Intelligent charging station operation and maintenance management system

Abstract

The application relates to the technical field of operation and maintenance management, and discloses a smart charging station operation and maintenance management system, which comprises a phase sequence monitoring circuit, the phase sequence monitoring circuit comprises resistors R1, a switching tube Q1, an optical coupler U1, a resistor R3 and a resistor R5, the first end of the resistor R1 is connected with a-phase electricity through a first voltage reduction circuit, the second end of the resistor R1 is connected with the first input end of the optical coupler U1, the second input end of the optical coupler U1 is connected with the first end of the switching tube Q1, the first end of the resistor R3 is connected with b-phase electricity through a second voltage reduction circuit, the second end of the resistor R3 is connected with the control end of the switching tube Q1, the second end of the switching tube Q1 is connected with c-phase electricity through a third voltage reduction circuit, the first output end of the optical coupler U1 is connected with a 5V power supply through the resistor R5, the first output end of the optical coupler U1 is connected with the first input end of a master control unit, and the second output end of the optical coupler U1 is grounded. Through the technical scheme, the problem of unstable operation of the reverse phase monitoring circuit in the related art is solved.

Description

Technical Field

[0001] This invention relates to the field of operation and maintenance management technology, specifically to a smart charging station operation and maintenance management system. Background Technology

[0002] With the government's promotion and policy support for new energy vehicles, more and more people are choosing them as their mode of transportation. At the same time, this has created new demands for the construction and operation of charging infrastructure, requiring charging stations to improve network operation security and service convenience, and to achieve multi-channel service quality assurance and on-site resolution of service issues. The investment, construction, and sound operation of charging stations are essential guarantees for the development of the new energy electric vehicle industry, and the operation and maintenance management system of charging stations is the foundation supporting their normal operation. This system provides assurance for the normal operation of charging stations. Among these systems, online monitoring of power distribution at charging stations is a crucial component, supporting the operation and maintenance work. During the power grid's power supply process, reverse phase faults may occur. Under reverse phase sequence, equipment reduces power output, affecting the charging speed of charging piles and reducing charging efficiency, thus impacting the user experience. When a reverse phase fault occurs in the power grid, the relevant personnel should be notified promptly for maintenance to avoid affecting the normal use of charging piles. However, existing reverse phase monitoring circuits suffer from complex structures and unstable operation, leading to delays in the detection of reverse phase faults by staff. Summary of the Invention

[0003] This invention proposes a smart charging station operation and maintenance management system, which solves the problem of unstable operation of the reverse phase monitoring circuit in related technologies.

[0004] The technical solution of the present invention is as follows: The intelligent charging station operation and maintenance management system includes a phase sequence monitoring circuit, a main control unit, and a wireless communication unit. The phase sequence monitoring circuit is connected to the main control unit, and the main control unit communicates with a monitoring terminal via the wireless communication unit. The phase sequence monitoring circuit includes a resistor R1, a switch Q1, an optocoupler U1, a resistor R3, a resistor R4, and a resistor R5. The first end of the resistor R1 is connected to phase a through a first step-down circuit. The second end of the resistor R1 is connected to the first input terminal of the optocoupler U1, and the second input terminal of the optocoupler U1 is connected to the first end of the switch Q1. The first end of the resistor R3 is connected to phase b through a second step-down circuit, and the second end of the resistor R3 is connected to the control terminal of the switch Q1. The control terminal of the switch Q1 is connected to the second end of the switch Q1 through the resistor R4. The second end of the switch Q1 is connected to phase c through a third step-down circuit. The first output terminal of the optocoupler U1 is connected to a 5V power supply through the resistor R5. The first output terminal of the optocoupler U1 is connected to the first input terminal of the main control unit, and the second output terminal of the optocoupler U1 is grounded.

[0005] Furthermore, the present invention also includes a voltage monitoring circuit, which includes a current transformer T1, resistors R6, R7, R9, and R10, and an operational amplifier U5. The first input terminal of the current transformer T1 is connected to the phase voltage Va, the second input terminal of the current transformer T1 is connected to the neutral line, the first output terminal of the current transformer T1 is connected to the non-inverting input terminal of the operational amplifier U5 through the resistor R7, the second output terminal of the current transformer T1 is connected to a 2.5V voltage, the second output terminal of the current transformer T1 is connected to the inverting input terminal of the operational amplifier U5 through the resistor R9, the resistor R6 is connected in parallel between the first and second output terminals of the current transformer T1, the output terminal of the operational amplifier U5 is connected to the inverting input terminal of the operational amplifier U5 through the resistor R10, and the output terminal of the operational amplifier U5 is connected to the second input terminal of the main control unit.

