An alternating current virtual load metering device

Abstract

The application discloses an alternating current virtual load metering device, which comprises a PC control end, a controllable single-phase alternating current source and a pulse acquisition module; the output end of the controllable single-phase alternating current source is connected with the input end of a charging pile, the output gun head of the charging pile is connected with the input end of the controllable single-phase alternating current source, so that the controllable single-phase alternating current source is short-circuited with the charging pile; the output end of the controllable single-phase alternating current source outputs specific voltage and current to simulate an actual power consumption state; the pulse acquisition module acquires the pulse output signal of an electric energy meter inside the charging pile; and the PC control end calculates the working error of the electric energy meter by the acquired pulse output signal and the pulse constant of the internal measurement standard of the charging pile. The controllable single-phase alternating current source is short-circuited with the charging pile to form a closed loop, and the controllable alternating current source only outputs the voltage and current signals (virtual load) simulating the actual power consumption state, so that energy waste in the detection process is fundamentally avoided, the total energy consumption in the batch detection scene is greatly reduced, and the low-carbon development trend is met.

Description

Technical Field

[0001] This invention relates to the field of charging pile power detection technology, and in particular to an AC virtual load metering device. Background Technology

[0002] Under the global trend of low-carbon development, new energy vehicles are rapidly becoming more widespread as an important carrier of green travel. Charging piles, as a core supporting facility for new energy vehicles, have their metering accuracy directly related to user rights and market regulation. With the rapid increase in the number of charging piles in the market, the demand for metering performance testing of charging piles is becoming increasingly urgent.

[0003] Current charging pile metering and testing methods mostly employ actual load testing, which involves simulating electricity consumption scenarios by connecting an actual load (such as a resistance box or simulated load) and then comparing the readings of a standard meter with those of the charging pile's internal electricity meter to detect errors. However, this actual load testing method has significant drawbacks: it consumes a large amount of electricity during actual load operation, especially in batch testing scenarios, where energy loss is particularly prominent and does not meet the development requirements of low-carbon testing. Secondly, the existing actual load testing method requires a long time for a single test, resulting in low testing efficiency. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of the prior art by providing an AC virtual load metering device.

[0005] The objective of this invention is achieved through the following technical solution: an AC virtual load metering device, comprising a PC control terminal, a controllable single-phase AC source, and a pulse acquisition module; the output terminal of the controllable single-phase AC source is connected to the input terminal of a charging pile, and the output nozzle of the charging pile is connected to the input terminal of the controllable single-phase AC source, so that the controllable single-phase AC source and the charging pile are short-circuited; the output terminal of the controllable single-phase AC source outputs specific voltage and current to simulate the actual power consumption state; the pulse sampling module acquires the pulse output signal of the energy meter inside the charging pile and uploads it to the PC control terminal; the PC control terminal calculates the working error of the energy meter based on the acquired pulse output signal and the pulse constant of the measurement standard inside the charging pile.

[0006] Preferably, the calculation method for the operating error of the electricity meter is as follows: obtain the pulse constant of the electricity meter inside the charging pile. The pulse constant of the internal measurement standard of the charging pile Collect the actual number of pulses m output by the electricity meter within N theoretical pulse time periods, and calculate the fixed pulse count. ,

[0007] Calculate the number of pulses The calculation method is as follows:

[0008] ;

[0009] Then calculate the operating error of the electricity meter. The calculation formula is as follows:

[0010] ;

[0011] In the formula, This is a predetermined systematic error.

