4-Unit Cascade Dual Buck Inverter Using Control Systems

Abstract

This paper presents different series concept cascading four single units of dual buck inverter based on dual buck topology with phase-shift control using control systems. The dual buck type inverters are still VSI, but with the unique topology and operation, they do not have the shoot-through worries, which lead to greatly enhanced reliability. With phase-shifted PWM fed to different cascade units, zero crossing distortion is eliminated. The phase-shift control increases the equivalent switching frequency by N times that of single-unit inverter, which leads to lower current ripple. A 1 kW, 120 V ac output cascade dual buck inverter system has been built to validate the proposed topology and by comparing the results of single unit dual buck inverter, 2- unit , 3-unit and 4-unit cascade dual buck inverter at 1kW . The THD is reduced for 4-unit cascade inverter when compared with 3-unit cascade inverter. This is proved by using FFT analysis in MATLAB SIMULINK.