Detection circuit for controlling abnormal guide points in direct current charging pile

Abstract

The application provides a detection circuit for controlling guide point anomaly in a direct current charging pile, which is electrically connected with a control guide signal generation circuit and a control circuit, provides anomaly state detection when the electric vehicle is electrically connected with the direct current charging pile, and provides real-time protection for the direct current charging pile. The detection circuit comprises: a control guide signal potential discrimination module; a charging and discharging module electrically connected with the control guide signal potential discrimination module; and a controller protection trigger module electrically connected with the charging and discharging module; wherein the control guide signal potential discrimination module discriminates the voltage level of the input control guide signal, starts the charging and discharging module to charge the control guide signal output from the control guide signal potential discrimination module to be higher than a preset steady-state voltage value within a preset time period, starts the controller protection trigger module to provide real-time protection for the direct current charging pile.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of direct current charging for electric vehicles, and in particular to a detection circuit for controlling abnormality of a pilot point in a direct current charging pile. BACKGROUND

[0002] In response to the increasingly urgent global environmental changes and climate warming issues, the automobile industry has increasingly emphasized the production of electric vehicles. As electric vehicles become increasingly popular, the charging system for electric vehicles has also attracted increasing attention. Charging piles are electric energy supply devices for electric vehicles, and as electric vehicles and charging pile systems become increasingly diverse, interoperability and standard consistency between different components become increasingly important. In order to identify the source of interruptions during charging and conduct reliability and robustness tests for various disturbances, consistency coverage tests need to be conducted in an open test system. In response to the matching problems between different components of various manufacturers, the Charging Interface Initiative (CharIN e.V.) as an open protocol for major global electric vehicle manufacturers, develops and establishes various electric vehicle charging standards to improve the convenience and cost efficiency of charging infrastructure. There are currently three charging protocol standards in the world: the Combined Charging System (CCS) is used in Europe and North America, GB / T 27930 and GB / T 18487 are used in China, and CHAdeMO is used in Japan, etc. specifications for different charging interfaces.

[0003] Taking the Combined Charging System (CCS) as an example, it only needs to use one charging interface on the vehicle, so that customers can use all existing charging methods for charging: single-phase alternating current (AC) charging, fast three-phase AC charging, direct current (DC) charging at home or ultra-fast DC charging at public charging stations. Among them, the charging process that meets the IEC 61851 specification of the Combined Charging System (CCS) standard defines four electric vehicle charging modes:

[0004] Mode 1: charging using single-phase power supply, maximum current 16A, no pilot signal.

[0005] Mode 2: charging using single / three-phase power supply, maximum current 32A, with pilot signal.

[0006] Mode 3: charging using single / three-phase power supply, maximum current 63A, charging pile provides pilot signal.

[0007] Mode 4: direct current charging with maximum 400V / 125A.

[0008] Mode 1 does not involve communication between the vehicle and the charging infrastructure, such as a charging post, but charging in modes 2, 3, and 4 is based on PWM signals, which communicate via the CP (Control Pilot) connection. If the vehicle and the charging post both support upper-layer communication, the signals must be modulated as PWM signals, i.e. Power Line Communication (PLC), in accordance with the Home Plug Green PHY standard. In principle, all PLC-based charging communication requires transmission via PWM. Therefore, a complete test system must handle both communication modes.

[0009] The present disclosure mainly focuses on the detection technology of abnormal conditions of the Control Pilot (CP) point when the charging interface of the Combined Charging System (CCS) is used in Europe and North America. When a direct current charging post charges an electric vehicle in accordance with the CCS protocol, how to determine the current state of the CP point at different time sequences. For example, real-time detection protection when the CP point is short-circuited or open-circuited. Traditionally, when a direct current charging post charges an electric vehicle in accordance with the CCS protocol, the modem detects the state change of the CP point and transmits the state of the CP point by software. The time of the modem is not as fast as the hardware response, which may cause errors and cannot protect in real time. Therefore, the present disclosure provides a hardware circuit to realize the detection and protection of the CP point state, so that when the CP point is short-circuited, open-circuited, or other problems occur during authentication in accordance with the CCS protocol, the direct current charging post can detect errors in real time and perform protection. However, in practical applications, other specifications of direct current charging posts can also follow the scheme provided by the present disclosure to make similar improvements, and are not limited to direct current charging posts using the CCS protocol.

