A circuit for reducing the standby power consumption of old charging piles

Abstract

The present invention provides a circuit for reducing the standby power consumption of old charging piles, belonging to the field of electric vehicle charging piles. The present invention includes an AC contactor and an AC contactor control circuit, wherein the normally open contacts of the AC contactor are connected in series between the power grid and the input end of the charging pile power module, and the AC contactor control circuit includes: two comparators and a second controllable component, wherein the first comparator is used to compare the voltage of the connection confirmation signal CC1 with the first reference voltage, and the second comparator is used to compare the voltage of the connection confirmation signal CC1 with the second reference voltage, and when the voltage of CC1 is between the first reference voltage and the second reference voltage, the second controllable component is controlled to be turned on, so that the coil of the AC contactor is energized; when the voltage of CC1 is less than the first reference voltage or greater than the second reference voltage, the second controllable component is controlled to be turned off, so that the coil of the AC contactor is de-energized. The present invention can significantly reduce the standby power consumption of old charging piles.

Description

Technical Field

[0001] The invention relates to a circuit for reducing the standby power consumption of an old charging pile, and belongs to the field of electric vehicle charging piles. Background Art

[0002] During the rapid development of the charging pile industry, the charging pile standards have been formulated and revised many times. Due to historical reasons such as irregular market competition and unclear standards in the early stage, a large number of charging piles built in the early stage have encountered many problems in the current use process. For example, the control part and power module of the old charging piles are working at the same time when in standby mode, resulting in large standby power consumption of the old charging piles, which does not meet the requirements of the new national standard. Although the old charging piles can be directly replaced with new charging piles with lower standby power consumption, since these old charging piles have not yet reached their design life, if they are directly dismantled and rebuilt, a lot of manpower and material resources will be consumed. Therefore, it is expected that the problem of high standby power consumption can be solved by upgrading and renovating these old charging piles. Summary of the invention

[0003] The object of the present invention is to provide a circuit for reducing the standby power consumption of old charging piles, so as to solve the problem of high standby power consumption of old charging piles.

[0004] In order to achieve the above-mentioned purpose, the present invention provides a circuit for reducing the standby power consumption of old charging piles, including an AC contactor and an AC contactor control circuit, the normally open contacts of the AC contactor are connected in series between the power grid and the input end of the charging pile power module, the input signal of the AC contactor control circuit is the connection confirmation signal CC1 between the charging gun and the vehicle, and the output signal of the AC contactor control circuit is whether to allow the coil of the AC contactor to be energized; the AC contactor control circuit includes: two comparators and a second controllable component, the first comparator is used to compare the voltage of the connection confirmation signal CC1 with a first reference voltage, and the second comparator is used to compare the voltage of the connection confirmation signal CC1 with a second reference voltage, and the second controllable component is controlled to be turned on according to the comparison results of the two comparators, and then the second controllable component controls whether the coil of the AC contactor is energized; the second reference voltage is greater than the first reference voltage;

[0005] When the voltage of the connection confirmation signal CC1 is between the first reference voltage and the second reference voltage, the second controllable component is controlled to be turned on, so that the coil of the AC contactor is energized, and then the normally open contact of the AC contactor is closed, so that the charging pile power module is energized, and the charging pile power module works normally;

[0006] When the voltage of the connection confirmation signal CC1 is less than the first reference voltage or greater than the second reference voltage, the second controllable component is controlled to be turned off, so that the coil of the AC contactor is de-energized, and then the normally open contact of the AC contactor is disconnected, so that the charging pile power module is de-energized and the charging pile power module stops working.

[0007] The beneficial effect of the present invention is as follows: the present invention adds an AC contactor and an AC contactor control circuit to the input end of the power module of the old charging pile with high standby power consumption, and uses the connection confirmation signal CC1 between the charging gun on the charging pile and the vehicle to determine whether the charging pile is in working state or standby state. When it is determined that the charging pile is in standby state, the power supply of the power module is cut off, thereby achieving the purpose of reducing the standby power of the charging pile. Among them, two comparators are used to determine whether the voltage of the connection confirmation signal CC1 is between the first reference voltage and the second reference voltage. If so, it is determined that the charging pile is in working state. At this time, the normally open contact of the AC contactor is controlled to be closed to energize the power module, and the power module is used to charge the vehicle; if not, it is determined that the charging pile is in standby state. At this time, the normally open contact of the AC contactor is controlled to be disconnected to make the charging pile power module lose power, and the charging pile power module stops working. The present invention has the following advantages: it can be improved directly on the original old charging pile, without changing the power module and charging controller of the original charging pile and the original wiring harness, while keeping all the components of the original charging pile unchanged, and only an AC contactor and an AC contactor control circuit are added to the input end of the power module, and the labor cost and material cost are extremely low. After the improvement, the standby power consumption of the old charging pile with standby power consumption problem can be reduced by up to 90%.

