The invention provides a
model prediction control strategy and a modulation method for a three-phase four-wire three-level
inverter, and the control strategy comprises the steps: building a
mathematical model according to the working principle of the
inverter, carrying out the
discretization of the model through employing a forward
Euler method, calculating the predicted values of the output
voltage at the next two moments, and carrying out the prediction of the output
voltage at the next two moments; an
inverter side bridge arm
voltage reference value at the current moment is obtained by combining an output voltage cost function, the inverter side bridge arm
voltage reference value is input into a modulation module after passing through a wave trap, a driving
signal for driving a switch tube is obtained through a modulation method of the modulation module, and a model filtering
inductance value is obtained through a real-time filtering
inductance parameter identification method with low-pass filtering; according to the modulation method, dual-modulation wave
carrier modulation or sine
pulse width modulation is selected by judging the fluctuation amplitude of the neutral-point voltage on the direct-current side of the inverter and the balance capacity of the neutral-point voltage of each phase and comprehensively considering the neutral-point voltage balance and the
system efficiency on the direct-current side in combination with a fuzzy control method. According to the invention, the multi-objective optimization control of the output voltage quality and the
system efficiency when the inverter is provided with the balanced / unbalanced load can be realized.