Traditional Buck-boost Converter Research Articles

Closed Loop Control of DSMST Converter for Ev Applications

Transformerless step-down and step-up DC-DC topologies are currently extensively employed in a variety of applications. A positive output voltage SEPIC-type DC-DC converter without a transformer is proposed in this article. This configuration has the benefit of input continuous current over the traditional buck-boost converter, making it better suited for use with electric vehicles. Moreover, it has an increase in gain that is quadratic of the voltage gain of a standard topology. Also, the suggested converter has a constant current output, which decreases the output voltage ripple and reduces the current stress on the converter's output capacitor. As a result, this converter can generate an extensive range of voltages with less input and output ripples. In addition, closed loop control of DSMST converter is presented in the paper using PI control Ziegler- Nichols method. In the end, simulation findings are shown to support the converter's closed loop study.

Research on High-Performance Multiphase DC–DC Converter Applied to Distributed Electric Propulsion Aircraft

The performance of power converter of electric propulsion aircraft (EPA), which should have high efficiency, high power density and high reliability, affects the volume, weight and efficiency of the whole electric aircraft (EA). This paper proposes a novel DC-DC converter with gallium nitride (GaN) transistors. Firstly, the working modes and main operation waveforms of the converter are analyzed. The new converter can achieve ZVS and ZCS through auxiliary soft switch branches. Compared with the traditional Buck-Boost converter, the soft switching capability of the proposed converter allows operation at very high frequency and has a higher efficiency. The multiphase interleaving magnetic integration technology is adopted to realize the modular design, which not only meets the requirements of high power and low ripple, but also eliminates right half-plane zero in boost mode, achieves high dynamic response and improves the power density. A novel parallel multiphase inverse coupled inductor (ICI) and a symmetrical array ICI are proposed, to allow a high-density and high-efficiency bidirectional DC-DC converter design for hybrid energy storage system of EPA. Finally, the proposed ICI prototype was compared with the state-of-the-art commercial ICI product, and the comprehensive performance of the converter was verified through steady-state, transient, efficiency and thermal experiments.

An Efficient Non-Inverting Buck-Boost Converter with Improved Step Up/Down Ability

In this article, a new non-inverting buck-boost converter with superior characteristics in both bucking and boosting is presented. The proposed converter has some distinct features, such as high step-up/-down ability and low voltage/current stress on its switching devices. The voltage gain of the proposed converter is double the reported value for the traditional buck-boost converter. Although it has three switches, the three switches operate simultaneously, hence no dead-time is required. Two out of the three switches are under voltage stress equal to half of the output voltage. The overall efficiency of the system is promising because of the ability to select devices with low voltage drops. Converter analysis and steady-state performance in both continuous conduction mode (CCM) and discontinuous conduction mode (DCM) are presented in detail. A 1 kW hardware prototype of the converter was implemented in the laboratory; with a step-up ratio of 3.5 and 1 kW power, the measured efficiency is above 95.4%, and with step-up ratio 8, it is around 91.5%.

High Efficiency and Voltage Conversion Ratio Bidirectional Isolated DC-DC Converter for Energy Storage System

This paper proposes a high efficiency and conversion ratio bidirectional isolated DC-DC converter with three-winding coupled inductor, which can fulfil storage system charging and discharging. The proposed topology is improved from traditional Buck-Boost converter. By integrating coupled inductor and switched-capacitor into power stage, the proposed converter can achieve the merits of isolation and bidirectional power flow. The proposed topology has only four switches and a common core coupled inductor, which greatly reduces design costs and achieves high step-up/step-down voltage gain without excessive duty cycles or high turns ratios. In addition, the proposed also has the function of leakage inductance energy recovery, which can recover all the energy stored in the leakage inductance to improve efficiency, and the main switches has a zero voltage switching (ZVS) feature. This paper implements a 500 W converter to verify the feasibility of the proposed topology through software simulation and experiment results, and conducts theoretical analysis, formula derivation, operation principle analysis, and non-ideal analysis. Finally, the experimental results show that the highest efficiency of the step-up and step-down modes are 96.8% and 96.4%, respectively.

A Transformer less Buck Boost Converter with Positive Output Voltage

Some industrial applications require high step-up and step-down voltage gain. The transformer less buck-boost converter has high voltage gain than that of traditional buck-boost converter without extreme duty cycles. A transformer less buck-boost converter with simple structure is obtained by inserting an additional switched network into the traditional buck-boost converter. The two power switches of the buck-boost converter operate synchronously. The operating principles of the buck-boost converter operating in continuous conduction modes are presented. A new buck- boost converter is presented by providing a feedback to the converter. By this, constant output voltage can be maintained under varying load conditions in both buck and boost operation. The output voltage of 40V (step—up mode)/8V (step down mode) is obtained with input voltage 18V and the outcomes are approved through recreation using PSIM MODEL.

