High-performance multicell series inverter-fed induction motor drive

Mohammed Khodja ,Ahmed Allali ,Mohamed Badreddine Benabdallah ,Djelloul Rahiel ,Houari Merabet Boulouiha ,Abdelkader Chaker ,Mouloud Denaï

doi:10.1007/s00202-016-0472-4

Abstract

The multilevel voltage-source inverter (VSI) topology of the series multicell converter developed in recent years has led to improved converter performance in terms of power density and efficiency. This converter reduces the voltage constraints between all cells, which results in a lower transmission losses, high switching frequencies and the improvement of the output voltage waveforms. This paper proposes an improved topology of the series multicell inverter which minimizes harmonics, reduces torque ripples and losses in a variable-speed induction motor drive. The flying capacitor multilevel inverter topology based on the classical and modified phase shift pulse width modulation (PSPWM, MPSPWM) techniques are applied in this paper to minimize harmonic distortion at the inverter output. Simulation results are presented for a 2-kW induction motor drive and the results obtained demonstrate reduced harmonics, improved transient responses and reference tracking performance of the voltage in the induction motor and consequently reduced torque ripples.

Highlights

Many variable speed induction motor drive applications require high torque dynamics and low torque ripples to meet the requirements of high productivity and improved accuracy
This paper is organized as follows: Section 2 describes the topology of the flying capacitor multilevel inverter (FCMI) driving an induction motor and presents the generalized switching law for FCMI based on the phaseshifted PWM (PSPWM) strategy
This study focuses on a three phase five-level multicell inverter topology to highlight the following two results: (i) Increased voltage levels: By increasing the level of the structure, the stress on the IGBTs can be reduced, the multicell inverter provides more levels than the NPC or cascade inverter topologies

Summary

Introduction

Many variable speed induction motor drive applications require high torque dynamics and low torque ripples to meet the requirements of high productivity and improved accuracy. As compared to field oriented control (FOC), DTC implementation minimises the use of machine parameters [7,8] while maintaining the advantages of fast transient response characteristics These two control techniques have a major disadvantage as they exhibit ripples at high torque and flux values which results in high acoustic noise [9]. Rotor flux oriented vector control of the induction motor based on a series multicell converter is proposed to improve the quality of the three-phase currents and minimising torque ripples. This paper is organized as follows: Section 2 describes the topology of the flying capacitor multilevel inverter (FCMI) driving an induction motor and presents the generalized switching law for FCMI based on the phaseshifted PWM (PSPWM) strategy.

Overview of the multicell converter

PSPWM switching control

Simulation results

Findings

Conclusion