[0010] Generally speaking, the CP voltage detection system of the direct current charging post of the electric vehicle is monitored by electronic or mechanical means to monitor the connection state between the electric vehicle and the power supply device (direct current charging post).

[0011] In addition, when the CP point changes state during the charging process of the direct current charging post in accordance with the CCS protocol, the time of the modem to detect and transmit the state change of the CP point cannot catch up with the hardware response, which may cause errors (such as sudden short-circuit or open-circuit conditions) and cannot protect in time. SUMMARY

[0012] Based on the above-mentioned defects, in order to meet the CE (CONFORMITE EUROPEENNE) certification when the DC charging pile, according to the CCS Protocol, when the CP point occurs short circuit, open circuit and other problems, real-time error detection and protection can be performed, the present application proposes a detection circuit for controlling the abnormality of the guide point in the DC charging pile, wherein the detection circuit is electrically connected with the control guide signal generation circuit and the control circuit to provide abnormal state detection when the electric vehicle is electrically connected with the DC charging pile, and to provide real-time protection for the DC charging pile, the detection circuit comprises: a control guide signal potential discrimination module; a charge-discharge module electrically connected with the control guide signal potential discrimination module; and a controller protection trigger module electrically connected with the charge-discharge module; wherein the control guide signal potential discrimination module discriminates the voltage level of the input control guide signal to start the charge-discharge module to charge the control guide signal output by the potential discrimination module to be higher than a preset steady-state voltage value within a preset time period, so as to start the controller protection trigger module to provide real-time protection for the DC charging pile.

[0013] In an embodiment, the control guide signal potential discrimination module comprises: a first voltage dividing circuit for generating two reference voltage levels, a first reference voltage level and a second reference voltage level; a first comparator; a second comparator; and a control guide signal input end; wherein the first reference voltage level and the second reference voltage level are input to the inverting input end of the first comparator and the non-inverting input end of the second comparator as potential reference bases, and the control guide signal input end is electrically connected with the non-inverting input end of the first comparator and the inverting input end of the second comparator for inputting the control guide signal filtered by a rectifier circuit to remove the negative potential signal, the first reference voltage level is higher than the second reference voltage level.

[0014] In an embodiment, the voltage value of the first reference voltage level ranges from 0 to 11V, and the voltage value of the second reference voltage level ranges from 0 to 1V.

[0015] In an embodiment, the charging and discharging module comprises: a first charging and discharging circuit; and a second charging and discharging circuit; wherein the first charging and discharging circuit is electrically connected to the output terminal of the first comparator and the input terminal of the controller protection trigger module, so as to provide a charging fast and discharging slow function for the control guide signal output via the output terminal of the first comparator, and charge to a value greater than a first steady state voltage value within a first time period, so as to start the controller protection trigger module to provide real-time protection for the DC charging pile; wherein the second charging and discharging circuit is electrically connected to the output terminal of the second comparator and the input terminal of the controller protection trigger module, so as to provide a fast charging function for the control guide signal output via the output terminal of the second comparator, and charge to a value greater than a second steady state voltage value within a second time period, so as to start the controller protection trigger module to provide real-time protection for the DC charging pile.

[0016] In an embodiment, the first charging and discharging circuit comprises: a charging and discharging circuit formed by a first power supply, a first resistor, a second resistor, a first diode connected in parallel with the second power supply, a first capacitor, and a ground; wherein one end of the first resistor is electrically connected to the power supply, the other end is electrically connected to the output terminal of the first comparator, the anode end of the first diode in the parallel circuit of the first diode connected in parallel with the second power supply is electrically connected to the output terminal of the first comparator, the cathode end of the first diode in the parallel circuit is electrically connected to one end of the first capacitor, and the other end of the first capacitor is grounded.

[0017] In an embodiment, the second charging and discharging circuit comprises: a charging and discharging circuit formed by a second power supply, a third resistor, a fourth resistor, a second capacitor, and a ground; wherein one end of the third resistor is electrically connected to the power supply, the other end is electrically connected to the fourth resistor electrically connected to the output terminal of the first comparator, one end of the second capacitor is electrically connected to the common connection point of the third resistor and the fourth resistor, and the other end of the second capacitor is grounded.

