Embeded control of Z-Source inverter

Abstract

Traditionally Voltage Source Inverter (VSI) and Current Source Inverter (CSI) fed induction motor drives have a limited output voltage range. Conventional VSI and CSI support only current buck DC-AC power conversion and need a relatively complex modulator. The limitations of VSI and CSI are overcome by Z-source inverter. The Z-source inverter system employs 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 (i.e. 325V for 230V AC) regardless of the input voltage. The proposed Z-source inverter system provides ridethrough capability during voltage sags, reduces line harmonics, improves power factor and reliability, and extends the output voltage range. Analysis, simulation, and experimental results were presented to demonstrate these features. This system reduces harmonics, electromagnetic interference noise and it has low common mode noise. Index Terms: current source inverter (CSI), voltage source inverter (VSI), Z-source inverter (ZSI), electro magnetic interference (EMI)