Power-Hardware-in-the-Loop Based Emulation of a Variable Flux Machine

Electric machine emulation allows testing of the drive inverter and controller of an electric drive system, prior to manufacture of a physical machine prototype. This paper presents the emulation of a variable flux machine (VFM). In VFMs, air-gap flux can be controlled by changing the magnetization level of the magnets using a current pulse; leading to several advantages over permanent magnet (PM) machines. The VFM emulator system proposed in this paper uses a detailed look-up table based machine model for the purpose of emulation. This allows the machine emulator to mimic all machine magnetic and geometric behaviors such as saturation and torque ripple. Additionally, the machine emulator proposed in this paper uses high-performance high-bandwidth linear amplifiers as power amplifiers. This enables a high bandwidth (leading to a high accuracy) machine emulation. A control description for the proposed machine emulator system and a look-up table data verification of the VFM against a physical machine is initially presented. Experimental results are then presented to validate the utility of the proposed VFM emulator system to emulate various machine transient behaviors. Experimental results obtained from the emulator are subsequently compared against the experimental results obtained from a physical VFM drive to comment on the emulation accuracy.