Testing of electrical machines using power electronic converters

Electrical machines such as motor, generator, and transformer are tested to evaluate their performance characteristics such as their efficiency, voltage regulation etc. These tests requires loading of electrical machines using passive elements such as resistance, inductance and capacitance. During testing of any machine, huge amount of energy consumption take place especially when machine needs to be kept under test for a long duration of time. Hence the energy cost associated is also high for testing large rated machine. This paper proposes a pair of power electronic converter (rectifier and inverter set) that act as a load which can be resistive, inductive or capacitive in nature. The converter is also capable of regenerating the consumed power during testing of machines and feed the power back to the grid. The converter set is made to act as loader and regenerator by controlling the active and reactive power independently from machine to converter and from converter to grid. To obtain a decoupled control of active and reactive power flow, the control scheme is implemented in d-q reference frame using vector control approach. Based upon the value of active and reactive power reference, the converter is modeled to emulate any kind of resistive, inductive, capacitive or any combination of these loads. The propose model can also be used for power factor improvement.