Buck Functions Research Articles

Effect of polyvinyl alcohol on angora buck spermatozoa survival and function following cryopreservation

Effect of polyvinyl alcohol on angora buck spermatozoa survival and function following cryopreservation

Three new DC-to-DC Single-Switch Converters

This paper presents a new family of three previously unidentified dc-to-dc converters, buck, boost, and buck-boost voltage-transfer-function topologies, which offer advantageous transformer coupling features and low capacitor dc voltage stressing. The three single-switch, single-diode, converters offer the same features as basic dc-to-dc converters, such as the buck function with continuous output current and the boost function with continuous input current. Converter time-domain simulations and experimental results (including transformer coupling) support and extol the dc-to-dc converter concepts and analysis presented.

Fuzzy Logic Controller for Variable Boost Function in Quasi Z Source Indirect Matrix Converter during Voltage Sag Condition

This paper presents a fuzzy logic controller to vary the voltage transfer ratio of Quasi Z Source Indirect Matrix Converter (QZSIMC) for application in induction motor drive during unbalanced input voltage and variable drive speed. A fuzzy logic controller achieves the variation of the voltage transfer ratio from 0.866 to 5 by modifying the shoot through duty ratio of the quasi z source network. Modification in the shoot through duty ratio of the rectifier results in the improvement of the voltage boost factor of the quasi network which in turn varies the voltage transfer ratio. The fuzzy controller varies the shoot through duty ratio with input voltage error and set speed error. The proposed fuzzy-based QZSIMC can attain variable boost as well as buck function with variable shoot through duty ratio. Thus, this proposed method overcomes the limitation of constant boost. The proposed fuzzy-based QZSIMC widens the operating range of the induction motor during all the input voltage sag conditions and reduces the stress on the switches. The simulation results validate the quality performance of the proposed induction motor drive.

English

Renewable energy sources are being widely used for Distributed Generation (fuel cells, solar panels, Wind power generators etc..,) because of their advantages. But they produce a very low output voltage. To interconnect a low-dc-voltage to residential loads a special voltage matching converter is required. This paper presents a back to back connection of cascaded quasi-Z-source network based step up DC/DC converter and 3-level diode clamped inverter. The proposed system reduces the component stresses and size of the converter. This network provides voltage boost and buck functions in single stage without any additional switches by the introduction of special switching strategy. The proposed cascaded qZSI inherits all the advantages of the traditional solution (voltage boost and buck functions in a single stage, continuous input current, and improved reliability). The results are analyzed by Matlab- Simulink environment.

Photovoltaic Power Generation System with Extended Boost Quasi-Z-Source Inverter

This paper proposes a extended boost quasi-Z-source inverter (qZSI) which is used as power conditioning unit for residential solar powered system .The proposed topology used is extended boost quasi Z source inverter and implemented using three phase induction motor. The cascaded qZSI is derived by the adding of one diode, one inductor and two capacitors to the conventional qZSI. The proposed two-stage qZSI has all the advantages of conventional qZSI such as voltage boost and buck functions, continuous input current, improved reliability and a new feature such that it reduces the shoot-through duty cycle by over the 30% for the same voltage boost factor qZSI. The main focus of this paper is to generate residential power using low power input of renewable energy like solar along with two stage qZSI (cascaded qZSI), single phase isolation transformer, and a voltage doubler rectifier and three phase induction motor. Two- stage qZSI in shoot-through and non-shoot-through operating modes is analysed theoretically. The simulation and experimental results are also discussed and presented using MATLAB/simulink. Index Terms— Quasi-Z-source inverter(qZSI),Power conditioning unit(PCU),Voltage doubler rectifier(VDR), photovoltaic system (PV),Maximum power point tracking(MPPT).

Development of Zeta Converter for Permanent Magnet Brushless Direct Current Motor

Converter plays a vital role in modern transferable electronic devices and systems. In the battery operated transferable devices, the battery supplies an input voltage to the converter which in turn converts into the desired voltage. Buck-boost, Cuk, SEPIC and Zeta converter are meeting the operational requirements of DC-DC converters. The DC-DC converters are used in both buck function as well as boost function. But the advantage of Zeta converter is that, it does not suffer the polarity reversal problem. The aim of the proposed work is to design a Zeta converter which can be used to drive the Permanent Magnet Brushless Direct Current Motor. The proposed Zeta converter is suggested to control the speed of the Permanent Magnet Brushless Direct Current Motor, according to the generated switching sequence. The proposed work is generally used for low power applications and occasionally used for medium power applications.

