A Novel Method of Measurement of Synchronous Machine Losses Using Synthetic Loading

Synthetic loading of synchronous machines can be used to test machines for temperature rise and total losses without the need for attaching mechanical load to the shaft. A new phase modulation technique of the voltage is proposed in lieu of the traditional dual-frequency method that suffers from cumbersome equipment and also predicts higher losses. A simple bang-bang dc switch is used to modulate the excitation current of an induction generator. System modeling was performed using the traditional two-axis method, and has proven that the method is feasible. Practical test results are shown to validate the simulated performance. It is shown that the only constraint of this synthetic loading is to maintain the RMS values of the current and voltage at rated values.