Abstract—A novel buck-boost inverter with three switching
devices appropriate for small renewable energy applications
was proposed. Operating principles, four different operating
modes and pulse energy modulation (PEM) method under
discontinuous inductor current conduction mode are discussed
in this paper. It also describes the design of hardware, such as
the power circuit, fly-back transformer and control circuit,
and the design of software, such as analog-to-digital converter,
zero-crossing signals capturing and PEM signal generation. A
400W experimental set-up of the novel inverter system
connected to the grid was constructed to verify the operation of
buck-boost inverter and PEM modulation method.
Experimental results conclude the buck-boost inverter can
transfer the energy from dc source to ac grid efficiently. It can
provide sinusoidal output current under wide range of dc input
voltage.