Soft-switching Buck Converter Research Articles

Analysis, Design, and Investigation of a Soft-Switched Buck Converter With High Efficiency

In this article, a new simple buck converter with zero voltage switching (ZVS) performance and almost zero output current ripple is proposed. The proposed structure's auxiliary circuit contains a capacitor and an inductor without any switches, which makes it possible to minimize the switching losses and eliminate other additional losses. The main power diode also turns <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</small> under zero current switching condition and the reverse recovery losses of the power diode is minimized. Eliminating the switching losses and the reverse recovery losses allows the converter to operate with high power efficiency, which makes it a good option for high power efficiency-required applications. In this article, five operational modes are explained. The design section includes the designing criteria of the components. Also, the efficiency analysis, control system for stabilizing the output voltage, and applying a variable inductor to ensure the soft-switching operation are analyzed. The comparison results are also discussed. Moreover, an experimental prototype of the proposed structure at 200 W output power and 75 kHz frequency is built to prove the above-mentioned advantages. Finally, the soft-switching waveforms are obtained for different output powers with various duty cycles and equal switching frequency to verify the ZVS performance of the converter at different loads and changes in input voltage and duty cycle.

Study and analysis of a DC–DC soft‐switched buck converter

In this study, a soft-switched buck converter is proposed and analysed. In this structure, by adding an auxiliary inductor and two auxiliary capacitors, zero-voltage switching condition for switch's turn on and near to soft-switching condition for switch's turn off are provided. Furthermore, the power diode turns off under zero-current switching condition. As a result, switching losses and reverse recovery losses have been eliminated, and the proposed converter can provide high efficiencies. To prove the mentioned advantages, a 200 W laboratory prototype of the proposed converter is built and its results are investigated completely. On the basis of these results, the proposed converter can provide 96.1% experimental efficiency at 200 W output power, which proves the 96.78% theoretical efficiency. Also, in comparison results, it is shown that this converter not only provides higher efficiency in comparison with other structures, but also it has less components and simpler structure than other related buck converters.

Improvement of maximum power point tracking (MPPT) efficiency using grey wolf optimization (GWO) algorithm in photovoltaic (PV) system

Photovoltaics are becoming very popular, because the system does not produce pollution and can be installed anywhere, including in remote areas. However, in the use of photovoltaic found some common problems, it is difficult to get maximum and stable power. Therefore, to overcome these problems using Maximum Power Point Tracking method. On a photovoltaic system it is necessary to determine which converter will be used to increase the power output of the photovoltaic. The design of MPPT using gray wolf optimization algorithm that can track the output power quickly and reduce the oscillation in photovoltaic system. The result of the maximum power tracker using the gray wolf optimization algorithm is better than the incremental conductance algorithm of up to 0,4 s. Converters are used using soft - switching buck converter method to overcome the power losses that often arise in PV systems. The result of power output using soft-switching buck converter is greater than using buck converter. When comparing the efficiency of photovoltaic systems using the gray wolf optimization algorithm increases from using the incremental conductance algorithm.

An efficient soft switching buck converter scheme for charging lead acid battery from PV source

In this paper, a high efficiency soft switched two channel interleaved buck converter scheme for charging a lead acid battery bank is presented. This scheme uses the incremental conductance (INC) maximum power point tracking (MPPT). An internal model control system (IMC) is used for controlling the charging of the battery in the constant current mode, constant voltage mode, and trickle mode depending upon the state of charge (SOC) of the battery. Various subsystems of simulation and the results are presented. The simulation results are validated experimentally by using a 125 W photovoltaic (PV) panel unit and a 36 A H lead acid battery. The real time experiment is performed under climatic conditions of Madurai which is a city located in Tamil Nadu, India. The result of the proposed system has been compared against the Perturb and observe MPPT scheme. The results of both simulation and the experiment reveal that the proposed soft switched, internal model controller incorporated INC scheme of MPPT offers more close tracking of the PV power and is more efficient.

Buck Converter with Soft-Switching Cells for PV Panel Applications

In power conversion of photovoltaic (PV) energy, a hard-switching buck converter always generates some disadvantages. For example, serious electromagnetic interference (EMI), high switching losses, and stresses on an active switch (metal-oxide-semiconductor-field-effect-transistor, MOSFET), and high reverse-recovery losses of a freewheeling diode result in low conversion efficiency. To release these disadvantages, a buck converter with soft-switching cells for PV panel applications is proposed. To create zero-voltage-switching (ZVS) features of the active switches, a simple active soft-switching cell with an inductor, a capacitor, and a MOSFET is incorporated into the proposed buck converter. Therefore, the switching losses and stresses of the active switches and EMI can be reduced significantly. To reduce reverse-recovery losses of a freewheeling diode, a simple passive soft-switching cell with a capacitor and two diodes is implemented. To verify the performance and the feasibility of the proposed buck converter with soft-switching cells for PV panel applications, a prototype soft-switching buck converter is built and implemented by using a maximum-power-point-tracking (MPPT) method. Simulated and experimental results are presented from a 100 W soft-switching buck converter for PV panel applications.

Switched resonator DC/DC converter with a single switch and small inductors

A new single-switch, soft-switching buck converter is presented here. The converter switch is turned on and off at zero current switching condition without using any auxiliary switch. The operation of the proposed converter is based on a resonance between two small inductors and a small capacitor. As a result, the size and weight of the converter is reduced. The proposed converter is analysed and its operating modes are explained in detail. The design considerations of the proposed buck converter are presented. The experimental results of the prototype converter confirm the theoretical analysis. Finally, it is shown that the proposed converter can perform as a buck-boost converter by employing an additional switch.

Interleaved soft-switching buck converter with coupled inductors

This paper presents an interleaved soft-switching buck converter with coupled inductors to extend duty ratio for high step-down voltage applications. In the proposed converter, a single-capacitor t...

Nonisolation Soft-Switching Buck Converter With Tapped-Inductor for Wide-Input Extreme Step-Down Applications

In this paper, a new zero-voltage switching (ZVS) buck converter with a tapped inductor (TI) is proposed. This converter improves the conventional tapped inductor critical conduction mode buck converters that have the ZVS operation range determined by the TI turn ratios. It includes another soft switching range extension method, the current injection method, which gives an additional design freedom for the selection of the turn-ratios and enables the optimal design of the winding ratio of the TI so that the efficiency may be maximized. This soft-switching buck converter is suitable for wide input range step-down applications. The principle of the proposed scheme, analysis of the operation, and design guidelines are included. Experimental results of the 100-W prototype dc-dc converter are given for hardware verification also. Finally, based on the proposed soft-switching technique, a new soft-switching topology family is derived.