scholarly journals A Single-Stage Asymmetrical Half-Bridge Flyback Converter with Resonant Operation

2018 ◽  
Author(s):  
Chung-Yi Ting ◽  
Yi-Chieh Hsu ◽  
Jing-Yuan Lin ◽  
Chung-Ping Chen
Keyword(s):  
Pulse Width Modulation ◽  
Input Voltage ◽  
Resonant Mode ◽  
Voltage Regulation ◽  
Single Stage ◽  
Duty Ratio ◽  
Switching Frequency ◽  
Zero Voltage Switching ◽  
Analysis And Design ◽  
Frequency Controller

This paper proposes a single-stage asymmetrical half-bridge fly-back (AHBF) converter with resonant mode using dual-mode control. The presented converter has an integrated boost converter and asymmetrical half-bridge fly-back converter and operates in resonant mode. The boost-cell always operates in discontinuous conduction mode (DCM) to achieve high power factor. The presented converter operates simultaneously using a variable-frequency-controller (VFC) and pulse-width-modulation (PWM) controller. Unlike the conventional single-stage design, the intermediate bus voltage of this controller can be regulated depending on the main power switch duty ratio. The asymmetrical half-bridge fly-back converter utilizes a variable switching frequency controller to achieve the output voltage regulation. The asymmetrical half-bridge fly-back converter can achieve zero-voltage-switching (ZVS) operation and significantly reduce the switching losses. Detailed analysis and design of this single-stage asymmetrical half-bridge fly-back converter with resonant mode is described. A wide AC input voltage ranging from 90 to 264 Vrms and output 19 V/ 120 W prototype converter was built to verify the theoretical analysis and performance of the presented converter.

scholarly journals High-Power Multimodular Matrix Converters and Modulation

2021 ◽  
Author(s):  
Jiacheng Wang
Keyword(s):  
High Power ◽  
Pulse Width Modulation ◽  
Low Voltage ◽  
Input Voltage ◽  
Duty Ratio ◽  
Modulation Scheme ◽  
Switching Frequency ◽  
Space Vector ◽  
Phase Switching ◽  
Matrix Converters

High-power multimodular matrix converters (MMMCs) comprising multiple threephase to single-phase matrix converter modules have emerged as a viable topology candidate for medium-voltage adjustable speed drives. As a combination of direct power conversion and cascaded multilevel structure, the MMMCs inherit features such as elimination of dc capacitors, four quadrant operation capability, employment of lowvoltage devices only, and superior output waveform quality under a limited device switching frequency. Due to their particular topological structure, modulation scheme design for the MMMCs is not straightforward and complicated. The presented work is mainly focused on development of suitable modulation schemes for the MMMCs. Several viable schemes as well as their corresponding switching patterns are proposed and verified by both simulation and experimental results. In order for the MMMCs to produce sinusoidal waveforms at both input and output ac terminals, a direct transfer matrix based modulation scheme is presented. It is revealed that a suitable modulation strategy for the MMMCs should aim at fabricating the total input current on the primary side of the isolation transformer. For topologies with more than two modules in cascade on each output phase, switching period displacement is necessary among modules to generate multilevel output waveforms. An indirect space vector based modulation scheme for the MMMCs is developed. With a few presumptions satisfied and viewed from a certain perspective, the MMMCs can still be modeled indirectly and be divided into fictitious rectifier and inverter stages. Therefore, space vector modulation methods can be independently applied to both stages for duty ratio calculation, before the results are converted and combined for determining per-phase output pulses. A new output switching pattern providing improved harmonic performance is also proposed. A novel modulation scheme based on diode rectifier emulation and phase-shifted sinusoidal pulse-width modulation is proposed. The method sacrifices input power factor adjustment, but enables the use of an indirect module construction leading to significantly reduced device count and complexity. Strategy for reducing additional switchings caused by input voltage ripples is also implemented and explained. In addition to simulation verifications, all the proposed schemes are further tested experimentally on a low-voltage prototype built in the lab. Details about the prototype implementation are introduced.

scholarly journals Efficiency Boost of a Quasi-Z-Source Inverter: A Novel Shoot-Through Injection Method with Dead-Time

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4216
Author(s):  
Ivan Grgić ◽  
Dinko Vukadinović ◽  
Mateo Bašić ◽  
Matija Bubalo
Keyword(s):  
Pulse Width Modulation ◽  
Dead Time ◽  
Operation Mode ◽  
Input Voltage ◽  
Duty Ratio ◽  
Switching Frequency ◽  
Injection Method ◽  
Laboratory Setup ◽  
Switching Dynamics ◽  
Three Phase