[0006] Furthermore, the voltage monitoring circuit described in this invention also includes a resistor R11 and a capacitor C4. The first end of the resistor R11 is connected to the output terminal of the operational amplifier U5, the second end of the resistor R11 is grounded through the capacitor C4, and the second end of the resistor R11 is connected to the second input terminal of the main control unit.

[0007] Furthermore, the present invention also includes a temperature monitoring circuit, which includes a thermistor RT1, a resistor R21, a resistor R20, a transistor Q2, and a resistor R19. The first terminal of the thermistor RT1 is connected to a 5V power supply, and the second terminal of the thermistor RT1 is connected to the base of the transistor Q2. The first terminal of the resistor R21 is connected to a 5V power supply, and the second terminal of the resistor R21 is connected to the base of the transistor Q2. The base of the transistor Q2 is grounded through the resistor R20. The collector of the transistor Q2 is connected to a 5V power supply, and the emitter of the transistor Q2 is grounded through the resistor R19. The emitter of the transistor Q2 is connected to the third input terminal of the main control unit.

[0008] Furthermore, the present invention also includes a protection circuit, which includes an optocoupler U2, resistors R13 and R14, a switching transistor Q3, and a relay K1. The first input terminal of the optocoupler U2 is connected to a 5V power supply, the second input terminal of the optocoupler U2 is connected to the first output terminal of the main control unit, the first output terminal of the optocoupler U2 is connected to a 12V power supply through resistor R13, the second output terminal of the optocoupler U2 is connected to the control terminal of the switching transistor Q3 through resistor R14, the first terminal of the switching transistor Q3 is connected to the first input terminal of the relay K1, the second terminal of the switching transistor Q3 is grounded, the second input terminal of the relay K1 is connected to a 12V power supply, the normally closed terminal of the relay K1 is connected to the power grid, and the common terminal of the relay K1 is connected to a charging pile.

[0009] The working principle and beneficial effects of this invention are as follows: In this invention, the phase sequence monitoring circuit is used to monitor whether there is a reverse phase fault in the power grid supplying the charging station. When there is a reverse phase fault in the power grid, the phase sequence monitoring circuit sends the reverse phase fault to the main control unit in the form of an electrical signal. Then, the main control unit sends the fault signal to the monitoring terminal through the wireless communication unit so as to notify the relevant personnel to take corresponding maintenance measures.

[0010] The working principle of the phase sequence monitoring circuit is as follows: the first step-down circuit, the second step-down circuit, and the third step-down circuit convert the Va phase power, Vb phase power, and Vc phase power of the power grid into low-voltage AC signals with the same frequency as the three-phase AC power. Under normal power grid phase sequence, the a phase power leads the b phase power by 120°, the b phase power leads the c phase power by 120°, and the c phase power leads the c phase power by 120°.

[0011] Based on the characteristics of three-phase AC power, when the power grid phase sequence is normal, the simultaneous conduction time of switch Q1 and optocoupler U1 is relatively long. When optocoupler U1 is on, its first output terminal outputs a low level, meaning that the low level output time of optocoupler U1 is relatively long within one cycle. Therefore, when the power grid phase sequence is normal, the first input terminal of the main control unit receives a narrow pulse signal. When the power grid has a reverse phase sequence, assuming that phase c leads phase b, this results in a short simultaneous conduction time of switch Q1 and optocoupler U1 within one cycle. That is, the high level output time of optocoupler U1 is relatively long within one cycle. Therefore, when the power grid has a reverse phase sequence, the first input terminal of the main control unit receives a wide pulse signal.

[0012] When a phase is lost in the power grid, the switch Q1 will be turned off regardless of which phase is lost, and the optocoupler U1 will also be turned off. Therefore, when a phase is lost in the power grid, the optocoupler U1 outputs a high-level signal.

