Modified SEPIC Converter Performance for Grid-connected PV Systems under Various Conditions

Abstract

Step-up converter is widely used to increase DC voltage level on PV systems either off-grid or grid connected. One of the step-up converters often used in PV systems is SEPIC converter. To improve its performance, many SEPIC converters have been modified. However, performance on various conditions has not been further investigated. In this study, the modified SEPIC converter was investigated under various change conditions for grid-connected PV applications. This converter was modelled and simulated using PSIM software. The modified SEPIC converter received input from PV array 15 kWp, and its output was connected to the three-phase inverter with grid and load. The irradiance level and ambient temperature were varied to test its performance and compared to Boost converter and SEPIC converter. For all tests, the performance of modified SEPIC converter was better than other step-up converters because it was able to rectify the quality of output voltage and more efficient.

A modified Cuk DC-DC converter for DC microgrid systems

“…Thus, the losses in modified Cuk DC-DC power converter is lower than the conventional ones. In (16,17) show that for the same output voltages, the power loss in modified Cuk DC-DC power converter is lower than the conventional boost DC-DC power converter.…”

“…Figure 2 shows that a DC-DC converter is used as an interface between the DC grid and DC energy sources and between the DC grid and battery energy storage. Various DC-DC power converters for these purposes have been proposed in the literature [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. Though the DC-DC converter can be isolated or nonisolated, the nonisolated DC-DC converter is preferred because of power loss consideration.…”

Sliding-mode controller for a step up-down battery charger with a single current sensor

“…Applying partial fraction decomposition and the inverse Laplace transformation to (29) leads to the timedomain waveform reported in (31).…”

“…To design the bus voltage behavior, the following performance criteria are defined: maximum bus voltage deviation ∆vdc and settling time ts after a step current perturbation with amplitude |I dc |. The first performance criterion is analyzed by deriving the time-domain waveform (31) as (32):…”

“…boost and buck based solutions [2], [7]- [11], [28]. Moreover, the Zeta converter has an inductor at the output port connected to the DC bus [6], [28]- [31], which makes possible to control the bus voltage with high precision and, at the same time, this enables the converter to provide a continuous current to the DC bus, reduces the harmonic components present in the microgrid; this is an advantage over battery chargers based on converters with discontinuous output current, e.g. buck and buck-boost based solutions [15], [32]- [34].…”