter capacitor C1.

[0060] Please continue to refer to Figure 3In the present application, a power supply voltage VCC is connected to the positive power supply pin of the first operational amplifier U1A. The power supply voltage VCC is a low voltage and is generally set at about 24V. The negative power supply pin of the first operational amplifier U1A is grounded, and a third unidirectional conductive element 13 is connected between the output terminal of the first operational amplifier U1A and the inverting input terminal of the first operational amplifier U1A.

[0061] According to the working characteristics of the operational amplifier, when the voltage value of the non-inverting input terminal of the first operational amplifier U1A is greater than the voltage value of the inverting input terminal of the first operational amplifier U1A, the voltage of the output terminal of the first operational amplifier U1A is consistent with the power supply voltage VCC. Since the value of the power supply voltage VCC is greater than the conduction voltage drop of the first unidirectional conductive element 21, the first unidirectional conductive element 21 will be turned on, and the third unidirectional conductive element 13 is reversely connected between the output terminal of the first operational amplifier U1A and the inverting input terminal of the first operational amplifier U1A, so the third unidirectional conductive element 13 will be cut off. At this time, the power supply voltage VCC will quickly charge the energy storage element 22 until the voltage value at both ends of the energy storage element 22 is equal to the voltage value of the input signal, and the charging of the energy storage element 22 is terminated.

[0062] In an optional embodiment, the first unidirectional conductive element 21 and the third unidirectional conductive element may also be configured in the form of a diode. The first unidirectional conductive element 21 corresponds to Figure 3 The diode D2 and the third unidirectional conductive element 13 correspond to Figure 3 From the diode D3 in FIG. 1 , it can be observed that the anode of the diode D2 is connected to the output terminal of the first operational amplifier U1A, the anode of the diode D2 is connected to the non-inverting input terminal of the second operational amplifier U1B, the anode of the diode D3 is connected to the inverting input terminal of the first operational amplifier U1A, and the cathode of the diode D3 is connected to the output terminal of the first operational amplifier U1A.

[0063] Furthermore, the energy storage element 22 can be configured as a capacitor, corresponding to Figure 3 When the voltage value of the non-inverting input terminal of the first operational amplifier U1A is greater than the voltage value of the inverting input terminal of the first operational amplifier U1A, the voltage of the output terminal of the first operational amplifier U1A is consistent with the power supply voltage VCC. Since the value of the power supply voltage VCC is greater than the conduction voltage drop of the diode D2, the diode D2 will be turned on, and the diode D3 is reversely connected between the output terminal of the first operational amplifier U1A and the inverting input terminal of the first operational amplifier U1A, so the diode D3 will be cut off. At this time, the power supply voltage VCC will quickly charge the capacitor C2 until the voltage value across the capacitor C2 is equal to the voltage value of the input signal, thereby ending the charging of the capacitor C2.

[0064] Continuing with the example of the first voltage 6V and the second voltage 12V, when the charging pile is powered normally, the power supply voltage VCC will charge the capacitor C2 until the voltage across the capacitor C2 is equal to the voltage value of the input signal, which is 6V. When the CP line of the charging pile is disconnected during the charging process, the CP signal will jump to a 12V voltage signal. Similarly, the power supply voltage VCC will quickly charge the capacitor C2 until the voltage across the capacitor C2 is equal to the voltage value of the input signal, which is 12V.

[0065] It should be noted that the third unidirectional conductive element 13 is provided in the present application to clamp the further amplification of the input signal, thereby effectively suppressing overcharging of the capacitor C2.

[0066] As an optional embodiment, the present application sets a third resistor R3 in parallel at both ends of the energy storage element 22, one end of the energy storage element 22 and the third resistor R3 are commonly connected between the first unidirectional conductive element 21 and the in-phase input terminal of the second operational amplifier U1B, and the other end of the energy storage element 22 is commonly connected to the third resistor R3 and then grounded.

[0067] When the first unidirectional conductive element 21 is set to a diode D2, the third unidirectional conductive element 13 is set to a diode D3, and the energy storage element 22 is set to a capacitor C2, the present application further sets a third resistor R3 in parallel at both ends of the capacitor C2. It can be observed that one end of the capacitor C2 and the third resistor R3 are commonly connected between the diode D2 and the in-phase input terminal of the second operational amplifier U1B, and the other end of the capacitor C2 is commonly connected to the third resistor R3 and then grounded.

