The invention discloses a quasi-PCI and PI combined control single-phase photovoltaic grid-connected
inverter current control method in the technical field of
new energy photovoltaic power generation.The method comprises the following steps of: adding a
cut-off frequency into a proportional complex integral (PCI) controller to form a quasi-PCI controller; realizing a complex number field in a single-phase quasi PCI through a
lag output item of a second-order generalized
interactor (SOGI); taking a difference value between a given grid-connected current iref and an actual grid-connected current iL as the input of the quasi-PCI controller; taking a difference value between a grid-connected current
direct current quantity reference value IL-dc and a grid-connected current
direct current quantity as an input of a PI controller; and after the output of the quasi PCI controller and the output of the PI controller are added, controlling the switching-on and switching-off of an
inverter switching tube through PWM modulation. According to the invention, the influence of
power grid voltage fluctuation and
frequency offset on the grid-connected current is suppressed, the direct-current component of the grid-connected current is eliminated, and high-
quality control is realized while the design of a non-isolated photovoltaic grid-connected
inverter current controller is simplified.