A Position Sensorless Control Strategy for PMSM Drives With Single-Phase Current Sensor

This article aims to provide a more credible control scheme or a fault-tolerant control strategy for permanent magnet synchronous motor (PMSM) drives without a position sensor. Considering that, a position sensorless control strategy is proposed using only one phase current sensor. First, the mathematical model of full-order sliding mode observer (FSMO) is established in the stationary reference frame. Second, the coordinate transformation and notch filter (NF) are carried out for the only measurable phase current to calculate the current error information, which is needed by the FSMO. Third, a phase-locked loop (PLL) is employed to estimate the position. The motor parameter variation effect on the position estimation is evaluated. The observer's stability and parameter design method are analyzed through the Lyapunov theory. The proposed method utilizes a single current sensor to reconstruct the three-phase current and position signals, which improves the economy of inverters and provides the possibility of fault-tolerant control with few sensors. Compared with existing methods, it is simpler to implement and does not require changing the power unit structure. Finally, experiments have shown that the proposed method is comparable to the full-current-sensor method in terms of position estimation and control performance. Compared to the traditional method, the proposed method has higher accuracy of position estimation and better dynamic and steady-state control performance.