Buck converter

About: Buck converter is a research topic. Over the lifetime, 22530 publications have been published within this topic receiving 313580 citations. The topic is also known as: Buck Chopper & step-down converter.

Design of a maximum power tracking system for wind-energy-conversion applications

Abstract: A wind-generator (WG) maximum-power-point-tracking (MPPT) system is presented, consisting of a high-efficiency buck-type dc/dc converter and a microcontroller-based control unit running the MPPT function. The advantages of the proposed MPPT method are that no knowledge of the WG optimal power characteristic or measurement of the wind speed is required and the WG operates at a variable speed. Thus, the system features higher reliability, lower complexity and cost, and less mechanical stress of the WG. Experimental results of the proposed system indicate near-optimal WG output power, increased by 11%-50% compared to a WG directly connected via a rectifier to the battery bank. Thus, better exploitation of the available wind energy is achieved, especially under low wind speeds.

Evaluating MPPT Converter Topologies Using a Matlab PV Model

Abstract: An accurate PV module electrical model is presented based on the Shockley diode equation. The simple model has a photo-current current source, a single diode junction and a series resistance, and includes temperature dependences. The method of parameter extraction and model evaluation in Matlab is demonstrated for a typical 60W solar panel. This model is used to investigate the variation of maximum power point with temperature and isolation levels. A comparison of buck versus boost maximum power point tracker (MPPT) topologies is made, and compared with a direct connection to a constant voltage (battery) load. The boost converter is shown to have a slight advantage over the buck, since it can always track the maximum power point.

Direct power control of PWM converter without power source voltage sensors

Abstract: This paper proposes a novel control strategy of a pulsewidth modulation (PWM) converter with no power-source voltage sensors. The strategy has two main features to improve a total power factor and efficiency, taking harmonic components into account without detecting the voltage waveforms. One feature is a direct instantaneous power control technique for the converter, which has been developed to control the instantaneous active and reactive power directly by selecting the optimum switching state of the converter. The other feature is an estimation technique of the power-source voltages, which can be performed by calculating the active and reactive power for each switching state of the converter from the line currents. A digital-signal-processor-based experimental system was developed, and experimental tests were conducted to examine the controllability. As a result, it was confirmed that the total power factor and efficiency were more than 97% and 93% over the load power range from 200 to 1400 W, respectively. These results have proven the excellent performance of the proposed system.

A new, continuous-time model for current-mode control (power convertors)

Abstract: A current-mode control power convertor model that is accurate at frequencies from DC to half the switching frequency is described for constant-frequency operation. Using a simple pole-zero transfer function, the model is able to predict subharmonic oscillation without the need for discrete-time z-transform models. The accuracy of sampled-data modeling is incorporated into the model by a second-order representation of the sampled-data transfer function which is valid up to half the switching frequency. Predictions of current loop gain; control-to-output; output impedance; and audio susceptibility transfer functions were confirmed with measurements on a buck converter. The audio susceptibility of the buck converter can be nulled with the appropriate value of external ramp. The modeling concentrates on constant-frequency pulse-width modulation (PWM) converters, but the methods can be applied to variable-frequency control and discontinuous conduction mode. >

