Power conversion is the process of converting electrical energy from one form to another, such as changing the voltage or conversion from alternating current (AC) to direct current (DC) to adapt to the needs of an electronic device. Power converters are used in a wide variety of applications, including industrial drives and renewable energy systems such as photovoltaic (PV) systems and wind energy systems. Demand for renewable energy is increasing, and most of these new energy sources are coupled to our AC grid through power electronic-based power converters and large bulky isolation transformers. The attributes of these converters, including their weight, volume, efficiency, cost, and lifetime, have a significant impact on the performance of renewable energy systems and industrial factories. In PV systems, power converters are responsible for more than 50% of the total failures, and need to be replaced once or twice within the lifetime of a PV module. Moreover, a 500kW isolated PV inverter weighs more than 4,500kg and requires a crane for installation, which imposes additional costs on the system. Advanced high-performance power converters can operate with improved power densities, lifetime, and efficiency, while reducing the costs associated with shipping, installation, repair, and replacement of traditional converters.
Project Innovation + Advantages:
Northeastern University will develop a new class of universal power converters that can be used in a wide range of applications including renewable energy systems, automotive, and manufacturing technologies. Northeastern will focus the project on the design, simulation, prototyping, and experimental evaluation for PV systems. This project proposes a new class of converters that can both step up and step down the voltage. This converter uses a very small film capacitor for transferring the power from the input to the output. The proposed technology eliminates the need for electrolytic capacitors, and can double the lifetime and reliability of power converters. The power density of this class of power converters is also high since it can use an integrated, single-phase, high-frequency transformer instead of heavy and bulky low-frequency transformers. In this project, two 3kW prototypes will be fabricated and tested. The first will use silicon insulated-gate bipolar transistors and its switching frequency will be below 10kHz. The second prototype will employ silicon carbide (SiC) metal oxide semiconductor Field-Effect Transistors (MOSFETs) with the target switching frequency at 50kHz. Significant reduction (6X) in inverter weight and improvement in inverter efficiency (> 1.5%) is expected in the proposed solution that combines the novel circuit topology and the SiC transistors over traditional PV inverters.