Constrained Predictive Controllers for High-Performance Sensorless IPMSM Drive Systems With Full-Range Speed Operations

A constrained predictive speed controller with an input current limit and a constrained predictive current controller (CPCC) with an input voltage limit are proposed for high-performance sensorless interior permanent magnet synchronous motor (IPMSM) drive systems. Recent predictive controllers for sensorless IPMSM drives tend to focus on unconstrained predictive controllers, which do not consider the voltage or current limitations of inverters and may cause responses that are not smooth. The proposed constrained predictive controllers in this article solve these problems by imposing constraints in the performance index for real-time optimization. Simplified numerical solutions that use Hildreth quadratic programming are used to identify active constraints, and then the control inputs are limited within their physical ranges. In addition, a simple external load estimator based on the Lyapunov function is designed to compensate for external load disturbances. Moreover, a current-slope-based rotor position estimation method, which does not require any extra hardware or high-frequency signal generators or occupy any dc-link voltage, is implemented to accurately estimate the rotor position and speed. The proposed method in this article improves the dynamic performance and reduces computational complexity when implemented in sensorless IPMSM drive systems. The proposed methods have quick transient responses, excellent load disturbance responses, good tracking capabilities, and good robustness. The sensorless IPMSM drive system proposed in this article is operated at full-range speeds, from 1 to 3000 r/min. Several simulations and experimental results validate the effectiveness of the proposed constrained predictive controllers.