Synchronization to the network without voltage zero-cross detection

Many power electronics devices require to be synchronized to the network. Classical synchronization solutions are based on zero-cross detection of line voltage, but since this approach is very sensitive to the voltage distortion, a new method is suggested, attempting to perform on-line recalculation of line voltage´s fundamental harmonic. Besides the theoretical basis of the new synchronization method, experimental results are given. The method was tested with parallel active power filter, intended to compensate fundamental reactive power as well as reactive power due to line current harmonic distortion. Motorola´s MC68332 microcontroller was applied, providing the filter current reference determination and concurrently performing the synchronization algorithm.