Alternating current power failure detection circuit of alternating current charging pile

Abstract

The utility model relates to an alternating current power failure detection circuit of an alternating current charging pile, and belongs to the field of detection circuits, the alternating current power failure detection circuit comprises a switch module used for conducting current of a positive half cycle of alternating current and stopping current of a negative half cycle of the alternating current, and the switch module is connected with an alternating current power supply phase line; and the alternating current power failure detection module is respectively connected with the alternating current power supply zero line and the switch module, generates high and low level conversion, and comprises a power failure detection end. According to the invention, direct real-time detection of the power failure condition of the AC side can be realized without AC-DC conversion.

Description

TECHNICAL FIELD

[0001] The application relates to the field of detection circuits, in particular to an alternating current power-off detection circuit of an alternating current charging pile. BACKGROUND

[0002] The alternating current power-off detection of the alternating current charging pile can process, save and return important data in the operation process of the charging pile in a timely manner when power failure (or power outage) occurs, so as to ensure the continuity and integrity of the charging pile operation data.

[0003] The alternating current power-off detection circuit of the existing alternating current charging pile needs to convert alternating current into direct current through an AC-DC conversion device, and then needs to pass through active or passive electronic devices for voltage reduction, so as to reduce the voltage to a signal suitable for the microprocessor to identify the level, and then identify the power-off state of the alternating current pile.

[0004] However, the existing charging pile power-off detection circuit has some defects, such as the need for a complex AC-DC conversion device, the occupation of a large circuit board area, the reduction of reliability due to many circuit elements, and the existence of safety risks; in addition, the fault of the voltage reduction element may cause high voltage to enter the low voltage area, and burn the electronic element; at the same time, the detection circuit indirectly judges whether the alternating current exists through the change of the direct current level, which has hysteresis and cannot monitor the alternating current power-off situation in real time. CONTENT OF THE INVENTION

[0005] In order to solve the problems existing in the prior art, the application provides an alternating current power-off detection circuit of an alternating current charging pile, which can directly and real-timely detect the power-off situation of the alternating current side without AC-DC conversion.

[0006] The application provides an alternating current power-off detection circuit of an alternating current charging pile, which adopts the following technical scheme:

[0007] An alternating current power-off detection circuit of an alternating current charging pile is used for power-off detection of the alternating current side of the alternating current charging pile, the alternating current side includes an alternating current power supply phase line and an alternating current zero line, and the alternating current power-off detection circuit of the alternating current charging pile includes:

[0008] A switch module for conducting the current of the positive half cycle of the alternating current and preventing the current of the negative half cycle of the alternating current, the switch module is connected with the alternating current power supply phase line;

[0009] An alternating current power-off detection module connected with the alternating current power supply zero line and the switch module respectively and generating high-low level conversion, and the alternating current power-off detection module includes a power-off detection end.

[0010] By adopting the technical scheme, when the AC side is normally powered by the AC power, one positive half cycle of current and one negative half cycle of current are generated in one cycle of the AC power, the switch module only allows the positive half cycle of current of the AC power to pass through the AC power-off detection module, and the negative half cycle of current of the AC power is prevented from passing through the AC power-off detection module, so that the power-off detection end connected with the AC power-off detection module can detect the change of the level, and when the high-low level change occurs, the normal power-on state is determined, and whether the AC power is in the power-off state can be determined without AC-DC conversion.

[0011] The application further provides that the AC power-off detection module comprises an optoelectronic coupler, a positive input terminal of the optoelectronic coupler is connected with the switch module, a negative input terminal of the optoelectronic coupler is connected with the AC neutral line, and an output terminal of the optoelectronic coupler is connected with the power-off detection end.

[0012] By adopting the technical scheme, the AC power can cause the level of the output terminal of the optoelectronic coupler to change alternately between high and low levels, and the change between high and low levels of the power-off detection end connected with the optoelectronic coupler can be detected, so that it is confirmed that the current AC power is not in the power-off state, and only one optoelectronic coupler is needed, that is, the light-emitting diode of the optoelectronic coupler emits light when current passes through, and is extinguished when there is no current, so that the power-off state of the AC power can be displayed, and the number of devices is saved.

[0013] The application further provides that the collector of the output triode of the optoelectronic coupler is connected with the power-off detection end, the collector of the output triode of the optoelectronic coupler is further connected with a power supply, and the emitter of the triode is grounded.

[0014] By adopting the technical scheme, when the positive half cycle of the AC power arrives, the collector pin of the output terminal of the optoelectronic coupler changes to 0V, and when the negative half cycle of the AC power arrives, the collector pin of the output terminal of the optoelectronic coupler changes to the voltage of the power supply, so that the change between high and low levels in the power-off detection end can be detected.