[0013] Compared with traditional phase sequence monitoring circuits, the circuit structure of this invention is simple. In addition, traditional phase sequence monitoring circuits can only monitor phase sequence, while phase loss monitoring requires additional circuits. The phase sequence monitoring circuit of this invention can simultaneously monitor phase sequence faults and phase loss faults of the power grid. Attached Figure Description

[0014] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0015] Figure 1 This is a circuit diagram of the phase sequence monitoring circuit in this invention; Figure 2 This is the output waveform diagram of the phase sequence monitoring circuit in this invention; Figure 3 This is a circuit diagram of the voltage monitoring circuit in this invention; Figure 4 This is a circuit diagram of the temperature monitoring circuit in this invention; Figure 5 This is a circuit diagram of the protection circuit in this invention. Detailed Implementation

[0016] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0017] Example 1 like Figures 1-2 As shown, this embodiment proposes a smart charging station operation and maintenance management system, including a phase sequence monitoring circuit, a main control unit, and a wireless communication unit. The phase sequence monitoring circuit is connected to the main control unit, and the main control unit communicates with the monitoring terminal through the wireless communication unit. The phase sequence monitoring circuit includes a resistor R1, a switch Q1, an optocoupler U1, a resistor R3, a resistor R4, and a resistor R5. The first end of the resistor R1 is connected to phase a through a first step-down circuit, and the second end of the resistor R1 is connected to the first input terminal of the optocoupler U1. The second input terminal of the optocoupler U1 is connected to the first end of the switch Q1. The first end of the resistor R3 is connected to phase b through a second step-down circuit, and the second end of the resistor R3 is connected to the control terminal of the switch Q1. The control terminal of the switch Q1 is connected to the second end of the switch Q1 through a resistor R4. The second end of the switch Q1 is connected to phase c through a third step-down circuit. The first output terminal of the optocoupler U1 is connected to a 5V power supply through a resistor R5. The first output terminal of the optocoupler U1 is connected to the first input terminal of the main control unit, and the second output terminal of the optocoupler U1 is grounded.

[0018] In this embodiment, the phase sequence monitoring circuit is used to monitor whether there is a reverse phase fault in the power grid supplying the charging station. When there is a reverse phase fault in the power grid, the phase sequence monitoring circuit sends the reverse phase fault to the main control unit in the form of an electrical signal. Then, the main control unit sends the fault signal to the monitoring terminal through the wireless communication unit so as to notify the relevant personnel to take corresponding maintenance measures.

[0019] Specifically, the working principle of the phase sequence monitoring circuit is as follows: the first step-down circuit, the second step-down circuit, and the third step-down circuit convert the Va phase power, Vb phase power, and Vc phase power of the power grid into low-voltage AC signals with the same frequency as the three-phase AC power. Under normal power grid phase sequence, the a phase power leads the b phase power by 120°, the b phase power leads the c phase power by 120°, and the c phase power leads the c phase power by 120°.

[0020] Based on the characteristics of three-phase AC power, when the power grid phase sequence is normal, the simultaneous conduction time of switch Q1 and optocoupler U1 is relatively long. When optocoupler U1 is on, its first output terminal outputs a low level, meaning that the low level output time of optocoupler U1 is relatively long within one cycle. Therefore, when the power grid phase sequence is normal, the first input terminal of the main control unit receives a narrow pulse signal. When the power grid has a reverse phase sequence, assuming that phase c leads phase b, this results in a short simultaneous conduction time of switch Q1 and optocoupler U1 within one cycle. That is, the high level output time of optocoupler U1 is relatively long within one cycle. Therefore, when the power grid has a reverse phase sequence, the first input terminal of the main control unit receives a wide pulse signal.

[0021] When a phase is lost in the power grid, the switch Q1 will be turned off regardless of which phase is lost, and the optocoupler U1 will also be turned off. Therefore, when a phase is lost in the power grid, the optocoupler U1 outputs a high-level signal.

[0022] Compared to traditional phase sequence monitoring circuits, the circuit structure of this embodiment is simple. In addition, traditional phase sequence monitoring circuits can only monitor phase sequence, while phase loss monitoring requires additional circuitry. The phase sequence monitoring circuit of this embodiment can simultaneously monitor both phase sequence faults and phase loss faults in the power grid.

[0023] In this embodiment, the first step-down circuit, the second step-down circuit, and the third step-down circuit are each composed of a step-down transformer.

[0024] like Figure 3As shown, this embodiment also includes a voltage monitoring circuit, which includes a current transformer T1, resistors R6, R7, R9, and R10, and an operational amplifier U5. The first input terminal of the current transformer T1 is connected to the Va phase power, and the second input terminal of the current transformer T1 is connected to the neutral line. The first output terminal of the current transformer T1 is connected to the non-inverting input terminal of the operational amplifier U5 through resistor R7. The second output terminal of the current transformer T1 is connected to a 2.5V voltage. The second output terminal of the current transformer T1 is connected to the inverting input terminal of the operational amplifier U5 through resistor R9. Resistor R6 is connected in parallel between the first and second output terminals of the current transformer T1. The output terminal of the operational amplifier U5 is connected to the inverting input terminal of the operational amplifier U5 through resistor R10. The output terminal of the operational amplifier U5 is connected to the second input terminal of the main control unit.