Real-time performance evaluation of two-quadrant z-source DC-DC converter for DC drive

This paper contributes to real-time performance evaluation of two-quadrant z-source DC-DC converter drive for industrial application. Regulating the switching duty ratio of the converter produces the desired output voltage level. Z-source DC-DC converter has additional qualities over a traditional buck-boost converter such as higher boost factor at low switching duty ratio, more reliable, inherent short circuit protection and impedance network that behaves as a second-order filter. Z-source converter-fed separately excited DC-drive model is developed in MATLAB/Simulink and executed in field programmable gate array (FPGA)-based real-time digital simulator (RTDS) at fixed-time step of 10 μs and the constant switching frequency is 5 KHz. The real-time simulation results present the real-time performance of the z-source converter-fed DC-drive system during motoring and regenerative braking mode. Small signal analysis is done using state space averaging approach to design a suitable controller for closed-loop drive system. A laboratory-based low voltage hardware prototype of z-source DC-DC converter system is developed utilising a real-time digital simulator (OP5600) as a rapid control prototype.

Buck-boost converter with simple gate control for renewable energy applications

ABSTRACT A buck-boost converter capable of operation without dead-time or overlap-time for renewable energy application is proposed. The converter’s capability of operating without dead-time or overlap-time is possible because it utilized quasi-impedance source converter (q-ZSC) topology. Its gain is the same as that of traditional buck-boost converter. Elimination of dead-time and overlap-time reduces control complexities and permits higher frequency operation, which implies the use of inductors and capacitors with small ratings. Based on a specification for 12 V photovoltaic application, the components values required for the specification were determined. Operation of the proposed converter was simulated and a hardware prototype successfully developed to verify its operation using a 100 kHz switching signals without dead-time and overlap-time at different operating modes.

A Single-Switch Quadratic Buck–Boost Converter With Continuous Input Port Current and Continuous Output Port Current

A single-switch quadratic buck–boost converter with continuous input port current and continuous output port current is proposed in this paper. Compared with the traditional buck-boost converter, the proposed converter can obtain a wider range of the voltage conversion ratio with the same duty cycle. Moreover, the proposed converter can operate with continuous input port current and continuous output port current compared to the existing counterparts with inherently discontinuous input port current and discontinuous output port current. The operating principle and steady-state performance of the proposed converter under continuous inductor current mode is analyzed in detail. Then, the comparison between the proposed converter and the existing quadratic buck–boost converters has been conducted to demonstrate the unique features of the proposed one. Finally, experimental results from a prototype built in the lab are recorded to verify the effectiveness and validity of the proposed quadratic buck–boost converter.

High‐voltage‐boosting converter with charge pump capacitor and coupling inductor combined with buck–boost converter

A novel high-voltage-boosting converter is presented herein, which combines the traditional buck-boost converter, the charge pump capacitor and the coupling inductor. By doing so, the proposed converter possesses a high-voltage conversion ratio, which can be obtained based on not only the duty cycle, but also the turn ratio so as to increase design feasibility. Above all, the used switch is driven without isolation and hence the gate driving circuit is relatively simple, thereby upgrading the industrial application capability of this converter. In this study, the basic operating principles and the associated mathematical deductions are firstly described in detail, and finally some experimental results are provided to demonstrate the effectiveness of the proposed high-voltage-boosting converter.

Study on Nonlinear Phenomena in Buck-Boost Converter with Switched-Inductor Structure

The switched-inductor structure can be inserted into a traditional Buck-Boost converter to get a high voltage conversion ratio. Nonlinear phenomena may occur in this new converter, which might well lead the system to be unstable. In this paper, a discrete iterated mapping model is established when the new Buck-Boost converter is working at continuous conduction current-controlled mode. On the basis of the discrete model, the bifurcation diagrams and Poincare sections are drawn and then used to analyze the effects of the circuit parameters on the performances. It can be seen clearly that various kinds of nonlinear phenomena are easy to occur in this new converter, including period-doubling bifurcation, border collision bifurcation, tangent bifurcation, and intermittent chaos. Value range of the circuit parameters that may cause bifurcations and chaos are also discussed. Finally, the time-domain waveforms, phase portraits, and power spectrum are obtained by using Matlab/Simulink, which validates the theoretical analysis results.

Step-up converter combining KY and buck-boost converters

A step-up converter is presented, which combines the KY converter and the traditional buck-boost converter. By doing so, the limitations on voltage conversion ratio of the KY converter, up to two, can be improved. Aside from this, such a converter possesses a non-pulsating output current, thereby not only decreasing current stress on the output capacitor but also reducing output voltage ripple.

Two Types of KY Buck–Boost Converters

A novel voltage-bucking/boosting converter, named as KY buck-boost converter (i.e., 2D converter), is presented herein. Unlike the traditional buck-boost converter, this converter possesses fast transient responses, similar to the behavior of the buck converter with synchronous rectification. In addition, it possesses the non-pulsating output current, thereby not only decreasing the current stress on the output capacitor but also reducing the output voltage ripple. Furthermore, it has the positive output voltage, different from the negative output voltage of the traditional buck-boost converter. Above all, there are two types of KY buck-boost converters presented herein. In this paper, the basic operating principles of the proposed converters are first illustrated in detail, and second, some experimental results are offered to verify the effectiveness of the proposed topologies.