New sensorless vector control of PMSM by discrete-time voltage injection of PWM carrier frequency — Positive- and negative-phase amplitudes extraction method

摘要

This paper presents a new sensorless vector control method for permanent-magnet synchronous motors (PMSMs) that employs discrete-time high-frequency voltage injection. The frequency range of the injected voltage is almost the same as that of the pulse width modulation (PWM) carrier used in inverters. This allows high-speed phase estimation and a high-performance drive, and possibly low acoustic noise caused by the injected voltage. The nearly carrier-frequency current associated with the injected voltage must be analyzed in a discrete-time manner. In the range of carrier-frequency, a simple approximation of continuous-time analyses of the high-frequency current cannot be applied. Based on the new discrete-time analyses, this paper reconstructs the conventional rotor phase estimation method that extracts positive- and negative-phase amplitudes of the high-frequency current. The usefulness of the proposed method is verified through extensive experiments.