Der Z-Umrichter in Systemen der regenerativen Energieerzeugung

The present doctoral investigation focuses on the Z-Source Inverter (ZSI) and its application in distributed generation of electrical energy out of renewable sources. The range of low powers is especially considered as it is important for the energy supply in remote and rural regions. The ZSI is considered here as a feasible alternative to other well-known and proven concepts of power electronic systems for the energy conversion. The basic task for the power generation system is to harvest the available energy under the special conditions imposed by the renewable source. Depending on the water level, sunlight or wind conditions the voltage of the primary source has fluctuations and is not directly usable. Therefore, the power electronics has to convert the fluctuating voltage in an alternating voltage with constant amplitude and frequency. The ZSI seems to be especially suitable for this purpose as it allows an operation with variable input –as it is often the case in renewable sources- and constant output voltage. In addition, it offers an inherent robustness since a shoot through in the power bridge is not dangerous, it is rather part of the functional principle and allows the voltage boosting of the ZSI.
The research was concentrated to the water turbines in the power range P