[0025] When a charging station's charging piles are charging an electric vehicle, significant fluctuations in the grid voltage can affect the charging piles' efficiency. Unstable charging voltage can also impact the battery. Therefore, monitoring the grid voltage is crucial. This embodiment includes three identical voltage monitoring circuits, each used to monitor the three phases of the grid. Taking phase a's voltage as an example: In this embodiment, the voltage of phase a is determined by the current of phase a. Current transformer T1 is used to monitor the current of phase a and convert the large current of alternating current into a small current output. The current signal output by current transformer T1 is converted into a voltage signal after passing through resistor R6. However, this voltage signal is an alternating positive and negative electrical signal. Operational amplifier U5 constitutes a voltage boosting circuit, which is used to convert the alternating positive and negative electrical signal into an electrical signal that varies from 0 to 5V and sends the signal to the main control unit. The main control unit determines whether the grid voltage is within a reasonable range based on the voltage signal.

[0026] like Figure 3 As shown, the voltage monitoring circuit in this embodiment also includes a resistor R11 and a capacitor C4. The first end of the resistor R11 is connected to the output terminal of the operational amplifier U5, the second end of the resistor R11 is grounded through the capacitor C4, and the second end of the resistor R11 is connected to the second input terminal of the main control unit.

[0027] In this embodiment, the electrical signal output by operational amplifier U5 may contain spike pulses. These spike pulses can cause misjudgments by the main control unit. The voltage of these spike pulses is very high, and they may also damage the main control unit. Therefore, a filter circuit is added to the output of operational amplifier U5 to make the electrical signal received by the main control unit more stable. The filter circuit consists of resistor R11 and capacitor C4.

[0028] like Figure 4As shown, this embodiment also includes a temperature monitoring circuit, which includes a thermistor RT1, resistors R21 and R20, a transistor Q2, and a resistor R19. The first end of the thermistor RT1 is connected to a 5V power supply, and the second end of the thermistor RT1 is connected to the base of the transistor Q2. The first end of resistor R21 is connected to a 5V power supply, and the second end of resistor R21 is connected to the base of the transistor Q2. The base of the transistor Q2 is grounded through resistor R20. The collector of the transistor Q2 is connected to a 5V power supply, and the emitter of the transistor Q2 is grounded through resistor R19. The emitter of the transistor Q2 is connected to the third input terminal of the main control unit.

[0029] In addition to phase sequence faults and voltage faults in the power grid, temperature can also affect the normal operation of charging piles. Temperature changes can cause changes in the output voltage of charging piles. Therefore, it is necessary to monitor the ambient temperature of the charging station and take corresponding temperature compensation measures based on the temperature changes to suppress the impact of temperature on charging piles.

[0030] Specifically, the working principle of the temperature monitoring circuit is as follows: Thermistor RT1 is used to monitor the ambient temperature. When the ambient temperature rises, the resistance of thermistor RT1 increases, the base current of transistor Q2 decreases, and the voltage across resistor R19 decreases. When the ambient temperature drops, the resistance of thermistor RT1 decreases, the base current of transistor Q2 increases, and the voltage across resistor R19 increases. The main control unit can determine the ambient temperature of the charging station based on the voltage across resistor R19.

[0031] like Figure 5 As shown, this embodiment also includes a protection circuit, which includes an optocoupler U2, resistors R13 and R14, a switching transistor Q3, and a relay K1. The first input terminal of the optocoupler U2 is connected to a 5V power supply, the second input terminal of the optocoupler U2 is connected to the first output terminal of the main control unit, the first output terminal of the optocoupler U2 is connected to a 12V power supply through resistor R13, the second output terminal of the optocoupler U2 is connected to the control terminal of the switching transistor Q3 through resistor R14, the first terminal of the switching transistor Q3 is connected to the first input terminal of the relay K1, the second terminal of the switching transistor Q3 is grounded, the second input terminal of the relay K1 is connected to a 12V power supply, the normally closed terminal of the relay K1 is connected to the power grid, and the common terminal of the relay K1 is connected to the charging pile.

[0032] When a phase sequence fault or abnormal voltage occurs in the power grid, relevant personnel should be notified immediately. At the same time, the connection between the power grid and the charging pile should be disconnected to avoid further impact on the charging pile or the battery of the electric vehicle.

