Five-Dimensional Switching-Table-Based Direct Torque Control of Six-Phase Drives

Abstract

This paper proposes a novel five-dimensional switching table-based direct torque control (5D-DTC) strategy for asymmetrical six-phase induction machines (6PIMs). As is wellknown, classical DTC of 6PIM is penalized by significant stator current harmonics, which are mapped into the non-energy subspace (x − y subspace). The concept of virtual voltage vectors (VVs) has been frequently perceived as able to tackle the problem of x − y currents. Such a concept maintains zero average voltsecond in the x − y subspace, which in turn suppresses current harmonics due to discrete PWM implementation to a great extent compared to the classical DTC. However, it still cannot effectively compensate for x − y currents, mainly arising from dead band effect and machine/converter asymmetry, due to lack of dedicated regulators for x − y currents. Indeed, the x − y currents can be fully suppressed only in the presence of active control over them. This paper incorporates additional hysteresis regulators of x − y currents into the direct torque control strategy. In the proposed 5D-DTC scheme, there are in total five indexes for optimal selection of VVs as torque, stator flux, x − y currents, and stator flux position indexes. In this way, a clustering method is developed for synthesizing VVs to cover all possible cases of the switching table. A beneficial feature in comparison with three-dimensional switching table-based DTC (3D-DTC) is effective suppression of x − y currents with a rather simple structure, without increasing the switching frequency, and without decreasing DC-link utilization. Experimental results confirm the effectiveness of the proposed technique.

Advanced Electrical Motors and Control Strategies for High-quality Servo Systems - A Comprehensive Review

“…Among them, the space vector modulation DTC (SVM-DTC) strategy has attracted considerable attention due to its ability to provide a fast torque response and low torque and flux ripples [98][99] . In addition, the switching-table DTC (ST-DTC) strategy has been widely researched owing to its fewer computational requirements, ease of implementation, and lower switching frequency [100][101] .…”

A Comparative Study of Cutting-Edge Bi-Directional Power Converters and Intelligent Control Methodologies for Advanced Electric Mobility

“…Lookup Table-based Model Predictive Direct Torque Control (LUT-MPDTC) enhances the performance of a synchronous generator with a Vienna rectifier by reducing torque and flux ripples and minimizing computational problems compared with traditional DTC. [100]. As a novel approach based on current minimization, this study aims to determine the optimum values of the reference flux linkage in a vehicle control strategy, thereby improving its drivetrain efficiency.…”