Abstract
As one of the high-frequency voltage injection approaches for sensorless drive of salient-pole permanent-magnet synchronous motors, there is the constant-amplitude non-rotational high-frequency voltage injection approach. The conventional analyses about characteristics of the high-frequency current due to the voltage injection are limited to near zero speed. Consequently, the approach was basically restricted to the low speed drive. This paper gives new analyses about characteristics of high-frequency current, which take the rotor speed into account and are valid in wide speed range, in contrast to the conventional analyses. On the basis of the new analyses, this paper proposes a new rotor phase estimation method for the constant-amplitude non-rotational high-frequency voltage injection approach, which is valid for wide speed range. The new analyses and rotor phase estimation method can allow extensive use of the constant-amplitude non-rotational high-frequency voltage injection approach in wide speed range.