[0018] In an embodiment, the controller protection trigger module comprises: a second voltage dividing circuit for generating a third reference voltage level; a third comparator, the inverting input terminal of which inputs the third reference voltage level as a potential reference, and the non-inverting input terminal of which inputs the steady state voltage value output by the charging and discharging module and compares it with the third reference voltage level; when the steady state voltage value is higher than the third reference voltage level, the third comparator outputs a high level signal to the control circuit electrically connected thereto, so as to provide real-time protection for the DC charging pile.

[0019] In an embodiment, the third reference voltage level ranges from 0 to 5V.

[0020] In one embodiment, the control circuit is a digital signal processor integrated circuit, which includes a micro control unit, a microprocessor or other integrated circuits with similar functions.

[0021] In one embodiment, the control circuit controls a relay to disconnect the DC power supply unit in the DC charging station from the battery of the electric vehicle, and the DC charging station provides real-time protection.

[0022] In one embodiment, the preset time period is less than 30 ms.

[0023] In one embodiment, the first steady-state voltage value ranges from 0 to 9 V, and the second steady-state voltage value is 12 V. BRIEF DESCRIPTION OF DRAWINGS

[0024] The components, features, and advantages of the present application can be better understood from the detailed description that follows, taken in conjunction with the accompanying drawings, in which:

[0025] Figure 1(A) depicts a simplified system architecture of a DC charging station charging an electric vehicle in the prior art.

[0026] Figure 1(B) depicts a control guide circuit schematic of a DC charging station charging an electric vehicle in the prior art.

[0027] Figure 2(A) shows the relationship between the CP point voltage signal and the change in the electrical connection between the DC charging station and the electric vehicle under normal conditions when the DC charging station follows the CCS protocol procedure.

[0028] Figure 2(B) shows the relationship between the CP point voltage signal and the change in the electrical connection between the DC charging station and the electric vehicle under abnormal conditions (loose condition) when the DC charging station follows the CCS protocol procedure.

[0029] Figure 3(A) shows a schematic diagram of a configuration in which a detection circuit is arranged in a DC charging station charging an electric vehicle according to a preferred embodiment of the present application.

[0030] Figure 3(B) shows a detailed configuration schematic of a detection circuit arranged in a DC charging station according to a preferred embodiment of the present application.

[0031] Figure 3(C) shows the charge-discharge curve generated by the first charging loop in the charge-discharge module through the CP potential discrimination module in the detection circuit when the electrical connection between the DC charging station and the electric vehicle is loose and generates an abnormal CP PWM signal according to a preferred embodiment of the present application.

[0032] Main component symbol explanation:

[0033] DC charging station 10

[0034] Communication unit-I 101

[0035] DC power supply unit 103

[0036] Isolation monitoring unit 105

[0037] Main switch / relay 107

[0038] Electric vehicle 20

[0039] Communication unit-II 201

[0040] High voltage system 203

[0041] Disconnecting device 205

[0042] Detection circuit 140

[0043] Control circuit 149

[0044] CP potential discrimination module 1401

[0045] Charge / discharge module 1402

[0046] Controller protection triggering module 1403

[0047] First comparator 145a

[0048] Second comparator 145b

[0049] Third comparator 145c

[0050] Curve 301 DETAILED DESCRIPTION

[0051] Some preferred embodiments of the present application will now be described in more detail. It should be appreciated, however, that the preferred embodiments of the present application are provided for purposes of illustration and description only, and are not intended to limit the present application. In addition, the present application can be implemented in a wide variety of other embodiments, except as explicitly described otherwise, the scope of the present application is not limited to the explicitly described embodiments.

[0052] Generally, Europe and North America use the Combined Charging System (CCS) charging interface, which adds two DC fast charging pins based on SAE J1772, and IEC 61581 as a global standard for electric vehicle charging interfaces, which specifies the basic standard for pilot connection electrical signals between the charging pile and the electric vehicle on-board charger (OBC) electronic device. The above communication interaction is used to ensure the physical connection between the two and communicate the power supply under certain conditions, such as chargeable capacity and ensure that there are no safety concerns.

[0053] Figure 1(A) depicts a simplified DC charging pile to electric vehicle charging system architecture, where the DC charging pile 10 includes: communication unit-I 101, DC power supply unit (including charging controller) 103, isolation monitoring unit 105, power supply interface (PP, PE, CP, N, L1, DC+, DC-), and main switch / relay 107, etc.; electric vehicle 20 includes: communication unit-II 201, high-voltage system (including battery) 203, disconnect device 205, and corresponding interface (PP, PE, CP, N, L1, DC+, DC-), etc., where the power supply interface N, L1 is not shown in the figure.

