The invention discloses a direct
power control method for inhibiting
voltage fluctuation of a DC-side
bus of a photovoltaic grid-connected
inverter, and belongs to the technical field of converter control. The method comprises the steps of establishing a
photovoltaic power generation system, determining instantaneous
active components v<alpha> and i<alpha> and instantaneous
reactive components v<beta> and i<beta> of a
power grid, realizing the
maximum power point tracking of a photovoltaic array by adopting a fixed-step
perturbation and observation method, determining the disturbance power Pswith a short wavy line thereon by a
disturbance observer through a correction link; respectively taking output signals [nu]<^>P and [nu]<^>Q of two PI controllers as the input of a feedforward
decoupling controller to construct a feedforward decoupling model, obtaining
voltage control signals e<alpha> and e<beta> by combining the output uP and uQ of the feedforward decoupling
system based on
voltage v<alpha> and v<beta> of the
power grid, and carrying out [alpha][beta] / abc conversion on the
voltage control signals e<alpha> and e<beta> to obtain an SPWM
control signal e<a, b, c> of the
inverter. According to the invention, the feedforward disturbance is introduced into the voltage outer loop, and the zero steady-state error tracking of the
DC bus voltage can be ensured by adopting a simpleproportional controller; it does not need to obtain phase information of the
power grid voltage and does not need to perform synchronous rotation coordinate transformation, so that the stability problem caused by the use of a phase-looked loop (PLL) is avoided.