PROJECT TITLE :

Saliency-Based Position Estimation of Permanent-Magnet Synchronous Machines Using Square-Wave Voltage Injection With a Single Current Sensor

ABSTRACT:

This paper presents a saliency-primarily based position sensorless drive of permanent-magnet (PM) machines using a single current sensor for cost-effective applications. For the single current sensor system, the dc-link current is measured for the reconstruction of 3-section currents. The section current reconstruction will solely be realized when active voltages are applied. This limitation ends up in six immeasurable areas for this reconstruction using the pulsewidth modulation. So as to implement the saliency-based mostly sensorless drive, a square-wave voltage is injected to minimize the harmonics of reconstructed saliency current for the rotor position estimation. By injecting a sq.-wave voltage on the direction of the rotor -axis, the injection voltage vector is nearly perpendicular to the elemental voltage vector at low speed. The saliency mirrored current or the basic current can be separately reconstructed by the dc-link current, leading to the reduced reconstruction errors and improved sensorless performance. By using the proposed signal injection technique on one sensor system, the saliency-primarily based sensorless drive will work on an internal PM machine with a salient ratio of at 1p.c rated speed (sixty/600zero r/min) under full torque load based on the experimental evaluation.