Comparative Study and Overview of Field-Oriented Control Techniques for Six-Phase PMSMs

Marek Furmanik,Pavol Rafajdus,Lukáš Gorel,Daniel Konvičný

doi:10.3390/app11177841

Abstract

This paper targets the main current trend in automotive motor control applications, i.e., six-phase permanent−magnet synchronous machines. Multiphase machines have been studied for more than one decade, but they are currently becoming more and more important for automotive technology. Increased safety and improved reliability are the two main reasons why six-phase machines conquer safety-critical motor control applications. The paper provides a detailed description, analysis, and comparison of two field-oriented control strategies for six-phase machines. The article consists of four main parts: (1) a general introduction of the application field of six-phase machines; (2) a description of two different field-oriented control techniques; (3) a presentation of the experimental results, e.g., frequency and step response analysis, as well as a comparison between a mathematical model and a real system; (4) a detailed comparison of strategies including pros and cons, with a strong focus on the main advantages.

Highlights

Multiphase electric machines have been frequently discussed in recent years by professionals worldwide, where the term “multiphase” refers to machines with more than three phases
The results of various authors have described an improvement in efficiency, the harmonic spectrum of MMF, a lower phase current and torque ripple, and, most significantly, parameters related to the system’s fault tolerance and redundancy [1,2,3,4,5]
Multiphase machines are used in high-power applications for a reduction in phase current stress, e.g., huge cargo ships, mills, and wind power plants [6,7]

Summary

Introduction

Multiphase electric machines have been frequently discussed in recent years by professionals worldwide, where the term “multiphase” refers to machines with more than three phases. In various applications and research works, two main approaches can be recognized according to the number of current controllers used for torque− and flux−producing components of a whole machine. In [11], a vector space decomposition (VSD) method was introduced as a control of torque/flux components in one orthogonal subspace, with current harmonics elimination. A method with only two current sensors for the field-oriented control of a six-phase machine was shown in [14]. A working cycle of these applications includes operation below the rated power, where the pure two-controller method will not fulfill the best qualitative parameters of the drive, since phase current harmonics lead to additional losses.

System Realization and Comparison

Conclusions