[0068] Optionally, the present application further connects a fourth resistor R4 between the inverting input terminal of the first operational amplifier U1A and the output terminal of the second operational amplifier U1B. It can be observed that one end of the fourth resistor R4 is connected to the third unidirectional conductive element 13 and then connected to the inverting input terminal of the first operational amplifier U1A, and the other end of the fourth resistor R4 is connected to the inverting input terminal of the second operational amplifier U1B and then connected to the output terminal of the second operational amplifier U1B.

[0069] Specifically, one end of the fourth resistor R4 and the anode of the diode D3 are connected together and then connected to the inverting input terminal of the first operational amplifier U1A, and the other end of the fourth resistor R4 and the inverting input terminal of the second operational amplifier U1B are connected together and then connected to the output terminal of the second operational amplifier U1B.

[0070] The present application forms a voltage follower circuit by connecting the inverting input terminal of the second operational amplifier U1B with the output terminal of the second operational amplifier U1B, thereby ensuring that the voltages of the input and output of the second operational amplifier U1B remain consistent, accurately transmitting the collected voltage value VOUT across the capacitor C2 to the output comparison unit 30 for judgment, and setting the fourth resistor R4 to provide negative feedback for the first operational amplifier U1A, thereby effectively improving the anti-interference capability of the disconnection detection circuit.

[0071] For further information, please refer to Figure 4 , which is a circuit schematic diagram of the optocoupler isolation unit 40 in the disconnection detection circuit provided in an embodiment of the present application. The above-mentioned output comparison unit 30 includes a comparator U2A, and the non-inverting input terminal of the comparator U2A is connected to the reference voltage through the fifth resistor R5. The inverting input terminal of the comparator U2A is connected to the output terminal of the second operational amplifier U1B through the sixth resistor R5. The present application compares the reference level of the non-inverting input terminal of the comparator U2A with the voltage value VOUT across the capacitor C2 collected by the inverting input terminal of the comparator U2A, and determines whether the input signal is disconnected according to whether the voltage value of the input signal jumps from the first voltage to the second voltage.

[0072] Of course, the comparator U2A may also be configured as other devices or MCU processors. In principle, as long as the voltage value VOUT across the capacitor C2 can be compared with the reference level to determine whether the voltage value of the input signal jumps from the first voltage to the second voltage, the present application does not impose any further restrictions on the specific configuration of the comparator U2A.

[0073] Furthermore, according to the requirements of international standards, if the CP is disconnected during the charging process, not only should the disconnection be detected quickly within 30ms, but the output current should also be reduced to below 5A. Therefore, it is particularly important to disconnect the output within the specified time.

[0074] In the relevant technology, the national standard charging pile and the European standard charging pile need to communicate and interact in a unified manner. Therefore, the national standard charging pile exported overseas needs to add a PLC (Power Line Communication) module to realize the charging communication protocol conversion between the electric vehicle and the charging pile. Since the PLC module communicates with the vehicle through PLC, it communicates with the charging pile in the CAN (Controller Area Network) communication mode after conversion. For details, please refer to Figure 5 , which is a communication interaction principle diagram of a charging pile provided in the related art. This communication method has a communication delay during the conversion process, resulting in the charging pile being unable to promptly learn of the CP disconnection situation, and failing to meet the requirements of international standards.

[0075] To disconnect the output within the specified time, please refer to Figure 2 , which is a schematic diagram of the structure of the disconnection detection circuit provided in the embodiment of the present application Figure 2 In the present application document, an optocoupler isolation unit 40 capable of timely disconnecting the output is also provided, and the optocoupler isolation unit 40 is connected to the output comparison unit 30 .

[0076] As an optional embodiment, the above-mentioned optocoupler isolation unit 40 includes a photoelectric coupling element 41, the primary side of the photoelectric coupling element 41 is connected to the output end of the comparator U2A, and the secondary side of the photoelectric coupling element 41 is connected to the load through a contactor (not shown in the figure). The optocoupler isolation unit 40 set in the present application is used to receive the level signal output by the output comparison unit 30. When the level signal is a first level, the photoelectric coupling element 41 is turned on to disconnect the contactor from the load, thereby realizing rapid disconnection of the output.

