Active <i>Q</i> Flux Concept for Sensorless Control of Synchronous Reluctance Machines

Abstract

In this article, we propose a new scheme to use active flux on the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">q</i> -axis for sensorless control of synchronous reluctance machines (SynRMs). Conventionally, “active flux” on the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">d</i> -axis is adopted to convert a salient-pole machine into a fictitious nonsalient-pole machine. However, the injected <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">d</i> -axis flux can deteriorate high-frequency injection (HFI) sensorless control performance or even run the system into unstable region at low speed. This article demonstrates that active flux on the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">q</i> -axis can support back EMF sensorless control at high speed and improve low-speed HFI performance substantially. A seamless transition from HFI sensorless method to back EMF voltage method is attained after adopting the proposed active <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">q</i> flux. The experimental results are used to validate the proposed method.