Unity Power Factor Operation in Microgrid Applications Using Fuzzy Type 2 Nested Controllers

Abstract

The issue of low-power factor operation microgrids was reported for several layouts. Although numerous power factor improvement strategies have been applied and tested, various concerns remain to be addressed such as transient performance, simplicity of implementation, and satisfying the power-quality standards. The presented research aimed to design and implement controllers that can improve the transient response of microgrids due to changes in the load demand and achieve a near-unity power factor at the AC grid side, to which the DC microgrid is connected. Due to the nonlinear nature of microgrids, as they rely on power electronics converters, a Fuzzy type 2 controller was designed, implemented, and tested. The focus was given to improving the power factor of the DC microgrids. The validation of the proposed technique was verified by comparing its performance with Fuzzy type 1 and autotuned conventional PI controllers. To achieve the set aims, two nested control loops were designed with an inner current loop and an outer voltage loop. Besides MATLAB/Simulink simulations, a 10 kHz-sampling dSPACE platform was used to implement the suggested system. Two operational scenarios were tested: (1) a step change in the DC link voltage and (2) a change in the AC load (increase and decrease) at the output of the power inverter, connected to the DC grid. The simulation and experimental results confirmed that the proposed Fuzzy type 2 controller performed better than the other two techniques regarding the dynamic response, steady-state error, and compliance with power quality standards. Conventional approaches develop controllers using a linearized model, which limits the model accuracy and ignores higher-order variability. The method employs the nonlinear model. Fuzzy type 2 can better approximate high-precision problems than Fuzzy type 1.

Intelligent Type-2 Fuzzy Logic Controller for Hybrid Microgrid Energy Management with Different Modes of EVs Integration

“…Comparative analyses highlight the proposed controller's improved performance over conventional controllers and optimization techniques, showcasing its efficacy in stabilizing multi-area islanded AC microgrids. In [28], a Fuzzy type 2 controller is introduced to address low-power factor issues in microgrids, focusing on DC microgrids. By improving transient responses and aiming for near-unity power factors, this controller outperforms classical FLC and PI controllers in dynamic response, steady-state error, and power quality standards, validated through MATLAB/Simulink and dSPACE platform tests.…”

Design of Dual-Notch-Filter-Based Controllers for Enhancing the Dynamic Response of Universal Single-Phase Grid-Connected Power Converters

“…Mains-interfacing power conversion systems are typically obliged by power quality standards to interchange sinusoidal-shaped current with the utility grid [1][2][3]. As a result, alternating instantaneous power is exchanged between the two entities, formed by a DC component and a power component pulsating at twice the mains base frequency [4][5][6]. While the DC component is transferred to/from the load/source in order to carry the energy, the pulsating power constituent should not be allowed to reach the load/source to avoid lifetime reduction and excessive losses [7][8][9].…”