[0054] The DC charging pile uses Pulse Width Modulation (PWM) communication method to test the connection status of the DC charging pile and electric vehicle charging, and cable power supply. When the DC charging pile charges according to the CCS protocol, the DC charging pile 10 generates a control pilot (CP) digital communication signal to start the sequence, and the CP point will present different frequencies, duty cycles, and level differences according to different timing conditions. Traditionally, a function or test sequence is used in the DC charging pile 10, which proposes a sequence of test requirements and events / conditions that must be met, so that the electric vehicle 20 connected to the DC charging pile 10 tests and starts charging in sequence, the process is as follows: State A (electric vehicle 20 has not yet connected to DC charging pile 10), +12V; State B (electric vehicle has connected to charging pile, but has not yet prepared for charging), +9V; State C (electric vehicle 20 is connected to DC charging pile 10, preparing for charging), +6V; State D (electric vehicle 20 is connected to DC charging pile 10, preparing for charging, with ventilation requirements), +3V; and other states.

[0055] Referring to Fig. 1(B), the control pilot circuit of the DC charging station for charging the electric vehicle is depicted. In state A, the electric vehicle 20 is not connected to the DC charging station 10, and the switching switch S1 in the DC charging station 10 circuit is connected to the +12V DC power supply, and the voltage level of the CP point is detected to be +12V (the CP point of the DC charging station 10 is in an open state). In state B, the electric vehicle 20 is connected to the DC charging station 10, but is not ready for charging, and the oscillator generating circuit 121 in the DC charging station 10 is connected to the switching switch S1, i.e., connected to the +12V (1KHz, PWM signal) power supply, and the switching switch S2 in the control pilot circuit of the electric vehicle 20 is open, and in this state, the voltage level of the CP point is detected to be +9V (i.e., a loop (i.e., the control pilot circuit) is formed by +12V, S1, resistor R1', CP, diode D, R3', and PE, and the voltage level of the CP point in this loop is +9V), and a vehicle control circuit 207 is formed by diode D, S2, R2', R3', and PE, to confirm the compatibility of the electric vehicle 20 and the DC charging station 10. One example is that the DC charging station 10 requires authorization (e.g., RFID or mobile phone) to apply authorization to allow charging, but if such authorization is not provided, the DC charging station will not oscillate the control pilot signal. In state C, the DC charging station 10 will be provided with authorization to allow charging, and charging is enabled, and the switching switch S1 in the control pilot circuit of the DC charging station 10 circuit is connected to the oscillator generating circuit 121, to generate an oscillating pilot signal (1KHz + / -12V) provided to the control pilot circuit and causing the switching switch S1 and the oscillator generating circuit 121 to close, and the switching switch S2 in the control pilot circuit is closed, and a loop (the control pilot circuit) is formed by the + / -12V oscillating pilot signal, S1, resistor R1', CP, diode D, R3' / / R2' ( / / represents parallel connection), and PE, and the voltage level of the CP point in this loop is reduced to +6V. In state D, the electric vehicle is connected to the DC charging station, and is ready for charging, and when ventilation is required (usually in fast charging mode), a 270Ω resistor is additionally connected in parallel to the loop formed by the + / -12V oscillating pilot signal, S1, resistor R1', CP, diode D, R3' / / R2' ( / / represents parallel connection), and PE, so that the voltage level of the CP point in this loop is reduced to +3V.

[0056] Referring to Figs. 1(A)-(B), after the DC charging station 10 confirms the connection with the electric vehicle 20, the PP point is locked, so that the electric vehicle 20 charging interface is locked with the DC charging station 10 interface. According to the time sequence, the charging procedure is as follows. The communication unit-I 101 on the DC charging station 10 and the communication unit-II 201 on the electric vehicle establish communication (PLC, CP communication) to communicate charging condition limit variables, such as V out> 60V or the detection of electric vehicle 20 and DC charging pile 10 incompatible to stop charging program. When the electric vehicle 20 from state B to state C / D, at this time the DC charging pile 10 has entered the state of allowing charging, the high voltage system 203 of electric vehicle 20 is isolated and continues to return the isolation state, the DC charging pile 10 confirms the isolation detection success and "recognize" immediately with "Ready" reply to the communication unit-II 201 of electric vehicle 20, that is, the completion of the charging line detection. Then, the electric vehicle 20 requires pre-charging test, that is, the DC charging pile 10 provides DC power, current <2A, at this time the main switch / relay 107 of DC charging pile 10 is closed, when V out Less than the allowable safety range and current <2A, the battery voltage of electric vehicle is less than 20V, the electric vehicle closes the disconnect device 205, and then allows charging (including fast charging) in the next stage. When power down occurs, the electric vehicle 20 sends a request to the DC charging pile 10 to stop power output, and after the current is less than 1A, the electric vehicle opens (open circuit) the disconnect device 205, and then the DC charging pile opens the main switch / relay 107.