[0015] The application further provides that the switch module comprises a first diode, a positive terminal of the first diode is connected with the AC phase line, and a negative terminal of the first diode is connected with the positive input terminal of the optoelectronic coupler.

[0016] By adopting the technical scheme, only one first diode is needed to turn on or turn off the current of the AC side, so as to control the current entering the optoelectronic coupler, change the high-low level of the collector of the output terminal of the optoelectronic coupler, save the number of devices, reduce the cost of devices, reduce the area occupied by the circuit, and facilitate the layout of the circuit board.

[0017] The application further provides that the input end of the optoelectronic coupler is reversely connected in parallel with a second diode, the positive electrode of the second diode is connected with the negative electrode of the input end of the optoelectronic coupler and the zero line of the alternating current, and the negative electrode of the second diode is connected with the positive electrode of the input end of the optoelectronic coupler and the negative electrode of the first diode.

[0018] By adopting the above technical scheme, the reverse connection in parallel of the second diode and the optoelectronic coupler can avoid the input reverse voltage from exceeding the withstand voltage of the light-emitting diode inside the optoelectronic coupler.

[0019] The application further provides that the first protection module is arranged between the collector of the output triode of the optoelectronic coupler and the power supply.

[0020] By adopting the above technical scheme, the excessive current provided by the power supply can be avoided to damage the triode at the output end of the optoelectronic coupler.

[0021] The application further provides that the first protection module is a current-limiting resistor.

[0022] By adopting the above technical scheme, when the collector of the triode at the output end of the optoelectronic coupler is at a high level, the current-limiting resistor can limit the working current provided by the power supply to protect the optoelectronic coupler.

[0023] The application further provides that the second protection module is arranged between the positive electrode of the first diode and the phase line of the alternating current power supply.

[0024] By adopting the above technical scheme, the excessive current flowing into the phase line of the alternating current power supply can be avoided to damage the first diode.

[0025] The application further provides that the second protection module is a current-limiting resistor.

[0026] By adopting the above technical scheme, the current-limiting resistor can limit the current flowing into the first diode from the phase line of the alternating current power supply, so as to prevent the current from being too large to damage the first diode or other circuit elements.

[0027] In summary, the application has the following beneficial effects:

[0028] The present application reflects whether a power outage has occurred on the current AC side by observing whether a high-low level conversion occurs in the photoelectric coupler in the AC power loss detection module. There is no need to convert the AC power into DC power for detection, and only the first diode is used to conduct or cut off the current generated by the positive half-cycle conversion of the AC power, so that the high and low level changes are generated through the photoelectric coupler. By detecting the level state of the power loss detection end, it can be confirmed that there is no power loss on the current AC side. In addition, only one first diode is needed to control the current entering the photoelectric coupler, causing the high and low levels of the collector at the output end of the photoelectric coupler to alternately change, thereby reducing the number of components used, reducing costs, and improving circuit reliability. The circuit occupies a small area, which is convenient for circuit board layout. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the circuit structure of this application.

[0030] Reference numerals: 1. switch module; 2. AC power failure detection module; 3. first protection module; 4. second protection module. DETAILED DESCRIPTION

[0031] The following is combined with Figure 1 This application is described in further detail.

[0032] refer to Figure 1 In this embodiment, a circuit for detecting AC power loss in an AC charging pile using a photocoupler U8 is used to detect power loss on the AC side of the AC charging pile, which includes the AC power phase line Lin and the AC neutral line Nin. The AC power loss detection circuit for the AC charging pile includes a switch module 1 connected to the AC power phase line Lin, and an AC power loss detection module 2 connected to the AC power neutral line Nin and the switch module 1, respectively. The AC power loss detection module 2 includes a power loss detection terminal connected to the power-off pin of the main control chip. The AC power loss detection module 2 is configured to detect alternating high and low levels between the power phase line Lin and the AC neutral line Nin, and to provide feedback on the level changes at the power loss detection terminal. When the switch module 1 is powered on the AC side, it allows the current in the positive half-cycle of the AC power to pass through the AC power failure detection module 2, and prevents the current in the negative half-cycle of the AC power from passing through the AC power failure detection module 2. The AC power failure detection module 2 can detect the periodic changes of the AC power and feedback the alternating high and low level states to determine whether the AC power is in a power failure state.

