A hybrid flyback LED driver with utility grid and renewable energy interface
In renewable energy sources, the objective is maximum extraction and utilization of the available power. In this paper a hybrid flyback converter with multi ports-an AC Grid, a PV and a DC LED ports — is proposed to be used as an LED driver. The converter has the capability to achieve two objectives: first to maintain a continuous supply to the LED lighting system either from the Photovoltaic (PV) panel or the grid, and second to achieve maximum utilization of the solar PV panel by tracking the maximum power point and exporting surplus power to the grid, or getting the power deficit from the grid. The topology of the converter, operating principle, modes of operation and control structure are presented in this work. The concept of the hybrid flyback converter is verified using Matlab Simulink®. An experimental prototype is developed and tested for a 120-watt system, with 35 VDC solar panels, 120 Vrms 60 Hz grid and 24 VDC LED lights.
Design of Current Controller for Stand-Alone Type Solar Street Light using Low-Cost Device
Background/Objectives : In recent years, the use of renewable energy tends to be drawing attention due to global warming and deterioration of environmental problems. Methods/Statistical analysis : Electrical grid construction utilizing sunlight, which is attracting attention as a next generation energy source among them, is being actively advanced, and this paper focused on the design of street lights using solar power generation. Findings : As a light source, energy saving and environmentally friendly LEDs were adopted. Due to the characteristics of the LED is sensitive to the current and temperature changes, so LED driving drivers for constant current control are required. Also, because the solar power generation time and the street lamp operation time are different, energy time shift is carried out through the battery, and because of the LED driving and battery charging needs constant current control, so constant current control design is indispensable. Improvements/Applications : In this paper, in order to reduce the price burden in the design of the controller, we designed the battery charge drive and the LED driver using the low-cost device. We also constructed a solar street light system based on the proposed method and verified its validity.
Autonomous controller based on synchronous generator dq0 model for micro grid inverters
The parallel operation of voltage source inverter (VSI) in microgrid could benefit from characteristics of synchronous generator (SG) such as the kinetic energy stored in rotor, the self-isochronous and the droop characteristics if inverter can behave like generator in power system. Therefore an autonomous controller based on dq0 model of SG for microgrid inverter is proposed to mimic the above those characteristic of SG. Moreover, the inverter is designed to serve as either UF node or PQ node in micro grid by integrating a virtual primary frequency regulator (VPFR) and a virtual excitation regulator (VER) in the proposed controller. The results of simulation show the excellent performances of the proposed autonomous controller on voltage regulation, power sharing and seamless mode transfer.