[0008] Furthermore, in the above-mentioned circuit for reducing the standby power consumption of old charging piles, the AC contactor control circuit also includes a timer and a first controllable component. Whether the first controllable component is turned on is controlled according to the comparison results of the two comparators, and then the first controllable component controls the timer to output a high level or a low level, and the timer controls whether the second controllable component is turned on; wherein, when the voltage of the connection confirmation signal CC1 is obtained by comparison to be between the first reference voltage and the second reference voltage, the first controllable component is controlled to be turned on, so that the timer outputs a high level, and then the second controllable component is controlled to be turned on, so that the coil of the AC contactor is energized; when the voltage of the connection confirmation signal CC1 is obtained by comparison to be less than the first reference voltage or greater than the second reference voltage, the first controllable component is controlled to be turned off, so that the timer outputs a low level after a delay setting time, and then the second controllable component is controlled to be turned off, so that the coil of the AC contactor is de-energized.

[0009] The beneficial effect of doing so is that by adding a timer, the power module can be turned off with a delay to dissipate heat, which is beneficial to extending the service life of the power module.

[0010] Further, in the above-mentioned circuit for reducing the standby power consumption of old charging piles, the output ends of the first comparator and the second comparator are commonly connected to the control end of the first controllable component, the input end of the first controllable component is connected to the external power supply through a resistor, and the output end is grounded; the TH pin of the timer is connected to one end of the first capacitor, the other end of the first capacitor is grounded, and the TH pin of the timer is also connected to the input end of the first controllable component through the first branch and the second branch respectively; the first branch includes at least two resistors connected in series, and the second branch includes at least a diode and a resistor connected in series; the TR pin of the timer is connected to one end of the second capacitor, the other end of the second capacitor is grounded, and the TR pin of the timer is also connected to the input end of the first controllable component through a third branch, and the third branch includes at least one resistor;

[0011] When the first controllable component is turned on, the voltage of the timer TR pin is pulled down to a level lower than the trigger voltage of the timer TR pin, and at the same time, the first capacitor is discharged through the second branch, so that the voltage of the timer TH pin is reduced to below the trigger voltage of the timer TH pin, the timer TR pin is triggered, and the timer outputs a high level;

[0012] When the first controllable component is turned off, the voltage of the timer TR pin is pulled up to a level greater than the trigger voltage of the timer TR pin. At the same time, the external power supply charges the first capacitor through the first branch, so that the voltage of the timer TH pin increases. After the set time, the voltage of the timer TH pin increases to a level greater than the trigger voltage of the timer TH pin, the TH pin of the timer is triggered, and the timer outputs a low level.

[0013] Furthermore, in the above-mentioned circuit for reducing the standby power consumption of old charging piles, the AC contactor control circuit also includes an intermediate relay, and the second controllable component is used to control whether the coil of the intermediate relay is energized, and the normally open contact of the intermediate relay is connected in series with the coil of the AC contactor; when the second controllable component is turned on, the coil of the intermediate relay is energized, so that the normally open contact of the intermediate relay is closed, and the coil of the AC contactor is energized; when the second controllable component is turned off, the coil of the intermediate relay loses power, so that the normally open contact of the intermediate relay is disconnected, and the coil of the AC contactor loses power.

[0014] Furthermore, in the above-mentioned circuit for reducing the standby power consumption of old charging piles, the AC contactor control circuit also includes an operational amplifier; the connection confirmation signal CC1 is connected to the non-inverting terminal of the operational amplifier, and the inverting terminal of the operational amplifier is connected to the output terminal of the operational amplifier; the output terminal of the operational amplifier is connected to the non-inverting terminal of the first comparator through a first resistor divider circuit on the one hand, and is connected to the inverting terminal of the second comparator through a second resistor divider circuit on the other hand; the inverting terminal of the first comparator is connected to the first reference voltage, and the non-inverting terminal of the second comparator is connected to the second reference voltage.

