The researches on adaptive synchronized grid-connected of small generator

Automatic synchronized grid-connected requires that voltage difference, frequency difference and phase angle difference between power network and generator are all in the permitted scope, so the generator can connect to the power network smoothly. This paper bases on voltage difference, frequency difference and phase angle difference to deduce the impulse current when the contactor closes, and researches the relationship between frequency difference and angular phase difference. Consider that the frequency of generator fluctuates sometimes, the paper provides a hardware design method which is based on Atmega16L, and uses the idea of changing sampling interval to realize generator frequency measurement and realtime adjustment, ensure frequency difference between generator and power network is smaller, so the impulse current will be also much smaller. The design is tested by experiment, and the result proofs that the adaptive adjustments to generator frequency is feasible.