Generalized INFORM Method with Variable Modulation Frequency for High Dynamic Low Speed Sensorless Control of PMSM

Sensorless control is a research hotspot in control field because of its low cost and high reliability. The Indirect Flux detection by On-line Reactance Measurement (INFORM) method is the position sensorless control method proposed for the low speed drive of PMSM. However, the injection pattern of traditional INFORM method degrades the current loop bandwidth and hence the dynamic quality due to the decrease of vector control frequency. In this paper, a generalized INFORM method with arbitrary injection angle is proposed to avoid possible problems when sector switching or reconstructing phase current by single current sampling, along with a new modulation method with adaptive switching frequency to improve the dynamic performance of INFORM method.