Model Predictive Torque Control of a Hybrid Excited Axial Field Flux-Switching Permanent Magnet Machine

Jilong Zhao,Mingyao Lin,Xiaowei Quan

doi:10.1109/access.2020.2973360

Abstract

Hybrid excited axial field flux-switching permanent magnet (HEAFFSPM) machine is a novel stator excitation hybrid excited synchronous machine, which combines the advantages of the axial field flux-switching permanent magnet machine and wound field machine. In this paper, two model predictive torque control (MPTC) methods with flux-adjusting strategy implementation for the HEAFFSPM machine, including the MPTC and MPTC with duty cycle control (MPTC-DCC) by optimizing the active voltage vector duration to reduce the torque and flux ripples, are proposed and comparatively investigated. Based on the theoretical analysis, a discrete-time model of the HEAFFSPM machine is established. Considering the flux-enhancing/-weakening strategies, the different multi-objective cost functions are designed. The multiple right weight coefficients are analyzed and chosen to optimize the operating performance of the drive system. The results indicate that the proposed MPTC-DCC method reduces the torque and flux ripples significantly compared with MPTC method, and the drive system has better steady performance. Meanwhile, the load capability in the whole speed region is improved and the constant power operating range is broadened by using the proposed flux-adjusting strategy.

Highlights

Recently, stator permanent magnet (PM) axial field flux-switching PM (AFFSPM) machines have received wide attention. These machine combine the feature of the axial flux PM machine [1]–[5] and flux-switching machine [6]–[10], which exhibit a lot of advantages including short axial length, compact and robust structure, as well as high power/torque density, and so on [11]–[15]
The hybrid excited AFFSPM (HEAFFSPM) machine is a novel stator excitation hybrid excited synchronous machine (HESM), which combines the characteristics of the AFFSPM machine and the wound field machine, and is an excellent candidate for variable-speed applications such as electric vehicles (EVs)
Some control strategies based on the vector control (VC) method for the HESM have been reported in the scientific and technical literature

Summary

INTRODUCTION

Stator permanent magnet (PM) axial field flux-switching PM (AFFSPM) machines have received wide attention. By regulating the amplitude and polarity of the excitation current in the field windings, hybrid excitation operating modes including PM, flux-enhancing, and flux-weakening can be implemented. J. Zhao et al.: MPTC of a HEAFFSPM Machine capability in the constant power region was improved and the range of speed regulation was broadened. In [26], a novel control strategy, based on the principle of the voltage error regulation method while the field current is controlled towards zero in the flux-weakening mode, for a hybrid excited FSPM machine was proposed. The minimal winding copper losses operation was performed to enhance the load capability in the entire speed region and broaden the wide speed operating range, but it was not suitable for the large saliency ratio HESM. Due to the flux-switching feature, the pole number is equal to the number of pole pairs

MATHEMATICAL MODEL

REFERENCE CURRENT AND FLUX CALCULATION

SIMULATION

EXPERIMENTAL VERIFICATION

CONCLUSION