[0015] Furthermore, in the above-mentioned circuit for reducing the standby power consumption of old charging piles, the first controllable component is a first transistor, the output ends of the first comparator and the second comparator are commonly connected to the base of the first transistor, the emitter of the first transistor is grounded, and the collector of the first transistor is connected to an external power supply via a resistor; the collector of the first transistor is connected to the first capacitor via the first branch and the second branch respectively on the one hand, and is connected to the second capacitor via the third branch on the other hand.

[0016] Furthermore, in the above-mentioned circuit for reducing the standby power consumption of old charging piles, the second controllable component is a second transistor, the output end of the timer is connected to the base of the second transistor, the emitter of the second transistor is grounded, and the collector of the second transistor is connected in series with the coil of the intermediate relay.

[0017] Furthermore, in the above-mentioned circuit for reducing the standby power consumption of old charging piles, the non-inverting end of the first comparator is also connected to the output end of the first comparator via a first resistor-capacitor parallel circuit.

[0018] Furthermore, in the above-mentioned circuit for reducing the standby power consumption of old charging piles, the non-inverting end of the second comparator is also connected to the output end of the second comparator via a second resistor-capacitor parallel circuit.

[0019] Furthermore, in the above-mentioned circuit for reducing the standby power consumption of old charging piles, the base of the first transistor is also grounded via a third resistor-capacitor parallel circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the connection between the AC contactor and its control circuit and the power module in the circuit embodiment of the present invention;

[0021] Figure 2 A circuit diagram of a circuit for reducing the standby power consumption of an old charging pile in a circuit embodiment of the present invention;

[0022] Figure 3 It is a connection diagram of the intermediate relay and the AC contactor in the circuit embodiment of the present invention. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0024] Circuit Example:

[0025] Through the study of the standby power consumption of the early old charging piles, it is found that the control part and the power module inside the early old charging piles are working at the same time when they are in standby mode. The standby power consumption of the old charging piles includes two parts: the standby power consumption of the control part and the standby power consumption of the power module. Among them, the maximum standby power consumption of the control part is about 200W. The standby power consumption of the power modules produced in the early stage is relatively large, and some single modules even reach 300W. According to the standby power consumption data of the old charging piles actually tested, the standby power consumption of the existing old charging piles is generally above 2KW, and some are even as high as 3KW. In fact, when the charging pile is in standby mode, only the interactive terminal connecting the charging pile and the operation platform and the charging controller of the charging pile itself are required to work, and the power module does not need to work when it is in standby mode. Therefore, if the power module of the old charging pile can be stopped when the charging pile is in standby mode, and the power module is started to charge the vehicle when the charging pile is charging the vehicle, the standby power consumption of the old charging pile will be greatly reduced.

[0026] Based on the above research results, this embodiment proposes a circuit for reducing the standby power consumption of old charging piles, such as Figure 1 As shown, the circuit includes an AC contactor and an AC contactor control circuit. The AC contactor includes a coil part and a normally open contact part. The normally open contact of the AC contactor is connected in series between the power grid and the input end of the charging pile power module. The input signal of the AC contactor control circuit is the connection confirmation signal CC1 between the charging gun and the vehicle. The output signal of the AC contactor control circuit is whether to energize the coil of the AC contactor. When it is detected that the voltage of the connection confirmation signal CC1 is between the first reference voltage and the second reference voltage, the AC contactor control circuit controls the coil of the AC contactor to be energized, the normally open contact of the AC contactor is closed, the charging pile power module is energized, and the power module works normally to charge the vehicle; when it is detected that the voltage of the connection confirmation signal CC1 is not between the first reference voltage and the second reference voltage (including the voltage of the connection confirmation signal CC1 is less than the first reference voltage or greater than the second reference voltage), the AC contactor control circuit controls the coil of the AC contactor to lose power, the normally open contact of the AC contactor is disconnected, the charging pile power module loses power, and the power module stops working.

