Direct current charging guide isolation detection circuit

Abstract

The utility model relates to the field of charging piles, and provides a direct current charging guide isolation detection circuit, which comprises a power supply circuit, a voltage comparison conversion circuit and an optical coupler isolation module, the input end of the power supply circuit is connected with a power supply inside a charging pile, and the output end of the power supply circuit provides working voltage for the voltage comparison conversion circuit and the optical coupler isolation module. The input end of the voltage comparison and conversion circuit is connected with a CC1 signal returned by a charging gun, the output end of the voltage comparison and conversion circuit is connected with the input end of the optocoupler isolation module, the optocoupler isolation module is used for converting a voltage signal of the CC1 signal into a level sampling signal, and the output end of the optocoupler isolation module is connected with a control module of a charging pile. The photoelectric isolation module is used for carrying out photoelectric isolation on the level sampling signal; when a new energy automobile is charged, a charging pile end connection confirmation voltage signal is converted into a digital isolation signal, the anti-interference capability of sampling is improved, and the detection accuracy is ensured.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of charging pile, specifically, a direct current charging guide isolation detection circuit. BACKGROUND

[0002] With the development of science and technology and the demand of environmental protection and energy saving, new energy vehicles are more and more, and the application of vehicle charging pile is more and more widely, and it is particularly important to improve the safety of charging. It is necessary to make real-time judgment on the connection state of the charging gun and the vehicle charging port during the whole charging process, which is the safety guarantee of the interface connection. According to the national standard GB / T18487.1, the charging guide circuit is usually used to connect and confirm between the charging connector and the charging socket. The connection state between the charging gun and the vehicle charging port is confirmed by different voltage signals CC1. The stability and accuracy of CC1 signal are very important for the safety and reliability of the charging system.

[0003] If the CC1 signal is abnormal, it may cause the charging to be interrupted or the safety hidden danger to appear in the charging process. The existing charging pile mostly adopts direct connection sampling for CC1 signal. However, in the high-voltage and high-power scene of charging pile, the internal electrical equipment is more likely to produce great electromagnetic interference in the charging process. At this time, if the circuit is directly connected to the sampling, the signal is easy to be disturbed, which leads to inaccurate identification, and even causes the control system to collapse in serious cases. UTILITY MODEL CONTENT

[0004] The utility model solves the problem of how to provide a direct current charging guide isolation detection circuit for converting and isolating CC1 voltage signal.

[0005] In order to solve the above problems, the utility model provides a direct current charging guide isolation detection circuit, which comprises: a power supply circuit, a voltage comparison conversion circuit and an optical coupling isolation module. The input end of the power supply circuit is connected with the power supply inside the charging pile, and the output end provides working voltage for the voltage comparison conversion circuit and the optical coupling isolation module. The input end of the voltage comparison conversion circuit is connected with the CC1 signal transmitted back by the charging gun, and the output end is connected with the input end of the optical coupling isolation module, which is used for converting the voltage signal of the CC1 signal into a level sampling signal. The output end of the optical coupling isolation module is connected with the control module of the charging pile, which is used for photoelectric isolation of the level sampling signal.

[0006] Further, the voltage comparison conversion circuit comprises a first voltage dividing circuit, a signal sampling circuit, a first operational amplifier and a second operational amplifier, an input end of the first voltage dividing circuit is connected to an output end of the power supply circuit, after voltage dividing of an output voltage of the power supply circuit, a first voltage dividing point and a second voltage dividing point are formed, the first voltage dividing point and the second voltage dividing point are connected to reverse input ends of the first operational amplifier and the second operational amplifier respectively, an input end of the signal sampling circuit is connected to a CC1 signal, an output end outputs a sampling voltage, when a charging gun head buckle is pressed, the sampling voltage is higher than the first voltage dividing point voltage, when the charging gun head is inserted into a charging gun seat and the buckle is not released, the sampling voltage is lower than the first voltage dividing point voltage and higher than the second voltage dividing point voltage, when the charging gun head is inserted into the charging gun seat and the buckle is released, the sampling voltage is lower than the second voltage dividing point voltage, same direction input ends of the first operational amplifier and the second operational amplifier are connected to the sampling voltage.

[0007] Further, the signal sampling circuit comprises a first resistor and a second resistor, a first end of the first resistor is connected to the CC1 signal, a first end of the second resistor is connected to a second end of the first resistor, and the sampling voltage is output, and a second end is connected to the ground.

[0008] Further, the first voltage dividing circuit comprises a third resistor, a fourth resistor and a fifth resistor, a first end of the third resistor is connected to the output end of the power supply circuit, a first end of the fourth resistor is connected to a second end of the third resistor, and the first voltage dividing point is formed, a second end of the fourth resistor is connected to a first end of the fifth resistor, and the second voltage dividing point is formed, and a second end of the fifth resistor is connected to the ground.

