A High-Performance Single-Phase Bridgeless Interleaved PFC Converter with Over-Current Protection

In AC to DC conversion boost converter is a key element. Conventional power factor corrected boost converter used for the purpose of AC to DC conversion have disadvantages like low power factor and high value of total harmonic distortion. These disadvantages can be eliminated in Bridgeless Interleaved power factor corrected boost converter. Self-commutating devices are used in these converters for the purpose of switching according to load rating. A protection circuit is provided which will isolate the converter from supply when current in load goes above the rated value of load current. When the load varies, the output voltage is maintained constant by providing the closed loop control. The Comparison Study between different topology can be find out to ensure BLIL topology’s merits. The simulation of BLIL converter is done using MATLAB. The protection circuit of BLIL converter is simulated using MATLAB and The closed loop implementation of BLIL inoder to stabilize the output voltage with low ripples in the output. Keywords-Uninterrupted Power Supplies(UPS),Battery energy storage systems(BESS), Bridgeless interleaved ( BLIL),Adjustable Speed Drives(ASD), Power Factor Correction(PFC) ,Bridgeless Converters , Boost conveters INTRODUCTION AC-DC conversion of electric power is widely used in adjustable-speed drives (ASDs),switch-mode power supplies (SMPSs), uninterrupted power supplies (UPSs), and utility interface with nonconventional energy sources such as solar PV, battery energy storage systems (BESSs), in process technology such as electroplating, welding units, battery charging for electric vehicles, and power supplies for telecommunication systems, measurement and test equipment. There are different types of AC-DC converters such as conventional boost converter, bridgeless boost converter and interleaved boost converter are common AC-DC PFC topologies. These AC-DC converters involve a number of non-linear devices which reduce the system power factor and introduce harmonics in the power system leading to adverse effects. Hence it is essential to use a suitable power factor correction technique to condition the supply current. One such Active Power Factor corrected AC-DC Converter topology is Bridgeless Interleaved Boost Topology, which results in an improved supply power factor and reduced line current harmonics. Bridgeless Interleaved Boost Topology can also improve efficiency due to the elimination of the boost diode rectifier bridge. The conventional boost converter, bridgeless boost converter and interleaved boost converter are common ACDC converters. The conventional boost topology is the most popular topology for PFC applications. With this topology, the output capacitor ripple current is very high and as the power level increases, the diode bridge losses significantly degrade the efficiency. The bridgeless boost converter is good for a low to medium power range, up to approximately 1 kW [2]. It is an attractive solution for applications at power levels greater than 1 kW. This topology solves the problem of heat management in the input rectifier diode bridge, but it introduces increased EMI [7]. Another disadvantage of this topology is the floating input line with respect to the PFC stage ground, which makes it impossible to sense the input voltage without a low frequency transformer or an optical coupler. Also, in order to sense the input current, complex circuitry is needed to sense the current in the MOSFET and diode paths separately, since the current path does not share the same ground during each half-line cycle. The interleaved boost converter, consists of two boost converters in parallel so the input current is the sum of the two inductor currents in LB1 and LB2. Interleaving yields several advantages. The ripple currents in these inductors are out of phase, so they tend to cancel each other therefore reduce the high frequency input ripple current caused by the switching action, so the input EMI filter can be smaller. Additionally, the topology also inherently has the advantage of paralleling semiconductors to reduce conduction losses [7]. Finally, interleaving also reduces output capacitor high frequency ripple. One significant drawback of the interleaved boost PFC converter is that similar to the boost PFC converter, it retains the problem of heat management in the input diode bridge. In order to achieves high efficiency and low EMI bridgeless interleaved (BLIL) topology is used[1]. BLIL topology can achieve high efficiency at power levels above 3 kW due to the elimination of the boost diode Rectifier Bridge and low EMI due to interleaving [3]. In this paper, BLIL topology is simulated for different duty ratio to understand the comparison between PFC correction levels that happens in a circuit. This converter retains the same semiconductor device count as the interleaved boost PFC converter but the merits are on higher side than the conventional converters. BLIL topology is protected by using a control switch for permanent isolation and non-permanent isolation. This model significantly improves the reliability of the circuit even the extra switching causes losses but making it closed loop control the output voltage and reduction in ripple in the output voltage. International Journal of Engineering Research and General Science Volume 3, Issue 4, July-August, 2015 ISSN 2091-273