[0027] According to the current national standard for charging piles: when the charging gun establishes a physical connection with the vehicle, the voltage of the connection confirmation signal CC1 is 4V, and the voltage error range is between 3.2V and 4.8V. When the charging gun is physically disconnected from the vehicle, the voltage of the connection confirmation signal CC1 is 12V; and when the charging gun is physically connected to the vehicle, it indicates that a vehicle has requested charging and the charging pile is in working state. At this time, the power module of the charging pile should be allowed to work normally to charge the vehicle. When the charging gun is physically disconnected from the vehicle, it indicates that no vehicle has requested charging and the charging pile is in standby state. At this time, the power supply of the power module can be cut off, thereby achieving the purpose of reducing the standby power consumption of the charging pile. Based on this, in this embodiment, the first reference voltage is set to 3.2V and the second reference voltage is set to 4.8V. It should be noted that the values ​​of the first and second reference voltages are set to cover the upper and lower limits of the voltage error range of the connection confirmation signal CC1. If the voltage error range of the connection confirmation signal CC1 between the charging gun and the vehicle changes when the charging gun is physically connected to the vehicle in the future, the values ​​of the first and second reference voltages need to be adaptively changed.

[0028] The AC contactor control circuit of this embodiment is as follows Figure 2 As shown, it includes: an operational amplifier U100, a first comparator (i.e., comparator U300), a second comparator (i.e., comparator U200), a timer U400, an intermediate relay, a first transistor (i.e., transistor Q1), a second transistor (i.e., transistor Q2), a first capacitor (i.e., capacitor C6), a second capacitor (i.e., capacitor C5), etc.; wherein,

[0029] The connection confirmation signal CC1 between the charging gun and the vehicle is connected to the in-phase terminal of the operational amplifier U100 via the resistor R1. The in-phase terminal of the operational amplifier U100 is also grounded via the capacitor C1 to filter out noise. The inverting terminal of the operational amplifier U100 is connected to the output terminal of the operational amplifier U100.

[0030] The output terminal of the operational amplifier U100 is connected to the non-inverting terminal of the comparator U300 through a first resistor voltage divider circuit (composed of resistors R3 and R4 connected in parallel) on the one hand, and is connected to the inverting terminal of the comparator U200 through a second resistor voltage divider circuit (composed of resistor R5) on the other hand;

[0031] The inverting terminal of the comparator U300 is connected to the first reference voltage (i.e., reference 1, which is 3.2V) via the resistor R2, and the non-inverting terminal of the comparator U300 is also connected to the output terminal of the comparator U300 via the first RC parallel circuit (composed of a resistor R8 and a capacitor C3 connected in parallel);

[0032] The in-phase terminal of the comparator U200 is connected to the second reference voltage (i.e., reference 2, which is 4.8V) via the resistor R6, and the in-phase terminal of the comparator U200 is also connected to the output terminal of the comparator U200 via the second RC parallel circuit (composed of a resistor R7 and a capacitor C2 connected in parallel);

[0033] The output ends of the comparator U300 and the comparator U200 are commonly connected to the base of the transistor Q1, the emitter of the transistor Q1 is grounded, and the collector of the transistor Q1 is connected to the external power supply 15VA via the resistor R11; the base of the transistor Q1 is also connected to the external power supply 15VA via the resistor R9, and the base of the transistor Q1 is also grounded via a third RC parallel circuit (composed of a parallel resistor R10 and a capacitor C4);

[0034] The collector of the transistor Q1 is connected to one end of the capacitor C6 (the other end of the capacitor C6 is grounded) through the first branch and the second branch respectively, and is also connected to one end of the capacitor C5 through the third branch (composed of a resistor R13), and the other end of the capacitor C5 is grounded; wherein the first branch is composed of resistors R12 and R16 connected in series, and the resistance values ​​of R12 and R16 are large; the second branch is composed of a diode D1 and resistors R14 and R15, and the resistance values ​​of R14 and R15 are very small, the resistors R14 and R15 are connected in parallel, the cathode of the diode D1 is connected to the collector of the transistor Q1, and the anode of the diode D1 is connected to the non-grounded end of the capacitor C6 through the parallel resistors R14 and R15; as other implementations, the circuit configurations in the first, second, and third branches can be adjusted according to actual needs, for example, the number of resistors in the branches can be adjusted; Figure 2 As shown, in this embodiment, the transistor Q1 has 4 pins, wherein the pin 4 and the pin 2 of Q1 are both the collector of Q1. In practical applications, a transistor with 3 pins may also be selected as Q1, and the transistor with 3 pins does not have the pin 4.

