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This paper proposes a new topology of cascaded transformer based multilevel inverter using single Z-source. The suggested circuit consists of only one Z network and single DC voltage source, as a result installation area is reduced. In this topology the output voltage amplitude is not limited to DC voltage source and transformers turns ratios similar to traditional cascaded transformer based multilevel inverter and can be increased with Z network shoot-through state control. Besides, it is more reliable against short circuit. In this paper, by using particular switching algorithm, the modulation index of inverter is kept constant and output voltage is controlled by a shoot-through duty ratio, therefore Total Harmonic Distortion (THD) of output voltage is nearly constant for different boost ratio. The performance of suggested inverter and switching algorithm are validated with simulation results using MATLAB/SIMULINK software.

This paper proposes the use of a novel three-phase PWM rectifier-inverter topology for doubly fed induction generator (DFIG) applications. The topology uses only nine IGBT devices for ac/ac conversion through a dc link. As compare to conventional back-to-back ac/ac converters, the numbers of power semiconductor switches are reduced in the suggested converter. The proposed topology results in reduction of installation area and cost. The operating principle, control strategy and characteristics of DFIG based proposed ac/ac converter is described in this paper. The performance of proposed DFIG is validated with simulation results using MATLAB/SIMULINK software.

This paper proposes a new topology of Z-source based cascaded multilevel inverter. In this topology the output voltage is not limited to DC voltage source similar to traditional cascade multilevel inverter and can be increased with Z network shoot-through state control. Besides, it is more reliable against short circuit. Performance of suggested topology in the closed-loop control scheme is described in the Dynamic Voltage Restorer (DVR) structure. Compensation capability of the proposed DVR increases. The operating principle, switching algorithm and characteristics of proposed topology are described in this paper. The performance of suggested inverter and switching algorithm are validated with simulation results using MATLAB/SIMULINK software.