Output and zero cross detection circuit for alternating current charging pile and charging pile control system

Abstract

An output and zero-cross detection circuit for an AC charging pile and a charging pile control system, the output and zero-cross detection circuit comprises a first AC output end connected with a charging pile anode output end; the second alternating current output end is connected with the charging pile cathode output end; the voltage source is used for providing pull-up voltage; the optocoupler module comprises an optocoupler, the optocoupler comprises a signal transmitting end positive electrode, a signal transmitting end negative electrode, a signal receiving end positive electrode and a signal receiving end negative electrode, the signal transmitting end positive electrode of the optocoupler is connected with the first alternating current output end, and the signal transmitting end negative electrode of the optocoupler is connected with the second alternating current output end; the negative electrode of the signal receiving end of the optocoupler is grounded, and the positive electrode of the signal receiving end of the optocoupler is connected with a signal output port and the voltage source. According to the embodiment of the utility model, the output state of the charging pile is monitored, and the zero crossing point of the output voltage of the AC charging pile can be effectively detected.

Description

Technical Field

[0001] This utility model relates to the field of charging technology, specifically to an output and zero-crossing detection circuit and a charging pile control system for AC charging piles. Background Technology

[0002] With the rapid development of the new energy vehicle industry, AC charging piles, as an important charging infrastructure, have been widely used in public parking lots, residential areas, commercial complexes and other places. AC charging piles are mainly used to provide AC power for electric vehicles and work with on-board chargers to complete battery charging.

[0003] Existing AC charging piles typically use relays with feedback contacts or sampling via voltage transformers and operational amplifier circuits. However, relays with feedback contacts are limited in selection and expensive, while the voltage transformer + operational amplifier solution, although highly accurate, is complex and costly. For zero-crossing detection, the commonly used solution is operational amplifier sampling + comparator processing. Although it provides high-precision zero-crossing detection, it also leads to complex circuitry, large board area, redundancy in the overall design, and increased costs. Utility Model Content

[0004] In order to solve the above-mentioned problems in the existing technology, the purpose of this utility model is to provide an output and zero-crossing detection circuit and a charging pile control system for AC charging piles, which solves the redundancy of the overall circuit design in the existing technology and reduces costs.

[0005] The technical solution adopted in this utility model is as follows:

[0006] Firstly, an output and zero-crossing detection circuit for an AC charging pile is provided, including a positive output terminal and a negative output terminal of the charging pile, and...

[0007] The first AC output terminal is connected to the positive output terminal of the charging pile.

[0008] The second AC output terminal is connected to the negative output terminal of the charging pile.

[0009] A voltage source is used to provide pull-up voltage;

[0010] An optocoupler module includes an optocoupler comprising a positive terminal for transmitting a signal, a negative terminal for transmitting a signal, a positive terminal for receiving a signal, and a negative terminal for receiving a signal. The positive terminal for transmitting the signal of the optocoupler is connected to the first AC output terminal, and the negative terminal for transmitting the signal of the optocoupler is connected to the second AC output terminal. The negative terminal for receiving the signal of the optocoupler is grounded, and the positive terminal for receiving the signal of the optocoupler is connected to the signal output port and the voltage source.

[0011] Furthermore, the optocoupler module also includes a pull-up resistor, and the positive terminal of the signal receiving end of the optocoupler is connected to the voltage source through the pull-up resistor.

[0012] Optionally, a filtering unit is also included, one end of which is connected to the pull-up resistor and the positive terminal of the signal receiving end of the optocoupler, and the other end of which is connected to the negative terminal of the signal receiving end of the optocoupler and the ground terminal.

[0013] Furthermore, the filtering unit includes at least one filtering capacitor, one end of which is connected to the positive terminal of the signal receiving end of the optocoupler and the signal output port, and the other end of which is connected to the negative terminal of the signal receiving end of the optocoupler and the ground terminal.

[0014] Optionally, it also includes a current limiting protection unit, which is connected between the first AC output terminal and the optocoupler, and / or connected between the second AC output terminal and the optocoupler;

[0015] in,

[0016] The current limiting protection unit is used to limit the current flowing through the signal transmitting end of the optocoupler.

[0017] Furthermore, the current limiting protection unit includes a first resistor and / or a second resistor, wherein the first resistor is connected between the first AC output terminal and the positive terminal of the signal transmitting terminal of the optocoupler, and / or the second resistor is connected between the second AC output terminal and the negative terminal of the signal transmitting terminal of the optocoupler.

