Combined Fuzzy and Predictive Controller for Unity Power Factor Converter

This paper treats a design of combined control of a single phase power factor correction (PFC). The strategy of the proposed control is based on two parts, the first, for the outer loop (DC output regulated voltage), and the second govern the input current of the converter in order to achieve a sinusoidal form in phase with the grid voltage. Two kinds of regulators are used, Fuzzy controller for the outer loop and predictive controller for the inner loop. The controllers are verified and discussed through simulation under MATLAB/Simulink platform. Also an experimental confirmation is applied. Results present a high dynamic performance under various parameters changes. Keywords—Boost converter, harmonic distortion, Fuzzy, prediction, unity power factor. I.INTRODUCTION ECENTLY, the power converters have been employed in a wide range of industrial sectors and energy conversion. Due to increase energy demands and appear renewable energy (photovoltaic and wind), researches in power converters have become an interest topic today. Moreover, more than 60% of the utility power dissipated before it is finally consumed due to: network pollution, harmonics distortion and insufficiency of power supplies; for these reasons, many countries in the world created legalism to limit energy dissipation. One of these laws is producing an electronics appliances have a highperformance with low harmonic distortion. To fulfill these goals, power factor corrector (PFC) appears such as an enabling technology for improvement of power supplies. The main feature of latest power converters that improved the requirement of efficiency, fast operation and sophistication in performance, have achieved by a switching mode operation. This later includes two states (ON/OFF) fashion and has been developed due to new invention in semiconductor technologies [1]. In literature, there are many kinds of power converters. Among these converters, the boost converter is currently the most popular, which is used in a wide range of electronic appliances. To ensure the converted AC/DC, usually a bridge of diodes is used, this later tends to have a non-sinusoidal current and a low power factor nearly to 0.6 due to nonlinear behavior of circuit. To solve this problem one mean possible: add PFC circuit. Moreover, the cost global of devices will be increased with 10 to 25%; on the other hand, the cost of saved energy will cover the cost of PFC. Abdelhalim Kessal is with the Bordj Bou Arréridj University, Faculty of Sciences & Technology, Algeria (e-mail: ([email protected]). Active PFC increases in recent few years in wide range of industrial power supplies. This later involves a pre-regulator between the rectifier and the load (Fig. 1) [2]. By controlling of applied switching, the current will be taken its sinusoidal drawn like source voltage, also the total harmonic distortion (THD) will be decreased. Several control strategies have been proposed for the control of boost converters, such as PI control [3], neural networks [4], predictive control [5]-[8], fuzzy logic control [9] sliding mode control [2], and other [10], [11].Taking into account the efficiency of devices, ensuring conversion with less weight and cost. The fuzzy logic with predictive method can be a suitable solution. Fuzzy logic is considered as solution when a high nonlinearity and ambiguity of the system have been considered. It is used in many areas such as: identification, control and diagnostic of a complex system [12]. The fuzzy logic is founded by Zadeh in 1963 [13]. Construction and understand are very easy because the controller does not need mathematical modeling; According to Zadeh concept, the system behavior is converted to linguist rules, this later is used to develop a control strategy [14]. The application of fuzzy logic for power factor corrector can give improvements [9], because it can enhance the performance of the system and offers good responses during the variation of load values or output voltage reference value. There is several works which use fuzzy logic for APFC, but these works apply high number of rules, which will exhibit an additional cost and decrease the rapidity of devices. So, in this work we try using FLC with a few rules number compared to previous works. Meanwhile, the predictive control has been introduced to current control, this later has been extended for a wide range of power converter and electric derives. This kind of control allows the system to present good robustness. The primary task of this work is to develop a new method based on predictive control and Takagi Sugeno Fuzzy logic for single phase active power factor correction in order to supply by sinusoidal current in phase with grid voltage. The simulation under Matlab/Simulink and its implementation on real time by using dSPACE1104 are carried out for improve the efficiency and possibility of commercialization this technique in future. Also, several robustness tests have been done, by the changing load values and output voltage reference. II.MATHEMATICAL MODELING The basic conception of the boost converter is illustrated in Fig. 1. According to state of the switch, two function modes are founded. The first mode operation Fig. 1 (b), in this case Combined Fuzzy and Predictive Controller for Unity Power Factor Converter Abdelhalim Kessal R World Academy of Science, Engineering and Technology International Journal of Electrical, Computer, Energetic, Electronic and Communication Engineering Vol:8, No:9, 2014 1534 International Scholarly and Scientific Research & Innovation 8(9) 2014 scholar.waset.org/1999.5/10003982 In te rn at io na l S ci en ce I nd ex , E le ct ri ca l a nd C om pu te r E ng in ee ri ng V ol :8 , N o: 9, 2 01 4 w as et .o rg /P ub lic at io n/ 10 00 39 82 the switch S is turned on (S= 1), the current will be accumulates. Also, the energy has been saved in the inductor and the capacitor supplies the load. The second mode operation Fig. 1 (c), the switch S is turned off (S= 0). The quantity of stored energy in the inductor and the source energy both will be transferred to the output (capacitor–load). Moreover, the power circuit has been changed his mode. The model of boost PFC can be represented as (1) [2], [3], [9].