Abstract
This paper presents a new method for suppressing circulation currents in a motor simulator system. In conventional system a large transformer at grid frequency has to be used to avoid circulation currents between the motor simulator and a test inverter; further a regenerative converter is required too. In the proposed system, the high frequency components of the circulation current are suppressed by means of a common mode choke, and the low frequency components are suppressed by controlling the zero-phase current. Furthermore, a small medium frequency common mode choke is used instead of both a regenerative converter and the grid frequency transformer. In addition, the proposed system can be used to simulate the transient response of the motor.
The proposed method is validated on the basis of simulation and experimental results. The primary current waveforms with distortions due to voltage errors caused the dead time agree well in the case of the motor simulator and the actual motor. Further, the low frequency component of the circulation current is suppressed to a value less than 1% of the fundamental component in the proposed system.
