Multivariable-PI-based DQ Current Control of Voltage Source Converters with Superior Axes Decoupling Capability

This paper presents a linear direct-quadrature (dq) current control strategy for voltage source converters (VSCs) in a rotating reference frame (RRF). The described method is based on Multivariable proportional-integral (PI) regulators and provides fast dynamics and zero steady state error. Contrary to the well-known conventional PI-based control strategies in rotating reference frames, the presented method provides practically decoupled axes with superior disturbance rejection capability. Moreover, its implementation is relatively simple and does not impose excessive structural complexity compared to its conventional PIbased competitors. The method is applicable to both single and three phase systems, and also to anisotropic three-phase systems, e.g., synchronous motors with different direct and quadrature impedances driven by VSCs. Implementing a three-phase test system, the performance of the presented method is experimentally evaluated.