scholarly journals Multiple-Output DC-DC Converters with a Reduced Number of Active and Passive Components

2019 ◽  
Vol 9 (3) ◽  
pp. 28
Author(s):  
Mert Turhan ◽  
Juan C. Castellanos ◽  
Marcel A. M. Hendrix ◽  
Jorge L. Duarte ◽  
Elena A. Lomonova
Keyword(s):  
Pulse Width Modulation ◽  
Control Method ◽  
Pulse Frequency ◽  
Buck Converter ◽  
Pulse Frequency Modulation ◽  
Passive Components ◽  
The Third ◽  
Magnetic Cores ◽  
Converter Topologies ◽  
Active Switch

Multiple-output converters have been widely used where individual outputs are required. Compared with conventional separate converters, the advantage of multiple outputs is to have a lower number of active and passive components. In this paper, first, a pulse-width-modulation (PWM)-pulse-frequency-modulation (PFM) method is used for two-output converters that have only one coil and one active switch. Secondly, three-output converter topologies are proposed where the third output is controlled by phase delay (PD). These converters need only two coils and two active switches to regulate three outputs. How to obtain PD at different switching frequencies is discussed next, and a PWM-PFM-PD controlled five-output buck converter is presented. The proposed solution uses only two active switches and two magnetic cores to adjust five-output voltages independently. A modeling and digital control method are proposed in order to regulate the five output voltages. A prototype circuit with independent 15 V/1.5 A, 12 V/1.5 A, 5 V/0.8 A, −5 V/0.6 A and 3.3 V/0.45 A outputs is assembled to validate the analysis, and it was proved that it regulates the output voltages at different loads.

scholarly journals Design Methodology of Tightly Regulated Dual-Output LLC Resonant Converter Using PFM-APWM Hybrid Control Method

Energies ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 2146
Author(s):  
HwaPyeong Park ◽  
Mina Kim ◽  
HakSun Kim ◽  
JeeHoon Jung
Keyword(s):  
Design Methodology ◽  
Control Method ◽  
Hybrid Control ◽  
Pulse Frequency ◽  
Voltage Regulation ◽  
Resonant Converter ◽  
Pulse Frequency Modulation ◽  
Load Range ◽  
Worst Case ◽  
Llc Resonant Converter

A dual-output LLC resonant converter using pulse frequency modulation (PFM) and asymmetrical pulse width modulation (APWM) can achieve tight output voltage regulation, high power density, and high cost-effectiveness. However, an improper resonant tank design cannot achieve tight cross regulation of the dual-output channels at the worst-case load conditions. In addition, proper magnetizing inductance is required to achieve zero voltage switching (ZVS) of the power MOSFETs in the LLC resonant converter. In this paper, voltage gain of modulation methods and steady state operations are analyzed to implement the hybrid control method. In addition, the operation of the hybrid control algorithm is analyzed to achieve tight cross regulation performance. From this analysis, the design methodology of the resonant tank and the magnetizing inductance are proposed to compensate the output error of both outputs and to achieve ZVS over the entire load range. The cross regulation performance is verified with simulation and experimental results using a 190 W prototype converter.

scholarly journals Three-Phase Five-Level Cascade Quasi-Switched Boost Inverter

Electronics ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 296 ◽  
Author(s):  
Van-Thuan Tran ◽  
Minh-Khai Nguyen ◽  
Cao-Cuong Ngo ◽  
Youn-Ok Choi
Keyword(s):  
Pulse Width Modulation ◽  
Control Method ◽  
Operating Principle ◽  
Modulation Scheme ◽  
Pwm Control ◽  
Passive Components ◽  
Power Semiconductor ◽  
Imbalance Problem ◽  
Three Phase ◽  
Comprehensive Comparison

This paper presents a three-phase cascaded five-level H-bridge quasi-switched boost inverter (CHB-qSBI). The merits of the CHB-qSBI are as follows: single-stage conversion, shoot-through immunity, buck-boost voltage, and reduced passive components. Furthermore, a PWM control method is applied to the CHB-qSBI topology to improve the modulation index. The voltage stress across power semiconductor devices and the capacitor are significantly lower using improved pulse-width modulation (PWM) control. Additionally, by controlling individual shoot-through duty cycle, the DC-link voltage of each module can achieve the same values. As a result, the imbalance problem of the DC-link voltage can be solved. A detailed analysis and operating principle with the modulation scheme and comprehensive comparison for the CHB-qSBI are illustrated. The experimental and simulation results are presented to validate the operating principle of the three-phase CHB-qSBI.

