AUTHOR=Ijaz Muhammad , Nazir Rabia , Alhussein Musaed , Ahmad Jameel , Aurangzeb Khursheed , Saleem Faisal 

TITLE=Digital resonant control of power converters under variable grid frequency conditions

JOURNAL=Frontiers in Energy Research

VOLUME=Volume 11 - 2023

YEAR=2023

URL=https://www.frontiersin.org/journals/energy-research/articles/10.3389/fenrg.2023.1272329

DOI=10.3389/fenrg.2023.1272329

ISSN=2296-598X

ABSTRACT=Proportional Resonant (PR) controller has the advantage of regulating sinusoidal current and voltage with low steady-state error. Power systems are usually designed, operated, and controlled in discrete time domain; therefore, the applications and conclusions of conventional PR controllers cannot be applied directly to digital systems. Several discretization methods are available to implement PR controller digitally, however, the effect of these discretization methods on the desired gain of PR controllers under varying reference frequency scenario is not very well researched. Due to various factors such as intermittent nature of renewable energy resources, distributed generation and imbalance between source and load demand, grid frequency varies in small limits around the nominal value. The effect of these grid frequency variations on the performance of the resonant controlled power converter needs to be assessed. In this research PR controller discretized using Zero Order Hold (ZOH), Impulse Invariant (II) method and Zero Pole Matching (ZPM) techniques are applied along with the deadbeat controller. Performance of PR controllers based on ZOH, II, and ZPM discretization techniques in combination with the conventional deadbeat control are reported 16 in the presence of variable frequency reference signal which imitates a practical grid. A single-phase Pulse-Width Modulated (PWM) inverter which is an integral part of modern power system is used as an application system. The objective of this paper is to find the efficient digital PR controller that will effectively track both fixed and variable reference frequency signal with lower Total Harmonic Distortion (THD) and approximately zero steady state error. Simulation results shows that steady state error and THD with only deadbeat controller are 4.9 V and 4.82% respectively, while in case of proposed d ZPM based 1 Ijaz et al.digital PR controller it decreased to 0.12 V and 0.45% respectively, which shows the superiority of the proposed method.