[0012] Preferably, the controllable single-phase AC source includes an MCU controller, a single-phase signal source, a DC power supply, and a UI-to-Amplification (UI) conversion circuit. The single-phase signal source is connected to the input terminal of the MCU controller, the output terminal of the MCU controller is connected to a digital isolation circuit, the digital isolation circuit is connected to a PI regulator, and an AD sampler is connected to the digital isolation circuit. The single-phase signal source sets voltage and current values ​​as given signals, the MCU controller outputs corresponding output signals, and the output signals are input to the PI regulator through the digital isolation circuit. The PI regulator outputs control signals. The PI regulator is connected to a filter amplification module, and the filter amplification module and the DC power supply are simultaneously connected to the input terminal of the UI-to-Amplification (UI) conversion circuit. The output terminal of the UI-to-Amplification (UI) conversion circuit is connected to a range switching circuit, which is also connected to... The load and differential amplifier are connected. The differential amplifier is connected to the input of the proportional circuit. The first and second outputs of the proportional circuit are connected to the inverting follower circuit and the follower circuit, respectively. The inverting follower circuit is connected to the PI regulator, and the follower circuit is connected to the AD sampler. The output of the PI regulator is connected to the filter amplification module. The control signal output by the PI regulator is amplified by the filter amplification module to obtain the amplified control signal. The DC circuit modulates the corresponding AC output signal according to the amplified control signal and outputs it to the load and differential amplifier through the range switching circuit. The amplified control signal is amplified by the differential amplifier, the proportional circuit, and the inverting follower circuit to obtain the input control signal. The PI regulator combines the input control signal and the output signal of the MCU controller and outputs the control signal through a linear combination.

[0013] Preferably, the control signal output by the PI regulator The calculation formula is as follows:

[0014] ;

[0015] In the formula, Given a signal, For output signal, The overshoot of the closed-loop system is T, and the response speed is T. For a given signal With output signal The resulting control deviation; .

[0016] Preferably, the filtering and amplification module includes a fourth-order Butterworth low-pass filter circuit and a Darlington amplifier circuit.

[0017] Preferably, the controllable single-phase AC source also includes an overvoltage protection circuit; the control signal output by the PI regulator is filtered by a fourth-order Butterworth low-pass filter circuit and then input to the overvoltage protection circuit, which is connected to the MCU controller through an IO isolation input module.

[0018] Preferably, the pulse output terminal of the internal energy meter of the charging pile is connected to the acquisition line, which outputs two signals, WPH and WPL. The pulse acquisition module includes a WPH signal line and a WPL signal line. The WPH signal line is connected to the negative terminal of diode D1, and the positive terminal of diode D1 is simultaneously connected to the pull-down resistor PTC1 and the first input terminal of optocoupler H9. The WPL signal line is connected to the negative terminal of diode D2, and the positive terminal of diode D2 is simultaneously connected to the pull-down resistor PTC2 and the second input terminal of optocoupler H9. A capacitor C43 is provided between the WPH signal line and the WPL signal line. The first output terminal of optocoupler H9 is connected to the first... The branch connects to the non-inverting input of voltage comparator U10, and the second output of optocoupler H9 is grounded; the inverting input of voltage comparator U10 is connected to both the second and third branches. The second branch is connected to a 5V positive voltage and has a resistor R38 installed on it. The third branch is grounded and has a resistor R39 installed on it; the positive power supply terminal of voltage comparator U10 is connected to a 5V positive voltage; the output of voltage comparator U10 is connected to the input of Schmitt trigger inverter U6 through the fourth branch, and the output of Schmitt trigger inverter U6 outputs a pulse signal; the positive power supply terminal of Schmitt trigger inverter U6 is connected to a 5V positive voltage.

[0019] Preferably, the first branch is connected to the fifth branch and the sixth branch. The fifth branch is connected to a resistor R36 and a 5V positive voltage. The sixth branch is connected to a capacitor C39 and is grounded. The fourth branch is connected to the seventh branch and the eighth branch. The seventh branch is connected to a resistor R37 and a 5V positive voltage. The eighth branch is connected to a capacitor C40 and is grounded. A resistor R35 and a capacitor C44 are connected in parallel between the first branch and the fourth branch.

[0020] Preferably, a clock sampling module is also included. The clock sampling module includes a communication circuit, a GPS module, and a satellite search antenna. The satellite search antenna acquires outdoor GPS signals and uploads them to the PC control terminal to display the current clock time.

