Optimal switching sequence model predictive current control for grid connected inverter
The traditional model predictive current control method of grid connected inverter only predicts the current waveform at a single point during the control cycle,ignoring the output current ripple caused by the change of inverter switch state.To solve this problem,an improved model predictive current con-trol strategy of optimal switching sequence grid connected inverter was proposed.Firstly,in order to re-duce the switching times and optimize the spectrum distribution,the space voltage vector combination was rearranged,and six groups of switch sequences were designed.According to the switch sequences,a vec-tor duration calculation method based on deadbeat was proposed;Secondly,eight current prediction points were set in a control cycle to calculate the current prediction error generated by the action of the switch sequence in the control cycle,and the value function of predictive control was constructed by ac-cumulating the current prediction error. The switch sequence with the lowest value function was selected as the optimal sequence combination,which improves the waveform quality of grid connected current;Fi-nally,effectiveness of the proposed strategy in reducing the output current ripple of grid connected invert-er was verified by experiments.
grid connected invertermodel predictive current controloptimal switching sequencedead-beat controloptimize value function
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