Z-source Inverter Fed Induction Motor Drives – a Space Vector Pulse Width Modulation Based Approach

Z Source inverters have recently been proposed as an alternative power conversion concept for adjustable speed AC drives (ASD) with both voltage buck and boost capabilities as they allow inverters to be operated in the shoot through state. It utilizes an exclusive Z – source network (LC component) to link the main inverter circuit to the power source (rectifier). By controlling the shoot-through duty cycle, the inverter system using IGBTS, provide ridethrough capability during voltage sags, reduces the line harmonics, improves power factor, increases reliability and extends output voltage range. Advanced and Computation-intensive Space vector Pulse Width Modulation (SVPWM) Z-source inverter based approach is proposed in this paper. SVPWM allows the operation of inverter in Over modulation region. Possibly, it is the best among all the PWM techniques for variable speed applications. This proposed strategy considers the inverter as a single unit and greatly reduces the complexity and cost when compared with traditional systems. Simulation has been performed for 10HP induction motor with SVPWM impedance source inverter and the results are experimentally verified to demonstrate these new features. It has reduced harmonics, low switching stress power and low common mode noise.