[0021] The beneficial effects of this invention are:

[0022] 1. Traditional real-load testing methods require the connection of a resistance box to simulate an actual load. During the testing process, electrical energy is converted into heat or other forms of energy and consumed (especially in high-power testing scenarios where energy consumption is enormous). This invention forms a closed loop by short-circuiting a controllable single-phase AC power source with a charging pile. The controllable AC power source only outputs voltage and current signals simulating actual power consumption (virtual load), eliminating the need for real electrical energy to be consumed through the load. This fundamentally avoids energy waste during the testing process and significantly reduces the total energy consumption in batch testing scenarios, aligning with the trend of low-carbon development. In real-load testing, the load equipment (such as a high-power resistance box) itself also consumes additional energy (such as power for cooling fans). However, the core component of the virtual load device in this invention (the controllable single-phase AC power source) consumes far less power than the actual load, further reducing the overall energy demand of the testing system.

[0023] 2. Traditional real-load testing requires multiple time-consuming steps, including load connection, parameter adjustment, stabilization waiting, and heat dissipation cooling (especially after high-power testing, it is necessary to wait for the load to cool down before the next test can be performed). This invention directly outputs the set voltage and current signals through a controllable AC source, eliminating the need for physical load adjustment and stabilization waiting. The current testing process can be ended once the pulse signal within a specific time period is acquired. Furthermore, there is no residual heat issue after the test, allowing for rapid commencement of the next testing process. This significantly shortens the cycle time of a single test and greatly improves testing efficiency. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the principle of the present invention.

[0025] Figure 2 This is a schematic diagram of the module connection for a controllable single-phase AC power source.

[0026] Figure 3 This is the circuit diagram of the pulse acquisition module. Detailed Implementation

[0027] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.

[0028] Those skilled in the art should understand that, in the disclosure of this invention, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the above terms should not be construed as limiting this invention.

[0029] It is understood that the term "a" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element can be one, while in another embodiment, the number of the element can be multiple, and the term "a" should not be understood as a limitation on the number.

[0030] like Figures 1 to 3 As shown, an AC virtual load metering device includes a PC control terminal, a controllable single-phase AC source, a pulse acquisition module, and a clock sampling module.

[0031] The output terminal of the controllable single-phase AC power source is connected to the input terminal of the charging pile, and the output nozzle of the charging pile is connected to the input terminal of the controllable single-phase AC power source, so that the controllable single-phase AC power source and the charging pile are short-circuited. The output terminal of the controllable single-phase AC power source outputs a specific voltage and current to simulate the actual power consumption state. The pulse sampling module collects the pulse output signal of the power meter inside the charging pile and uploads it to the PC control terminal. The PC control terminal calculates the working error of the power meter by using the collected pulse output signal and the pulse constant of the measurement standard inside the charging pile.

[0032] Specifically, the calculation method for the working error of the electricity meter is as follows: Obtain the pulse constant of the electricity meter inside the charging pile. The pulse constant of the internal measurement standard of the charging pile Collect the actual number of pulses m output by the electricity meter within N theoretical pulse time periods, and calculate the fixed pulse count. ,

[0033] Calculate the number of pulses The calculation method is as follows:

[0034] ;

[0035] Then calculate the operating error of the electricity meter. The calculation formula is as follows:

[0036] ;

[0037] In the formula, This is a predetermined systematic error.

[0038] Among them, the pulse constant of the electricity meter inside the charging pile This information can be obtained from the nameplate on the electricity meter; it is a known constant, and the unit is... The pulse constant of the internal measurement standard of the charging pile. This refers to the pulse constant of the standard source, reference meter, or metering chip used for calibration or comparison inside the charging pile, with units of 1000 kJ / m². , where is a known quantity. This is a predetermined systematic error, a value that is set in advance to account for operational errors. Further corrections are needed. If no corrections are required, The value of is 0.