[0009] Further, the optocoupler isolation module comprises two optocoupler isolation circuits with the same structure, wherein an input end of a first optocoupler isolation circuit is connected to an output end of the first operational amplifier, and an input end of a second optocoupler isolation circuit is connected to an output end of the second operational amplifier.

[0010] Further, the first optocoupler isolation circuit comprises a first optocoupler transistor, a sixth resistor and a seventh resistor, an input end of the first optocoupler transistor is connected to the output end of the first operational amplifier through the sixth resistor, a first lead of an output end of the first optocoupler transistor is connected to a 3.3V voltage through the seventh resistor, and a second lead is connected to a receiving end of a control module of the charging pile.

[0011] Further, the power supply circuit comprises a DC-DC isolation conversion circuit and a voltage stabilizing circuit, an input end of the DC-DC isolation conversion circuit is connected to a power supply provided inside the charging pile, output ends of the DC-DC isolation conversion circuit provide 5V voltages to the voltage comparison conversion circuit and the voltage stabilizing circuit respectively, an input end of the voltage stabilizing circuit is connected to the 5V voltage, and output ends of the voltage stabilizing circuit provide 3.3V voltages to the voltage comparison conversion circuit and the optocoupler isolation module respectively.

[0012] Further, the DC-DC isolation conversion circuit comprises an isolation converter, a first capacitor, a second capacitor and a first inductor, a first end of the first inductor is connected with the power supply, a second end of the first inductor is connected with an input end of the isolation converter, the first capacitor is arranged between the first end of the first inductor and the ground, and the second capacitor is arranged between an output end of the isolation converter and the ground.

[0013] Further, the voltage stabilizing circuit comprises a low-dropout voltage stabilizer, a third capacitor and a fourth capacitor, an input end of the voltage stabilizer is connected with the output end of the isolation converter, an output end of the voltage stabilizer outputs a 3.3V voltage, the third capacitor is arranged between the input end of the voltage stabilizer and the ground, and the fourth capacitor is arranged between the output end of the voltage stabilizer and the ground.

[0014] Compared with the prior art, the utility model has the beneficial effects that:

[0015] After the CC1 signal is collected, the voltage comparison conversion circuit and the optocoupler isolation module perform voltage signal conversion on the CC1 signal through voltage division comparison conversion, form two stable high and low level digital signals output to the charging pile internal control module, avoid the voltage fluctuation when the CC1 signal receives external interference, and further reduce the interference influence through the isolation of the optocoupler, so that the charging pile can accurately identify the connection state between the charging gun and the vehicle charging port, and ensure the charging safety. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 It is the overall principle structure schematic view of the embodiment of the utility model;

[0017] Figure 2 It is the principle structure schematic view of the DC-DC isolation conversion circuit of the embodiment of the utility model;

[0018] Figure 3 It is the principle structure schematic view of the voltage stabilizing circuit of the embodiment of the utility model;

[0019] Figure 4 It is the principle structure schematic view of the voltage comparison conversion circuit and the optocoupler isolation module of the embodiment of the utility model. DETAILED DESCRIPTION

[0020] In order to make the above purpose, features and advantages of the utility model more obvious and easy to understand, the specific embodiments of the utility model are described in detail below with reference to the drawings.

[0021] In the description of the utility model, it is necessary to explain that, unless there is definite stipulation and limitation, the terms "arrange", "install", "connect", "connect" should be understood broadly, for example, it can be fixed connection, also can be detachable connection, or integrally connected, it can be mechanical connection, it can be direct connection, also can be indirect connection through intermediate medium, it can be the communication inside two elements, for ordinary skilled in the art, the specific meaning of the above terms in the utility model can be understood according to specific circumstances.

[0022] In the description of the present application, the description of the terms "embodiment", "one embodiment" and "one embodiment" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or embodiment are included in at least one embodiment or embodiment of the present application.In the present application, the illustrative description of the above terms does not necessarily refer to the same embodiment or embodiment.Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or embodiments in a suitable manner.

[0023] As Figure 1 The utility model provides a direct current charging guide isolation detection circuit, including: power supply circuit, voltage comparison conversion circuit and photoelectric isolation module, the input of power supply circuit connects the power supply inside charging pile, and the output provides working voltage for voltage comparison conversion circuit and photoelectric isolation module, the input of voltage comparison conversion circuit connects the CC1 signal that charging gun transmits back, and the output of voltage comparison conversion circuit is connected with the input of photoelectric isolation module, is used for converting the voltage signal of CC1 signal into level sampling signal, and the output of photoelectric isolation module is connected with the control module of charging pile, is used for photoelectric isolation to level sampling signal.

