Search

This paper deals with the problems of harmonic pollution generated by the DC-AC converters and its reduction techniques. The study is carried out on a single-phase pulse width modulation (PWM) inverter with pre-calculated commutation angles. The algorithms are implemented on a PIC 18F4550 microcontroller and allows the obtention of a sinusoidal output current with low distortion, the quality of the output voltage waveform is evaluated by the use of Fourier spectral analysis. The optimization consists on the resolution of a set of equations issued from different criteria such as certain harmonics cancellation or, more generally, on distortion minimization. We prouve here that by accurate switching angle calculations and control, we can completely cancel low order harmonics. This is ensured in the inverter by a high precision algorithms programmed on the microcontroller system.

Intermittency of renewable resources represents a major impediment that restricts their integration in microgrids. This paper presents an approach that can contribute to solve this issue by the prediction of near-term future renewable power production, mainly wind power and photovoltaic power, based on weather forecasts. After knowing the future renewable power production, the electric grid manager needs to find the optimal operating plan in order to efficiently integrate the predicted renewable production and to optimally operate other controllable components of the microgrid such as fuel-based generators, energy storage units and connectors to the commercial electric grid. We formulate this optimization problem as an integer linear program and exercise the model to study a number of practical issues surrounding microgrids.