Modeling, analysis, and motor drive application of quasi-Z-source indirect matrix converter

Purpose – The paper aims to propose a new type of three-phase quasi-Z-source indirect matrix converter (QZSIMC) to extend the voltage gain for application in the induction motor drives. Design/methodology/approach – A unique H-shape quasi-Z-source network is connected between the three-phase voltage source and traditional indirect matrix converter to achieve the voltage boost and buck in a single-stage power conversion. The complete space vector modulation (SVM) method is proposed to control the proposed QZSIMC. The output voltage amplitude of quasi-Z-source network can be boosted by the shoot-through of the front-end rectifier, so the whole system's voltage gain is extended. Meanwhile, the QZSIMC modeling and quasi-Z-source impedance parameter design are developed by using the state space averaging method. The design-oriented analysis based on small signal model is used to investigate the quasi-Z-source impedance parameter's impact on the QZSIMC's dynamic performance. A simulated application example employs a 4-kW induction motor drive to verify the proposed QZSIMC, the developed modulation method and parameter design method. Findings – The proposed QZSIMC can achieve high voltage gain larger than one and also can fulfill buck function, which widens the induction motor drive's operation range. The simulation results verify the proposed QZSIMC and SVM and also validate the quality performance of the proposed induction motor drive and all theoretical analysis and parameter design method. Originality/value – The proposed QZSIMC effectively overcomes the limitation of traditional indirect matrix converter, through extending the voltage gain larger than one. The systematic principle, analysis, parameter design, and simulation verification provide the proposed QZSIMC with a feasible approach in practical induction motor drive applications.

Impact of component losses on the voltage boost properties and efficiency of the QZS‐converter family

PurposeThis paper is devoted to the quasi‐Z‐source (qZS) converter family. Recently, the qZS‐converters have attracted high attention because of their specific properties of voltage boost and buck functions with a single switching stage. As main representatives of the qZS‐converter family, this paper aims to discuss the traditional quasi‐Z‐source inverter as well as two novel extended boost quasi‐Z‐source inverters.Design/methodology/approachSteady state analysis of the investigated topologies operating in the continuous conduction mode is presented. Input voltage boost properties of converters are compared for an ideal case. Mathematical models of converters considering losses in components are derived. Practical boost properties of converters are compared to idealized ones and the impact of losses on the voltage boost properties of each topology is justified. Finally, the impact of losses in the components on the boost conversion efficiency is analyzed.FindingsTo demonstrate the impact of component losses on the overall efficiency of the qZS‐converter, a number of experiments were performed. The impact of inductor winding resistance was compared with the forward voltage drop of qZS‐network diodes. It was found that the forward voltage drop of diodes has the highest effect on the efficiency. If the diodes are replaced with high‐power Schottky rectifiers with a low forward voltage drop (UD=0.6 V), the effective efficiency rise by at least 5 percent could be expected for all three qZS‐converter topologies. For the same operating parameters and component values, the traditional qZS‐converter had the highest efficiency of the qZS‐converter family. The boost converter was compared with the traditional qZS converter in terms of efficiency. It was found that the boost converter has an efficiency 2 percent higher in the boost operation mode and approximately the same efficiency in the non‐boost operation.Practical implicationsThe paper provides a good theoretical background for further practical studies. qZS‐converters have voltage boost and buck functions with a single switching stage, which could be especially advantageous in renewable energy applications.Originality/valueThe paper presents a detailed study of the qZS‐converter family. Mathematical models of converters considering losses in components are derived. It is the first time the boost converter is compared with the qZS converter.

Step-Up DC/DC Converters With Cascaded Quasi-Z-Source Network

This paper is devoted to the step-up dc/dc converter family with a cascaded quasi-Z-source network (qZS-network). The cascaded (two-stage) qZS-network could be derived by the adding of one diode, one inductor, and two capacitors to the traditional quasi-Z-source inverter (qZSI). The proposed cascaded qZSI inherits all the advantages of the traditional solution (voltage boost and buck functions in a single stage, continuous input current, and improved reliability). Moreover, as compared to the conventional qZSI, the proposed solution reduces the shoot-through duty cycle by over 30% at the same voltage boost factor. Theoretical analysis of the two-stage qZSI in the shoot-through and non-shoot-through operating modes is described. The proposed and traditional qZS-networks are compared. A prototype of a step-up dc/dc converter with the cascaded qZS-network was built to verify the theoretical assumptions. The experimental results are presented and analyzed. Finally, a further optimization method of the cascaded qZS-network is proposed, and some practical design issues are discussed.

Lossless Dynamic Models of the Quasi-Z-Source Converter Family

Lossless Dynamic Models of the Quasi-Z-Source Converter FamilyThis paper is devoted to the quasi-Z-source (qZS) converter family. Recently, the qZS-converters have attracted attention because of their specific properties of voltage boost and buck functions with a single switching stage, which could be especially beneficial in renewable energy applications. As main representatives of the qZS-converter family, the traditional quasi-Z-source inverter as well as two novel extended boost quasi-Z-source inverters are discussed. Lossless dynamic models of these topologies are presented and analyzed.