Pulse-width modulated DC-DC power converters

Abstract: Preface. About the Author. List of Symbols. 1 Introduction. 1.1 Classification of Power Supplies. 1.2 Basic Functions of Voltage Regulators. 1.3 Power Relationships in DC-DC Converters. 1.4 DC Transfer Functions of DC-DC Converters. 1.5 Static Characteristics of DC Voltage Regulators. 1.6 Dynamic Characteristics of DC Voltage Regulators. 1.7 Linear Voltage Regulators. 1.8 Topologies of PWM DC-DC Converters 1.9 Relationships among Current, Voltage, Energy, and Power. 1.10 Electromagnetic Compatibility. 1.11 Summary. 1.12 References. 1.13 Review Questions. 1.14 Problems. 2 BuckPWMDC-DCConverter. 2.1 Introduction. 2.2 DC Analysis of PWM Buck Converter for CCM. 2.3 DC Analysis of PWM Buck Converter for DCM. 2.4 Buck Converter with Input Filter. 2.5 Buck Converter with Synchronous Rectifier. 2.6 Buck Converter with Positive Common Rail. 2.7 Tapped-Inductor Buck Converters. 2.8 Multiphase Buck Converter. 2.9 Summary. 2.10 References. 2.11 Review Questions. 2.12 Problems. 3 Boost PWM DC-DC Converter. 3.1 Introduction. 3.2 DC Analysis of PWM Boost Converter for CCM. 3.3 DC Analysis of PWM Boost Converter for DCM. 3.4 Bidirectional Buck and Boost Converters. 3.5 Tapped-Inductor Boost Converters. 3.6 Duality. 3.7 Power Factor Correction. 3.8 Summary. 3.9 References. 3.10 Review Questions. 3.11 Problems. 4 Buck-Boost PWM DC-DC Converter. 4.1 Introduction. 4.2 DC Analysis of PWM Buck-Boost Converter for CCM. 4.3 DC Analysis of PWM Buck-Boost Converter for DCM. 4.4 Bidirectional Buck-Boost Converter. 4.5 Synthesis of Buck-Boost Converter. 4.6 Synthesis of Boost-Buck (Cuk) Converter. 4.7 Noninverting Buck-Boost Converters. 4.8 Tapped-Inductor Buck-Boost Converters. 4.9 Summary. 4.10 References. 4.11 Review Questions. 4.12 Problems. 5 Flyback PWM DC-DC Converter. 5.1 Introduction. 5.2 Transformers. 5.3 DC Analysis of PWM Flyback Converter for CCM. 5.4 DC Analysis of PWM Flyback Converter for DCM. 5.5 Multiple-Output Flyback Converter. 5.6 Bidirectional Flyback Converter. 5.7 Ringing in Flyback Converter. 5.8 Flyback Converter with Active Clamping. 5.9 Two-Transistor Flyback Converter. 5.10 Summary. 5.11 References. 5.12 Review Questions. 5.13 Problems. 6 Forward PWM DC-DC Converter. 6.1 Introduction. 6.2 DC Analysis of PWM Forward Converter for CCM. 6.3 DC Analysis of PWM Forward Converter for DCM. 6.4 Multiple-Output Forward Converter. 6.5 Forward Converter with Synchronous Rectifier. 6.6 Forward Converters with Active Clamping. 6.7 Two-Switch Forward Converter. 6.8 Summary. 6.9 References. 6.10 Review Questions. 6.11 Problems. 7 Half-Bridge PWM DC-DC Converter. 7.1 Introduction. 7.2 DC Analysis of PWM Half-Bridge Converter for CCM. 7.3 DC Analysis of PWM Half-Bridge Converter for DCM. 7.4 Summary. 7.5 References. 7.6 Review Questions. 7.7 Problems. 8 Full-Bridge PWM DC-DC Converter. 8.1 Introduction. 8.2 DC Analysis of PWM Full-Bridge Converter for CCM. 8.3 DC Analysis of PWM Full-Bridge Converter for DCM. 8.4 Phase-Controlled Full-Bridge Converter. 8.5 Summary. 8.6 References. 8.7 Review Questions. 8.8 Problems. 9 Push-Pull PWM DC-DC Converter. 9.1 Introduction. 9.2 DC Analysis of PWM Push-Pull Converter for CCM. 9.3 DC Analysis of PWM Push-Pull Converter for DCM. 9.4 Comparison of PWM DC-DC Converters. 9.5 Summary. 9.6 References. 9.7 Review Questions. 9.8 Problems. 10 Small-Signal Models of PWM Converters for CCM and DCM. 10.1 Introduction. 10.2 Assumptions. 10.3 Averaged Model of Ideal Switching Network for CCM. 10.4 Averaged Values of Switched Resistances. 10.5 Model Reduction. 10.6 Large-Signal Averaged Model for CCM. 10.7 DC and Small-Signal Circuit Linear Models of Switching Network for CCM. 10.8 Family of PWM Converter Models for CCM. 10.9 PWM Small-Signal Switch Model for CCM. 10.10 Modeling of the Ideal Switching Network for DCM. 10.11 Averaged Parasitic Resistances for DCM. 10.12 Small-Signal Models of PWM Converters for DCM. 10.13 Summary. 10.14 References. 10.15 Review Questions. 10.16 Problems. 11 Open-Loop Small-Signal Characteristics of Boost Converter for CCM. 11.1 Introduction. 