Abstract
This paper proposes a new generalized high-frequency voltage injection method for sensorless drive of salient-pole permanent-magnet synchronous motors. The injected high-frequency voltage has unique spatially-rotating ellipse-shape, whose both amplitudes of major and minor axes vary dependently of the motor speed, and can be designed through selecting a design parameter. The high-frequency current caused by the injected voltage, which has information of rotor phase to be estimated, is speed-independent, i.e. is not affected by the motor speed at all. Consequently, rotor phase can be estimated in wide speed range from zero to the rated speed. Through selection of the design parameter, property of the high-frequency current can be adjusted so that it fits for the associated motor-drive system consisting of a motor and an inverter. As a versatile phase estimation method for estimating rotor phase using the high-frequency current, the “mirror-phase estimation method" is re-constructed and re-proposed.
