DOI: https://doi.org/10.15407/techned2019.03.037 IMPROVEMENT OF THE STRUCTURE FOR THE CURRENT CONTROL LOOP WITH THE USE OF PWM FOR THE GRID INVERTER OF THE COMBINED POWER SUPPLY SYSTEM
Author Abstract Based on the analysis of the principle of current formation of a single-phase a grid bridge inverter for combined power system with combining the function of the active filter, there are opportunities to improve the structure of the output current control loop with PWM by reducing of the error in forming the output current to improve the harmonic composition of the grid current in the presence of non-linear load. The dependences for the amplitude of current pulsations and error for the main current harmonic are obtained in accordance with the inverter input voltage, modulation frequency and reactor inductance. It was found that for the harmonically law of variation of the derivative of the reference of current, the error in the formation of current is constant and is determined by the first harmonic of the grid voltage. The static compensation of the error according to the main harmonic of the current and the dynamic compensation of the current waveform distortion for nonlinear load are substantiated. The structure of the control system has been improved with the introduction of compensating circuits. The results of modeling the system “a grid - inverter - load” are given. References 11, figures 6.
Key words: combined power system, single-phase bridge grid inverter, PWM, current control loop, current error compensation, THD, modeling.
Received: 16.12.2018
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