Hardware-in-the-loop emulation of electrical drives using standard voltage source inverters

Testing voltage source inverters (VSI) by using a set of real machines is often unsatisfactory. In fact, besides not being economical, this method only allows cursory inspection since the behaviour of an inverter under test (IUT) can then almost be assessed under few typical working conditions. In order to overcome these drawbacks, the present paper describes a low-cost hardware-in-the-Loop (HiL) emulator for electric drives based on commercial IGBT voltage source inverters (VSI), the Virtual Machine (VM). Making use of several parallel-connected standard VSIs of the same type as the IUT, the VM is able to reproduce not only the steady state but also the dynamics of a real induction motor in a realistic way. This essential aspect is achieved by switching the IGBTs inside the inverters of the VM sequentially. Since the proposed HiL emulator is fully parameterizable, almost every induction machine within the power range of the IUT can be emulated. With the VM, extensive tests of power electronics devices can be carried out inexpensively and in short time intervals, a very convenient feature, especially for Small and Medium Enterprises (SMEs).