Speed Control of Load Torque Feedforward Compensation Based on Linear Active Disturbance Rejection for Five-Phase PMSM

Zhi Kuang,Bochao Du,C C Chan,Shumei Cui

doi:10.1109/access.2019.2950368

Abstract

This study focuses on the speed control problem of a five-phase permanent magnet synchronous motor (PMSM) in the presence of a variable load torque and unknown model parameters. To overcome the mutual transmission of motor torque ripple and load disturbance when the five-phase PMSM directly drives the load, a control method of load torque feedforward compensation based on linear auto disturbance rejection controller (LADRC) is proposed. First, the load torque observer is introduced to observe the load torque which is used as feedforward compensation to eliminate the effects of load torque changes. Second, an LADRC in the outer speed loop is presented to estimate the disturbance, and the stability of LADRC is analyzed. Third, the proposed torque feedforward method based on the LADRC is compared with the traditional proportional integral (PI) torque feedforward method. The PI regulators for current loops are designed. Finally, the simulation models are built and the control algorithms are both implemented using a TMS320F28335 DSP. The simulation and experiment results show that the proposed load torque feedforward compensation based on the LADRC produces excellent dynamic performance, such as smaller overshoot and faster response time. The proposed control scheme is robust and has a strong anti-disturbance ability, even in the case of large load torque disturbances.

Highlights

Owing to its fault-tolerant capability, high power density and high reliability, multiphase permanent magnet synchronous motor (PMSM) for variable speed applications have attracted considerable attention in various fields [1]
The active disturbance rejection controller (ADRC) is a nonlinear control method proposed by Han in 1998 [2], and its working principle is to regard the unknown dynamics as the extended state of the controlled object, and estimate it through extended state observer (ESO) and compensate its unknown dynamics in real time
The simulation results based on space vector pulse width modulation (SVPWM) for the five phase PMSM driven by a voltage source inverter are compared between the proposed control scheme and traditional proportional integral (PI) torque feedforward compensation under the same conditions

Summary

Introduction

Owing to its fault-tolerant capability, high power density and high reliability, multiphase permanent magnet synchronous motor (PMSM) for variable speed applications have attracted considerable attention in various fields [1]. Two disturbance torques between motor torque ripple and load are directly transmitted to each other. The control system for multiphase PMSM is nonlinear with strong coupling and multivariable conditions leading to poor speed characteristics. Contradiction between rapidity and overshoot in a wide speed range using proportional integral (PI) regulators, so it is of importance to find a way to resist the unpredictable disturbance as much as possible. The active disturbance rejection controller (ADRC) is a nonlinear control method proposed by Han in 1998 [2], and its working principle is to regard the unknown dynamics as the extended state of the controlled object, and estimate it through extended state observer (ESO) and compensate its unknown dynamics in real time. ADRC resists disturbances from the outside and inside by estimating the speed loop and flux linkage of the induction motor [3]. To further overcome the uncertainty of disturbances estimation error and control gain, the sliding mode control method based on ADRC is proposed [4], [5], and the model prediction based on ADRC is used to accurately estimate the model

Methods

Results

Conclusion