Low Switching Frequency Motor Drive Using All Switching Patterns Search based Direct Torque Control

This paper focuses on voltage-integral-based reference tracking modulation (VIRTM) and direct torque control (DTC), proposing the control strategy that minimizes switching frequency while achieving excellent dynamic performance. In the proposed scheme, the optimal voltage integral trajectory calculated by exhaustively searching all switching patterns in an offline process is applied to the DTC. One of the advantages of the proposed scheme is its superior versatility and robustness, as it does not rely on motor parameters. Secondly, it significantly reduces the switching frequency at all operating points while preserving the dynamic characteristics of DTC. The effectiveness of the proposed scheme has been validated through experiments, demonstrating up to a 28% reduction in switching frequency compared to conventional standard DTC.

I. Introduction

Industrial drive applications demand systems with high efficiency and excellent dynamic performance. The steady-state characteristics of the drive system place emphasis on reducing the switching frequency without worsening the stator current distortion.