New phase estimation methods dedicated to high-frequency voltage injections for sensorless PMSM drives

This paper proposes new rotor phase estimation methods dedicated to high-frequency voltage injections for sensorless drives of permanent-magnet synchronous motors. First of all, this paper proposes a new approach to rotor phase estimation that consists of two steps such as (a) detection of amplitudes of positive and/or negative components of high-frequency current induced by the voltage injections, (b) synthesis of a signal of positively correlated to rotor phase using the detected amplitudes. The synthesized positive correlation signal is used as an input to a PLL system that outputs a rotor phase estimate in the stationary reference frame. Secondly, taking the approach, this paper proposes new five phase estimation methods. They have general versatility such that they can be applied to various voltage injections.