Determination of frequencies in autonomous double output asynchronous generator

The voltage generated in autonomous operation of the asynchronous generator is investigated for the determination of the harmonics introduced by the nonlinear magnetic circuit and by the inverter. The analytical procedure shows the possibility of having more than one output frequency. In the case of the saturated magnetic circuit there is one synchronous and one asynchronous frequency. The asynchronous frequency is the fundamental, while the synchronous frequency is a noncharacteristic harmonic having a lower amplitude than the fundamental. Exact and approximate equations for the computation of frequencies are deduced. Under the assumption that the magnetic circuit is linear, one synchronous and two asynchronous frequencies appear in the generated waveform. During the test procedure the collected data of the generated and excitation voltage were recorded and processed by a discrete fast Fourier algorithm. The harmonic analysis identified the same frequencies as the analytical procedure