[0035] The TR pin (i.e., pin 2) of the timer U400 is connected to the non-grounded end of the capacitor C5, the TH pin (i.e., pin 6) of the timer U400 is connected to the non-grounded end of the capacitor C6, and the output end (i.e., pin 3) of the timer U400 is connected to the base of the transistor Q2 via the resistor R18;

[0036] The emitter of the transistor Q2 is grounded, the collector of the transistor Q2 is connected in series with the coil of the intermediate relay and the resistor R20 in sequence and then connected to the external power supply 15VA, and the base of the transistor Q2 is also grounded via a fourth resistor-capacitor parallel circuit (composed of a parallel resistor R19 and a capacitor C10);

[0037] The normally open contact of the intermediate relay is connected in series with the coil of the AC contactor.

[0038] Among them, the output status table of timer U400 is shown in Table 1:

[0039] Table 1 Output status table of timer U400

[0040]

[0041] In Table 1, 2 / 3VCC is the trigger voltage of the timer TH pin, 1 / 3VCC is the trigger voltage of the timer TR pin, and VCC is the power supply connected to the timer pin 8.

[0042] The working principle of the AC contactor control circuit is described in detail below:

[0043] (1) When the charging gun establishes a physical connection with the vehicle, the voltage range of the connection confirmation signal CC1 is 3.2V to 4.8V.

[0044] At this time, the outputs of comparator U300 and comparator U200 are both OC open (i.e., collector open). Under the action of the external power supply 15VA, transistor Q1 is turned on, and the voltage of pin 2 of timer U400 is pulled down to <1 / 3VCC. At the same time, capacitor C6 is rapidly discharged through resistors R14, R15 and diode D1, so that the voltage of pin 6 of timer U400 is rapidly reduced to <2 / 3VCC. Timer U400 outputs a high level, transistor Q2 is turned on, and the coil of the intermediate relay is energized, so that the normally open contact of the intermediate relay is closed, and then the coil of the AC contactor is energized, so that the normally open contact of the AC contactor is closed, and the power module of the charging pile is energized and starts working, and the charging pile starts to charge the vehicle.

[0045] (2) When the charging gun is physically disconnected from the vehicle, the voltage of the connection confirmation signal CC1 is higher than 4.8V.

[0046] At this time, the comparator U300 outputs OC open circuit, the comparator U200 outputs low level, and the transistor Q1 is turned off. Since the transistor Q1 is not conducting, the voltage of the pin 2 of the timer U400 quickly rises to >1 / 3VCC. At the same time, the external power supply 15VA charges the capacitor C6 through the resistors R11, R12, and R16. Since the resistance of R12 and R16 is very large, the charging speed of the capacitor C6 is very slow. The charging time needs to reach the set time t to charge the capacitor C6 to 2 / 3VCC. Therefore, before the charging time reaches the set time t, the voltage of the pin 6 of the timer U400 is always <2 / 3VCC. During this period, the pin 6 of the timer is When the voltage of pin 6 is <2 / 3VCC and the voltage of pin 2 is >1 / 3VCC, the timer keeps its original state and continues to output a high level. After the set time t is reached, the voltage of pin 6 of timer U400 rises to >2 / 3VCC. At this time, the voltage of pin 6 of timer U400 is >2 / 3VCC and the voltage of pin 2 is >1 / 3VCC. Timer U400 outputs a low level, transistor Q2 is turned off, the coil of the intermediate relay loses power, the normally open contact of the intermediate relay is disconnected, and then the coil of the AC contactor loses power, the normally open contact of the AC contactor is disconnected, the power module of the charging pile loses power and stops working, and the charging pile enters standby state.

[0047] (3) When the voltage of the connection confirmation signal CC1 is less than 3.2V due to abnormal reasons, the comparator U300 outputs a low level and the comparator U200 outputs OC open circuit. The working principle is the same as (2) and will not be repeated here.

[0048] This embodiment takes into account that during the process of charging the vehicle, the power module outputs a large current to charge the vehicle, which will cause the temperature of the power module to be very high. In order to extend the service life of the power module, after the charging gun is physically disconnected from the vehicle, the cooling fan is allowed to continue to work for a period of time to allow the temperature of the power module to drop, and then the power module is controlled to be powered off. This embodiment uses transistor Q1 and timer U400 to achieve delayed shutdown of the power module, which is conducive to extending the service life of the power module.