[0024] The power supply circuit includes a DC-DC isolation conversion circuit and a voltage stabilizing circuit. Figure 2 As shown in the figure, the DC-DC isolation conversion circuit includes a 5V-to-5V isolation converter U1, which can be B0505S-1WR3. Figure 3 As shown in the figure, the voltage stabilizing circuit includes a 5V-to-3.3V low-dropout voltage stabilizer U2, which can be LP5907-3.3. The 5V voltage provided by the internal circuit of the charging pile is filtered by the first inductor L1 and the first capacitor C1 and then provided to the isolation converter U1.

[0025] As shown in the figure, the voltage stabilizing circuit includes a 5V-to-3.3V low-dropout voltage stabilizer U2, which can be LP5907-3.3. Figure 4As shown, the CC1 signal input is sampled by the first resistor R1 and the second resistor R2, and then input to the non-inverting input terminals of the two operational amplifiers in U3, wherein the inverting input terminal of the first operational amplifier U3A is connected to the connection point of the third resistor R3 and the fourth resistor R4, and the inverting input terminal of the second operational amplifier U3B is connected to the connection point of the fourth resistor R4 and the fifth resistor R5; the output terminal of the first operational amplifier U3A is connected to the anode of the light-emitting diode in the first optocoupler transistor U4 through the sixth resistor R6, and the cathode of the light-emitting diode is connected to the isolated reference ground; the output terminal of the second operational amplifier U3B is connected to the anode of the light-emitting diode in the second optocoupler transistor U5 through the eighth resistor R8, and the cathode of the light-emitting diode is connected to the isolated reference ground; the collector of the first optocoupler transistor U4 is connected to the internal power supply 3.3V through the seventh resistor R7, and the emitter is connected to the internal power supply reference ground; the second optocoupler transistor U5 is connected to the internal power supply 3.3V through the ninth resistor R9, and the emitter is connected to the internal power supply reference ground.

[0026] The working principle of the utility model is as follows:

[0027] Taking the third resistor R3 as 10kΩ, the fourth resistor R4 as 4.7kΩ, and the fifth resistor R5 as 8.2kΩ as an example, the first and second voltage dividing points obtain 1.85V and 1.18V respectively; the CC1 signal is input to the operational amplifier after being divided by the first resistor R1 and the second resistor R2, and the ratio of the first resistor R1 and the second resistor R2 makes the voltage division of the CC1 signal at 6V lower than 1.85V and 4V lower than 1.18V.

[0028] According to the definition of GB / T 18487.1 standard, when the charging gun head is not in action, the CC1 signal is 6V, at this time, the non-inverting input voltage of the first operational amplifier U3A is less than the inverting input voltage, the operational amplifier output is low voltage, the light-emitting diode in the optocoupler transistor U4 is closed, the photoelectric transistor is closed, and IN1 is pulled up to the internal 3.3V; the non-inverting input voltage of the second operational amplifier U3B is greater than the inverting input voltage, the operational amplifier output is high voltage, the light-emitting diode in the optocoupler transistor U5 emits light, the photoelectric transistor is turned on, IN2 is pulled down to the internal ground level, and IN1 and IN2 are two level signals output to the charging pile control module;

[0029] When the charging gun head buckle is pressed down, the CC1 signal is 12V, the first operational amplifier U3A and the second operational amplifier U3B both output high voltage, the transistors in the optocoupler transistors U4 and U5 are all turned on, and IN1 and IN2 both output ground level;

[0030] When the charging gun head is inserted into the charging gun seat and the buckle is not released, the CC1 signal is 6V, the first operational amplifier U3A outputs low voltage, the inner transistor of the optocoupler transistor U4 is closed, IN1 is pulled up to 3.3V internally, the second operational amplifier U3B outputs high voltage, the inner transistor of the optocoupler transistor U5 is turned on, and IN2 is pulled low to the internal ground level.

[0031] When the charging gun head is inserted into the charging gun seat and the buckle is released, the CC1 signal is 4V, the first operational amplifier U3A and the second operational amplifier U3B both output low voltage, the inner transistors of the optocoupler transistors U4 and U5 are closed, IN1 and IN2 are pulled up to 3.3V internally, and high level is outputted.

[0032] In this way, the connection condition between the charging gun head and the gun seat can be accurately recognized by the charging pile through receiving the level condition of IN1 and IN2.

[0033] Although the present disclosure is disclosed as above, the protection scope of the present disclosure is not limited to this. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present disclosure, and these changes and modifications will fall within the protection scope of the present disclosure.

