A Novel Trajectory Planning for One-Loop Flatness-Based Control of PMSM

Abstract

Permanent Magnet Synchronous Motors (PMSMs) are used in a variety of industries, including aerospace, industrial control, and electric vehicles (EVs). Extensive research has been dedicated to the control and drive of PMSMs, with field-oriented control (FOC) gaining prominence in today’s industry. Despite its popularity, the nonlinear nature of the PMSM drive system impacts the dynamic performance when employing the traditional Proportional-Integral (PI)-based FOC method, particularly under varying operating points. Over the last decade, flatness-based control has emerged as a viable alternative to PI-based FOC in response to system nonlinearity. As a traditional approach, a cascaded flatness-based control structure has been proposed in the literature. This method, however, has lower dynamic performance due to its cascaded structure. The flatness-based control with only one control loop is suggested for improving the dynamic performance of the flatness-based control, especially for high-speed and low-inertia systems. This method, however, lacks current protection. This paper introduces a novel trajectory planning approach for the one-loop flatness-based control of PMSM drives. The focus is on addressing controller limits, an aspect that has received limited attention thus far. The proposed approach ensures control stability by considering the constraints of the maximum motor current (determined by the electrical specifications of the motor and driver) and the switching voltages, which depend on the DC-bus voltage. The method’s effectiveness is validated through simulation studies and experimental tests.

Keywords

• Permanent magnet synchronous motor (PMSM)
• flatness-based control
• trajectory planning/replanning
• optimization