The control target of grid-connected inverter system is to
improve the steady-state performance and dynamic
performance of the inverter output voltage. Steady state
performance refers to the stability load ability of output
voltage, dynamic performance refers to the output voltage at
the load level of dynamic response to sudden changes. When
the grid-connected inverter circuit by voltage source current
control is working, due to the current flowing through the
inductor L can not be mutated, therefore, adopt the method of
current clockwise closed-loop control. The given value of the
sine wave of the grid current is compared with the actual grid
current, and the got error signal after the treated of controller,
produce corresponding SPWM signal to control the work of
power device, and making the grid current waveform is sine
wave. Figure 6 is current control [10].