Omar Ellabban

A DSP-Based Dual-Loop Peak DC-link Voltage Control Strategy of the Z-Source Inverter

This paper proposes a direct dual-loop peak dc-link voltage control strategy, with outer voltage loop and inner current loop, of the Z-source inverter (ZSI). The peak dc-link voltage is estimated by measuring both the input and capacitor voltages. With this proposed technique, a high-performance output voltage control can be achieved with an excellent transient performance including input voltage and load current variations with minimized nonminimum phase characteristics caused by the right half-plane zero in the control to peak dc-link voltage transfer function. Both controllers are designed based on a third-order small-signal model of the ZSI using the direct digital control method. The performance of the proposed control strategy is verified by simulation and experimental results of a 30-kW ZSI prototype.

A Quasi-Z-Source Direct Matrix Converter Feeding a Vector Controlled Induction Motor Drive

This paper proposes a novel four-quadrant vector controlled induction motor (IM) adjustable speed drive (ASD) system based on a recently proposed matrix converter topology called quasi-Z-source direct matrix converter (QZSDMC). The QZSDMC is formed by cascading the quasi-Z-source impedance network and the conventional direct matrix converter (DMC). The QZSDMC can provide buck-boost operation with voltage transfer ratio controlled by controlling the shoot-through duty ratio and bidirectional operation capability. The control strategy, which is based on the indirect field oriented control algorithm, is able to control the motor speed from zero to the rated value under full load condition during motoring and regenerating operation modes. The operating principle of the proposed system is presented in detail. The simulation and the real-time implementation results, using dSPACE 1103 ControlDesk, validate the high performance of the proposed four-quadrants IM-ASD based on QZSDMC system. The proposed four-quadrant vector controlled IM-ASD system based on the QZSDMC topology overcomes the voltage gain limitation of the traditional DMC and achieves buck and boost condition in four-quadrant modes with reduced number of switches, therefore achieving low cost, high efficiency, and reliability, compared with back-to-back converter.

Z-Source Matrix Converter: An Overview

Conventional matrix converters (MCs) have limited voltage gain that is less than 0.866, whether for direct MC (DMC) or indirect MC (IMC). The Z-source MCs (ZSMCs) overcome the voltage gain limitation of the traditional MC and achieve buck and boost operation with reduced switches count, thereby achieving low cost, high efficiency, and reliability, compared to the back-to-back converter. Furthermore, it will leads to more MC industrial applications. This paper presents an up-to-date comprehensive overview of the different ZSMC topologies and their configurations, circuit analyses, modulation schemes, and applications. This study offers a comprehensive and systematic reference for the future development of the ZSMCs.