[0033] Specifically, when the AC power on the AC side is normally supplied, since the switch module 1 only allows the current in the positive half-cycle of the AC power to pass through the AC power loss detection module 2, and prevents the current in the negative half-cycle of the AC power from passing through the AC power loss detection module 2, the AC power loss detection module 2 will alternate between high and low levels after current is conducted, and this is displayed through the power loss detection end, so that it can be determined that the current AC side is in a normal power-on state; and when the AC side is powered off, since no current enters the AC power loss detection module 2, the AC power loss detection module 2 cannot alternate between high and low levels, and thus the power loss detection end is always in a high level state, so that it can be determined that the current AC side is in a power-off state, thus achieving the determination of whether the AC power is in a power-off state without converting the AC power into DC power through an AC-DC conversion device.

[0034] Furthermore, the AC power loss detection module 2 includes a photocoupler U8. The positive input terminal of the photocoupler U8 is connected to the switch module 1. Current flows from the switch module 1 to the input terminal of the photocoupler U8. The negative input terminal of the photocoupler U8 is connected to the AC neutral line Nin. The output terminal of the photocoupler U8 is connected to the power loss detection terminal. When the positive half-cycle of the AC power passes through the switch module 1, the photodiode in the photocoupler U8 turns on and emits light, which stimulates the phototransistor at the output terminal of the photocoupler U8 to turn on, and the collector pin of the output terminal of the photocoupler U8 changes to a low level. When the negative half-cycle of the AC power is prevented from passing through the photocoupler U8 by the switch module 1, the photodiode of the photocoupler U8 does not emit light, and the phototransistor at the output terminal also does not turn on. The collector pin of the output terminal of the photocoupler U8 changes to a high level. This alternating high and low level can be detected at the power loss detection terminal. In addition, the light-emitting diode of the photocoupler U8 emits light when current passes through and goes out when there is no current. Then, through the flashing state of the photocoupler U8, it can be judged that the current AC power is not in a power-off situation, and the power-off detection end shows alternating high and low levels.

[0035] At the same time, only one optocoupler, U8, is required to detect AC power failures, eliminating the need for multiple components and reducing circuit board space. Furthermore, optocoupler U8 electrically isolates high and low voltages. Even if a component is damaged, the characteristics of optocoupler U8 prevent the high voltage from flowing into the low-voltage area and damaging it, thus protecting the low-voltage circuit and improving circuit safety.

[0036] Furthermore, the collector of the transistor at the output end of the photocoupler U8 is connected to the power-off detection end, and the collector of the transistor at the output end of the photocoupler U8 is also connected to the power supply VDD. The emitter of the transistor is grounded. When the transistor at the output end of the photocoupler U8 is excited and turned on, the collector pin of the output end of the photocoupler U8 becomes a low level, and the voltage of the pin is 0V; when the transistor at the output end of the photocoupler U8 is not turned on, the collector pin level of the output end of the photocoupler U8 becomes a high level, and the voltage of the pin is provided by VDD. Therefore, the power-off detection end connected to the transistor at the output end of the photocoupler U8 can detect the alternating change of high and low levels.

[0037] Furthermore, the switch module 1 includes a first diode D30, the positive electrode of the first diode D30 is connected to the AC power phase line Lin, and the negative electrode of the first diode D30 is connected to the positive electrode of the input end of the photoelectric coupler U8. Only one first diode D30 is required to turn on or off the current on the AC side, serving as a control switch for the photoelectric coupler U8 to perform alternating high and low conversion, controlling the current entering the photoelectric coupler U8, and realizing the conversion of the high and low levels of the collector at the output end of the photoelectric coupler. At the same time, it saves the number of settings of multiple devices, can reduce the cost of devices, reduce the area occupied by the circuit, and facilitate the layout of the circuit board.

[0038] In addition, the positive and negative poles of the input terminal of the photoelectric coupler U8 are connected in reverse parallel with a second diode D24. The positive pole of the second diode D24 is connected to the negative pole of the input terminal of the photoelectric coupler U8 and the AC neutral line Nin, and the negative pole of the second diode D24 is connected to the positive pole of the input terminal of the photoelectric coupler U8 and the negative pole of the first diode D30. The reverse parallel connection of the second diode D24 can prevent the input reverse voltage from exceeding the withstand voltage value of the light-emitting diode inside the photoelectric coupler U8, thereby protecting the photoelectric coupler U8 from being damaged.

[0039] Furthermore, a first protection module 3 is provided between the collector of the transistor at the output end of the photoelectric coupler U8 and the power supply VDD. The first protection module 3 can prevent the excessive current provided by the power supply VDD from damaging the transistor at the output end of the photoelectric coupler U8 when the current passes through the photoelectric coupler U8.

[0040] Furthermore, the first protection module 3 is a current limiting resistor, that is, Figure 1 The resistor R113 in the photocoupler can limit the operating current provided by the power supply VDD when the collector of the transistor at the output end of the photocoupler U8 is at a high level, thereby protecting the photocoupler U8.

