International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395 -0056
Volume: 04 Issue: 02 | Feb -2017
p-ISSN: 2395-0072
www.irjet.net
A Single Switch High Gain Coupled Inductor Boost Converter Litty P Raju, Neetha John Department of Electrical and Electronics Engineering, Ilahia College of Engineering and Technology, Mulavoor P O, Muvattupuzha, Kerala, India ---------------------------------------------------------------------***--------------------------------------------------------------------applications, interleaved coupled inductor-based boost Abstract-A single switch high gain coupled inductor boost converter with closed loop control for low switch voltage stress. In this converter input energy acquired from the source is first stored in the magnetic field of coupled inductor and intermediate capacitor. In subsequent stages, it is passed on to the output section for load consumption. A passive clamp network around the primary inductor ensures the recovery of energy trapped in the leakage inductance, leading to drastic improvement in the voltage gain and efficiency of the system. Exorbitant duty cycle values are not required for high voltage gain, which prevents problems such as diode reverse recovery. Presence of a passive clamp network causes reduced voltage stress on the switch. This enables the use of low voltage rating switch (with low “on-state” resistance), improving the overall efficiency of the system. Closed loop simulation using PID controller of the converter is done with 40 V DC input and 400 W output power .
Key Words: Coupled inductor, high voltage gain, passive clamp, switched capacitor.
1.INTRODUCTION
In recent years, the boost dc/dc converters have been widely used to step up the renewable energy sources in various industrial applications such as ESS,UPS,EV etc. In those applications, a boost dc/dc converter generally step up the voltage to the high voltage output. For that reason , to obtain a high voltage gain, many converter topologies were reported[3]-[6] for this application. Direct voltage step up using high frequency transformer is a Simple and easily controllable converter providing high gain. Isolated current fed dc-dc converters[7]-[9] are example of this category. However, these topologies result in high voltage spikes across the switch (due to leakage inductance) and large ripple in primary side transformer current as the turns ratio in the high frequency transformer increases. Most of the nonisolated high voltage gain dc–dc power converters employ coupled inductor (to achieve higher voltage gain)[11] in contrast to a high frequency transformer used by the isolated versions . The coupled inductor-based dc–dc converter has advantages over isolated transformer-based dc–dc converter in minimizing current stress, using lower rating components and simple winding structure. Modeling procedure of the coupled inductor is described in [12]. For high power converter
converters [13]–[15] have also been proposed .
Voltage gain of the converter can be increased without increasing the duty cycle of the switch by connecting an intermediate capacitor in series with the inductor [6]. The intermediate energy storage capacitor with coupled inductor charges in parallel and discharges in series with the coupled inductor secondary. A demerit of coupled inductor-based systems is that they have to deal with higher leakage inductance, which causes voltage spikes across the main switch during turn-OFF time and current spike during turn-ON time, resulting in a reduction of the overall circuit efficiency. The effects of leakage inductance can be eliminated by using an active clamp network shown in [9], which provides an alternate path to recover leakage energy. But active clamp network is not as efficient as a passive clamp because of conduction losses across the power switch of the active clamp network. Active clamp network consists of a switch with passive components while passive clamp network [4] consists of passive components such as diode, capacitor, and resistor. The passive clamp circuit is more popular to reduce voltage stress across the converter switch by recycling leakage energy. To overcome such disadvantages of the conventional converters ,In this paper, we propose coupled inductor boost converter that features low switch voltage stress and high gain. To achieves high voltage through a coupled inductor connected in interleaved manner that charges an intermediate buffer capacitor and a passive clamp network to recover the leakage energy. Coupled inductor leads to the incorporation of “turns ratio” into the gain expression that leads to high efficiency without increasing the duty ratio. As compared to existing high-gain dc–dc converters, the number of passive components used in the proposed converter is less, which reduces the cost and improves the efficiency. Though the proposed converter is applicable to any low voltage source applications such as solar PV, fuel cell stack, battery, etc
2. A SINGLE CONVERTER
SWITCH
HIGH
GAIN
BOOST
The proposed converter is shown in Fig. 2.1. It is clear from Fig. 2.1 that the proposed converter consists of one passive clamp network, a coupled inductor(L1,L2),and an Page 108