Artificial loading of the induction motors using a matrix converter

The paper discuses the use of a frequency converter for artificial loading of an induction motor. The characteristic of the artificial loading requires a cyclic circulation of energy between the converter and motor in order to increase the motor current and torque to the rated values without any load on the motor shaft. It is known that standard converters have serious limitations regarding the circulating energy, and if the incoming energy exceeds the storage capacity of the DC-link capacitors, an overvoltage fault may occur in the converter. This limitation can be overridden by using a unidirectional power flow converter with high energy-storage capability in the DC-link or by using a bidirectional power flow converter with reduced energy storage. Two possible bi-directional power flow converter topologies are investigated: the back-to-back voltage source inverter (VSI) and the matrix converter. A comparative analysis of two bi-directional power flow converters shows that the energy stored in the reactive components of a matrix converter is minimized. It is proven that the matrix converter may be successfully used in artificial loading of the induction motors.