[0039] Traditional real-load testing methods require the connection of a resistance box to simulate an actual load. During the testing process, electrical energy is consumed as heat or other forms through the load (especially in high-power testing scenarios where energy consumption is enormous). This invention forms a closed loop by short-circuiting a controllable single-phase AC power source with a charging pile. The controllable AC power source only outputs voltage and current signals simulating actual power consumption (virtual load), eliminating the need for real electrical energy to be consumed through the load. This fundamentally avoids energy waste during the testing process and significantly reduces the total energy consumption in batch testing scenarios, aligning with the trend of low-carbon development. In real-load testing, the load equipment (such as a high-power resistance box) itself also consumes additional energy (such as power for cooling fans). However, the core component of the virtual load device in this invention (the controllable single-phase AC power source) consumes far less power than the actual load, further reducing the overall energy demand of the testing system.

[0040] Traditional load testing involves multiple time-consuming steps, including load connection, parameter adjustment, stabilization, and cooling (especially after high-power testing, the load must cool down before the next test can begin). This invention directly outputs set voltage and current signals from a controllable AC source, eliminating the need for physical load adjustment and stabilization. The current testing process ends once a pulse signal within a specific time period is acquired. Furthermore, there is no residual heat after testing, allowing for rapid re-initiation of the next test, significantly shortening the testing cycle and greatly improving efficiency.

[0041] The controllable single-phase AC power source includes an MCU controller, a single-phase signal source, a DC power supply, and a UI-to-Amplification (UI) conversion circuit. The single-phase signal source is connected to the input of the MCU controller, the output of the MCU controller is connected to a digital isolation circuit, the digital isolation circuit is connected to a PI regulator, and an AD sampler is connected to the digital isolation circuit. The single-phase signal source is set with voltage and current values ​​as given signals. The MCU controller outputs corresponding output signals, which are then input to the PI regulator via the digital isolation circuit. The PI regulator outputs a control signal. The PI regulator is connected to a filter amplification module. The filter amplification module and the DC power supply are both connected to the input of the UI-to-Amplification (UI) conversion circuit. The output of the UI-to-Amplification (UI) conversion circuit is connected to a range switching circuit, which is simultaneously connected to the load and... The differential amplifier is connected to the input of the proportional circuit. The first and second outputs of the proportional circuit are connected to the inverting follower circuit and the follower circuit, respectively. The inverting follower circuit is connected to the PI regulator, and the follower circuit is connected to the AD sampler. The output of the PI regulator is connected to the filter amplification module. The control signal output by the PI regulator is amplified by the filter amplification module to obtain the amplified control signal. The DC circuit modulates the corresponding AC output signal according to the amplified control signal and outputs it to the load and the differential amplifier through the range switching circuit. The amplified control signal is amplified by the differential amplifier, the proportional circuit, and the inverting follower circuit to obtain the input control signal. The PI regulator combines the input control signal and the output signal of the MCU controller and outputs the control signal through a linear combination.

[0042] Among them, the PI controller is a proportional-integral controller, which is a commonly used feedback controller in the field of automatic control. The PI controller achieves precise regulation of the system by combining the two control actions of proportional (P) and integral (I).

[0043] This controllable single-phase AC power source is an AC signal generation system based on closed-loop feedback control. Its core functions consist of four main components: signal setting, control regulation, power conversion, and signal sampling and feedback. Through the coordinated operation of the MCU controller, PI regulator, UI conversion amplifier circuit, and closed-loop feedback network, precise control of the output AC voltage and current is achieved. The core logic of the system architecture of this controllable single-phase AC power source is: setting signal → control regulation → power output → sampling feedback → dynamic correction, forming a complete closed-loop control chain.

[0044] The single-phase signal source, acting as a signal input module, allows the user to set the target voltage or current value on the PC control terminal. This value is then transmitted via RS485 communication to the single-phase signal source, generating a given signal, which is then transmitted to the MCU controller. Upon receiving the given signal, the MCU controller generates the corresponding initial control signal, which is then transmitted to the PI regulator via a digital isolation circuit. The digital isolation circuit serves to achieve electrical isolation between the control side and the power side, preventing power circuit interference from entering the control circuit and improving the system's anti-interference capability.

[0045] The PI controller is used to generate control signals. Its inputs are the MCU's output signal and the input control signal (feedback signal), and its output is the control signal for driving the power circuit. Specifically, the control signal output by the PI controller... The calculation formula is as follows:

[0046] ;

[0047] In the formula, Given a signal, For output signal, The overshoot of the closed-loop system is T, and the response speed is T. For a given signal With output signal The resulting control deviation; .

