Wide Speed Range Operation Strategy of Indirect Matrix Converter–Surface Mounted Permanent Magnet Synchronous Motor Drive

Nuofan Zou,Tingna Shi,Peng Song,Yan Yan

doi:10.3390/en14082277

Abstract

In order to expand the speed range for an indirect matrix converter–surface mounted permanent magnet synchronous motor drive (IMC-SPMSM), a wide speed range operation control strategy based on a flux-weakening control and an over-modulation method is proposed in this paper. In the stage of the inverter, an IMC over-modulation method is designed, which increases the fundamental voltage transmission ratio (VTR) to 1. In addition, considering the variation of the voltage limit boundary of the IMC with motor speed, flux-weakening control is implemented based on the voltage error feedback method, which maximizes the voltage utilization rate by setting the endpoint of the output voltage vector on the voltage boundary during the flux-weakening operation. In the stage of the rectifier, over-modulation is automatically switched on or off according to operation requirements by a modulation depth controller. Finally, experimental results show that the proposed strategy increases the maximum speed of the IMC-SPMSM by nearly 35% compared to the maximum torque per ampere (MTPA) method. Besides, the enlarged voltage margin by the rectifier stage over-modulation effectively shortens the setting time.

Highlights

Permanent magnet synchronous motors are widely used in aerospace, computational numerical control (CNC) spindle drives, industrial automation, and other fields, which often require a wide speed range, due to their high power density [1]
The flux-weakening control strategies for a classical vector control system with two inner current loops can be roughly divided into three categories: feedforward strategy, feedback strategy, and hybrid strategy
The feedforward strategy, just as its name implies, feedforwards a compensation component calculated from steady voltage equations of motor into its magnetic current reference

Summary

Introduction

Flux-weakening and over-modulation are the mostly used methods to obtain a wide speed range for a motor drive system under certain voltage supply and current [2]. The feedforward strategy, just as its name implies, feedforwards a compensation component calculated from steady voltage equations of motor into its magnetic current reference. The method in [3] uses a motor equation to calculate current reference values and considers stator resistance voltage drop. The feedback strategy is proposed to improve robustness of the system It usually uses voltage amplitude error [5], overmodulation voltage error [6], and action time of the active vector in space vector modulation (SVM) [7], which is not suitable for six-step operation, as feedback. Methods in [6,7]

Methods

Results

Conclusion