A First Order Sliding Mode Controller for Grid Connected Shunt Active Filter with a LCL Filter

Abstract

A first order sliding mode controller with appropriate parameters sliding surface (modeled in usual time domain and realized by transfer function) is considered here for LCL grid connected three phases three wires shunt active filter (SAF). If shunt active conditioners are already well known in compensation for the main types of current disturbances in the electrical power systems, it is also admitted that they generate some undesired components caused by VSI switching frequency. In order to prevent these components from spreading to the grid side, a LCL output filter is generally proposed. In this context, a VSI connected grid via a LCL filter is largely proposed for renewable energy systems, where the component to be injected into the grid is only the fundamental. Unfortunately, when the injected components include fundamental plus harmonics and for a LCL output filter associated to linear controllers, a phase shift appears, between the identified harmonics current and the injected current. This phase shift impacts negatively the current disturbances filtration and/or compensation of the SAF. Therefore, sliding mode controller with appropriate sliding surface, in both time and frequency domains, is proposed as nonlinear control method, to overcome the phase shift effects over the entire bandwidth, for the shunt active filter. Besides, a PWM-SM-Controller, with zero order hold in input of the PWM, will allow to operate in a fixed frequency, preventing a variable switching frequency effects. The rapidity, tracking and robustness of this proposed controller, within the SAF, are validated by Matlab, Simulink, Simscap-Sim_Power_System code.

Developed AC/DC/AC Converter Structure Based on Shunt Active Filter and Advanced Modulation Approach for Asymmetrical Cascade H-Bridge Multilevel Inverters

“…This topology is considered as a real-time current compensator that is typically connected in parallel, on the perturbing/nonlinear load side, between the load and the grid [20][21][22][23][24], [26]. With appropriate control, it mitigates precisely undesired perturbations such as harmonics, unbalance conditions, and reactive power compensation on the grid side [26][27].…”

Sensor Effects in LCL-Type Grid-Connected Shunt Active Filters Control Using Higher-Order Sliding Mode Control Techniques

“…The states of the system converge to the sliding surface in the presence of the bounded perturbations. However, it generates very-high-frequency switching control that could lead to overheating and consequently damage the power electronic devices of the inverter [ 18 , 20 ].…”

“…The proposed algorithms provide a good attenuation of the matched disturbances [ 19 ]. Note that the high-frequency switching control function, generated by SMC, may severly damage the power devices of VSI [ 20 ]. SMC, approximated by a sigmoid function or transformed by an artificial increase in the relative degree followed by an integrator (AIRD), provide continuity to the control signal [ 18 ].…”

Three-phase Three-level Inverter Grid-tied PV System with Fuzzy Logic Control based MPPT

“…Since the capacitor lterC f decreases the power factor and unity power factor is desired in grid interactive inverter application [25], the capacitor value of the lter is usually limited to:…”

“…Higher DC voltage level will result in higher switching losses. So, total value of the inductance must be lower than the 10% of L b [26].The difference between L f1 and L f2 values can be selected for a unique value of the total inductance, L f1 /L f2 ratio is related to the maximum allowed value of the current ripple at the inverter and the grid side. Therefore, L f1 = L f2 .…”