Papers by Keyword: Grid-Connected

Abstract: This paper presents the design and control of a grid-connected flyback inverter with a DC active filter for photovoltaic (PV) cells. The proposed topology consists of a flyback DC-AC inverter and a DC active filter that can operate independently. The flyback inverter, controlled in digital peak current mode, regulates the full-wave rectified sinusoidal current later, which is alternately inverted and injected into the grid. The DC active filter regulates the smooth current/power drawn from a PV module by using cascaded proportional-integral (PI) controllers. Analysis, design and control of the proposed topology are presented. A 100W/220V/50Hz prototype is developed and tested. The experimental results show that the proposed flyback inverter with a DC active filter is capable of regulating a sinusoidal current fed into the grid, actively filtering the DC current/power and achieving reasonably high energy conversion efficiency.

Abstract: The impacts of grid voltage on grid current in distributed generation grid-connected inverters are analyzed, and a control strategy that can compensate harmonics and suppress DC bias is proposed. In comparison with traditional PR controller, the proposed PRI controller with an additional integral part obtains a higher gain in low frequency, and the controller has an apparent effort especially for suppressing DC bias. Finally the PRI controller is verified in a 50KW. The experimental results show that the PRI controller not only can reduce harmonics of grid current in the steady state but also can suppress DC bias rapidly in a dynamic process. The PRI controller is suitable for DGs since they typically contain low order harmonics which caused by nonlinear l three-level inverter loads.

Abstract: As coal, oil, natural gas and other non-renewable energy consumption and increasing energy demand, the utilization of solar energy as a new energy is greatly enhanced. In this work, a grid connected photovoltaic solar air conditioning system is designed, mainly comprised of solar panel, controller, inverter, room air conditioner and other parts. Air conditioning systems rely mainly on solar photovoltaic power; achieve the effect of energy conservation and environmental protection. The experimental result indicates that the system can achieve stable operation and the utilization of solar energy driving air conditioning system to save electricity. This air conditioning system is compared with the ordinary air conditioning system, SEER can increase 10.6 ~ 29.4%, HSPF can increase 6.25 ~ 18.5%.

Abstract: Based on the mathematical model of the three-phase two-stage PV grid inverter, the fuzzy-PID control strategy is applied in the grid connected control of PV system in this paper. The purpose of the intelligent control of photovoltaic grid connected inverter has been achieved. The digital simulation and physical simulation show that the fuzzy-PID control strategy can improve the PV system grid control dynamic process and get the smooth connection of the PV system with the power grid. At the same time, the harmonic pollution on the grid has been significantly reduced.

Abstract: Based on voltage space vector modulation, a distributed power grid-connected inverter (DPGCI) utilizing double loop control strategy is researched, the system is able to feedback power to grid with constant power and unity power factor. the static and dynamic performance is good. Firstly, a mathematical model of inverter system in two-phase synchronous rotating coordinate is built, based on this, a outer power loop and inner current loop control strategy is proposed, realizing the independent control of active and reactive power. Experimental results show the correctness and validity of the control strategy.

Abstract: In order to solve the islanding effect of single phase photovoltaic grid-connected system, by introducing some common passive and active detection, and generalizing the advantages and disadvantages of the two detections, we came up with and design an output energy changing method to achieve the detection and prevention of the islanding effect. Modeling and simulating this system under MATLAB , and the results show that the output energy changing method can detect the generation of islanding effect accurately, and achieve the anti-islanding effect effectively.