Design and implementation of sosmc based ga pso tuned pi controller for impedance source inverter using spwm and svpwm techniques

Abstract

The grid connected renewable energy system must have the balanced AC voltages during dynamic conditions. In order to supply clean power to the grid, the grid-connected power converters are necessary. To obtain the balanced AC voltage, the system must have the capability to buck and boost the input voltage to compensate the changes in the Renewable Energy Sources. Usually two stage converters are used for this purpose. The boost converter is used in the first stage to increase the voltage and the inverter is used in the second stage to convert DC to AC. Voltage Source Inverter (VSI) is commonly used, because of their ease of control and design. But Shoot-Through (ST) may occur, if the switches of same phase leg are triggered simultaneously. Another issue is that the traditional inverter adds the dead-band time into the control sequence resulting in output waveform distortion and increased %Total Harmonic Distortion (THD). Another conventional inverter such as Current Source Inverter (CSI) is not commonly used because of its commutation problem. CSI also provides sluggish performance at light load and at high frequency and creates stability issues, which make it impossible to use them alone in grid connected applications. To alleviate these problems in VSI and CSI, Multilevel Inverters (MLIs) are introduced to produce sinusoidal AC voltages with less % THD. VSI, CSI and MLI are used for two stage conversion. The major challenges in two stage conversion are reduced power conversion performance, reduced reliability, high switching stress, high power loss, high cost, increased number of components and separate controller for boost converter and VSI / CSI are required. These limitations can be overcome by single stage Z-Source Inverter (ZSI) with its remarkable ability to handle line variations. newline