The research on stability of deadbeat current control in shunt active power filter

Abstract

The control time delay and the passive component variation were the major disadvantages of the deadbeat current control. It could induce system oscillation and even stability to be lost. In order to get the relation of stability with control time delay and the system parameters variation, a new stability criterion method based on W′ transform was proposed. A new current loop transfer function including delay effect and the inductor parameter variation was acquired, and then the transfer function in W′ domain based on the new transfer function in Z domain was obtained by W′ transform. The exact relation of stability with control time delay and the inductor parameter variation was acquired according to the Bode diagram and Routh criterion, and the concrete method which could deal with stability problem in deadbeat current control was given. A prototype 5kVA single-phase shunt active power filter was set up for the proof of concept. The prototype system was operated at 20 kHz switching frequency and was controlled by TMS320F28335 DSP. Experimental results proved the validity of the proposed scheme.