Abstract-In this paper, four different topologies of soft-switching boost converter using a simple auxiliary resonant circuit for solar power system are reviewed. These converters have simple structure, low cost and ease of control and are applicable for photovoltaic applications. Also, these topologies raise efficiency and, minimize switching losses by adopting soft-switching method using resonance. As we know efficiency, number of components and, voltage and current stresses are effective in selecting the converter for different applications. Therefore we need to choose the optimal boost converter considering above indexes. Efficiency, number of components and voltage and current stresses of these soft-switching boost converters have been compared in this paper to choose the optimal converter for photovoltaic application.Index Terms-Soft-switching, boost converter, photovoltaic, comparison.
I. INTRODUCTIONRecently, Photovoltaic (PV) energy has attracted interest as a next generation energy source. It is capable of solving the problems of global warming and energy exhaustion caused by increasing energy consumption. The output voltage and power of the solar cell is easily changed by the surrounding conditions such as irradiation and temperature. So, a switching mode converter usually is used maximum power point tracking between solar cells and output inverter. Boost is the most simple and popular topology. Nonisolated DC-DC conversion applications like photovoltaic (PV) grid-connected power systems, electric vehicles (EV), fuel cells, uninterruptible power supplies (UPS), and high-intensity-discharge (HID) lamps for automobile headlamps call for high-performance step-up techniques [1,2]. The common approach to these applications is a classical boost converter having simple structure, continuous input current, and clamped switch voltage stress to the output voltage.Several kinds of soft-switching PWM converters, have been proposed in recent years trying to reduce switching losses, diode reverse recovery current, and the electromagnetic interference (EMI) noise of the pulse width modulation (PWM) controlled converters [3], [4]. Passive methods use only resonant inductors, capacitors, and diodes to achieve soft switching at turn-on and turn-off of the switches. Active methods use resonant inductors, capacitors, diodes, and auxiliary active switches to reduce switching loss due to main power switches. Recently, zero-voltage/current transition (ZVT/ZCT) PWM converters are proposed in addition to traditional zero voltage/current switching (ZVS/ZCS), which diminish voltage/current stresses of the main switch and achieve the soft switching of the main switch [5], [6].However, the auxiliary circuit for resonance increases the complexity of the circuit, as well as its cost. For some resonant converters with an auxiliary switch, the main switch enables soft-switching, while the auxiliary switch performs hard switching. These converters cannot improve the whole system's efficiency owning to the switching losses of the auxil...