Hysteresis Model Predictive Current Control for PMSM With LC Filter Considering Different Error Shapes

Stefan Walz,Marco Liserre

doi:10.1109/ojpel.2020.3000466

Abstract

This paper investigates three-phase two-level VSI hysteresis-based Model Predictive Control (MPC) for permanent magnet synchronous machines with different current error shapes. To limit the motor current harmonics and prevent overheating of the magnets, motor filters (mostly LC filters) are often used. The hysteresis-based MPC is investigated to provide high dynamic performance and limit the size of the filter. To compensate the resonance introduced by the LC filter and to improve system efficiency, a virtual resistor active damping strategy is implemented. To avoid additional sensors, the filter states are determined by a Luenberger Observer. However, up to now these strategies have never been investigated together with MPC and different current error shapes for motor applications. Simulation results for the different strategies prove the performance efficiency and experimental tests verify the results in a laboratory environment.

Highlights

For electrical drive applications, the field-oriented control (FOC) with a cascaded speed and current regulator is used in industry since many years
The permanent magnet synchronous machine is the first choice for many applications and due to the compact size, high power density and good efficiency permanent magnet machines are widely used in industry [1]
From the dq-error current circle, square, and hexagon it can be seen, that the Model Predictive Control (MPC) requires a current bound of 7.5A, 7.1A, and 8.0A and stays perfectly inside the bounds, while the PI Control has bigger current variations

Summary

Introduction

The field-oriented control (FOC) with a cascaded speed and current regulator is used in industry since many years. The permanent magnet synchronous machine is the first choice for many applications and due to the compact size, high power density and good efficiency permanent magnet machines are widely used in industry [1]. At low ratios of switching frequency to electrical frequency ( fsw/ fel ) the linear control gets instable. For medium to high power drives, the switching frequency fsw has to be kept low [3], [4]. In case the natural filtering due to the machine inductances is not sufficient, the low pulse ratio results in high current and voltage harmonics and can heat up the permanent magnets of the machine. To prevent overheating and irreversible demagnetization, a filter may be used to reduce the accruing harmonics [5]

Methods

Results

Conclusion