Model-Free Filter-Based Single-Loop Output-Feedback System Design for PMSMs With Critically Damped Performance

This article designs a filter-based output-feedback system to regulate the speed of permanent magnet synchronous motors (PMSMs), which structures a simple single-loop form compensated by feed-forward terms. The proposed controller design framework considerably reduces the dependence level of the PMSM model by requiring partial nominal parameter values for control law and removing the model structure and whole parameter information for the filter. The main advantages consist of two parts. First, the proposed observer employs the second-order pole-zero cancelation (PZC) technique to continuously extract the speed and acceleration from noisy position measurements by the rotary encoder, independent from the PMSM model. Second, the PZC filter-based proportional–integral control forms a single-loop feedback system including the active damping injection and disturbance observer, which assigns the critically damped performance to the closed-loop system by specially structuring the feedback gains. The performance improvement derived by the closed-loop analysis is validated through an experimental comparison study using a prototype 700-W PMSM controlled by the 32-b microprocessor.