The invention discloses a three-phase grid-connected
inverter and a model-free prediction control method thereof. The method comprises the following steps: constructing a first-order current super-local prediction model based on an
inverter model; constructing an extended
state observer based on the first-order current super-local prediction model, and performing current prediction and lumped disturbance prediction by using the extended
state observer; calculating an output
voltage reference value according to the current prediction value and the lumped disturbance prediction result; and constructing a cost function by comprehensively considering the candidate
voltage vectors and the neutral point potential according to the output
voltage reference value, screening from the candidate voltage vectors to obtain an optimal
voltage vector by taking the minimum cost function as a target, and controlling the three-phase grid-connected
inverter based on the switching state corresponding to the optimal
voltage vector. According to the method, a model-free prediction framework is combined with disturbance compensation and a parameter adaptive mechanism, so that the influence of parameter mismatch is effectively overcome, the robustness is improved, and low-
harmonic output, rapid dynamic response and stable midpoint potential control are realized.