Photovoltaic inverter with isolation transformer

What is a transformerless PV inverter?

The single-phase transformerless PV inverters have become an industrial technology for a long time in grid integration of solar plants. In recent years, these string inverter topologies lower than 5 kW rated power have been widely used in low power solar micro inverters.

Do PV circuits need an isolation transformer?

However, inclusion of the isolation transformer brings extra power loss and accounts for further board space, which means more cost. The isolation requirements of the PV circuits and grid-tied circuits need to be considered separately for this case.

What are the different types of isolators used in solar power conversion?

In a solar power conversion system, different types of isolators are adopted to serve various functions. Isolated gate drivers are used to drive insulated gate bipolar transistors (IGBTs) or metal-oxide semiconductor field-effect transistors (MOSFETs) in the high-voltage power stage.

How do photovoltaic inverters work?

In the particular case of grid-connected photovoltaic inverters, most of the power converter topologies use a transformer operating at low or at high frequency, which provides galvanic isolation between photovoltaic panels and electrical grid. Low frequency transformers are big, heavy and expensive, and introduce additional losses in the system.

How is a power transformer isolated?

Isolation between the input and output is provided by the insulation layers between the primary coil and the secondary coil. For efficient power transfer across isolation, a self oscillating high frequency oscillator is used to drive the primary for the power transformer, and high frequency Schottky diodes are used to provide rectified dc voltage.

What is a solar PV inverter?

Early solar PV inverters were simply modules that dumped power onto the utility grid. Newer designs emphasize safety, intelligent grid integration, and cost reduction. Designers are looking to new technology, not used in existing solar inverter modules, to improve performance and reduce cost.