Evaluation of Using RDFT Method for Grid Synchronisation

The proposed work measures the accuracy of synchronization to grid using filtering technique. Where two algorithms of Recursive Discrete Fourier Transform (RDFT) are used, each one turned for a specific frequency. The algorithms are implemented using STM microcontroller. It is shown from the results, that this method can provide accurate calculations and can comply with the domestic standards of synchronisation. The need of such a method can be clear at load-side, as grid waveform can be distorted due to non-linear loads or heavy electronic loads with rectifier filter. Distorting grid with unwanted harmonics can make synchronisation difficult while using Zero Crossing Detectors (ZCD) or Phase Locked Loop (PLL). The RDFT tool, is fast and accurate method to detect waveform by filtering out undesirable perturbation. STM32F4 microcontroller was used to implemented the method and Results were obtained. The results show that using two RDFT method provides high accuracy in comparison to other.