A Simplified Modulation Strategy of Nine-Switch Inverter to Cut Off Half of Switching Modes

Nine-switch inverters were designed by sharing three-switches to realize dual-outputs, which are normally realized by two three phase inverters with 12 power semiconductors. Therefore, its modulation strategy is very complex and hard to implement. For this reason, a simplified modulations strategy for the nine-switch inverter is proposed. Based on the switched system model, m-modes controllability of the nine-switch inverter is first proposed to design a simplified space vector pulse width modulation (SVPWM) strategy. Compared with the conventional SVPWM strategies, the newly proposed switching scheme cannot only reduce half of the operating modes but also reduce the switching frequencies. It is significant since it can simplify the control, increase power efficiency and reduce economy cost. Finally, a prototype is designed to verify the proposed modulation strategy.