Error Compensation Method for DC Shunt

In the energy metering circuit of non-vehicle-mounted chargers, voltage is collected through a voltage divider network, and current is collected through a shunt. A shunt, typically made of manganese copper, generates heat when current passes through it. The resistance value of the shunt changes with its temperature, leading to a nonlinear relationship between the voltage output at both ends of the shunt and the current flowing through it before thermal equilibrium is reached. In this study, two commonly used shunts were selected, and their voltage-time curves at different currents were tested to analyze the relationship between measurement error and time. The least squares fitting method was applied to compensate for the error of one of the shunts. This approach improved the accuracy of DC current measurement and ensured the accuracy and reliability of trade settlement data for charging facilities.