[0018] Optionally, it also includes at least one clamping diode, the cathode of which is connected between the first AC output terminal and the positive terminal of the signal transmitting terminal of the optocoupler, and the anode of which is connected between the second AC output terminal and the negative terminal of the signal transmitting terminal of the optocoupler.

[0019] Optionally, it also includes an MCU, wherein the signal output port is connected to the zero-crossing detection port of the MCU. When the AC charging pile is in the charging start-up state, the zero-crossing detection port of the MCU determines the zero-crossing point and outputs a detection signal according to the level flip of the signal output port.

[0020] Secondly, this utility model also proposes a charging pile control system, including the output and zero-crossing detection circuit and relay for AC charging piles as described above. The relay includes a common terminal, at least one switchable connection terminal, and a control terminal. The control terminal is used to output a detection signal according to the zero-crossing point to drive the connection or disconnection between the common terminal and the switchable connection terminal. The common terminal of the relay is connected between the second AC output terminal and the negative output terminal of the charging pile, and the connection terminal of the relay is connected between the first AC output terminal and the positive output terminal of the charging pile.

[0021] Furthermore, it also includes a relay driving module, which is used to convert the zero-crossing output detection signal into a relay control signal. The relay driving module is connected to the control terminal of the relay and outputs the relay control signal.

[0022] This utility model embodiment uses optocoupler isolation detection to monitor the output status of the charging pile and can effectively detect the zero-crossing point of the AC charging pile output voltage. Compared with the existing technology using a relay with feedback contact or voltage transformer + operational amplifier sampling scheme, the circuit structure is simpler and the cost is relatively lower. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the output and zero-crossing detection circuit for an AC charging pile according to this utility model.

[0025] Figure 2 This is a schematic diagram of a charging pile control system according to this utility model;

[0026] Figure 3 This is a circuit diagram of an output and zero-crossing detection circuit for an AC charging pile according to this utility model;

[0027] Figure 4 This is a voltage waveform diagram of the signal output port and the signal transmitting end of the optocoupler of this utility model.

[0028] Figure label:

[0029] 100. First AC output terminal;

[0030] 200, Second AC output terminal; VCC, Voltage source;

[0031] 300, optocoupler module; U1, optocoupler; R3, pull-up resistor;

[0032] 400, Filter unit; C1, Filter capacitor;

[0033] 500, Current limiting protection unit; R1, First resistor; R2, Second resistor;

[0034] D1, Clamping diode;

[0035] A1, Signal output port;

[0036] 600. Relay driver module; Detailed Implementation

[0037] The present invention will be further described in detail below with reference to the accompanying drawings.

[0038] This specific embodiment is merely an explanation of the present utility model and is not intended to limit the present utility model. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive element, but as long as they are within the scope of the claims of the present utility model, they are protected by patent law.

[0039] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0040] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0041] Reference Figure 1 This utility model embodiment provides an output and zero-crossing detection circuit for an AC charging pile, including:

[0042] The positive output terminal and the negative output terminal of the charging pile;

[0043] The first AC output terminal 100 is connected to the positive output terminal of the charging pile;

[0044] The second AC output terminal 200 is connected to the negative output terminal of the charging pile.

[0045] A voltage source VCC is used to provide the pull-up voltage; and

[0046] Optical coupler module 300 includes optical coupler U1, which includes a positive terminal for transmitting a signal, a negative terminal for transmitting a signal, a positive terminal for receiving a signal, and a negative terminal for receiving a signal. The positive terminal for transmitting a signal of optical coupler U1 is connected to the first AC output terminal 100, and the negative terminal for transmitting a signal of optical coupler U1 is connected to the second AC output terminal 200. The negative terminal for receiving a signal of optical coupler U1 is grounded, and the positive terminal for receiving a signal of optical coupler U1 is connected to the signal output port A1 and the voltage source VCC.

[0047] This utility model embodiment uses optocoupler U1U1 isolation detection to monitor the output status of the charging pile and can effectively detect the zero-crossing point of the AC charging pile output voltage. Compared with the existing technology using a relay with feedback contact or voltage transformer + operational amplifier sampling scheme, the circuit structure is simpler and the cost is relatively lower.

