Harmonic current conpensation in a single-phase grid connected photovoltaic system sypplying nonlinear load

Unity Proportional Gain Resonant and Gain Scheduled Proportional (PR-P) Controller-Based Variable Perturbation Size Real-Time Adaptive Perturb and Observe (P&O) MPPT Algorithm for PV Systems

“…The problem associated with the use of the ideal PR controller transfer function is that it attains infinite gain at 𝜔 𝑟 . The introduced infinite gain leads to an infinity quality factor which cannot be achieved in either analog or digital applications [28]. Stability problems associated with the infinite gain at the resonant frequency are prevented with a non-ideal PR controller which is generated by introducing damping to the ideal transfer function [29], [30].…”

“…The transfer function of the boost converter in terms of duty ratio to input voltage can be derived by substituting (28) into (26) as:…”

Symmetrical Pole Placement Method-Based Unity Proportional Gain Resonant and Gain Scheduled Proportional (PR-P) Controller With Harmonic Compensator for Single Phase Grid-Connected PV Inverters

“…The ideal PR controller transfer function frequency response attains a phase shift and an infinite gain only at the resonant frequency ( ) that sets the steady-state error to zero and consequently enables to track sinusoidal reference signal efficiently at any specified resonant frequency. However, the ideal PR controller causes stability issues due to the infinite gain in applications [25]. Prevention of this problem is achieved with implementation of a non-ideal PR controller generated by introducing damping to the ideal transfer function [18], [19].…”

“…Among these the synchronous reference frame (SRF) and the instantaneous reactive power (IRP) theories are the most addressed applications in literature [23], [24]. The problem associated with the applications of these theories for the single phase PV system is the existing of the one phase variable only that obliges the creating of another virtual orthogonal variable with a 90 degree phase shift operation at the fundamental frequency [25]. In addition to those common theories, another proposed technique for the current control and the compensation of the selected harmonics is the adaptive control which contains several algorithms within itself such as the Least Mean Square (LMS) [26], the Decorrelation Normalized Least Mean Square (DNLMS) [27] and the Fractional Normalized Least Mean Square (FNLMS) [28].…”

“…The problem associated with the applications of these theories for the single phase PV system is the existing of the one phase variable only that obliges the creating of another virtual orthogonal variable with a 90 degree phase shift operation at the fundamental frequency [25]. In addition to those common theories, another proposed technique for the current control and the compensation of the selected harmonics is the adaptive control which contains several algorithms within itself such as the Least Mean Square (LMS) [26], the Decorrelation Normalized Least Mean Square (DNLMS) [27] and the Fractional Normalized Least Mean Square (FNLMS) [28]. Even though the adaptive control method has higher efficiency, its concept remains a challenge in terms of complexity and requirement of large number of calculations.…”