Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 2

duty ratio Related Publications

2 Reduced Rule Based Fuzzy Logic Controlled Isolated Bidirectional Converter Operating in Extended Phase Shift Control for Bidirectional Energy Transfer

Authors: Pramod Agarwal, Anupam Kumar, Abdul Hamid Bhat

Abstract:

Bidirectional energy transfer capability with high efficiency and reduced cost is fast gaining prominence in the central part of a lot of power conversion systems in Direct Current (DC) microgrid. Preferably, under the economics constraints, these systems utilise a single high efficiency power electronics conversion system and a dual active bridge converter. In this paper, modeling and performance of Dual Active Bridge (DAB) converter with Extended Phase Shift (EPS) is evaluated with two batteries on both sides of DC bus and bidirectional energy transfer is facilitated and this is further compared with the Single Phase Shift (SPS) mode of operation. Optimum operating zone is identified through exhaustive simulations using MATLAB/Simulink and SimPowerSystem software. Reduced rules based fuzzy logic controller is implemented for closed loop control of DAB converter. The control logic enables the bidirectional energy transfer within the batteries even at lower duty ratios. Charging and discharging of batteries is supervised by the fuzzy logic controller. State of charge, current and voltage for both the batteries are plotted in the battery characteristics. Power characteristics of batteries are also obtained using MATLAB simulations.

Keywords: Fuzzy Logic Controller, rule base, membership functions, state of charge, duty ratio, dual active bridge converter, bidirectional power flow, extended phase shift

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1 Design and Implementation of a Fan Coil Unit Controller Based on the Duty Ratio Fuzzy Method

Authors: Kai Li, Liang Zhao, Jili Zhang

Abstract:

A microcontroller-based fan coil unit (FCU) fuzzy controller is designed and implemented in this paper. The controller employs the concept of duty ratio on the electric valve control, which could make full use of the cooling and dehumidifying capacity of the FCU when the valve is off. The traditional control method and its limitations are analyzed. The hardware and software design processes are introduced in detail. The experimental results show that the proposed method is more energy efficient compared to the traditional controlling strategy. Furthermore, a more comfortable room condition could be achieved by the proposed method. The proposed low-cost FCU fuzzy controller deserves to be widely used in engineering applications.

Keywords: Experiment, fuzzy controller, fan coil unit, duty ratio

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