Claims

1. A direct current charging pilot isolation detection circuit, characterized by, The application relates to a power supply circuit, a voltage comparison conversion circuit and an optical coupling isolation module, wherein the input end of the power supply circuit is connected with a power supply inside a charging pile, the output end of the power supply circuit provides working voltage for the voltage comparison conversion circuit and the optical coupling isolation module, the input end of the voltage comparison conversion circuit is connected with a CC1 signal transmitted back by a charging gun, the output end of the voltage comparison conversion circuit is connected with the input end of the optical coupling isolation module, the voltage signal of the CC1 signal is converted into a level sampling signal, and the output end of the optical coupling isolation module is connected with a control module of the charging pile to realize photoelectric isolation of the level sampling signal. The voltage comparison conversion circuit comprises a first voltage dividing circuit, a signal sampling circuit, a first operational amplifier and a second operational amplifier, the input end of the first voltage dividing circuit is connected with the output end of the power supply circuit, the output voltage of the power supply circuit is divided to form a first voltage dividing point and a second voltage dividing point, the first voltage dividing point and the second voltage dividing point are respectively connected with the reverse input ends of the first operational amplifier and the second operational amplifier, the input end of the signal sampling circuit is connected with the CC1 signal, the output end outputs a sampling voltage, when a charging gun head buckle is pressed, the sampling voltage is higher than the voltage of the first voltage dividing point, when the charging gun head is inserted into a charging gun seat and the buckle is not released, the sampling voltage is lower than the voltage of the first voltage dividing point and higher than the voltage of the second voltage dividing point, when the charging gun head is inserted into the charging gun seat and the buckle is released, the sampling voltage is lower than the voltage of the second voltage dividing point, and the same direction input ends of the first operational amplifier and the second operational amplifier are connected with the sampling voltage.

2. The direct current charge pilot isolation detection circuit of claim 1, wherein, The signal sampling circuit comprises a first resistor and a second resistor, the first end of the first resistor is connected with the CC1 signal, the first end of the second resistor is connected with the second end of the first resistor and outputs the sampling voltage, and the second end is connected with the ground.

3. The direct current charge pilot isolation detection circuit of claim 2, wherein, The first voltage dividing circuit comprises a third resistor, a fourth resistor and a fifth resistor, the first end of the third resistor is connected with the output end of the power supply circuit, the first end of the fourth resistor is connected with the second end of the third resistor to form the first voltage dividing point, the second end of the fourth resistor is connected with the first end of the fifth resistor to form the second voltage dividing point, and the second end of the fifth resistor is connected with the ground.

4. The direct current charge pilot isolation detection circuit of claim 3, wherein, The optical coupling isolation module comprises two optical coupling isolation circuits with the same structure, wherein the input end of the first optical coupling isolation circuit is connected with the output end of the first operational amplifier, and the input end of the second optical coupling isolation circuit is connected with the output end of the second operational amplifier.

5. The direct current charge pilot isolation detection circuit of claim 4, wherein, The first optical coupling isolation circuit comprises a first optical coupling transistor, a sixth resistor and a seventh resistor, the input end of the first optical coupling transistor is connected with the output end of the first operational amplifier through the sixth resistor, the first lead line of the output end of the first optical coupling transistor is connected with a 3.3V voltage through the seventh resistor, and the second lead line is connected with the receiving end of the control module of the charging pile.

6. The direct current charge pilot isolation detection circuit of claim 5, wherein, ​ 7. The direct current charge pilot isolation detection circuit of claim 1, wherein, The power supply circuit comprises a DC-DC isolation conversion circuit and a voltage stabilizing circuit, an input end of the DC-DC isolation conversion circuit is connected with a power supply provided inside a charging pile, and an output end of the DC-DC isolation conversion circuit provides 5V voltage for the voltage comparison conversion circuit and the voltage stabilizing circuit respectively, an input end of the voltage stabilizing circuit is connected with the 5V voltage, and an output end of the voltage stabilizing circuit provides 3.3V voltage for the voltage comparison conversion circuit and the opto-isolator module respectively.

8. The direct current charge pilot isolation detection circuit of claim 7, wherein, The DC-DC isolation conversion circuit comprises an isolation converter, a first capacitor, a second capacitor and a first inductor, a first end of the first inductor is connected with the power supply, a second end of the first inductor is connected with an input end of the isolation converter, the first capacitor is arranged between the first end of the first inductor and the ground, and the second capacitor is arranged between an output end of the isolation converter and the ground.

9. The direct current charge pilot isolation detection circuit of claim 8, wherein, The voltage stabilizing circuit comprises a low-dropout voltage stabilizer, a third capacitor and a fourth capacitor, an input end of the voltage stabilizer is connected with the output end of the isolation converter, an output end of the voltage stabilizer outputs 3.3V voltage, the third capacitor is arranged between the input end of the voltage stabilizer and the ground, and the fourth capacitor is arranged between the output end of the voltage stabilizer and the ground.

Images