[0057] From the above description of the prior art, it can be seen that the CP signal actually plays a core role, and in various cases, the sequence of events / conditions required and must be met is controlled by the timing sequence, so that the electric vehicle connected to the charging pile tests and starts charging in sequence. Since the CP signal directly plays the role of judging the above-mentioned various states, directly affects the system performance and safety of the whole charging pile, therefore, correctly detecting the CP point voltage level is the most critical.

[0058] In addition, the DC charging pile charges according to the CCS protocol, when the CP point changes state, due to the detection of the time of the CP point state change transmitted by the software cannot catch up with the hardware response, it may cause the error condition (such as sudden short circuit or open circuit condition) to protect the situation. In view of the above situation, the present application designs a hardware circuit to realize the detection state protection.

[0059] When a DC charging station follows the CCS protocol, under normal circumstances, as shown in Figure 2(A), after charging is complete, the CP point voltage signal changes from State C to State B until the charging plug is removed from the electric vehicle, and the CP point voltage signal maintains a steady-state voltage of 12V. As shown in Figure 2(B), after charging is complete, the CP point voltage signal changes from State C to State B, maintains a steady-state voltage of 12V for a short period, and then generates a PWM signal. This situation should not occur. When the situation shown in Figure 2(B) occurs, the CP point is in an abnormal state, that is, a sudden open circuit occurs in the charging connection. Another situation is a sudden short circuit occurs in the charging connection, and the CP point voltage signal maintains a steady-state voltage of 0V. When the above-mentioned CP point abnormalities occur, they are all sudden and emergency situations, requiring the DC charging station to complete the protection action within the time defined by the relevant regulations.

[0060] At this time, as shown in Figure 2(B) State B, the voltage signal at point CP is initially within 5% of the PWM duty cycle during potential transformation. Therefore, it is necessary to develop relevant circuits for real-time detection and protection to prevent malfunctions that could damage related hardware, especially charging stations and electric vehicle batteries.

[0061] The most important aspect of developing this detection circuit is its focus on real-time detection and protection to prevent malfunctions. Therefore, this circuit must first be able to detect and determine the current state of the charging point (CP). For example, charging station regulations stipulate that when the charging plug becomes loose (mitigation), the charging current must drop to less than 5A within 30ms and the charging voltage must drop to less than 60V within 100ms.

[0062] This invention proposes a detection circuit 140 for detecting the voltage level of the CP point on the control guidance circuit, as shown in FIG3(A). The detection circuit 140 is electrically coupled to the oscillator generation circuit 121 (used as a CP signal generation circuit) via resistor R1′ and switch S1 to provide detection of abnormal CP signals when the electric vehicle 20 is connected to the DC charging pile 10, and outputs the detected CP signal to the control circuit 149. The control circuit 149 can control the operation of switch S1 and main switch / relay 107 based on the received CP signal, and can communicate with the communication unit-I 101.

[0063] In a preferred embodiment, the control circuit 149 is a digital signal processor integrated circuit (DSP IC), such as a microcontroller unit (MCU), a microprocessor, or other IC with similar functions.

