Versatile High-Frequency Current Correlation Method with High-Frequency Integral-Type PLL for Sensorless Drive of PMSMs

Abstract

This paper proposes a new high-frequency current correlation method with a high-frequency integral-type PLL as a versatile rotor-phase estimation method using stator current caused by high-frequency voltage injection for sensorless drive of salient-pole permanent-magnet synchronous motors. The proposed method has the following advantages. 1) It can be applied for the voltage injection under various conditions. 2) In principle, it can be used for the accurate estimation of rotor phase over a wide speed range. 3) The high-frequency integral-type PLL is extended to higher order for versatility. 4) An analytical method for designing the PLL has been established. 5) It guarantees stable phase estimation. 6) It ensures that the high-frequency noises do not appear in the estimated rotor phase.