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Power Electronic Converters
Published in Iqbal Husain, Electric and Hybrid Vehicles, 2021
DC/DC converters can be designed to either step-up or step-down the input DC voltage. Depending on the location of the two switches and the inductor and capacitor, the three basic second-order DC/DC converter topologies are buck, boost and buck-boost converters. A buck converter is a step-down converter, and a boost converter is a step-up converter, while a buck-boost converter can be operated in either mode. Improved topologies are available with two switching devices and two diodes, and additional storage elements. Consequently, the order of the converter also increases with the additional components. Examples of higher-order converters are Cuk and Sepic converters. All of these DC/DC converters are used to convert an unregulated DC voltage into a regulated DC output voltage; hence, the converters are known as switching regulators.
Converter Design
Published in Majid Jamil, M. Rizwan, D. P. Kothari, Grid Integration of Solar Photovoltaic Systems, 2017
Majid Jamil, M. Rizwan, D. P. Kothari
On the basis of the voltage stepping operation, the DC to DC converters can be classified as follows: Buck converter: A buck converter is a step-down converter that produces a lower average output voltage than the DC input voltage.Boost converter: A boost converter is a step-up converter that produces a higher average output than the DC input voltage.Buck–boost converter: A buck–boost converter is a step-up as well as a step-down converter that produces a higher or a lower value of output voltage compared to the applied input voltage, depending upon the duty cycle of operation.
Ordinary DC/DC Converters
Published in Fang Lin Luo, Hong Ye, Power Electronics, 2018
Traditional buck–boost converter is convenient to be used for some applications that require the output voltage be either higher or lower than the input voltage. On the contrary, its output voltage polarity is negative, which is restricted for many applications, for example, solar energy systems. Figure 5.10 shows the circuit of positive output buck–boost converter. The output voltage is calculated by the formula, () V2=k1−kV1
Buck-boost converter with simple gate control for renewable energy applications
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2020
Muhammad Ado, M Saad BinArif, Awang Jusoh, Abdulhamid Usman Mutawakkil, Ibrahim Mohammed Danmallam
Buck-boost converter is a type of DC-DC converters capable of increasing or decreasing the magnitude of a DC voltage. Traditional and four-switch buck-boost converters shown in Figures 1 and 2 respectively are types of buck-boost converters. Each of these two buck-boost converters have restrictions with respect to the gate signal required to control it. The traditional buck-boost converter requires an overlap-time in order to avoid its inductor (L) from being open when open-circuit (OC) occurs. OC refers to the scenario where the switches of common leg of a bridge circuit (e.g. S and S of Figures 1 and 2 or S and S of Figure 2) are all simultaneously OFF. Although the use of freewheeling diode as removes this requirement but results in lower efficiency and frequency restriction (Yousefzadeh and Maksimovic 2006). The four-switch buck-boost converter requires both overlap-time to avoid OC which results in the inductor (L) of Figure 2 to be open and dead-time to avoid shoot-through (ST) which results in the input voltage source and capacitor of Figure 2 from being short circuited (Ren et al. 2009). ST refers to the scenario where the switches of common leg of a bridge circuit are all simultaneously ON (Ado et al. 2018b).
Design and Economic Evaluation of Low Voltage DC Microgrid based on Hydrogen Storage
Published in International Journal of Green Energy, 2021
Mohd Alam, Kuldeep Kumar, Viresh Dutta
Present study demonstrates the designing and techno-economic analysis of a low voltage (48 V) DC microgrid using RPGs such as PV and FC with storage mediums (lead-acid, Li-ion, MH, and high-pressure hydrogen storage) for the laboratory load application. A 48 V DC output voltage buck-boost converter is designed in the laboratory which stabilizes the variable voltage of power generators to constant voltage and interconnect the power generators, load and energy storage systems. The buck-boost converter performance has been studied using the simulation and experimental environments. Simulation results confirms the functionality of the DC-DC converter under different operational modes. Designed DC-DC converter also operates the induction heating system which can be utilized in the MH system for heating demand during the hydrogen discharging. Techno-economic analysis shows the battery storage is much economical than hydrogen storage system. In battery storage system, Li-ion battery shows faster charging/discharging and efficient operation. However, if high-pressure hydrogen is considered then the LCOE is reduced significantly as compared to metal hydride storage. Therefore, this kind of low voltage DC microgrid offers an efficient, safe, and simple system to meet the residential load demand such as lighting, cooling, mobile phone charging, and drinking water requirements. The maximum efficiency of designed buck-boost converter is found to ≈ 87%. As DC microgrid is gaining popularity to cater the load demand, the applications of energy storage are very crucial and present study can be useful for other researchers to assess the technological competitiveness of this technology.
Parallel-Connected Buck–Boost Converter with FLC for Hybrid Energy System
Published in Electric Power Components and Systems, 2021
Mustafa Ergin Şahin, Halil İbrahim Okumuş
A variable input voltage is converted to a stable output voltage changing the switching signal duty ratio to control the buck–boost converter. The difference between the required reference voltage value and the measured output voltage value is defined as a system error [61]. The reference voltage is r(k), and the measured output voltage is y(k) for sampling frequency (k). The error and changes in error voltages are calculated using Eqs. (1) and (2)