An Induction Machine Emulator for High-Power Applications Utilizing Advanced Simulation Tools With Graphical User Interfaces

In this paper, a method is presented for removing the risk associated with the testing and development of novel drive system topologies, prototype electrical machines, advanced control system strategies, or a combination of the aforementioned without using any real motors/generators. The test platforms for low-power machines are relatively inexpensive and accessible; however, as power levels increase into the upper kilowatt and megawatt range, validation of prototype machines and drives becomes costly. The proposed induction machine emulator (IME) platform utilizes the power hardware-in-the-loop concept in conjunction with a high-fidelity machine model and load dynamics. The electrical machine and its load dynamics are simulated with a real-time digital simulator, which generates appropriate control commands to a power electronics-based voltage amplifier that interfaces to a variable speed drive (VSD). Specifically, the current draw is recreated by altering the phase and magnitude of a voltage amplifier connected to a VSD under test via a unique transformer-based LCL-type coupling network. Based on the proposed concept, the use of a multiwinding, tap-changing transformer establishes a truly versatile and universal test platform for a wide range of power levels. In addition, this paper presents a control strategy in the synchronously rotating reference frame in dq coordinates for the power electronic converters in IME operation. Experimental results at the 25-kVA power level validate the feasibility and highly dynamic performance of the proposed test platform.