[0048] The stability and accuracy of the actual output voltage and current are ensured through dynamic feedback regulation of the PI regulator.

[0049] The filtering and amplification module processes the control signal output from the PI regulator, removing high-frequency noise and amplifying it to a level sufficient to drive the power circuit. This module includes a fourth-order Butterworth low-pass filter and a Darlington amplifier. The fourth-order Butterworth low-pass filter, through two cascaded second-order circuits, achieves a flat passband, a steep transition band, and thorough stopband attenuation. This filtering ensures signal purity by filtering high-frequency noise. The Darlington amplifier is a composite amplification unit composed of two cascaded transistors. By injecting the output current of the preceding transistor into the base of the following transistor, it achieves extremely high current gain and input impedance.

[0050] The control signal is processed by the filtering and amplification module and then fed into the UI conversion and amplification circuit. The UI conversion and amplification circuit consists of multiple IGBT devices.

[0051] This circuit receives two inputs: a filtered and amplified control signal (modulation command) and a DC power supply (energy source). Through pulse width modulation or linear amplification, the DC power supply is converted into an AC output signal (voltage or current) corresponding to the control signal, achieving DC-AC energy conversion and signal modulation.

[0052] The range switching circuit controls the output at different voltage and current levels. Based on the required output signal amplitude, the range switching circuit matches the load characteristics to ensure the output signal maintains accuracy across different ranges, while also protecting the circuit from overload damage.

[0053] The DC power supply modulates the corresponding AC signal through the pre-amplifier circuit and outputs the corresponding voltage and current to drive the charging pile. At the same time, it collects real-time data through an external standard meter and displays the data on the software interface.

[0054] To achieve precise output control, the system monitors the output and corrects deviations in real time through a multi-level feedback loop. The specific method is as follows:

[0055] Signal sampling: The output of the range switching circuit is connected to both the load and the differential amplifier. The differential amplifier performs differential sampling on the actual output signal (voltage or current), suppresses common-mode interference, and extracts the true signal.

[0056] Signal conditioning: After the sampled signal's amplitude is adjusted by a proportional circuit, it is split into two paths: one path is processed by an inverting follower circuit and used as a feedback signal input to the PI regulator, where it is compared with the setpoint signal to generate a deviation; the other path is processed by a follower circuit and input to an AD sampler, where the MCU records or displays the actual output value. The PI regulator continuously adjusts its output based on the real-time deviation, providing real-time dynamic feedback regulation of the current and voltage outputs to achieve precise closed-loop feedback regulation, ultimately ensuring that the actual output stably tracks the setpoint value.

[0057] The controllable single-phase AC power source also includes an overvoltage protection circuit. The control signal output from the PI regulator is filtered by a fourth-order Butterworth low-pass filter circuit before being input to the overvoltage protection circuit. The overvoltage protection circuit is connected to the MCU controller via an I / O isolation input module. The overvoltage protection circuit is directly connected to the filtered control signal link, enabling real-time monitoring of the dynamic changes in the system output voltage. When an abnormal load, circuit fault, or abnormal control signal causes the output voltage to exceed the safety threshold, the overvoltage protection circuit can quickly identify the overvoltage condition and trigger the protection mechanism (cutting off the drive signal and limiting output power) to prevent excessive voltage from damaging the load equipment or the internal circuitry of the AC power source, significantly improving system safety.

[0058] The overvoltage protection circuit is connected to the MCU controller through the IO isolation input module. The IO isolation input module uses optocoupler or electromagnetic isolation technology to electrically isolate the power side where the overvoltage protection circuit is located from the control side where the MCU controller is located, cutting off the direct circuit connection between the two. This isolation can effectively eliminate the grounding loop formed by the grounding potential difference between the high and low voltage sides, avoid the loop current from interfering with the normal operation of the MCU controller, and prevent dangerous voltage from entering the low voltage control side when the high voltage side fails, thus protecting the MCU and surrounding low voltage circuits from damage.

