Modeling and Experimental Validation of 5-level Hybrid H-bridge Multilevel Inverter Fed DTC-IM Drive

Abstract

-This paper aims to improve the performance of conventional direct torque control (DTC) drives proposed by Takahashi by extending the idea for 5-level inverter. Hybrid cascaded H-bridge topology is used to achieve inverter voltage vector composed of 5-level of voltage. Although DTC is very popular for its simplicity but it suffers from some disadvantages like-high torque ripple and uncontrollable switching frequency. To compensate these shortcomings conventional DTC strategy is modified for five levels voltage source inverter (VSI). Multilevel hysteresis controller for both flux and torque is used. Optimal voltage vector selection from precise lookup table utilizing 12 sector, 9 torque level and 4 flux level is proposed to improve DTC performance. These voltage references are produced utilizing a hybrid cascaded H-bridge multilevel inverter, where inverter each phase can be realized using multiple dc source. Fuel cells, car batteries or ultra-capacitor are normally the choice of required dc source. Simulation results shows that the DTC drive performance is considerably improved in terms of lower torque and flux ripple and less THD. These have been experimentally evaluated and compared with the basic DTC developed by Takahashi.

Review of recent advancements of direct torque control in induction motor drives – a decade of progress

“…To overcome this, techniques to synthesise intermediate voltage vectors in two‐level inverter [47, 48, 69] and DTC using special converters are introduced. Special converters like matrix converters [44, 94–96, 109–111] and multilevel inverters [49–52, 97, 98, 112–119] provided more voltage vectors for better control options. This allowed to design modified switching table, increased torque hysteresis levels [47, 69] and selecting optimised voltage vector to provide maximum torque rate under dynamic conditions [48] for better controllability and reliability.…”

High-Performance Standalone Photovoltaic Water Pumping System Using Induction Motor

“…The torque ripples cause additional noise and mechanical vibrations. Different solutions are proposed in the literature to overcome these disadvantages [18,19]. In this paper, a fuzzy logic controller (FLC) is proposed to improve the performance of DTC.…”

Research on Control of Permanent Magnet Synchronous Motor Based on Second-Order Sliding Mode

“…Refs. [10][11][12] consider the use of multi-level control power converters, which can make multiple spatial voltage vectors act on the motor. This method makes the flux linkage and torque in the DTC system smooth, and the total harmonic distortion is small, but it greatly increases the hardware cost and complexity of the system.…”