An emulation platform for mimicking unbalanced loads and sources

Abstract

Abstract With the increasing penetration of power electronic equipment for various day to day applications, several testing methods are also gaining attention. Power level emulation is a popular technique which is typically employed for mimicking the behaviour of a source or load in real-time. Most of the available literature deals with the power level emulation of balanced loads and sources. This paper presents the details of control schemes and an emulator based on a four leg VSI, which is capable of mimicking unbalanced sources and loads. A flexible control scheme with a common inner inductor current loop is proposed for both the positive and negative sequence components, for the unbalanced load and source emulations. The proposed emulator is capable of emulating both types of unbalances — those in which only positive and negative sequence components exist (3 wire systems) and those in which the zero sequence components also exist in addition to the above mentioned components (4 wire systems). The modelling and control aspects are validated through simulations using Matlab Simulink and through experiments on the laboratory prototype emulator.