The Bypass Power Supply Implementation for Medium Voltage AC Drive with Cascaded H-bridge Converter

A frequency converter based on a multilevel pulse-width modulation inverter makes developing a novel approach power supply changeover from the frequency converter to the grid, as well as increasing the reliability an urgent task due to a widespread and a high cost one. The paper presents a brief review of the bypass power supply implementation for the medium voltage AC drive with a cascaded H-bridge converter. Special attention was paid to the solution with using a current balancing reactor and a preliminary voltages synchronization. To illustrate a proper operation of the method the experiment was performed through the downscaled prototype of the frequency converter based on a 7-level cascaded H-bridge converter inverter. The experimental results proved the effectiveness of the technique for the AC drives with the cascaded H-bridge converter multilevel inverter.