Abstract

The conventional cascaded H - bridge converters suffers with demerits like more switching losses as it consists of\nseries H- bridge cells. Moreover, the output voltage contains harmonics and often these, are beyond the acceptable limits. In\nthe literature, various methods are available on zero sequence voltage and these techniques requires a large capacitor to inject\nvoltage such capacitors are required whenever the unbalanced voltages appears in the system. The cause for unbalanced\nvoltages is faults in the networks. It also suffers with practical issues with capacitor size. Similarly, the negative sequence\nvoltage injection also suffers with handling issues and hence STATCOM is limited to certain range of capacitors only. This\nmakes us to propose a new control technique to overcome such limitations. A combination of both zero sequence voltage and\nnegative sequence currents are used to operate STATCOM. These techniques can handles the consequences due to\nunsymmetrical conditions arise from various system faults. This control technique is also used in cascaded H-bridge in\nSTATCOM topology to improve the performance. MATLAB is used to test the effectiveness of the proposed method.