[0064] The detection circuit 140 is implemented by improving the hardware circuitry so that the CP potential can be detected before the software when it is abnormal. This allows the hardware circuit to trigger the protection mechanism first, enabling the protection to be activated quickly enough to protect the entire charging pile. For circuit details, please refer to Figure 3(B). The detection circuit 140 includes a CP potential discrimination module 1401, a charging / discharging module 1402, and a controller protection trigger module 1403. The CP potential discrimination module 1401 includes a first voltage divider circuit formed by a +12V power supply, resistors R1, R2, R3, and a grounding point. This circuit generates two reference voltage levels: a first reference voltage level V... ref1 and the second reference voltage level V ref2 The aforementioned first reference voltage level V ref1 and the second reference voltage level V ref2 The inputs are respectively connected to the inverting input (-) of a first comparator 145a and the non-inverting input (+) of a second comparator 145b as a potential reference and the CP signal input. The non-inverting input (+) of the first comparator 145a and the inverting input (-) of the second comparator 145b are connected to input the CP signal, whose negative potential signal has been filtered out by a rectifier circuit (not shown). The charging / discharging module 1402 has two charging / discharging circuit branches, namely a first charging / discharging circuit and a second charging / discharging circuit. The first charging / discharging circuit includes a charging / discharging circuit formed by a +12V power supply (first power supply), resistor R4 (first resistor), resistor R5 (second resistor), a first diode D1 connected in parallel with R5 (R5 / / D1), a first capacitor C1, and a ground point. One end of resistor R4 (first resistor) is electrically connected to the +12V power supply, and the other end is electrically connected to the output of the first comparator 145a. R5... One end of D1 (the anode of D1) is electrically connected to the output of the first comparator 145a, and the other end of R5 / / D1 (the cathode of D1) is electrically connected to one end of the first capacitor C1, the other end of the first capacitor C1 is grounded; the second charging and discharging circuit includes a charging and discharging circuit formed by a +12V power supply (second power supply), resistor R6 (third resistor), resistor R7 (fourth resistor), a second capacitor C2, and a grounding point. One end of resistor R6 is electrically connected to the +12V power supply, and its other end is electrically connected to resistor R7, which is electrically connected to the output of the first comparator 145a. The common contact of resistors R6 and R7 is electrically connected to one end of the second capacitor C2, and the other end of the second capacitor C2 is grounded; the controller protection trigger module 1403 consists of a second voltage divider circuit and a third comparator 145c, wherein the second voltage divider circuit includes a +12V power supply, resistors R8 and R9, and a grounding point, used to input a third reference voltage level V. ref3 The aforementioned third reference voltage level V ref3The non-inverting input (+) of the third comparator 145c is electrically connected to the first and second charge-discharge circuits through a second diode D2 and a third diode D3, respectively, for inputting the voltage signal output by the charge-discharge module 1402. The output of the third comparator 145c is electrically connected to the control circuit 149 for controlling the operation of the switch S1 and the main switch / relay 107, thereby providing real-time protection for the charging pile and the battery of the electric vehicle. The second diode D2 and the third diode D3 can prevent signal backflow.

[0065] In an embodiment, the voltage value of the first reference voltage level V ref1 ranges from 0 to 11V; the voltage value of the second reference voltage level V ref2 ranges from 0 to 1V; and the voltage value of the third reference voltage level V ref3 ranges from 0 to 5V.

[0066] When the CP signal (after rectification and filtering) is input to the detection circuit 140, the voltage level of the CP signal is discriminated by the two (first and second) comparators (145a, 145b) in the CP potential discrimination module 1401. If the voltage level of the input CP signal is higher than V ref1 , the first comparator 145a outputs a high-level signal to start the first charge-discharge circuit. This corresponds to the situation shown in FIG. 2(B), where the CP point is in an abnormal state, i.e., the charging connection is suddenly disconnected and then restored to contact. The CP point signal will recover from +12V steady voltage (because of contact) to generate a 12V PMW signal. When this situation occurs, the first charging circuit, which is started and has at least a charge-discharge circuit composed of R5 / / D1 and a capacitor C1, has the characteristics of fast charging and slow discharging, so that the first charging circuit can charge the CP signal output by the first comparator 145a to a first steady voltage value V sat1 within a first time period t1. The steady voltage value V sat is input to the non-inverting input (+) of the third comparator 145c in the controller protection trigger module 1403 through D2, and the voltage level of the first steady voltage value V sat1 is higher than the three reference voltage levels V ref3 , so that the output of the third comparator 145c outputs a high-level signal to drive the control circuit electrically connected thereto and then disconnect the main switch / relay 107 between the DC power supply unit 103 of the DC charging pile 10 and the battery 203 of the electric vehicle 20, thereby providing real-time protection for the DC charging pile 10 and the battery 203.