[0077] Furthermore, a seventh resistor and an eighth resistor are arranged between the output end of the comparator U2A and the primary side of the photoelectric coupling element 41, one end of the seventh resistor is connected to the output end of the comparator U2A, the other end of the seventh resistor is connected to the primary side of the photoelectric coupling element 41 after being connected together with the eighth resistor, and the other end of the eighth resistor is connected to the power supply voltage.

[0078] Specifically, the above-mentioned optocoupler element 41 can be set as an optocoupler OP1. At this time, the non-inverting input terminal of the comparator U2A is connected to the reference voltage through the fifth resistor R5, and the inverting input terminal of the comparator U2A is connected to the output terminal of the second operational amplifier U1B through the sixth resistor R6. A seventh resistor R7 and an eighth resistor R8 are also arranged between the output terminal of the comparator U2A and the primary side of the optocoupler OP1. One end of the seventh resistor R7 is connected to the output terminal of the comparator U2A, and the other end of the seventh resistor R7 is connected to the primary side of the optocoupler OP1 after being connected to the eighth resistor R8. The other end of the eighth resistor is connected to the power supply voltage VCC.

[0079] Furthermore, the positive power pin of the comparator U2A is connected to the power supply voltage VCC, the negative power pin of the comparator U2A is grounded, the first end of the primary side of the photocoupler OP1 is connected to the power supply voltage VCC, the first end of the primary side of the photocoupler OP1 is connected to the seventh resistor R7 and the eighth resistor R8 which are connected together, and the secondary side of the photocoupler OP1 is connected to the load through a contactor.

[0080] In an embodiment of the present application, when the voltage value across capacitor C2 is greater than the reference voltage, the comparator U2A determines that the voltage value of the input signal jumps from the first voltage to the second voltage, and outputs the first level to the photoelectric coupler OP1 to turn on the photoelectric coupler OP1. After the secondary side of the photoelectric coupler OP1 senses that the primary side is turned on, it drives the contactor to disconnect the connection with the load, thereby disconnecting the output in time; conversely, when the voltage value across capacitor C2 is less than the reference voltage, the comparator U2A determines that the voltage value of the input signal is maintained at the first voltage, and outputs the first level to the photoelectric coupler OP1 to disconnect the photoelectric coupler OP1.

[0081] In a specific embodiment, when the comparator U2A determines that the voltage value of the input signal jumps from the first voltage to the second voltage, the first level output to the photocoupler OP1 is a high level, and when the comparator U2A determines that the voltage value of the input signal is maintained at the first voltage, the second level output to the photocoupler OP1 is a low level, thereby controlling the duration of the entire process from CP disconnection to output disconnection within the time required by international standards.

[0082] It can be understood that the relationship between the first voltage, the second voltage and the reference voltage should satisfy the following relationship: first voltage < reference voltage < second voltage, and this application will not elaborate on this.

[0083] As an optional implementation, the output load can also be disconnected through a main control unit, which includes a device for receiving a secondary side output signal of the photoelectric coupling element 41. When the photoelectric coupling element 41 is turned on, the secondary side of the photoelectric coupling element 41 sends an output signal to the main control unit, so that the main control unit controls the contactor to disconnect from the load.

[0084] Specifically, the main control unit can be set in the form of a controller such as MCU (Microcontroller Unit), FPGA (Field Programmable Gate Array), or a single-chip microcomputer. Figure 4 VDD is the power supply of the main control unit. The secondary side of the photocoupler OP1 is connected to the main control unit through CP YX, so that when it is turned on, an output signal is sent to the main control unit through the lead CP YX, so that the main control unit controls the contactor to disconnect from the load.

[0085] It should be noted that the present application does not impose any further restrictions on the specific configuration of the main control unit. The main control unit may not be provided to directly drive the contactor to disconnect the load and increase the disconnection speed, and the present application does not impose any further restrictions on this.

[0086] Preferably, it can be observed that in the present application, the second resistor R2 and the filter capacitor C1 are connected together and then connected to the PE ground, the third resistor R3 and the capacitor C2 are connected together and then connected to the PE ground, the negative power supply pins of the first operational amplifier U1A, the second operational amplifier U1B and the comparator U2A are also connected to the PE ground, and the third terminal of the secondary side of the optocoupler OP1 is connected to the GND setting, thereby playing an isolation role and enhancing the anti-interference ability of the circuit.

