With the rapid growth of new energy vehicle ownership, the construction of public charging infrastructure is also accelerating. By the end of 2024, the number of charging piles in China has exceeded 10 million. As a kind of \u201dmeasuring instrument\u201d, the accuracy of charging piles' power measurement is directly related to consumers' rights and interests and operators' revenue.<\/p>\n
Charging pile current measurement is the core link of electric energy metering, and its accuracy requirement is much higher than that of ordinary electrical equipment. The state has strict regulatory requirements for the metering performance of charging pile, and the selection and application of shunt as the main current detection element of DC charging pile is crucial.<\/p>\n
Key Requirements:<\/p>\n
DC charger (charging post) metering requirements:<\/p>\n
Requirements for power quality indicators such as harmonics and power factor of charging facilities indirectly affect the choice of current measurement scheme.<\/p>\n
The shunt is currently the most mainstream current measurement solution for DC charging piles:<\/p>\n
Advantage:<\/strong><\/p>\n Typical parameters:<\/strong><\/p>\n Some charging piles use closed-loop Hall sensors, which have the advantage of natural isolation, but are more expensive and suffer from zero drift.<\/p>\n Select according to the charging pile power level:<\/p>\n According to JJG 1149 requirements, the current measurement error \u2264 \u00b1 0.5%, it is recommended to use 0.2% level shunt, leaving a margin for other sources of error in the system.<\/p>\n Charging pile working environment temperature range is wide (-20\u2103 to +55\u2103), TCR should be \u226450ppm\/\u2103, recommended \u226430ppm\/\u2103.<\/p>\n Measuring instruments require regular calibration, and the annual drift of the shunt should be<0.05% to ensure stable accuracy during the calibration cycle.<\/p>\n The charging pile may experience short-term overcurrent, and the shunt should be able to withstand 1.2 times the rated current for continuous operation and 2 times the rated current for short-term overload.<\/p>\n The charging pile needs to be tested for the first time by the metrological testing organization before leaving the factory, and the testing items include:<\/p>\n According to the requirements of the regulations, the DC charger calibration cycle is 2 years, need to be sent to the inspection or on-site calibration.<\/p>\n With the popularization of 800V high-voltage platform models, the power of superchargers is developing to 480kW or even higher, which puts higher requirements on the current specification and heat dissipation capability of the shunt.<\/p>\n The application of liquid-cooled charging guns and liquid-cooled charging piles has changed the thermal management of charging piles, and the selection and installation of shunts need to be adjusted accordingly.<\/p>\n The interaction between the charging pile and the vehicle and the power grid is more intelligent, and the real-time and precision requirements for current measurement continue to improve.<\/p>\n As a measuring instrument, the current measurement accuracy of charging pile is subject to strict regulations. With its high precision, low cost and long-term stability, the shunt has become the mainstream solution for DC charging pile current detection. In practical application, it is necessary to select a comprehensive model according to the charging pile power level, working environment, metering requirements and other factors, and pay attention to the signal conditioning, EMC protection, heat dissipation and other details in the system design, to ensure that it meets the national standards and protects the rights and interests of consumers.<\/p>","protected":false},"excerpt":{"rendered":" Interpretation of national standards related to charging pile power measurement, analysis of the application of shunt in charging pile and selection points.<\/p>","protected":false},"author":1,"featured_media":751,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[24],"tags":[],"class_list":["post-726","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-industry-news"],"yoast_head":"\n\n
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3.2 Hall sensor program<\/h3>\n
3.3 Comparison of Programs<\/h3>\n
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\n comparison term<\/th>\n splitter<\/th>\n Hall Sensors<\/th>\n<\/tr>\n \n accurate<\/td>\n 0.2%~0.5%<\/td>\n 0.5%~1.0%<\/td>\n<\/tr>\n \n (manufacturing, production etc) costs<\/td>\n \u4f4e<\/td>\n \u9ad8<\/td>\n<\/tr>\n \n incommunicado<\/td>\n Requires additional isolation<\/td>\n natural isolation<\/td>\n<\/tr>\n \n Zero Stability<\/td>\n talented<\/td>\n general<\/td>\n<\/tr>\n \n temperature stability<\/td>\n \u597d<\/td>\n general<\/td>\n<\/tr>\n \n degree of mainstreaming<\/td>\n Mainstream Programs<\/td>\n Supplementary Programs<\/td>\n<\/tr>\n<\/table>\n Fourth, the diverter selection points<\/h2>\n
4.1 Current Specification Matching<\/h3>\n
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4.2 Accuracy classes<\/h3>\n
4.3 Temperature coefficient<\/h3>\n
4.4 Long-term stability<\/h3>\n
4.5 Overload capacity<\/h3>\n
V. System design elements<\/h2>\n
5.1 Signal Conditioning Circuit<\/h3>\n
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5.2 Software algorithms<\/h3>\n
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5.3 EMC design<\/h3>\n
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5.4 Reliability design<\/h3>\n
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VI. Certification and calibration<\/h2>\n
6.1 Initial calibration<\/h3>\n
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6.2 Periodic calibration<\/h3>\n
6.3 Calibration recommendations<\/h3>\n
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VII. Market trends and outlook<\/h2>\n
7.1 High Power Charging<\/h3>\n
7.2 Liquid-cooled charging<\/h3>\n
7.3 Intelligent<\/h3>\n
VIII. Summary<\/h2>\n