[0059] A fourth-order Butterworth low-pass filter circuit is also provided between the proportional circuit and the inverted follower circuit.

[0060] The controllable single-phase AC power source can output specific voltage and current signals to accurately simulate various operating conditions of charging piles in actual use (such as rated load, light load, overload, etc.), ensuring that the testing environment is consistent with the real power consumption scenario. Compared with the parameter deviations that may exist in traditional loads (such as insufficient resistance value accuracy), the virtual load signal has higher stability and accuracy, providing a reliable benchmark for metering error detection.

[0061] The "load" mentioned in this invention refers to the internal AC energy meter of the charging pile that is connected to a controllable single-phase AC source in a short-circuit manner.

[0062] The pulse output terminal of the internal energy meter of the charging pile is connected to the acquisition line, which outputs two signals, WPH and WPL. The pulse acquisition module includes a WPH signal line and a WPL signal line. The WPH signal line is connected to the negative terminal of diode D1, and the positive terminal of diode D1 is simultaneously connected to the pull-down resistor PTC1 and the first input terminal of optocoupler H9. The WPL signal line is connected to the negative terminal of diode D2, and the positive terminal of diode D2 is simultaneously connected to the pull-down resistor PTC2 and the second input terminal of optocoupler H9. A capacitor C43 is placed between the WPH signal line and the WPL signal line. The first output terminal of optocoupler H9 is connected to the first branch. Connect the non-inverting input of voltage comparator U10 to ground; the second output of optocoupler H9 is grounded; the inverting input of voltage comparator U10 is connected to both a second branch and a third branch. The second branch is connected to a 5V positive voltage and has a resistor R38 installed on it; the third branch is grounded and has a resistor R39 installed on it; the positive power supply terminal of voltage comparator U10 is connected to a 5V positive voltage; the output of voltage comparator U10 is connected to the input of Schmitt trigger inverter U6 through a fourth branch, and the output of Schmitt trigger inverter U6 outputs a pulse signal; the positive power supply terminal of Schmitt trigger inverter U6 is connected to a 5V positive voltage.

[0063] The first branch is connected to the fifth and sixth branches. The fifth branch is connected to a resistor R36 and a 5V positive voltage. The sixth branch is connected to a capacitor C39 and is grounded. The fourth branch is connected to the seventh and eighth branches. The seventh branch is connected to a resistor R37 and a 5V positive voltage. The eighth branch is connected to a capacitor C40 and is grounded. The first and fourth branches are connected to a resistor R35 and a capacitor C44 in parallel.

[0064] When the WPL signal is low, the optocoupler H9 outputs a low level, which flows into the pull-down resistor PTC2 through diode D2. At this time, the optocoupler H9 is closed. When the WPH and WPL signals are in other states, the optocoupler H9 is not conducting. The voltage comparator U10 controls the output of its output terminal (pin 1) by comparing the inverting input terminal (pin 2) and the non-inverting input terminal (pin 3). The inverting input of voltage comparator U10 is connected to a +5V voltage and resistor R38. Voltage comparator U10 outputs a high level only when the input voltage at its non-inverting input (pin 3) is not less than +5V; otherwise, it outputs a low level. Therefore, when optocoupler H9 is not conducting, resistor R36 inputs a +5V high level to the non-inverting input (pin 3) of voltage comparator U10, resulting in a high output at pin 1. Otherwise, pin 1 outputs a low level. The output level from pin 1 of voltage comparator U10 is input to the Schmitt trigger inverter U6's input (pin 1) via resistor R37, inverting the output. When WPH is high and WPL is low, the optocoupler H9 is closed, the voltage comparator U10 is low at input and low at output, and the Schmitt trigger inverter U6 is high at output. The opposite occurs when WPH is low and WPL is high. Based on this principle, the pulse acquisition module ultimately outputs the corresponding pulse signal.

