Common Mode Rejection in Single DC-Link Fed PHIL Emulator

This research extends the idea of common mode rejection in a single DC-link fed emulator and drive inverter setup using a transformer. The study proposes a systematic method to design the PI controller for the magnetization current control at near-zero speed. The design is based on using the transformer parameters. Additionally, it introduces a method to implement a low-pass filter with amplitude and phase compensation to filter the harmonics in the current waveform. It is essential because the derivative of the current waveform is needed to compensate for the difference between the machine inductance and the coupling inductor. This study implements the described emulator for an actual motor and intends to study different modes of the motor operation on it, like a step change in load torque at non-zero speed and zero speed. The effectiveness of the magnetization current controller is proved by observing the current drawn on both ends of the transformer.