[0048] It should be noted that although this embodiment uses an AC charging pile system as an example, the technical solution of this utility model is not limited to this application scenario. It is also applicable to various AC power supply control systems, household or industrial electrical equipment, AC power protection devices, and other systems that require synchronous control based on AC signal zero-crossing detection. Therefore, those skilled in the art can make appropriate adjustments or extensions to the structure of this embodiment according to actual needs, which still fall within the protection scope of this utility model.

[0049] Reference Figure 3 In some embodiments, the optocoupler module 300 further includes a pull-up resistor R3. The positive terminal of the signal receiving end of the optocoupler U1 is connected to the voltage source VCC through the pull-up resistor R3. When the optocoupler U1 is not conducting, it can ensure that the positive terminal of the signal receiving end of the optocoupler U1 remains at a high level, prevent the signal from being floating, improve the stability of the signal, and enhance the anti-interference capability, ensuring that the MCU can correctly read the signal.

[0050] In this embodiment, the optocoupler module 300 is further illustrated with an example of a pull-up resistor R3. However, this embodiment is not limited to this. The optocoupler module 300 may include multiple pull-up resistors R3 to adapt to different circuit design requirements. For example, for signal processing units with different operating voltages or different input impedances, the pull-up resistors R3 can be adjusted or distributed according to the specific application to optimize signal quality and system compatibility.

[0051] In this embodiment, the positive terminal of the signal receiving end of the optocoupler U1 is connected to the voltage source VCC through the pull-up resistor R3 as an example. However, this embodiment is not limited to this. The pull-up resistor R3 can be replaced by other components, such as an active pull-up circuit, i.e., a MOSFET, a constant current source, or an IC with pull-up function, to further improve signal stability and adjust the pull-up current according to different operating environments to meet higher circuit reliability requirements.

[0052] Reference Figure 3 In some embodiments, a filtering unit 400 is also included. One end of the filtering unit 400 is connected to the pull-up resistor R3 and the positive terminal of the signal receiving end of the optocoupler U1, and the other end of the filtering unit 400 is connected to the negative terminal of the signal receiving end of the optocoupler U1 and the ground terminal. This can effectively suppress high-frequency interference, smooth the signal waveform, reduce the impact of noise on the signal output, and ensure that the zero-crossing detection signal read by the MCU is accurate and reliable.

[0053] Furthermore, the filtering unit 400 includes at least one filtering capacitor C1, one end of which is connected to the positive terminal of the signal receiving end of the optocoupler U1 and the signal output port A1, and the other end of which is connected to the negative terminal of the signal receiving end of the optocoupler U1 and the ground terminal.

[0054] In this embodiment, the filtering unit 400 includes a filtering capacitor C1 as an example. However, this embodiment is not limited to this. The filtering unit 400 may include multiple capacitors to optimize the filtering effect in different frequency ranges, or use a combination of capacitors with different capacitance values ​​to more effectively suppress noise and improve signal stability.

[0055] In this embodiment, the example is illustrated by connecting one end of the filter capacitor C1 to the positive terminal of the signal receiving end of the optocoupler U1 and the signal output port A1, and the other end of the filter capacitor C1 to the negative terminal of the signal receiving end of the optocoupler U1 and the ground terminal. However, this embodiment is not limited to this. As an example, the number of filter capacitors C1 is not limited to one; similarly, an LC filter circuit or an RC low-pass filter network can be used instead of the filter capacitor C1.

[0056] Reference Figure 3 In some embodiments, a current limiting protection unit 500 is further included, which is connected between the first AC output terminal 100 and the optocoupler U1, and / or connected between the second AC output terminal 200 and the optocoupler U1; wherein,

[0057] The current limiting protection unit 500 is used to limit the current flowing through the signal transmitting end of the optocoupler U1. By limiting the current flowing through the signal transmitting end of the optocoupler U1, the current limiting protection unit 500 prevents transient overcurrent from damaging the optocoupler U1 and improves the safety and reliability of the circuit. At the same time, the current limiting protection unit 500 can also suppress voltage fluctuations to a certain extent and improve signal stability.

[0058] Specifically, the current limiting protection unit 500 includes a first resistor R1 and / or a second resistor R2. The first resistor R1 is connected between the first AC output terminal 100 and the positive terminal of the signal transmitting terminal of the optocoupler U1, and / or the second resistor R2 is connected between the second AC output terminal 200 and the negative terminal of the signal transmitting terminal of the optocoupler U1.

