Asymmetrical grid control with power electronic regulator in distribution level

Abstract

As the amount of decentralised generation is continuously increasing, the control and maintenance of grid stability become more complex. This is mainly caused by a change of production capacities from the high-voltage area to the distribution network. As most renewable energy sources in the distribution network are nowadays connected to power electronic converters, harmonic distortion as well as asymmetries (electric vehicle chargers, household photovoltaic systems) are increased. To ensure stability, reliability, and efficiency of the energy distribution network, a grid regulator including asymmetrical and harmonic control is introduced. This grid regulator consists of two inverter systems, where one is connected by a series booster transformer in line, while the other is connected in parallel to the line, capable of decoupling network segments from each other. After a successful verification in simulation, the control structure is implemented in a real hardware setup. The results show that the introduced system is able to decouple network elements in case of an unbalanced situation as well as harmonic current and voltage distortion. To simplify inverter hardware a silicon carbide hardware topology is introduced with a reduced number of switches. Lower switching losses result in higher overall system efficiency.