[0041] Meanwhile, the positive pole of the first diode D30 and the phase line Lin of the alternating current power source are provided with the second protection module 4, and the second protection module 4 can avoid that the first diode D30 is damaged by the excessive current when the current provided by the phase line Lin of the alternating current power source passes through the first diode D30.

[0042] In addition, the second protection module 4 is a current limiting resistor, i.e. Figure 1 the resistor R116 in the current limiting resistor R116 can limit the excessive current when the current provided by the phase line Lin of the alternating current power source passes through the first diode D30, thereby protecting the first diode D30.

[0043] The implementation principle of the embodiment of the application is as follows: the phase line Lin and the zero line Nin of the alternating current power source establish a current path, when the positive half cycle of the alternating current flows through the switch module 1 and then the alternating current power failure detection module 2, the photoelectric diode in the photoelectric coupler U8 emits light to turn on, the photoelectric triode at the output end of the photoelectric coupler U8 is excited to turn on, and the collector pin at the output end of the photoelectric coupler U8 is changed to a low level of 0V; when the negative half cycle of the alternating current comes, the diode is unidirectionally turned on, at this time, the alternating current power failure detection module 2 cannot establish the current flow, the photoelectric diode of the photoelectric coupler U8 does not emit light, the photoelectric triode at the output end of the photoelectric coupler U8 is not turned on, and the collector pin of the photoelectric triode is at a high level and is the voltage of the power supply VDD. Therefore, when the alternating current is normally powered, the collector pin at the output end of the photoelectric coupler U8 is always in the alternating change of the high and low levels, and the change period is determined by the period of the alternating current; when the alternating current is powered off, at this time, no current flows through the alternating current power failure detection module 2, and the collector pin of the photoelectric triode at the output end of the photoelectric coupler U8 is always at a high level, and the high level state can be detected in the power failure detection end.

[0044] The above are the preferred embodiments of the application, and do not limit the protection scope of the application, so that: equivalent changes made according to the structure, shape, principle of the application should be covered in the protection scope of the application.

Claims

1. An AC power failure detection circuit for an AC charging pile, characterized in that: It is used to detect power failure on the AC side of the AC charging pile, where the AC side includes an AC power phase line and an AC neutral line. The AC power failure detection circuit of the AC charging pile includes: A switch module (1) for conducting current in the positive half cycle of alternating current and blocking current in the negative half cycle of alternating current, the switch module (1) being connected to the phase line of the alternating current power supply; An AC power failure detection module (2) is connected to the AC power neutral line and the switch module (1) respectively and generates high and low level conversion. The AC power failure detection module (2) includes a power failure detection terminal.

2. The AC power failure detection circuit of the AC charging pile according to claim 1, characterized in that: The AC power failure detection module (2) comprises a photoelectric coupler, the positive input terminal of the photoelectric coupler is connected to the switch module (1), the negative input terminal of the photoelectric coupler is connected to the AC power neutral line, and the output terminal of the photoelectric coupler is connected to the power failure detection terminal.

3. The AC power failure detection circuit of the AC charging pile according to claim 2, characterized in that: The collector of the transistor at the output end of the photoelectric coupler is connected to the power-off detection end, the collector of the transistor at the output end of the photoelectric coupler is also connected to the power supply, and the emitter of the transistor is grounded.

4. The AC power failure detection circuit of the AC charging pile according to claim 2, characterized in that: The switch module (1) comprises a first diode, the anode of the first diode is connected to the AC power phase line, and the cathode of the first diode is connected to the anode of the input end of the photoelectric coupler.

5. The AC power failure detection circuit of the AC charging pile according to claim 2, characterized in that: A second diode is connected in reverse parallel to the positive and negative poles of the input end of the photoelectric coupler, the positive pole of the second diode is connected to the negative pole of the input end of the photoelectric coupler and the AC neutral line, and the negative pole of the second diode is connected to the positive pole of the input end of the photoelectric coupler and the negative pole of the first diode.

6. The AC power failure detection circuit of the AC charging pile according to claim 3, characterized in that: A first protection module (3) is also provided between the collector of the transistor at the output end of the photoelectric coupler and the power supply.

7. The AC power failure detection circuit of the AC charging pile according to claim 6, characterized in that: The first protection module (3) is a current limiting resistor.

8. The AC power failure detection circuit of the AC charging pile according to claim 4, characterized in that: A second protection module (4) is further provided between the positive electrode of the first diode and the AC power phase line.

9. The AC power failure detection circuit of the AC charging pile according to claim 8, characterized in that: The second protection module (4) is a current limiting resistor.

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