An Equivalent Fundamental and Odd Harmonic Resonators Controller for a Single-phase Dynamic Voltage Restorer

In order to improve the compensation performance of a single-phase dynamic voltage restorer(DVR),a digital control strategy based on equivalent fundamental and odd harmonic resonators was proposed.By using a delay block which can be equivalent to a bank of resonators;it could reject the fundamental and odd harmonic disturbance effectively.The structure of controller was formed by a delay block,a proportional gain and a set of zero phase notch filters.The design principle of the parameters of controller was given in detail and design object was to ensure the stability of system.Both the supply voltage and load current feedforwards were added to increase the response speed and the ability of disturbances elimination.The proposed controller is simple in both structure and implementation,and it has good performances in harmonic compensation and dynamic response.Experimental results from a 2 kW DVR prototype confirm the validity of the design procedure and the effectiveness of the control method.