Single-Phase Inverter and Rectifier for High-Reliability Applications

With the depletion of fossil fuels and skyrocketed levels of CO_(2) in our atmosphere, Renewable Energy Resources, generated from natural, sustained, clean, and domestic resources, have caught the eye in recent years of both the industries and governments worldwide. In addition to finding these energy resources, new technologies are being sought to improve the efficiency of consuming the generated energy. Power Electronics is the key technology for both generation and the efficient consumption of energy. The recent trend in power electronics is to integrate the electronics into the source (Photovoltaic (PV)) or the load (light). For PV and outdoor lighting applications, this imposes a harsh, wide-range operating environment on the power electronics. Thus, the reliability of power electronics converters becomes a very crucial issue. It is required that the power electronics, used in such environments, have reliability indices, such as lifetime, which match with the source or load one. This eliminates the reoccurring cost of power electronics replacement. Relatively high efficiencies have been reported in the literature, and standards have been developed to measure it. However, the reliability aspect has not received the same level of scrutiny. In this study, two main aspects have been investigated: (1) A new methodology to evaluate the integrated power electronics that becomes more involved task; and (2) new topology and control schemes, for the single-phase DC/AC and AC/DC converters, which will improve the reliability. The proposed methodology has been applied for different PV Module-Integrated-Inverter (MII) that employs different power decoupling techniques. The results showed that the decoupling capacitor is the limiting lifetime component in all the studied topologies. Moreover, topologies use film capacitor instead of electrolytic capacitor showed an order of magnitude improvement in the lifetime. This clearly suggests that replacing the electrolytic capacitor by a high-reliability film capacitor will enhance the reliability of the PV MII. In the second part of this study, the ripple-port concept is applied for the single-phase DC/AC inverter and AC/DC rectifier, which allows for the usage of the minimum required decoupling capacitance. In conclusion, film capacitor can be used, which led to the improvement of the overall reliability and lifetime.