[0087] The present application charges the energy storage element 22 through the operational amplifier detection unit 10 until the voltage value across the energy storage element 22 is equal to the voltage value of the input signal, collects the voltage value across the energy storage element 22 through the voltage follower unit 20, and compares the voltage value across the energy storage element 22 with the reference voltage through the output comparison unit 30, and determines whether the input signal is disconnected based on whether the voltage value of the input signal jumps from the first voltage to the second voltage.

[0088] Furthermore, when the voltage value of the input signal jumps from the first voltage to the second voltage, it is determined that the input signal is disconnected, and at the same time, a first level is sent to the primary side of the optocoupler element 41 in the optoelectronic isolation unit, so that the optocoupler element 41 is turned on, so that the contactor is disconnected from the load, and the duration of the entire process from CP disconnection to output disconnection is controlled within the time required by the international standard; conversely, when the voltage value of the input signal is the first level, it is determined that the input signal is not disconnected, and a second level is sent to the primary side of the optocoupler element 41, and the optocoupler element 41 is in a disconnected state.

[0089] Of course, the main control unit can also be set to receive the output signal sent by the secondary side of the optocoupler element 41, and control the contactor to disconnect from the load through the main control unit, thereby disconnecting the output within a specified time, ensuring the timeliness of the entire process from CP disconnection to output disconnection.

[0090] Based on the above disconnection detection circuit, this application also provides a disconnection detection method, please refer to Figure 6 , is a flow chart of a disconnection detection circuit method provided in an embodiment of the present application, the detection method comprising the following steps:

[0091] S1: Get input signal;

[0092] S2: charging the energy storage element until the voltage value across the energy storage element is equal to the voltage value of the input signal;

[0093] S3: Compare the voltage value across the energy storage element with a reference voltage;

[0094] S4: When the voltage value across the energy storage element is greater than the reference voltage, the input signal is judged to be in a disconnected state based on the voltage value of the input signal jumping from the first voltage to the second voltage to output the first level; when the voltage value across the energy storage element is less than the reference voltage, the output signal is judged to be in a normally connected state based on the voltage value of the input signal maintaining the first voltage to output the second level.

[0095] For other details about the disconnection detection method for implementing the above technical solution, please refer to the description of the disconnection detection circuit provided in the above application embodiment, which will not be repeated here.

[0096] The disconnection detection circuit and detection method provided in the present application charges the energy storage element through an operational amplifier detection unit until the voltage value at both ends of the energy storage element is equal to the voltage value of the input signal, collects the voltage value at both ends of the energy storage element through a voltage follower unit, and compares the voltage value at both ends of the energy storage element with a reference voltage through an output comparison unit, and determines whether the input signal is disconnected based on whether the voltage value of the input signal jumps from a first voltage to a second voltage; when the voltage value of the input signal jumps from a first voltage to a second voltage, it is determined that the input signal is disconnected, and the connection with the load is disconnected, and the duration of the entire process from CP disconnection to output disconnection is controlled within the time required by international standards, so as to quickly and accurately detect whether the CP line of the charging pile is disconnected, thereby effectively ensuring the power supply safety of the charging pile.

[0097] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions 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 disconnection detection circuit, It is characterized in that It includes an operational amplifier detection unit, a voltage follower unit and an output comparison unit; The operational amplifier detection unit includes a first operational amplifier, and a voltage-dividing resistor element connected between a non-inverting input terminal of the first operational amplifier and an input signal; The voltage follower unit comprises a second operational amplifier, a first unidirectional conductive element is connected between a non-inverting input terminal of the second operational amplifier and an output terminal of the first operational amplifier, and an energy storage element is connected between the first unidirectional conductive element and the non-inverting input terminal of the second operational amplifier; The operational amplifier detection unit is used to charge the energy storage element when the first unidirectional conductive element is turned on, until the voltage value across the energy storage element is equal to the voltage value of the input signal; The output comparison unit includes a comparator connected to the output end of the second operational amplifier, and the comparator is used to compare the voltage value across the energy storage element with a reference voltage to determine whether the line is broken based on whether the voltage value of the input signal jumps from a first voltage to a second voltage.

