Research On Non Vehicle DC Charger DC Electric Energy Meter Verification Device For Electric Vehicle

DC power meter is a non-vehicle DC charger power metering device,its measurement accuracy directly affects the trade settlement of electricity and the interests of users,according to the user's demand for charging time limit,focusing on the future of the required charging current will be increasing This makes the high-current measurement a hotspot and difficulty for verification of non-vehicle DC chargers for electric vehicles.This article is designed to proceed from this realistic background and carry out the design research on the verification device for the off-board charger for electric vehicles.The main research contents and results are as follows:?1?Combining the characteristics of DC motor metering of non-vehicle DC chargers of electric vehicles,the working principle of DC metering and the basic composition of DC power meter are studied.According to the calibration principle of DC power meter,the DC power meter is used to verify the DC power.table.The verification device adopts the virtual load connection verification method,and the voltage verification circuit and the current verification circuit separately supply power,and the verification device has low power consumption.?2?Analyzed the use environment and performance index of the non-vehicle DC charger for DC electric energy meter of electric vehicle,and designed and implemented a verification device for non-vehicle charger DC electric energy meter of electric vehicle.The verification device hardware module is mainly composed of a standard DC power meter,a standard DC power supply,a control unit and an upper computer.According to the working principle of the calibrating device of the electric energy meter,the control unit of the calibrating device is mainly studied and designed,mainly including an MCU processor control module,a communication module,a pulse acquisition module and a power supply module.?3?Analyzed the relevant principle of the DC electric energy metering,according to the verification of the actual demand of the non-vehicle DC charger DC electric energy meter of the electric vehicle,determined the overall design index of the standard DC electric energy meter.The voltage is divided into three limits:350V,500V,800V,the current is divided into three limits:100A,200A,360A,and the accuracy level is 0.05.Based on the high-precision energy metering chip ADE7755and the management microprocessor C8051064,a high-precision wide-range standard DC power meter was designed and implemented.The large voltage sampling module uses a high-precision sampling resistor network to achieve a wide range of limited voltage sampling,and the large current sampling module uses a zero-flux DC current transformer combined with a conditioning circuit to achieve high-accuracy sampling of current wide limits.?4?Designed and realized high-voltage,high-current DC energy meter verification device,which can support?0³60?A high-current signal output with an accuracy better than 0.05%;?0⁸00?V DC voltage output with excellent accuracy At 0.02%.According to JJG842-2017"Electronic DC Watt-hour Meter Verification Regulations"stipulated verification wiring methods and verification items for the inspection of the DC power meter for verification.The test of the energy metering error,voltage measurement error,and current measurement error was performed on the detected DC power meter.The experimental results show that the detected DC power meter meets the energy metering requirements of the 1.0 meter.Based on the experimental results,the uncertainty of the verification device was analyzed,and the expanded uncertainty of the verification device for the DC electric energy meter of the non-vehicle DC charger for electric vehicles can reach 2.1×10^-4?k=2?.The verification device can complete the verification of a DC electric energy meter for a non-vehicle DC charger for electric vehicles of 1.0 class or less.