High performance Z-source network with reduced switch inverter

This paper presents the performance of a 4-switch, 3-phase high performance Z-source inverter (4S3P) fed cost effective induction motor (IM) drive system. In the proposed approach, instead of a conventional 6-switch, 3-phase inverter (6S3P) a 4-switch, 3-phase Z-source inverter is utilized. This reduces the cost of the inverter, the switching losses, and the complexity of the control algorithms and interface circuits to generate 6 PWM logic signals. Furthermore, the proposed high performance Z-source inverter system employs an IGBT switch before a unique LC network in the dc link and a small capacitor on the ac side of the diode front end. By controlling the shoot-through duty cycle, the Z-source can produce any desired output ac voltage, even greater than the line voltage. As a result, the new Z-source inverter system provides ride-through capability during voltage sags, reduces line harmonics, and reliability. Analysis, simulation, and experimental results will be presented to demonstrate these new features.