An AC-DC SEPIC CONVERTER FOR LIGHT EMITTING DIODE WITH CLASS E RESONANCE

Transcription

1 Volume 120 No , ISSN: (on-line version) url: An AC-DC SEPIC CONVERTER FOR LIGHT EMITTING DIODE WITH CLASS E RESONANCE R.Meenadevi 1, V.Geetha 2, and E.Annie Elisabeth Jebaseeli 3 1,2,3 Department of Electrical and Electronics 1,2,3 Sathyabama institute of science and technology Chennai devimalathi2010@gmail.com 2 geethasendray28@gmail.com 3 anniejebaseeli@gmail.com July 4, 2018 Abstract The advantages of superior longevity, fast response, small size, and color rendering, light-emitting diodes (LEDs) have been widely used for various lighting applications, such as signage lights, traffic lights, liquid crystal display television, back lights etc. The PFC stage achieves nearly a unit power factor (PF) and a low total harmonic distortion (THD), while the dc/dc converter provides a well-regulated output. Though easy to design, the two-stage LED driver is still less comparative due to the high cost of more than one independently controls circuits and power switches. In addition, the two-stage drivers require more components and have lower efficiency than the single-stage solution. So, the single-stage LED driver has been studied for many years, which consists of a PFC stage and a dc/dc converter by sharing active power switches and control circuits. Among these single-stage converters, seriesparallel resonance circuit

2 (SPRC, also called LLC) is a widely used topology for its soft-switching characteristics. A single-stage converter by organizing a dual buck-boost circuit with the coupled inductor and a half-bridge LLC resonant converter. Both the efficiency of the two circuits is higher than 89%, as the LLC resonant converter can achieve zero voltage switching (ZVS) in the primary side and zero current switching (ZCS) in the secondary side. Compared to the traditional two-stage converters, this single-stage solution saves one power switches and control circuit. Keywords: LED, AC DC converter,sepic,pfc. 1 Introduction Fig.2: Block diagram of the Sepic converter fed LED drive system The diagram shown in fig 2 described that the combined form of SEPIC and class E resonant converter, both have common switch as only one switch called active switch. that active switch act simultaneously for both the converters [1]-[3]. The following points are to refer the tank circuit for class E resonant circuit and bus capacitance 1. The capacitance cbus act as bus capacitance which store the certain amount of voltage as constant and supply its charges to the circuit when its needed 2. The capacitance cr and inductance lr act as tank circuit for the resonant circuit, its also store the voltage in its and it reduces according to switch operation by the pulses[4]- [6]. The tank circuit supplies its stored voltage to the primary side of the transformer

3 Fig.3: Sepic converter fed LED drive system (a) (b) (c) Fig.4: modes of operation of the Sepic converter fed LED Drive system (a)mode 1 when S [on],d6 [on],(b) mode 2 D6[on],(c)mode 3 S[off],D5[on] Mode 1: The switch S turns OFF, and the input current flows through L1, C1, and L2. Then when the drive signal arrives, S turns ON. The

4 voltages across L1 and L2 equal to the here, i0 is the initial current of L1. At the same time, secondary rectifier diode D6 turns ON. Magnetizing inductance Lm provides energy to capacitor Co, and then the voltage of transformer secondary side is clamped to output voltage. According to the coupling relationship, the reflected voltage of the primary side equals to a constant, leading to current decrease linearly. In this mode, only Cr and Lr take part in resonance[7]-[8]. The moment equals to resonant current ir, D6 turns OFF at ZCS state and this mode ends. Mode 2: The secondary diode D6 turns OFF at time t1, and the secondary side of the transformer divorces from the primary side. The resonant tank then is composed of Cs, Ls, and Lm. During this mode, the line voltage is still imposed on the inductance L1 and L2, so the currents through both L1 and L2 are still increasing until the turn-off signal arrives, and then reach its peak value. Mode 3: At time t2, S turns OFF, and then the bus voltage is imposed on L1 and L2, so the currents through L1 and L2 decrease linearly and freewheel through D1 to charge the bulk capacitor As for the operation of Class E, the current flowing through S diverts to the parallel capacitor Cs. Secondary filter diode D5 turns ON during this period, and then similarly to mode 2, ilm increases linearly. So Cs, Lr, and Cr all take part in resonance except for Lm. SIMULATION OF SEPIC CONVERTER FED LED DRIVE SYSTEM

5 Fig.5:Simulink model of the Sepic fed LED drive system. The utility frequency AC voltage fed to a bridged rectifier producing a DC voltage which is fed to a sepic converter along with a resonating circuit of LC component feeding a three winding transformer where the output voltage is tappexd and controlled by two diodes in the simulated circuit depicting the LED fed system and the output voltage of the system is controlled by tuning the Proportional and Integral value to produce the required needs of the LED system.the system is the MOSFET controlled converter circuit and the following fig 6 shows the output voltage across the load

6 Fig6: output voltage vs time Experimental setup The hardware implementation of the simulated circuit is made and the results are discussed along with the experiment and the fig 8 depicts the output and input voltage of the experimental setup and the tablr 1 states the comparison of the simulated system and the experimental setup. Fig7:Experimental setup of the Sepic converter fed LED drive system

7 (a) (b) Fig.8: (a)output voltage (b)input voltage of the Sepic fed LED drive system TABLE 1: COMPARISON OF SIMULATED RESULT AND EXPERIMENTAL SETUP 2 CONCLUSION This paper conveys the new single stage power factor correction with closed loop control by SEPIC and class E resonant converter by coupling together.it reverse power factor correction.the proposed LED driver which works in discontinuous conduction mode in this circuit there is only one switch for both continuous called active switch (MOSFET) it helps switching loses the system efficiency is

8 improved as much as 93% the power factor is (0.99). References [1] Meena Devi R et al., A Novel bridgeless SEPIC Converter for Power Factor Correction Energy Procedia 117(2017) [2] Meena Devi R, Fuzzy Logic Based Sensorless Speed Control of SEPIC Fed BLDC Drive International Journal of Applied Engineering Research vol:10 issue:2 pp2715. [3] R.Meena devi, Variable Sampling Effect for BLDC Motors using Fuzzy PI Controller Indian Journal of Science and Technology, Vol 8(35), DOI: /ijst/2015/v8i35/68960, December 2015 [4] Jae-Won Yang et al., Bridgeless SEPIC Converter with a Ripple-Free Input Current vol. 28, issue 7 pp july. [5] Kunapuli sahiti and V.Geetha, Simulation of series resonant inverter using pulse density modulation ARPN journal of engineering and applied sciences, vol.10, no.7, April [6] V Geetha, V Sivachidambaranathan,Multi carrier PWM switching technique for multilevel inverter for various loads Computation of Power, Energy Information and Commuincation (ICCPEIC), [7] R Vanitha, V Geetha, A high step up voltage gain of boost converter with switched capacitor technique using FLC for renewable energy system,computation of Power, Energy Information and Commuincation (ICCPEIC), [8] VGeetha, Implementation Of Isolated Full Bridge ZVS Pwm DC-DC Converter For High Voltage Application,International Journal of Applied Engineering Research,

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