In this paper, a digital hysteresis current limit controller is developed for Switched Inductor Quasi Z-Source Inverter (SLQZSI). Traditional methods like hysteresis current fixed limit and adjustable hysteresis current limit techniques changes the hysteresis bandwidth in accordance to modulating frequency and gradient of reference current. The operating shifting frequency of typical approaches oscillates and crosses the intended steady shifting frequency under noise. It leads to undesirable heavy interference between the phases and more power loss. In the planned digital hysteresis current limit technique, the hysteresis current limit is calculated by resolving the optimization problem. In the proposed approach the operating shifting frequency is kept same or inferior to the intended steady shifting frequency even under noise. Hence the planned digital hysteresis current limit algorithm maintains the output current steady and power loss is minimized which is not promised by the conservative techniques. To compare different control strategies in terms of nature of operating switching frequency and harmonic performance simulations are built on the MATLAB/SIMULINK

Grid-interactive solar photovoltaic (PV) systems are necessary for the current global scenario owing to their low cost and pollution-free energy source. The integration of PV systems in the power grid needs to be stabilized. To address this, this paper presents a composite controller that can synchronize Photovoltaic (PV) to the Grid, with bidirectional power flow in Grid. The proposed technique is explored with both RL and LCL filters. With grid synchronization of PV power generation, a control loop for power quality disturbance mitigation is simulated. The multicarrier SVPWM with DQ controller is used on the Grid Connected converter to mitigate Power Quality disturbances. MATLAB Simulink model is developed for the PV Grid setup and the validity of the composite controller is evaluated. The PI controllers are applied in the DQ-controlled PV integrated with the grid. Power quality parameters THD are found to be intact for both RL and LCL filters. The MATLAB simulation developed showed that the LCL filter has an incremental performance progression than using the RL filter. There is around a 3 to 4% improvement in the grid current THD while using the LCL filters instead RL filter for PV integration.

No abstract