New Sensorless Vector Control of PMSM by Rotating Voltage Injection of PWM Carrier Frequency

Abstract

This paper presents a new sensorless vector control method for permanent-magnet synchronous motors (PMSMs) by injecting a rotating high-frequency voltage. The frequency range of the injected voltage is almost the same as that of the PWM carrier. This allows high-speed phase estimation and a high performance drive, and possibly low acoustic noise due to the injected voltage. The proposed method injects a rotating high-frequency voltage for current modulation in the quasi-synchronous reference frame, demodulates the modulated current, and produces a phase estimate in the same reference frame. The demodulation and phase estimation are characterized by a small current sampling period, filter-less extraction of the modulated current, achievement of the maximum positive correlation region. In addition, no further phase compensation is required. The usefulness of the proposed method is verified via extensive simulations.