Development of the 1kW-class inverter unit with a small engine generator that conforms to “Guideline of the interconnection technology requirements” has succeeded. To connect distributed sources such as wind power generation, photovoltaic generation, or cogeneration to the utility grid, it is necessary to detect demand-side problems including the distributed sources (short circuit, ground fault, troubles in generated voltage or frequency) and to detect problems in the grid (power failure and troubles of voltage or frequency). It is also necessary to protect both electric power systems and distributed sources and electrical appliances. The inverter unit uses two types of islanding detection method that is passive one and active one. Total distortion factor is reduced to less than 1% by applying two kinds of input current to the power supply unit. Efficiency of the interconnection inverter unit has been achieved 91% and total efficiency of power generation of the cogeneration unit has been achieved 20%.
Article of Honda R&D Technical Review Vol.15 No.1 (145 - 150)