[0065] In this application, the voltage comparator U10 is an LM393. The Schmitt trigger inverter U6 is a 74HC14. The optocoupler H9 is a TLP521-1. Capacitors C39, C40, and C43 are all 0.1 microfarads each, and C44 is 47 picofarads. Pull-down resistor PTC1 is 1 kΩ. Pull-down resistor PTC2 is 1 kΩ. Resistor R35 is 200 kΩ, resistor R36 is 4.7 kΩ, resistor R37 is 4.7 kΩ, resistor R38 is 10 kΩ, and resistor R39 is 10 kΩ.

[0066] When the pulse acquisition module acquires pulse signals from the internal energy meter of the charging pile, it can connect to the pulse output terminal of the internal energy meter of the charging pile through one of the acquisition methods: electrical pulse acquisition line, photoelectric head acquisition line, or Bluetooth acquisition device, so as to realize diverse signal acquisition modes.

[0067] The present invention includes a clock sampling module, which includes a communication circuit, a GPS module and a satellite search antenna. The satellite search antenna acquires outdoor GPS signals and uploads them to a PC control terminal to display the current clock time.

[0068] This invention is not limited to the preferred embodiments described above. Anyone can derive other products in various forms under the guidance of this invention. However, regardless of any changes in shape or structure, any technical solution that is the same as or similar to this application falls within the protection scope of this invention.

Claims

1. An AC virtual load metering device, characterized in that, The system includes a PC control terminal, a controllable single-phase AC power source, and a pulse acquisition module. The output terminal of the controllable single-phase AC power source is connected to the input terminal of the charging pile, and the output nozzle of the charging pile is connected to the input terminal of the controllable single-phase AC power source, thus short-circuiting the controllable single-phase AC power source and the charging pile. The output terminal of the controllable single-phase AC power source outputs specific voltage and current to simulate actual power consumption. The pulse sampling module acquires the pulse output signal of the energy meter inside the charging pile and uploads it to the PC control terminal. The PC control terminal calculates the working error of the energy meter based on the acquired pulse output signal and the pulse constant of the measurement standard inside the charging pile. The controllable single-phase AC power source includes an MCU controller, a single-phase signal source, a digital isolation circuit, a PI regulator, a filter amplification module, a DC power supply, a UI conversion amplification circuit, and a range switching circuit, wherein: The single-phase signal source serves as a signal input module, whereby the user sets the target voltage or current value on the PC control terminal, generates a given signal, and transmits the signal to the MCU controller. After receiving the given signal, the MCU controller generates the corresponding initial control signal, which is then transmitted to the PI regulator via a digital isolation circuit. The input of the PI regulator is the output signal and feedback signal of the MCU controller, and the output is the control signal for the drive power circuit. The filtering and amplification module filters and amplifies the control signal output by the PI regulator and feeds it into the UI conversion and amplification circuit. The UI conversion and amplification circuit receives two inputs: the filtered and amplified control signal and the DC power supply, and converts the DC power supply into an AC output signal corresponding to the control signal. The range switching circuit matches the load characteristics to ensure that the output signal maintains accuracy under different ranges. The DC power supply modulates the corresponding AC signal through the front-end circuit and outputs the corresponding voltage and current to drive the charging pile. At the same time, it collects real-time data through an external standard meter and displays the data on the software interface. The controllable single-phase AC power source can output specific voltage and current signals to simulate various operating conditions of charging piles in actual use, ensuring that the testing environment is consistent with the real power consumption scenario.

2. The AC virtual load metering device according to claim 1, characterized in that, The calculation method for the operating error of the electricity meter is as follows: Obtain the pulse constant of the electricity meter inside the charging pile. The pulse constant of the internal measurement standard of the charging pile Collect the actual number of pulses m output by the electricity meter within N theoretical pulse time periods, and calculate the fixed pulse count. , Calculate the number of pulses The calculation method is as follows: ； Then calculate the operating error of the electricity meter. The calculation formula is as follows: ； In the formula, This is a predetermined systematic error.