[0049] To sum up, the circuit for reducing the standby power consumption of old charging piles in this embodiment adds an AC contactor and an AC contactor control circuit to the input end of the power module of the old charging pile with high standby power consumption, and uses the connection confirmation signal CC1 between the charging gun on the charging pile and the vehicle to determine whether there is a vehicle requesting charging. When the voltage of the connection confirmation signal CC1 is between 3.2V and 4.8V, it indicates that the charging gun and the vehicle have established a physical connection, then it is determined that a vehicle requests charging and the charging pile is in working state. At this time, the power module is powered on by controlling the normally open contacts of the AC contactor to close, and the vehicle is charged by the power module; when the voltage of the connection confirmation signal CC1 is 12V, it indicates that the physical connection between the charging gun and the vehicle is disconnected, then it is determined that no vehicle requests charging and the charging pile is in standby state. At this time, the normally open contacts of the AC contactor are controlled to be disconnected to cut off the power supply of the power module, thereby achieving the purpose of reducing the standby power loss of the charging pile.

[0050] The circuit of this embodiment for reducing the standby power consumption of old charging piles has the following advantages: it can be improved directly on the original old charging piles, without changing the power module and charging controller of the original charging piles and the original wiring harness, while keeping all the components of the original charging piles unchanged, and only adding an AC contactor and an AC contactor control circuit to the input end of the power module can be achieved, with extremely low labor and material costs. After the improvement, the standby power consumption of old charging piles with standby power consumption problems can be reduced by up to 90%.

[0051] like Figure 3 As shown, the control signal of the intermediate relay in the figure is Figure 2 In the circuit shown in the figure, the control signal of the intermediate relay is whether the transistor Q2 is turned on. Figure 3 It can be seen that in this embodiment, the collector of the transistor Q2 is connected in series with the coil of the intermediate relay, and the normally open contact of the intermediate relay is connected in series with the coil of the AC contactor, so as to control whether the coil of the AC contactor is energized by controlling whether the coil of the intermediate relay is energized, thereby indirectly controlling the opening or closing of the normally open contact of the AC contactor; as other implementation methods, the intermediate relay can also be omitted. In this case, the collector of the transistor Q2 is directly connected in series with the coil of the AC contactor, so that whether the coil of the AC contactor is energized can be directly controlled according to whether the transistor Q2 is turned on, thereby directly controlling the opening or closing of the normally open contact of the AC contactor.

[0052] As other implementation methods, if the delayed shutdown function of the power module is not needed in actual applications, related devices such as the transistor Q1 and the timer U400 can be omitted. At this time, the output ends of the comparators U300 and U200 can be directly used to control the base of the transistor Q2. The collector of the transistor Q2 is directly connected in series with the coil of the intermediate relay. Whether the coil of the intermediate relay is energized is controlled according to whether the transistor Q2 is turned on, and then whether the coil of the AC contactor is energized is controlled.

[0053] As another implementation, the transistor may be replaced by other controllable components, for example, the transistor may be replaced by a field effect transistor.

[0054] As another implementation, if the connection confirmation signal does not need to increase the driving capability in actual applications, the operational amplifier U100 can be omitted.