[0067] In a preferred embodiment, the first time period t1 is less than 30 ms; the first steady state voltage value V sat1 is in the range of 0 to 9 V.

[0068] Similarly, when the CP signal (after rectification and filtering) is input into the detection circuit 140, the voltage level of the CP signal is discriminated by two (first and second) comparators (145a, 145b) in the CP potential discrimination module 1401. If the voltage level of the input CP signal is lower than V ref2 , the second comparator 145b outputs a high level signal to start the second charging and discharging circuit. In this case, the CP point has a short circuit abnormal state, and the CP point signal is a steady state voltage of 0 V. When this condition occurs, the second charging circuit that is started can charge the CP signal output by the second comparator 145b to a second steady state voltage value V sat2 in a very short time t2, i.e. a second time period, and the voltage level of the second steady state voltage value V sat2 is input into the non-inverting input terminal (+) of the third comparator 145c in the controller protection trigger module 1403 via D3, and the voltage level of the second steady state voltage value V sat2 is higher than the three reference voltage levels V ref3 , so that the output terminal of the third comparator 145c outputs a high level signal to drive the control circuit electrically connected thereto, and then disconnects the main switch / relay 107 between the DC power supply unit 103 in the DC charging post 10 and the battery 203 in the electric vehicle 20, thereby providing real-time protection for the DC charging post 10 and the battery 203.

[0069] In a preferred embodiment, the second time period t2 is less than 9 ms; and the second steady state voltage value is 12 V.

[0070] The CP potential discrimination module 1401 discriminates the voltage level of the input control pilot (CP) signal to start the charging and discharging module 1402, so that it charges the control pilot signal output by the CP potential discrimination module 1401 to be greater than a preset steady state voltage value within a preset time period (less than 30 ms), thereby starting the controller protection trigger module 1403 to provide real-time protection for the DC charging post. In a preferred embodiment, the preset steady state voltage value is one of the first steady state voltage value or the second steady state voltage value, depending on whether the first or second charging circuit is started.

[0071] When the CP signal (after rectification and filtering) is input into the detection circuit 140, the voltage level of the CP signal is discriminated by two (first and second) comparators (145a, 145b) in the CP potential discrimination module 1401. If the voltage level of the input CP signal is between V ref1 and V ref2 , i.e. Vref2 <CP<V ref1 , then the first and second charging circuits in the charge-discharge module 1402 will not be activated (triggered), and the previous state of the main switch / relay 107 connecting the DC power supply unit 103 in the DC charging pile 10 and the battery 203 in the electric vehicle 20 is maintained.

[0072] Figure 3 (C) shows a measured charge-discharge curve. When the DC charging pile and the electric vehicle are disconnected due to abnormal CP PWM signals, the first charging circuit in the charge-discharge module 1402 is activated by the CP potential discrimination module 1401 in the detection circuit 140, and the curve 301 is the charge-discharge curve of the output voltage of the first charging circuit changing with time. The curve shows that the first charging circuit has the characteristics of fast charging and slow discharging.

[0073] The above examples are only used to illustrate the technical solutions of the present application, and not to limit it; although the present application and its benefits are described in detail with reference to the foregoing examples, those skilled in the art should understand that the foregoing examples can be modified, or some technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the claims of the present application.

Claims

1. A detection circuit for controlling a guide point anomaly in a direct current charging pile, characterized in that, The detection circuit comprises: a control guide signal potential discrimination module; a charge-discharge module electrically connected to the control guide signal potential discrimination module; a controller protection trigger module electrically connected to the charge-discharge module; and The control guide signal potential discrimination module discriminates the voltage level of the input control guide signal to start the charge-discharge module to charge the control guide signal outputted from the control guide signal potential discrimination module to a preset steady voltage value within a preset time period, so as to start the controller protection trigger module to provide real-time protection for the direct current charging pile. The detection circuit is electrically connected to the control guide signal generation circuit and the control circuit of the direct current charging pile to provide abnormal state detection when the electric vehicle is electrically connected to the direct current charging pile and to provide real-time protection for the direct current charging pile. The control guide signal potential discrimination module comprises: a first voltage dividing circuit for generating two reference voltage levels, a first reference voltage level and a second reference voltage level; a first comparator; a second comparator; and a control guide signal input end. The charge-discharge module comprises: a first charge-discharge loop and a second charge-discharge loop. The first charge-discharge loop is electrically connected to the output end of the first comparator and the input end of the controller protection trigger module to provide a function of fast charging and slow discharging for the control guide signal outputted from the output end of the first comparator and to charge to a preset first steady voltage value within a first time period, so as to start the controller protection trigger module to provide real-time protection for the direct current charging pile. The second charge-discharge loop is electrically connected to the output end of the second comparator and the input end of the controller protection trigger module to provide a function of fast charging for the control guide signal outputted from the output end of the second comparator and to charge to a second preset steady voltage value within a second time period, so as to start the controller protection trigger module to provide real-time protection for the direct current charging pile. The controller protection trigger module comprises: a second voltage dividing circuit for generating a third reference voltage level; and a third comparator with the third reference voltage level inputted to the inverting input end as a potential reference and the preset steady voltage value outputted from the charge-discharge module inputted to the non-inverting input end for comparison.