11.2 DC Characteristics. 11.3 Open-Loop Control-to-Output Transfer Function. 11.4 Delay in Open-Loop Control-to-Output Transfer Function. 11.5 Open-Loop Audio Susceptibility. 11.6 Open-Loop Input Impedance. 11.7 Open-Loop Output Impedance. 11.8 Open-Loop Step Responses. 11.9 Summary. 11.10 References. 11.11 Review Questions. 11.12 Problems. 12 Voltage-Mode Control of Boost Converter. 12.1 Introduction. 12.2 Circuit of Boost Converter with Voltage-Mode Control. 12.3 Pulse-Width Modulator. 12.4 Transfer Function of Modulator, Boost Converter Power Stage, and Feedback Network. 12.5 Error Amplifier. 12.6 Integral-Single-Lead Controller. 12.7 Integral-Double-Lead Controller. 12.8 Loop Gain. 12.9 Closed-Loop Control-to-Output Voltage Transfer Function. 12.10 Closed-Loop Audio Susceptibility. 12.11 Closed-Loop Input Impedance. 12.12 Closed-Loop Output Impedance. 12.13 Closed-Loop Step Responses. 12.14 Closed-Loop DC Transfer Functions. 12.15 Summary. 12.16 References. 12.17 Review Questions. 12.18 Problems. 13 Current-Mode Control. 13.1 Introduction. 13.2 Principle of Operation of PWM Converters with Peak-Current-Mode Control. 13.3 Relationship between Duty Cycle and Inductor-Current Slopes. 13.4 Instability of Closed-Current Loop. 13.5 Slope Compensation. 13.6 Sample-and-Hold Effect on Current Loop. 13.7 Current Loop in s -Domain. 13.8 Voltage Loop of PWM Converters with Current-Mode Control. 13.9 Feedforward Gains in PWM Converters with Current-Mode Control without Slope Compensation. 13.10 Feedforward Gains in PWM Converters with Current-Mode Control and Slope Compensation. 13.11 Closed-Loop Transfer Functions with Feedforward Gains. 13.12 Slope Compensation by Adding a Ramp to Inductor Current. 13.13 Relationships for Constant-Frequency Current-Mode On-Time Control. 13.14 Summary. 13.15 References. 13.16 Review Questions. 13.17 Problems. 13.18 Appendix: Sample-and-Hold Modeling. 14 Current-Mode Control of Boost Converter. 14.1 Introduction. 14.2 Open-Loop Small-Signal Transfer Functions. 14.3 Open-Loop Step Responses of Inductor Current. 14.5 Closed-Voltage-Loop Transfer Functions. 14.6 Closed-Loop Step Responses. 14.7 Closed-Loop DC Transfer Functions. 14.8 Summary. 14.9 References. 14.10 Review Questions. 14.11 Problems. 15 Silicon and Silicon Carbide Power Diodes. 15.1 Introduction. 15.2 Electronic Power Switches. 15.3 Intrinsic Semiconductors. 15.4 Extrinsic Semiconductors. 15.5 Silicon and Silicon Carbide. 15.6 Physical Structure of Junction Diodes. 15.7 Static I - V Diode Characteristic. 15.8 Breakdown Voltage of Junction Diodes. 15.9 Capacitances of Junction Diodes. 15.10 Reverse Recovery of pn Junction Diodes. 15.11 Schottky Diodes. 15.12 SPICE Model of Diodes. 15.13 Summary. 15.14 References. 15.15 Review Questions. 15.16 Problems. 16 Silicon and Silicon Carbide Power MOSFETs. 16.1 Introduction. 16.2 Physical Structure of Power MOSFETs. 16.3 Principle of Operation of Power MOSFETs. 16.4 Derivation of Power MOSFET Characteristics. 16.5 Power MOSFET Characteristics. 16.6 Mobility of Charge Carriers. 16.7 Short-Channel Effects. 16.8 Aspect Ratio of Power MOSFETs. 16.9 Breakdown Voltage of Power MOSFETs. 16.10 Gate Oxide Breakdown Voltageof Power MOSFETs. 16.11 Resistance of Drift Region. 16.12 Figures-of-Merit. 16.13 On-Resistance of Power MOSFETs. 16.14 Capacitances of Power MOSFETs. 16.15 Switching Waveforms. 16.16 SPICE Model of Power MOSFETs. 16.17 Insulated Gate Bipolar Transistors. 16.18 Heat Sinks. 16.19 Summary. 16.20 References. 16.21 Review Questions. 16.22 Problems. 17 Soft-Switching DC-DC Converters. 17.1 Introduction. 17.2 Zero-Voltage-Switching DC-DC Converters. 17.3 Buck ZVS Quasi-Resonant DC-DC Converter. 17.4 Boost ZVS Quasi-Resonant DC-DC Converter. 17.5 Zero-Current-Switching DC-DC Converters. 17.6 Boost ZCS Quasi-Resonant DC-DC Converter. 17.7 Multiresonant Converters. 17.8 Summary. 17.9 References. 17.10 Review Questions. 17.11 Problems. Appendix A Introduction to SPICE. Appendix B Introduction to MATLAB. Answers to Problems. Index.