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.

随着电力电子设备在各种日常应用中的渗透率不断提高，几种测试方法也受到关注。功率电平仿真是一种流行的技术，通常用于实时模拟源或负载的行为。现有的大多数文献都涉及平衡负载和电源的功率水平仿真。本文介绍了控制方案和基于四脚VSI的仿真器的详细信息，该仿真器能够模拟不平衡的源和负载。针对正序和负序分量，不平衡负载和源极仿真，提出了一种具有公共内部电感器电流环路的灵活控制方案。拟议的仿真器能够仿真两种类型的不平衡-除上述分量（4线系统）外，其中仅存在正序和负序分量（3线制），还存在零序分量的不平衡。通过使用Matlab Simulink进行的仿真以及实验室原型仿真器上的实验，可以验证建模和控制方面。