Evaluation of Predictive Current Control Techniques for PM BLDC Motor in Stationary Plane

Manish S Trivedi,Ritesh Kumar Keshri

doi:10.1109/access.2020.2978695

Manish S Trivedi, Ritesh Kumar Keshri

Open Access

https://doi.org/10.1109/access.2020.2978695

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Journal: IEEE Access	Publication Date: Jan 1, 2020
Citations: 38	License type: CC BY 4.0

Affiliation: Visvesvaraya National Institute of Technology

Abstract

In general, PM BLDC motors are injected with square wave phase currents through PI-PWM control in a-b-c reference plane to ensure maximum torque-per-ampere. The operation of PM BLDC motor in a stationary plane has shown considerable simplification in design, and analysis in the control techniques. The present paper considers the injection of square wave phase current through predictive current control strategies in the stationary plane. For the evaluation of performance, cases of deadbeat predictive control, hysteresis based predictive control, and finite control-set model predictive control (FCS-MPC) methods are considered. Control schemes have been designed for 48V, 660W PM BLDC motor. Comparative evaluation is carried out in terms of the harmonic components available in the current and torque, tracking of the current trajectory in the stationary plane in the low and high-speed region, and execution time of all the control methods. Considered predictive methods are tested on an experimental prototype, and control is implemented through digital Signal Processor (DSP) TMS320F28335. Evaluation leads to the conclusion that predictive control performs better than PI-PWM for reducing commutation torque ripple, keeping current harmonics under control. It is observed that predictive control strategies in the stationary plane, improve the torque-speed characteristic to the wider utilization of constant torque zone of operation as compared to conventional strategies.

Highlights

Permanent magnet (PM) brushless dc (BLDC) motor, with non-sinusoidal back-EMF waveform, uses rotor position information from hall sensors to inject phase current synchronized with the flat portion of the back-emf [1]
Torque ripple issue is addressed through the equalization of slopes of the incoming or outgoing phase currents as per the lower or higher speed range and realized by the PWM control techniques with appropriate duty ratio control of the respective phase switches of the inverter [8]–[10]
The evaluated predictive current control techniques are compared with conventional control technique to verify the performance, and it shows better performance than conventional current control technique for reducing commutation torque harmonic as well as tracking the ideal current, and they are easy to understand and implement

Summary

Introduction

Permanent magnet (PM) brushless dc (BLDC) motor, with non-sinusoidal back-EMF waveform, uses rotor position information from hall sensors to inject phase current synchronized with the flat portion of the back-emf [1]. Torque ripple issue is addressed through the equalization of slopes of the incoming or outgoing phase currents as per the lower or higher speed range and realized by the PWM control techniques with appropriate duty ratio control of the respective phase switches of the inverter [8]–[10]. These techniques require information about the commutation duration either by the computation through the employed micro-controller or dedicated hardware circuitry. In [11], the three-segment modulation method for a full-speed range is used for the generation of duty ratio, which is based on complex analytical

Objectives

Findings

Conclusion