Current derivative measurement using closed‐loop hall‐effect current sensor

Abstract

This paper discusses a method of the current derivative measurement using a standard closed-loop Hall-effect current sensor. The proposed method can operate with PWM-driven inverters and provides the estimation of motor-phase inductances required for an encoderless or self-sensing control. The method is based on the current transformation feature of the closed-loop sensor where a sensing inductor is connected in series with the measuring resistor. The voltage drop across the inductor is proportional to the current derivative. The experimental results are demonstrated that the measurement of the current derivative can be performed under a good accuracy, though the measurement should be executed while inverter is in the steady-state condition.