Machine emulator: Power-electronics based test equipment for testing high-power drive converters

Today the development process for power electronics includes modeling, simulation, control design, implementation in hardware and finally the test of the hardware at a suitable test bench. In case of drive systems, changing to a different type of machine or to a different rating of the machine requires only relatively few modifications of the control and its parameters. Nevertheless, at least the prototype has to be tested under conditions close to reality. In many cases even the test of each converter and its control is required before shipping to the customer. Prototype testing and production-side quality monitoring can be improved considerably concerning speed and cost if the machine the parameters of which depend on type and rating is replaced by a suitably designed and controlled converter. In this case modifications of the control of this "machine emulator" or "converter tester" are sufficient to adapt to the converter and control to be tested. It is important that the parameters of the converter and the parameters of the machine it is to emulate are largely decoupled by the control of the emulator. This paper describes the general concept of such a test equipment and shows practical results obtained from an industrial prototype which is by now ready for commissioning.