Design of an LLCL type filter for stand-alone PV systems’ harmonics

Abstract

This paper is regarding the design, modeling and simulation for reducing harmonics with passive LLCL filter in off-grid solar system. It is desired that current and voltage waveforms are to be in the sinusoidal form during energy generation from stand-alone solar systems. This condition can be provided by the most important one of the main factors which to determine the quality of electrical energy. Due to the harmonics produced by the non-linear loads, the waveform of the current and voltage is distorted from the sinusoidal form. The passive LLCL filter is designed and analyzed for mitigation of the total harmonic distortion for current (THD I) in the proposed offgrid PV system. The passive LLCL filter is practically installed between solar inverter and nonlinear load. Simulation results are in a good compliance with the theoretical analysis. This study describes a design methodology of a LLCL filter for off-grid power system with a comprehensive study of how to mitigate the harmonics in off-grid solar system. The using of a LLCL filter mitigates the THD I that injected by a six pulse rectifier which is used as a non-linear load. The simulation result shows that the reduction of THD I from 89.89% to 3.257%. This paper attempts to show that the using of LLCL filter with a stand-alone solar system can highly improve the power quality of the system.

Robust fractional order sliding mode control for solar based DC-AC inverter

“…(4). To generate the switching pulses, PWM (the obtained output signal is compared with a carrier wave) [24][25][26] is used comprising of a triangular waveform operating at 10 kHz switching frequency.…”

“…I-V characteristics of solar PV are widely non-linear for a PV module and have a single maximum power point.The module's highest energy output can be obtained independently of solar radiation circumstances, temperature and electrical load properties by MPPT [26]. They are Perturbing and observing (P&O), short-circuit fractional current, open-circuit fractional violation, constant voltage, neural technique and fugitive logic.…”

Advances in reduction of total harmonic distortion in solar photovoltaic systems: A literature review

“…Previous research likewise focused on the usage of PV systems as either stand‐alone or grid‐integrated, particularly in relation to THD production. Such investigations deal with the management of the nonlinear load, and THD is usually reduced by applying active, passive, and hybrid filters . Reducing the effects of nonlinear loads on the PV system performance is the third method of THD reduction.…”

“…Such investigations deal with the management of the nonlinear load, and THD is usually reduced by applying active, passive, and hybrid filters. 32,33 Reducing the effects of nonlinear loads on the PV system performance is the third method of THD reduction. Inductance, inductance, capacitance, and inductance (LLCL) passive filter was used for reducing harmonics in off-grid solar system, 32 while the performances of inductance, capacitance (LC) and inductance, capacitance and inductance (LCL) passive filters were compared in terms of THD reduction in a stand-alone PV system.…”

“…Reducing the effects of nonlinear loads on the PV system performance is the third method of THD reduction. Inductance, inductance, capacitance, and inductance (LLCL) passive filter was used for reducing harmonics in off‐grid solar system, while the performances of inductance, capacitance (LC) and inductance, capacitance and inductance (LCL) passive filters were compared in terms of THD reduction in a stand‐alone PV system . Using LLCL filter with a stand‐alone solar system substantially reduced THD and considerably improved the power quality of the system.…”