Faster Convergence Controller With Distorted Grid Conditions for Photovoltaic Grid Following Inverter System

Abstract

The hysteresis current controller (HCC) for grid following inverter (GFI) system with LCL-filter is a well-known controller for its robustness, fast reference tracking, better dynamics, and easier implementation compared to other controllers. However, HCC behaves differently while integrating such a system with solar photovoltaics (PV). The PV-based GFI system requires fast convergence while transferring maximum power from PV to the grid at minimum converter losses through GFI. This paper therefore proposes a modified double-band HCC (MDBHCC) with proportional resonant (PR) controller for single-phase PV integrated GFI system with LCL-filter. The proposed algorithm implements a unipolar symmetrical PWM strategy for reducing inverter switching losses through a sequential logic with an adaptive clock. It improves the variation in switching frequency and limits the maximum switching frequency of HCC while enhancing the total harmonic distortion (THD) of the injected current into the grid at the point of common coupling. To alleviate the power quality problems and achieve zero steady state error, the proposed MDBHCC with PR control operates at lesser % THD. Simulation and experimental results are presented, with a significant decrease in switching frequency and an improvement in grid current harmonics at both steady-state and dynamic conditions.INDEX TERMS GFI, hysteresis current control, LCL filter, power quality improvement, total harmonic distortion.

Active Disturbance Rejection Control of Photovoltaic Three-Phase Grid Following Inverters Under Uncertainty and Grid Voltage Variations

“…Step 1: Measure v pv (i.e. DC-link voltage v dc ), i pv and incremental change in PV power (∆P pv ) and apply the appropriate incremental conductance MPPT control mentioned in [21] to generate the reference DC link voltage (v * dc ).…”

“…Internal and external disturbances can be employed as feed-forward compensation terms for the GFI system control input, according to the ADRC theory mentioned in [8]. Consequently, it is possible to redefine the final control law of the GFI system, as given in (21).…”

Modified Proportionate Affine Projection Algorithm Based Adaptive DSTATCOM Control With Increased Convergence Speed

“…Several other switching schemes are available in the literature that include stationary reference frame (αβ-frame) enabled space vector modulation (SVM) scheme [34], model predictive control [35], direct power control [36], and sinusoidal PWM scheme in abc-frame [37]. However, the HCC method is faster irrespective of several disadvantages such as higher switching frequencies, variable switching frequencies, etc., [38]. The hysteresis band of (δ = 0.01) is selected for the appropriate operation of the proposed controller.…”

Photovoltaic Partial Shading Performance Evaluation With a DSTATCOM Controller

“…To ensure that the resonant frequency (f res ) is unaffected by the minimum switching frequency (f sw,min ), the frequency band is selected so that the maximum switching frequency (f sw,max ) does not exceed the calculated switching frequency limits of the Insulated-gate bipolar transistor (IGBT) switch [34]. VSC and filter design can be readily performed by establishing a switching frequency band as (28) [35].…”