3. The AC virtual load metering device according to claim 1, characterized in that, A single-phase signal source is connected to the input terminal of the MCU controller. The output terminal of the MCU controller is connected to a digital isolation circuit. The digital isolation circuit is connected to a PI regulator. An AD sampler is connected to the digital isolation circuit. The PI regulator is connected to a filter amplification module. The filter amplification module and the DC power supply are simultaneously connected to the input terminal of a UI conversion amplification circuit. The output terminal of the UI conversion amplification circuit is connected to a range switching circuit. The range switching circuit is simultaneously connected to the load and a differential amplifier. The differential amplifier is connected to the input terminal of a proportional circuit. The first and second output terminals of the proportional circuit are respectively connected to an inverting follower circuit and a follower circuit. The inverting follower circuit is connected to the PI regulator. The follower circuit is connected to the AD sampler. The output terminal of the PI regulator is connected to the filter amplification module. The control signal output by the PI regulator is amplified by the filter amplification module. The DC circuit modulates the corresponding AC output signal according to the amplified control signal and outputs it to the load and the differential amplifier through the range switching circuit. The amplified control signal is amplified by the differential amplifier, the proportional circuit, and the inverting follower circuit to obtain the input control signal. The PI regulator combines the input control signal and the output signal of the MCU controller and outputs the control signal through a linear combination.

4. The AC virtual load metering device according to claim 3, characterized in that, The control signal output by the PI regulator The calculation formula is as follows: ； In the formula, Given a signal, For output signal, The overshoot of the closed-loop system is T, and the response speed is T. For a given signal With output signal The resulting control deviation; .

5. An AC virtual load metering device according to claim 3, characterized in that, The filtering and amplification module includes a fourth-order Butterworth low-pass filter circuit and a Darlington amplifier circuit.

6. The AC virtual load metering device according to claim 3, characterized in that, The controllable single-phase AC source also includes an overvoltage protection circuit; the control signal output by the PI regulator is filtered by a fourth-order Butterworth low-pass filter circuit and then input to the overvoltage protection circuit, which is connected to the MCU controller through an IO isolation input module.

7. The AC virtual load metering device according to claim 1, characterized in that, The pulse output terminal of the internal energy meter of the charging pile is connected to the acquisition line, which outputs two signals, WPH and WPL. The pulse acquisition module includes a WPH signal line and a WPL signal line. The WPH signal line is connected to the cathode of diode D1, and the anode of diode D1 is simultaneously connected to pull-down resistor PTC1 and the first input terminal of optocoupler H9. The WPL signal line is connected to the cathode of diode D2, and the anode of diode D2 is simultaneously connected to pull-down resistor PTC2 and the second input terminal of optocoupler H9. A capacitor C43 is placed between the WPH and WPL signal lines. The first output terminal of optocoupler H9 is connected to a voltage comparator through a first branch. The non-inverting input of U10 and the second output of optocoupler H9 are grounded. The inverting input of voltage comparator U10 is connected to both a second and a third branch. The second branch is connected to a 5V positive voltage and has a resistor R38. The third branch is grounded and has a resistor R39. The positive power supply terminal of voltage comparator U10 is connected to a 5V positive voltage. The output of voltage comparator U10 is connected to the input of Schmitt trigger inverter U6 via a fourth branch. The output of Schmitt trigger inverter U6 outputs a pulse signal. The positive terminal of the power supply for the Schmitt trigger inverter U6 is connected to a 5V positive voltage.

8. An AC virtual load metering device according to claim 7, characterized in that, The first branch is connected to the fifth and sixth branches. The fifth branch is connected to a resistor R36 and a 5V positive voltage. The sixth branch is connected to a capacitor C39 and is grounded. The fourth branch is connected to the seventh and eighth branches. The seventh branch is connected to a resistor R37 and a 5V positive voltage. The eighth branch is connected to a capacitor C40 and is grounded. The first and fourth branches are connected to a resistor R35 and a capacitor C44 in parallel.

9. An AC virtual load metering device according to claim 1, characterized in that, It also includes a clock sampling module, which consists of a communication circuit, a GPS module, and a satellite search antenna. The satellite search antenna acquires outdoor GPS signals and uploads them to the PC control terminal to display the current clock time.

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