ERROR ELIMINATION FOR CURRENT CONTROL LOOP FOR MULTI-FUNCTIONAL SINGLE-PHASE GRID-CONNECTED INVERTER

Abstract

Purpose. Elimination of the error of the inverter current control loop by improving its structure and justifying the parameters, which will ensure compliance with the current quality standard at the common coupling to the distribution grid of the load and the multi-functional grid inverter at the output of the renewable source of electrical energy. Methodology. Synthesis of structure of current control loop based on analysis of processes in electrical circuits and computer simulation. Results. Relationships for determining the input voltage of the inverter, reactor inductance and modulation frequency in accordance with the grid voltage, the maximum values of the inverter current and the amplitude of its ripple when combining the function of the active power filter. Dependencies of the amplitude of the pulsations of the output current of the inverter and the errors in the fundamental harmonic in accordance with the voltage at the input of the inverter, the modulation frequency and inductance of the output reactor are obtained. Originality. The structure of the inverter current control loop has been improved with a combination of proportional, integrating and differentiating links, and their parameters have been determined to ensure compensation of the disturbing action on input of the reference and compensation of the error of current from the disturbing action of the grid voltage regardless of its value. Practical value. The obtained solutions are the basis for the design of converters of electric power systems with renewable sources of electricity with improved energy efficiency.

Keywords

• multi-functional single-phase grid-connected inverter
• nonlinear load
• PWM
• current control loop
• current error compensation
• THD
• simulation