2. The disconnection detection circuit according to claim 1, It is characterized in that The disconnection detection circuit further includes an optocoupler isolation unit connected to the output comparison unit; The optical coupling isolation unit comprises a photoelectric coupling element, a primary side of the photoelectric coupling element is connected to the output end of the comparator, and a secondary side of the photoelectric coupling element is connected to a load through a contactor; The optical coupling isolation unit is used to receive the level signal output by the output comparison unit. When the level signal is at a first level, the photoelectric coupling element is turned on to disconnect the contactor from the load.

3. The disconnection detection circuit according to claim 1, It is characterized in that The voltage-dividing resistor element comprises a first resistor and a second resistor, the first resistor is connected to the input signal and the non-inverting input terminal of the first operational amplifier respectively, one end of the second resistor is connected between the first resistor and the non-inverting input terminal of the first operational amplifier, and the other end of the second resistor is grounded; Wherein, the first resistor is smaller than the second resistor.

4. The disconnection detection circuit according to claim 3, It is characterized in that A second unidirectional conductive element is connected between the input signal and the first resistor, and a filter capacitor is connected in parallel at both ends of the second resistor.

5. The disconnection detection circuit according to claim 1, It is characterized in that The positive power supply pin of the first operational amplifier is connected to a power supply voltage, the negative power supply pin of the first operational amplifier is grounded, and a third unidirectional conductive element is connected between the output terminal of the first operational amplifier and the inverting input terminal of the first operational amplifier; When the voltage value of the non-inverting input terminal of the first operational amplifier is greater than the voltage value of the inverting input terminal of the first operational amplifier, the first unidirectional conductive element is turned on, the second unidirectional conductive element is turned off, and the power supply voltage charges the energy storage element until the voltage value across the energy storage element is equal to the voltage value of the input signal.

6. The disconnection detection circuit according to claim 1, It is characterized in that A third resistor is arranged in parallel at both ends of the energy storage element, one end of the energy storage element and the third resistor are connected between the first unidirectional conductive element and the in-phase input terminal of the second operational amplifier, and the other end of the energy storage element is connected to the third resistor and then grounded.

7. The disconnection detection circuit according to claim 5, It is characterized in that A fourth resistor is connected between the inverting input terminal of the first operational amplifier and the output terminal of the second operational amplifier. One end of the fourth resistor is connected to the inverting input terminal of the first operational amplifier and the third unidirectional conductive element. The other end of the fourth resistor is connected to the inverting input terminal of the second operational amplifier and the output terminal of the second operational amplifier.

8. The disconnection detection circuit according to claim 2, It is characterized in that The non-inverting input terminal of the comparator is connected to the reference voltage through a fifth resistor, and the inverting input terminal of the comparator is connected to the output terminal of the second operational amplifier through a sixth resistor; A seventh resistor and an eighth resistor are further provided between the output end of the comparator and the primary side of the photoelectric coupling element, one end of the seventh resistor is connected to the output end of the comparator, the other end of the seventh resistor is connected to the primary side of the photoelectric coupling element after being connected together with the eighth resistor, and the other end of the eighth resistor is connected to a power supply voltage; The first voltage is less than the reference voltage and less than the second voltage.

9. The disconnection detection circuit according to claim 2, It is characterized in that The disconnection detection circuit further comprises a main control unit for receiving a secondary side output signal of the photoelectric coupling element; The main control unit is used to receive the output signal of the secondary side of the photoelectric coupling element. When the photoelectric coupling element is turned on, the secondary side of the photoelectric coupling element sends the output signal to the main control unit, so that the main control unit controls the contactor to disconnect from the load.

10. A disconnection detection method, applied to the disconnection detection circuit according to any one of claims 1 to 9, It is characterized in that The following steps are involved: Get input signal; Charging the energy storage element until the voltage value across the energy storage element is equal to the voltage value of the input signal; Comparing the voltage value across the energy storage element with a reference voltage; When the voltage value across the energy storage element is greater than the reference voltage, the input signal is judged to be in a disconnected state by outputting a first level according to the voltage value of the input signal jumping from a first voltage to a second voltage; When the voltage value across the energy storage element is less than the reference voltage, the output signal is judged to be in a normal on state according to the voltage value of the input signal being maintained at the first voltage and at a second level.

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