[0059] In this embodiment, the current limiting protection unit 500 is described using an example of a first resistor R1 and a second resistor R2. However, this embodiment is not limited to this. The current limiting protection unit 500 can use multiple current limiting resistors connected in series or in parallel to adjust the current limiting effect according to specific application requirements. As an example, multiple resistors can be connected in series to share the voltage and improve the voltage withstand capability of the resistors; different numbers of current limiting resistors can also be used between the first AC output terminal 100 and the positive terminal of the signal transmitting terminal of the optocoupler U1 and / or between the second AC output terminal 200200 and the negative terminal of the signal transmitting terminal of the optocoupler U1 to optimize current control.

[0060] Reference Figure 3 In some embodiments, at least one clamping diode D1 is also included. The cathode of the clamping diode D1 is connected between the first AC output terminal 100 and the positive terminal of the signal transmitting terminal of the optocoupler U1, and the anode of the clamping diode D1 is connected between the second AC output terminal 200 and the negative terminal of the signal transmitting terminal of the optocoupler U1. The clamping diode D1 can provide reverse voltage clamping protection for the signal transmitting terminal of the optocoupler U1. When the AC voltage acts in reverse on the signal transmitting terminal of the optocoupler U1, the clamping diode D1 conducts, limiting the voltage within its forward conduction voltage range (the forward conduction voltage is generally around 0.7V), thereby preventing the optocoupler U1 diode from being subjected to excessively high reverse voltage and avoiding damage. In addition, the clamping diode D1 can also suppress transient high voltage surges, improving the reliability and stability of the circuit.

[0061] In some embodiments, the system also includes an MCU. The signal output port A1 is connected to the zero-crossing detection port of the MCU. When the AC charging pile is in the charging start-up state, the zero-crossing detection port of the MCU determines the zero-crossing point and outputs a detection signal according to the level flip of the signal output port A1, which can achieve accurate zero-crossing detection.

[0062] As an example, refer to Figure 2 and Figure 4 A charging pile control system is provided, including the output and zero-crossing detection circuit and relay for AC charging pile as described above. The relay includes a common terminal, at least one switchable connection terminal, and a control terminal. The control terminal is used to output a detection signal according to the zero-crossing point to drive the connection or disconnection between the common terminal and the switchable connection terminal. The common terminal of the relay is connected between the second AC output terminal 200 and the negative output terminal of the charging pile, and the connection terminal of the relay is connected between the first AC output terminal 100 and the positive output terminal of the charging pile.

[0063] In this embodiment, the MCU, acting as the processing unit of the charging pile control system, monitors the signal output of the optocoupler U1 to detect the zero-crossing point of the AC voltage output by the AC charging pile and controls the operation of the relay: When not charging, the relay is in the open state, there is no voltage at the signal transmitter of the optocoupler U1, the signal transmitter of the optocoupler U1 is not conducting, and the signal output port A1 is always at a high level. The zero-crossing detection port of the MCU also remains at a high level, indicating that the charging pile is not outputting voltage. The relay is not conducting, ensuring that the charging pile is in standby mode.

[0064] When the AC charging pile starts charging, the MCU receives the start command and controls the relay to close. After the relay closes, the signal transmitter of optocoupler U1 is connected to the AC voltage output by the AC charging pile. Due to the periodic change of the AC voltage, the signal transmitter of optocoupler U1 will conduct once every half cycle of the AC voltage. The waveform of the signal output port A1 shows an alternating high level for half a cycle and a low level for half a cycle. The MCU determines that the relay is closed and the charging pile is normally outputting voltage by detecting the level flip of the signal output port A1. The level flip position corresponds to the zero-crossing point of the AC voltage. At the same time, the relay switches its state according to the zero-crossing point signal to ensure that the relay is switched on and off at the zero-crossing point. Since the current is close to zero at the zero-crossing point, the current surge of the relay contacts is minimized, which can effectively reduce arcing, avoid relay contact burning, and improve the service life of the relay.

[0065] Furthermore, switching the relay state at the zero point can reduce electromagnetic interference and optimize the electromagnetic compatibility of the charging pile.

[0066] It should be noted that the zero-crossing output detection signal of the charging pile control system mentioned in this embodiment is the same as the zero-crossing output detection signal of the charging pile control circuit mentioned above, and the effect is the same.

[0067] Furthermore, it also includes a relay driver module 600, which is used to convert the zero-crossing output detection signal into a relay control signal. The relay driver module 600 is connected to the control terminal of the relay and outputs the relay control signal. To solve the technical problem that the MCU signal output capability is limited and may not be able to directly drive the relay, this embodiment sets up the relay driver module 600 to convert the zero-crossing output detection signal into a relay control signal and drive the relay control terminal to be turned on or off. On the basis of realizing signal logic conversion, the driving capability is further improved.