Influence of Electric Fields on Flow of Liquid Crystal Mixture in a Circular Tube With Electrode Surface

2003 ◽  
Author(s):  
Tetsuhiro Tsukiji ◽  
Tsuyoshi Mitani
Keyword(s):  
Liquid Crystal ◽  
Pressure Drop ◽  
Electric Fields ◽  
Pulse Width Modulation ◽  
Circular Tube ◽  
Pulse Frequency ◽  
Open Loop ◽  
Test Facility ◽  
Pulse Frequency Modulation ◽  
Crystal Mixture

Liquid crystal is one of functional fluids to control an apparent viscosity using an electric field intensity. It is also called ER (Electro-rheological) fluids. In the present experiment a liquid crystal mixture made of some kinds of the nematic liquid crystal is used. The responses of the pressure drop are examined when the liquid crystal mixture flows in a circular tube with the electrode walls on some parts of the inner surface of the tube for the constant flow rates. The four pair of the electrode is used and the voltages are added in the peripheral direction. When the voltages are applied on the liquid crystal mixture and removed, the pressure responses of the inlet of the circular tube are measured with the pressure transducer. On the other hand, the pulse-wave voltages are added to the electrodes to control the pressure drop using the pulse width modulation or the pulse frequency modulation. The diameter of the circular tube is 1.0mm. The isotropic-nematic transition is 90.0°C and smectic-nematic transition is −44.0°C for the liquid crystal mixture. The open-loop test facility with the liquid crystal mixture is set in a pyrostat to keep the temperature constant.

PWM/PFM Dual-Mode Synchronous Boost DC-DC Regulator

2013 ◽  
Vol 380-384 ◽  
pp. 3209-3212
Author(s):  
Wen Yuan Li ◽  
Jun Zhang
Keyword(s):  
Pulse Width Modulation ◽  
Pulse Frequency ◽  
Dual Mode ◽  
Pulse Frequency Modulation ◽  
Good Efficiency ◽  
Signal Regeneration ◽  
Soft Start ◽  
Start Up ◽  
Simulation Results ◽  
Surge Current

a novel peak current PWM/PFM dual-mode boost dc-dc regulator applying for neural signal regeneration is proposed in this paper. The converter can adaptively switch between pulse-width modulation (PWM) and pulse-frequency modulation (PFM) both with relatively high conversion efficiency. Soft-start circuit is designed to eliminate the surge current at the start up stage of the regulator, other protection modules are also contained. The paper analyzes the model and stability of the system. The operation frequency of the regulator is 1MHz. The simulation results show the efficiency of the system is relatively high in PWM mode, up to 95%, in PFM mode it also has good efficiency.

Implementation and Design of Voltage-Mode PFM Control Buck Power Converter

2013 ◽  
Vol 860-863 ◽  
pp. 2390-2394
Author(s):  
Min Chin Lee ◽  
Ruey Wun Jan
Keyword(s):  
Supply Voltage ◽  
Pulse Frequency ◽  
Power Converter ◽  
Buck Converter ◽  
Switching Frequency ◽  
Cmos Process ◽  
Pulse Frequency Modulation ◽  
Better Regulation ◽  
Chip Size ◽  
Voltage Feedback

A lower power consumption, smaller output ripple and better regulation buck dcdc converter controlled by voltage feedback and pulse-frequency modulation (PFM) mode is implemented in this paper. The converter operating in discontinuous conduction mode (DCM) is designed and simulated using the TSMC 0.18μm 1P6M CMOS Process. Hspice simulation results show that, the buck converter having chip size with power dissipation about 0.68mW. This chip can operate with input supply voltage from 1.2V to 1.8V, and switching frequency from 249KHz () to 50KHz (), and its output voltage can stable at 1.0V and less than 110mV ripple voltage at maximum loading current 100 mA.

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