Attenuation of High-Frequency PWM-Ripples in a Two-Level Voltage Source Inverter

The article is devoted to the two-loop control system design with a modified current controller. In the inner loop of the automatic control system a proportional-integral controller with a filter is used. It allows to significantly reduce the ripple component in the controller output signal, which is transmitted to the PWM input. The application of this approach makes it possible to eliminate the PWM saturation mode and improve the performance of the power converter. A procedure for calculating the parameters of a modified PI controller based on the time-scale separation method is proposed. The implementation of the proposed method was carried out for the design of a two-loop automatic control system for a three-phase voltage source inverter in the power supply system of an AC aircraft, with a constant frequency of 400 Hz and the value of the first harmonic of the output voltage of 115 V. The synthesis of the parameters of the control system for the converter was carried out in accordance with the requirements of GOST R 54073–2017. The efficiency of the designed control system was verified by simulation modeling in the Matlab/Simulink environment.