A New Configuration Using PWM Current Source Converters in Low-Voltage Turbine-Based Wind Energy Conversion Systems

Current source converter (CSC)-based wind energy conversion systems (WECSs) are recently gaining increasingly attention due to its reliable short-circuit protection. However, all existing CSC-based configurations are proposed for medium-voltage (MV) (3-4 kV) wind turbine systems, but not for low-voltage (LV) (690 V) systems which are dominating the market of WECS. The biggest challenge for using CSCs in LV systems is no proper switching devices in the market. This paper proposes a new configuration, where a proven modular LV voltage source converter is used as the generator-side converter to be compatible with an MV CSC. By such a design, MV CSCs are successfully used in LV systems with all advantages being inherited. In addition, this configuration features high reliability and reduced size and weight, thanks to the adoption of the modular converter. The performance of the configuration under normal and fault conditions are investigated. Apart from fulfilling traditional control objectives in WECS, a current balancing control is added to ensure safe operation. Additionally, limits and constraints of the configuration using in practice are discussed. Finally, simulation and down-scaled experimental results are presented.