2. The detection circuit for controlling the abnormality of the guide point in the direct current charging pile according to claim 1, wherein, The control guide signal potential discrimination module comprises: The first reference voltage level and the second reference voltage level are respectively inputted to the inverting input end of the first comparator and the non-inverting input end of the second comparator as potential references, and the control guide signal input end is electrically connected to the non-inverting input end of the first comparator and the inverting input end of the second comparator for inputting the control guide signal filtered by a rectifier circuit to remove the negative potential signal. The first reference voltage level is higher than the second reference voltage level.

3. The detection circuit for controlling the abnormality of the guide point in the direct current charging pile according to claim 2, characterized in that, The voltage value of the first reference voltage level ranges from 0 to 11V, and the voltage value of the second reference voltage level ranges from 0 to 1V.

4. The detection circuit for controlling the abnormality of the guide point in the direct current charging pile according to claim 2, characterized in that, The charge-discharge module comprises: ​ The preset steady-state voltage value is one of the first steady-state voltage value or the second steady-state voltage value.

5. The detection circuit for controlling the abnormality of the guide point in the direct current charging pile according to claim 4, characterized in that, The first charging and discharging circuit includes: a charging and discharging circuit formed by a first power supply, a first resistor, a second resistor, a first diode connected in parallel with the second resistor, a first capacitor, and a ground point, One end of the first resistor is electrically connected to the first power supply, and the other end is electrically connected to the output terminal of the first comparator. The anode end of the first diode in the parallel circuit of the second resistor and the first diode is electrically connected to the output terminal of the first comparator. The cathode end of the first diode in the parallel circuit is electrically connected to one end of the first capacitor, and the other end of the first capacitor is grounded.

6. The detection circuit for controlling the abnormality of the guide point in the direct current charging pile according to claim 4, characterized in that, The second charging and discharging circuit includes: a charging and discharging circuit formed by a second power supply, a third resistor, a fourth resistor, a second capacitor, and a ground point. One end of the third resistor is electrically connected to the second power supply, and the other end is connected to the fourth resistor electrically connected to the output terminal of the second comparator. The common point of the third resistor and the fourth resistor is electrically connected to one end of the second capacitor, and the other end of the second capacitor is grounded.

7. The detection circuit for controlling the guide point anomaly in the direct current charging pile according to claim 1, wherein, When the steady-state voltage value is higher than the third reference voltage level, the third comparator outputs a high level signal to the control circuit electrically connected thereto to provide real-time protection for the direct current charging pile.

8. The detection circuit for controlling the abnormality of the guide point in the direct current charging pile according to claim 7, characterized in that, The third reference voltage level ranges from 0 to 5V.

9. The detection circuit for controlling the abnormality of the guide point in the direct current charging pile according to claim 1, wherein, The control circuit is a digital signal processor integrated circuit, which includes a micro control unit or a microprocessor.

10. The detection circuit for controlling the abnormality of the guide point in the direct current charging pile according to claim 9, wherein, The control circuit controls a relay to disconnect the direct current power supply unit in the direct current charging pile from the battery of the electric vehicle, and the direct current charging pile provides real-time protection.

11. The detection circuit for controlling the abnormality of the guide point in the direct current charging pile according to claim 1, characterized in that, The preset time period is less than 30ms.

12. The detection circuit for controlling the abnormality of the guide point in the direct current charging pile according to claim 4, characterized in that, The first steady-state voltage value ranges from 0 to 9V, and the second steady-state voltage value is 12V.

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