Abstract:
Improved single-phase inverter topology is used to avoid the common-mode leak
age current in the transformerless PV grid-connected system. The condition of elim
inating common-mode leakage current in both the unipolar sinusoidal pulse width
modulation (SPWM) and the double frequency SPWM control method can be ap
plied to implement AC output in the presented inverter. By decoupling of two addi
tional switches connected to the dc side the efficiency and convenient thermal design
are improved. Besides, the higher frequency and lower current ripples are obtained
by adopting the double-frequency SPWM, and thus the total harmonic distortion of
the grid-connected current are reduced to 7 percentage. It is used for low ac power
application. Working of the proposed circuit and verification by simulation results
are discussed in this paper. Simulation is done in MATLAB R2010a version
