HIL simulation of machine drives utilizing the physics-based phase variable model of machines

This paper presents an approach for performing the hardware-in-the-loop simulation of PWM-based drive utilizing the physics-based phase variable machine model to represent the actual machine. A 6-pole 2 hp permanent magnet synchronous machine is used as an example. The physics-based phase variable model of the sample machines is built with parameters (inductances, flux linkages, and the cogging torque) obtained from solutions of nonlinear field computations covering a complete ac cycle. The developed physics-based phase variable model considers the variation of inductances and the flux linkages with the position of the rotor and the nonlinear magnetization property of the core. The accuracy of the developed machine model is compared with the FE model to examine its accuracy. The utilization of the developed physics-based phase variable model in the hardware-in-the-loop simulation of PWM-based machine drive is studied. A practical approach is proposed to achieve the real time simulation of the machine drive having a 50 mus time cycle of the machine model against the 0.1 mus time resolution of PWM hardware module. A voltage sensor and a filter are added between the PWM module and the machine model. The filter is purposely designed; its output equals to the actual average voltage produced by the inverter. The impact of the added voltage sensor and the filter is investigated to examine the effectiveness of the proposed approach. Prospective applications of the developed physics-based phase variable model and its utilization in hardware-in-the-loop simulation are suggested.