Plant-Independent Current Sensor Gain Error Compensation for Highly Dynamic Drives

Abstract

In this article, gain errors in current sensing for highly dynamic three-phase drives with three current sensor measurements are compensated without the aid of the machine plant model. As three current sensors are used, redundant information from the neutral current measurement is extracted by constructing its mathematical relation with the measured time-varying <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$dq$</tex-math></inline-formula> current. The proposed method compensates for non-symmetrical current sensor gain errors even in the presence of offset errors. A Recursive Sliding Window Least Square method is proposed to minimize the computation effort such that the method is suitable to be applied online. It does not incorporate a low-pass filter or averaging method based on electrical speed, making it suitable for highly dynamic applications. It is able to be applied in any three-phase AC machine, as the machine plant is not considered. Analysis, simulation and experimental results obtained from the hardware prototype by mimicking the actual application of high-precision mechatronics demonstrate the validity of the proposed method.