Review of Multilevel Inverters - Topologies, Control Techniques and Reduction of Leakage Current in Cascaded Multilevel Inverter

Multilevel inverters are a source of high power, often used in medium-voltage application. Multilevel converters have received increased interest recently due to high quality output waveform and decrease the harmonic distortion in the output waveform without decreasing the inverter power output. A multilevel inverter uses a series of semiconductor power converters, thus generating higher voltage. Reverse leakage current in a semiconductor device is the current from that semiconductor device when the device is reverse biased. In earlier method transformer is used for generating multilevel output and grid synchronization. Transformer increases the leakage current. Now transformer less method and sine modulation techniques are presented to reduce the leakage current. This paper presents a review on most important topologies, control techniques of multilevel inverters and reduction of leakage current.