Development of a new phase-angle controlled grid-connected PV system

In conventional grid-connected PV system, the control of real and reactive power is undertaken adjusting both modulation index and phase angle of the inverter. The maximum power point of the PV array is tracked by adjusting duty cycle of the dc-dc converter or modulation index of the inverter. The PWM pattern has to be optimized each time the index of modulation is changed which involves excessive computational complexities and time. In this paper, a new phase-angle controlled grid-connected PV system is simulated in Matlab where power flow is controlled adjusting the phase angle of the PV inverter keeping the modulation index constant and thereby maximum power from the PV array is extracted. Since modulation index is kept constant, PWM pattern is optimized only once and used for any phase angle value. This involves lesser computations and ensures optimized PWM pattern for inverter control that makes the system more efficient. Modelling, analysis and simulation results have been presented to show the effectiveness and simplicity of the proposed technique.