[0068] The above is only used to illustrate the technical solution of this utility model and not to limit it. Any other modifications or equivalent substitutions made by those skilled in the art to the technical solution of this utility model, as long as they do not depart from the spirit and scope of the technical solution of this utility model, should be covered within the scope of the claims of this utility model.

Claims

1. An output and zero-crossing detection circuit for an AC charging pile, characterized in that, Also includes: The first AC output terminal is connected to the positive output terminal of the charging pile. The second AC output terminal is connected to the negative output terminal of the charging pile. A voltage source is used to provide pull-up voltage; as well as An optocoupler module includes an optocoupler comprising a positive terminal for transmitting a signal, a negative terminal for transmitting a signal, a positive terminal for receiving a signal, and a negative terminal for receiving a signal. The positive terminal for transmitting the signal of the optocoupler is connected to the first AC output terminal, and the negative terminal for transmitting the signal of the optocoupler is connected to the second AC output terminal. The negative terminal for receiving the signal of the optocoupler is grounded, and the positive terminal for receiving the signal of the optocoupler is connected to the signal output port and the voltage source.

2. The output and zero-crossing detection circuit for AC charging piles according to claim 1, characterized in that, The optocoupler module also includes a pull-up resistor, and the positive terminal of the signal receiving end of the optocoupler is connected to the voltage source through the pull-up resistor.

3. The output and zero-crossing detection circuit for AC charging piles according to claim 2, characterized in that, It also includes a filtering unit, one end of which is connected to the pull-up resistor and the positive terminal of the signal receiving end of the optocoupler, and the other end of which is connected to the negative terminal of the signal receiving end of the optocoupler and the ground terminal.

4. The output and zero-crossing detection circuit for AC charging piles according to claim 3, characterized in that, The filtering unit includes at least one filtering capacitor. One end of the filtering capacitor is connected to the positive terminal of the signal receiving end of the optocoupler and the signal output port, and the other end of the filtering capacitor is connected to the negative terminal of the signal receiving end of the optocoupler and the ground terminal.

5. The output and zero-crossing detection circuit for AC charging piles according to claim 1, characterized in that, It also includes a current limiting protection unit, which is connected between the first AC output terminal and the optocoupler, and / or connected between the second AC output terminal and the optocoupler; wherein, The current limiting protection unit is used to limit the current flowing through the signal transmitting end of the optocoupler.

6. The output and zero-crossing detection circuit for AC charging piles according to claim 5, characterized in that, The current limiting protection unit includes a first resistor and / or a second resistor, wherein the first resistor is connected between the first AC output terminal and the positive terminal of the signal transmitting terminal of the optocoupler, and / or the second resistor is connected between the second AC output terminal and the negative terminal of the signal transmitting terminal of the optocoupler.

7. The output and zero-crossing detection circuit for AC charging piles according to claim 1, characterized in that, It also includes at least one clamping diode, the cathode of which is connected between the first AC output terminal and the positive terminal of the signal transmitting terminal of the optocoupler, and the anode of which is connected between the second AC output terminal and the negative terminal of the signal transmitting terminal of the optocoupler.

8. The output and zero-crossing detection circuit for an AC charging pile according to any one of claims 1 to 7, characterized in that, It also includes an MCU, and the signal output port is connected to the zero-crossing detection port of the MCU. When the AC charging pile is in the charging start-up state, the zero-crossing detection port of the MCU flips according to the level of the signal output port to determine the zero-crossing point and outputs a detection signal.

9. A charging pile control system, characterized in that, The device includes an output and zero-crossing detection circuit and a relay for an AC charging pile as described in any one of claims 1-8. The relay includes a common terminal, at least one switchable connection terminal, and a control terminal. The control terminal is used to output a detection signal based on the zero-crossing point to drive the connection or disconnection between the common terminal and the switchable connection terminal. The common terminal of the relay is connected between the second AC output terminal and the negative output terminal of the charging pile, and the connection terminal of the relay is connected between the first AC output terminal and the positive output terminal of the charging pile.

10. The charging pile control system according to claim 9, characterized in that, It also includes a relay drive module, which is used to convert the zero-crossing output detection signal into a relay control signal. The relay drive module is connected to the control terminal of the relay and outputs the relay control signal.

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