Multi-Phase Grid Interface System

Applications

A power converter is used in photovoltaic (PV) system or multi-phase system.

Problem Addressed

A PV system connected to an independent or public electricity grid can feed any excess electricity back into the grid. The feeding of electricity into the grid requires the transformation of direct current (DC) into alternating current (AC) by the power converter. However, electrical systems found in commercial and residential environments often operate on single or split-phase systems, and therefore, operate at a significantly lower power level and lower efficiency.

Technology

The invented power conversion circuit has an input port to receive a DC signal, and multiple output ports to provide a multi-phase AC signal at high efficiency and power levels. The power conversion circuit includes an inverter which converts the DC signal to AC signal, a transformer which provides electrical isolation and voltage transformation between the inverter and the output, and a cycloconverter which generates the multi-phase AC output signal. The power flow in the cycloconverter is controlled by switches which provides improved performance and efficiency for a given operating condition. Additionally, control over the switching frequency can be used to widen the input and output voltage operating ranges for a given set of load requirements.

Advantages

  • Improved performance and efficiency
  • Efficiently delivering excess generated power from photovoltaic system to the grid when available
  • Broad voltage operating ranges