Claims

1. A circuit for reducing the standby power consumption of old charging piles, characterized in that: It includes an AC contactor and an AC contactor control circuit. The normally open contacts of the AC contactor are connected in series between the power grid and the input end of the charging pile power module. The input signal of the AC contactor control circuit is the connection confirmation signal CC1 between the charging gun and the vehicle. The output signal of the AC contactor control circuit is whether to energize the coil of the AC contactor. The AC contactor control circuit includes: two comparators, a timer, a first controllable component and a second controllable component, the output ends of the two comparators are commonly connected to the control end of the first controllable component, the input end of the first controllable component is connected to the external power supply and the output end via a resistor, the other end of the first capacitor is grounded, and the TH pin of the timer is also connected to the input end of the first controllable component through the first branch and the second branch respectively; the first branch includes a resistor or a plurality of resistors connected in series, and the second branch includes at least a diode and a resistor connected in series; the TR pin of the timer is connected to one end of the second capacitor, and the other end of the second capacitor is grounded, and the TR pin of the timer is also connected to the input end of the first controllable component through a third branch, and the third branch includes at least one resistor; the first comparator is used to compare the voltage of the connection confirmation signal CC1 with the first reference voltage, and the second comparator is used to compare the voltage of the connection confirmation signal CC1 with the second reference voltage; the second reference voltage is greater than the first reference voltage; When the voltage of the connection confirmation signal CC1 is obtained by comparison to be between the first reference voltage and the second reference voltage, the first controllable component is controlled to be turned on, the voltage of the timer TR pin is pulled down to be less than the trigger voltage of the timer TR pin, and at the same time, the first capacitor is discharged through the second branch, so that the voltage of the timer TH pin is reduced to below the trigger voltage of the timer TH pin, the TR pin of the timer is triggered, and the timer outputs a high level, thereby controlling the second controllable component to be turned on, so that the coil of the AC contactor is energized, and then the normally open contact of the AC contactor is closed, so that the charging pile power module is energized, and the charging pile power module works normally; When the voltage of the connection confirmation signal CC1 is less than the first reference voltage or greater than the second reference voltage, the first controllable component is controlled to be turned off, and the voltage of the timer TR pin is pulled up to a level greater than the trigger voltage of the timer TR pin. At the same time, the external power supply charges the first capacitor through the first branch, so that the voltage of the timer TH pin increases. After the set time, the voltage of the timer TH pin increases to a level greater than the trigger voltage of the timer TH pin, and the TH pin of the timer is triggered, and the timer outputs a low level, thereby controlling the second controllable component to be turned off, de-energizing the coil of the AC contactor, and disconnecting the normally open contact of the AC contactor, de-energizing the charging pile power module, and stopping the charging pile power module from working.

2. The circuit for reducing the standby power consumption of old charging piles according to claim 1, characterized in that: The AC contactor control circuit also includes an intermediate relay, and the second controllable component is used to control whether the coil of the intermediate relay is energized, and the normally open contact of the intermediate relay is connected in series with the coil of the AC contactor; when the second controllable component is turned on, the coil of the intermediate relay is energized, so that the normally open contact of the intermediate relay is closed, and then the coil of the AC contactor is energized; when the second controllable component is turned off, the coil of the intermediate relay is de-energized, so that the normally open contact of the intermediate relay is opened, and then the coil of the AC contactor is de-energized.

3. The circuit for reducing the standby power consumption of old charging piles according to claim 2 is characterized in that: The AC contactor control circuit also includes an operational amplifier; the connection confirmation signal CC1 is connected to the non-inverting terminal of the operational amplifier, and the inverting terminal of the operational amplifier is connected to the output terminal of the operational amplifier; the output terminal of the operational amplifier is connected to the non-inverting terminal of the first comparator through a first resistor voltage divider circuit on the one hand, and is connected to the inverting terminal of the second comparator through a second resistor voltage divider circuit on the other hand; the inverting terminal of the first comparator is connected to the first reference voltage, and the non-inverting terminal of the second comparator is connected to the second reference voltage.

4. The circuit for reducing the standby power consumption of old charging piles according to claim 3 is characterized in that: The first controllable component is a first transistor, the output ends of the first comparator and the second comparator are commonly connected to the base of the first transistor, the emitter of the first transistor is grounded, and the collector of the first transistor is connected to an external power supply via a resistor; the collector of the first transistor is connected to the first capacitor via the first branch and the second branch respectively on the one hand, and is connected to the second capacitor via the third branch on the other hand.

5. The circuit for reducing the standby power consumption of old charging piles according to claim 4, characterized in that: The second controllable component is a second triode, the output end of the timer is connected to the base of the second triode, the emitter of the second triode is grounded, and the collector of the second triode is connected in series with the coil of the intermediate relay.

6. The circuit for reducing the standby power consumption of old charging piles according to claim 5, characterized in that: The non-inverting terminal of the first comparator is also connected to the output terminal of the first comparator via a first resistor-capacitor parallel circuit.

7. The circuit for reducing the standby power consumption of old charging piles according to claim 6, characterized in that: The non-inverting terminal of the second comparator is also connected to the output terminal of the second comparator via a second resistor-capacitor parallel circuit.

8. The circuit for reducing the standby power consumption of old charging piles according to claim 7, characterized in that: The base of the first transistor is also grounded via a third RC parallel circuit.

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