MULTI-LEVEL INVERTER SWITCHING STRATEGIES
In the article, the methods of switching stages of a multi-level inverter are studied. These techniques use pulse-width modulation for switching, which is obtained by comparing a reference sinusoidal signal and a sequence of triangular pulses. The article describes algorithms for obtaining a control sequence of pulses and examines how a particular strategy can reduce the coefficient of harmonic components of the output voltage of the inverter. To do this, Simulink simulates each of the strategies for different frequencies. Based on the simulation results, the dependence of the coefficient of nonlinear distortion on the frequency of the carrier oscillation for different switching strategies is obtained. The simulation was performed without filtering the output voltage of the inverter, and with the use of a low-pass filter. In addition, an experimental study of a sixlevel PWM inverter was performed. Using the Fluke 435-II electrical energy analyzer, oscillograms and spectrograms of the inverter are obtained. Harmonics of the output voltage are detected that differ in power from the entire spectrum.