[0033] When a phase sequence fault or abnormal voltage occurs in the power grid, the first output terminal of the main control unit outputs a low-level signal, the optocoupler U2 is turned on, the second output terminal of the optocoupler U2 outputs a high-level signal, the switching transistor Q3 is turned on, the relay K1 is energized and closed, and the normally closed terminal of the relay K1 is opened, thus disconnecting the connection between the power grid and the charging pile. The connection will be restored after the staff has resolved the fault.

[0034] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A smart charging station operation and maintenance management system, characterized in that, It includes a phase sequence monitoring circuit, a main control unit, and a wireless communication unit. The phase sequence monitoring circuit is connected to the main control unit, and the main control unit communicates with a monitoring terminal via the wireless communication unit. The phase sequence monitoring circuit includes resistor R1, switch Q1, optocoupler U1, resistors R3, R4, and R5. The first end of resistor R1 is connected to phase a through a first step-down circuit. The second end of resistor R1 is connected to the first input terminal of optocoupler U1. The second input terminal of optocoupler U1 is connected to the first end of switch Q1. The first end of resistor R3 is connected to phase b through a second step-down circuit. The second end of resistor R3 is connected to the control terminal of switch Q1. The control terminal of switch Q1 is connected to the second end of switch Q1 through resistor R4. The second end of switch Q1 is connected to phase c through a third step-down circuit. The first output terminal of optocoupler U1 is connected to a 5V power supply through resistor R5. The first output terminal of optocoupler U1 is connected to the first input terminal of the main control unit. The second output terminal of optocoupler U1 is grounded.

2. The intelligent charging station operation and maintenance management system according to claim 1, characterized in that, It also includes a voltage monitoring circuit, which comprises a current transformer T1, resistors R6, R7, R9, and R10, and an operational amplifier U5. The first input terminal of the current transformer T1 is connected to the phase voltage Va, and the second input terminal of the current transformer T1 is connected to the neutral line. The first output terminal of the current transformer T1 is connected to the non-inverting input terminal of the operational amplifier U5 through the resistor R7. The second output terminal of the current transformer T1 is connected to a 2.5V voltage. The second output terminal of the current transformer T1 is connected to the inverting input terminal of the operational amplifier U5 through the resistor R9. The resistor R6 is connected in parallel between the first and second output terminals of the current transformer T1. The output terminal of the operational amplifier U5 is connected to the inverting input terminal of the operational amplifier U5 through the resistor R10. The output terminal of the operational amplifier U5 is connected to the second input terminal of the main control unit.

3. The intelligent charging station operation and maintenance management system according to claim 2, characterized in that, The voltage monitoring circuit also includes a resistor R11 and a capacitor C4. The first end of the resistor R11 is connected to the output terminal of the operational amplifier U5, the second end of the resistor R11 is grounded through the capacitor C4, and the second end of the resistor R11 is connected to the second input terminal of the main control unit.

4. The intelligent charging station operation and maintenance management system according to claim 1, characterized in that, It also includes a temperature monitoring circuit, which comprises a thermistor RT1, resistors R21 and R20, a transistor Q2, and resistor R19. The first terminal of the thermistor RT1 is connected to a 5V power supply, and the second terminal of the thermistor RT1 is connected to the base of the transistor Q2. The first terminal of resistor R21 is connected to a 5V power supply, and the second terminal of resistor R21 is connected to the base of the transistor Q2. The base of the transistor Q2 is grounded through resistor R20. The collector of the transistor Q2 is connected to a 5V power supply, and the emitter of the transistor Q2 is grounded through resistor R19. The emitter of the transistor Q2 is connected to the third input terminal of the main control unit.

5. The intelligent charging station operation and maintenance management system according to claim 1, characterized in that, It also includes a protection circuit, which comprises an optocoupler U2, resistors R13 and R14, a switching transistor Q3, and a relay K1. The first input terminal of the optocoupler U2 is connected to a 5V power supply, the second input terminal of the optocoupler U2 is connected to the first output terminal of the main control unit, the first output terminal of the optocoupler U2 is connected to a 12V power supply through resistor R13, the second output terminal of the optocoupler U2 is connected to the control terminal of the switching transistor Q3 through resistor R14, the first terminal of the switching transistor Q3 is connected to the first input terminal of the relay K1, the second terminal of the switching transistor Q3 is grounded, the second input terminal of the relay K1 is connected to a 12V power supply, the normally closed terminal of the relay K1 is connected to the power grid, and the common terminal of the relay K1 is connected to the charging pile.

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