A quasi-Z-source inverter (qZSI) is a single-stage inverter that enables a boost of the input dc voltage through the utilization of a so-called shoot-through state (STS). Generally, the efficiency of the qZSI depends on the utilized STS injection method to a significant extent. This paper presents a novel method of STS injection, called the zero-sync method, in which the STS occurrence is synchronized with the beginning of the zero switching states (ZSSs) of the three-phase sinusoidal pulse width modulation (SPWM). In this way, compared to the conventional STS injection method, the total number of switchings per transistor is reduced. The ZSSs are detected by utilizing the SPWM pulses and the logic OR gates. The desired duration of the STS is implemented by utilizing the LM555CN timer. The laboratory setup of the three-phase qZSI in the stand-alone operation mode was built to compare the proposed zero-sync method with the conventional STS injection method. The comparison was carried out for different values of the switching frequency, input voltage, duty ratio, and load power. As a result of the implementation of the zero-sync method, the qZSI efficiency was increased by up to 4%. In addition, the unintended STSs, caused by the non-ideal switching dynamics of the involved transistors, were successfully eliminated by introducing the optimal dead-time as part of the modified zero-sync method. As a result, the efficiency was increased by up to 12% with regard to the conventional method.

scholarly journals Performance Improvement of PWM Control Methods for Voltage Step-Down in Series Resonant DC–DC Converters

Energies ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 4569
Author(s):  
Vadim Sidorov ◽  
Andrii Chub ◽  
Dmitri Vinnikov
Keyword(s):  
Power Conversion Efficiency ◽  
Conversion Efficiency ◽  
Pulse Width Modulation ◽  
Renewable Energy Sources ◽  
Power Conversion ◽  
Input Voltage ◽  
Voltage Regulation ◽  
Switching Frequency ◽  
Semiconductor Switches ◽  
Series Resonant

The paper is focused on galvanically isolated series resonant DC–DC converters (SRCs) with a low quality factor of the resonant tank. These converters provide input voltage regulation at fixed switching frequency and good power density. Different modulation methods at the fixed switching frequency enable the implementation of the voltage buck functionality in these converters. The SRC under study is considered as a step-up front-end DC–DC converter for the integration of renewable energy sources in DC microgrids. The paper evaluates the voltage buck performance of the SRC achieved by using different pulse-width modulation (PWM) methods including conventional PWM and shifted PWM. Moreover, the new PWM methods, i.e., the hybrid shifted PWM (HSPWM), improved shifted PWM (ISPWM), and hybrid PWM (HPWM), are proposed to overcome the disadvantages of the existing methods. They improve the power conversion efficiency in the buck mode by reducing the power losses in the semiconductor switches and the isolating transformer of the SRC. The proposed and the existing methods are benchmarked in terms of the components stresses and power conversion efficiency. The presented findings have been experimentally validated by the help of a 200 W prototype, which demonstrated the lowest power loss in the case of the HPWM.

scholarly journals High-Power Multimodular Matrix Converters and Modulation

2021 ◽  
Author(s):  
Jiacheng Wang
Keyword(s):  
High Power ◽  
Pulse Width Modulation ◽  
Low Voltage ◽  
Input Voltage ◽  
Duty Ratio ◽  
Modulation Scheme ◽  
Switching Frequency ◽  
Space Vector ◽  
Phase Switching ◽  
Matrix Converters

High-power multimodular matrix converters (MMMCs) comprising multiple threephase to single-phase matrix converter modules have emerged as a viable topology candidate for medium-voltage adjustable speed drives. As a combination of direct power conversion and cascaded multilevel structure, the MMMCs inherit features such as elimination of dc capacitors, four quadrant operation capability, employment of lowvoltage devices only, and superior output waveform quality under a limited device switching frequency. Due to their particular topological structure, modulation scheme design for the MMMCs is not straightforward and complicated. The presented work is mainly focused on development of suitable modulation schemes for the MMMCs. Several viable schemes as well as their corresponding switching patterns are proposed and verified by both simulation and experimental results. In order for the MMMCs to produce sinusoidal waveforms at both input and output ac terminals, a direct transfer matrix based modulation scheme is presented. It is revealed that a suitable modulation strategy for the MMMCs should aim at fabricating the total input current on the primary side of the isolation transformer. For topologies with more than two modules in cascade on each output phase, switching period displacement is necessary among modules to generate multilevel output waveforms. An indirect space vector based modulation scheme for the MMMCs is developed. With a few presumptions satisfied and viewed from a certain perspective, the MMMCs can still be modeled indirectly and be divided into fictitious rectifier and inverter stages. Therefore, space vector modulation methods can be independently applied to both stages for duty ratio calculation, before the results are converted and combined for determining per-phase output pulses. A new output switching pattern providing improved harmonic performance is also proposed. A novel modulation scheme based on diode rectifier emulation and phase-shifted sinusoidal pulse-width modulation is proposed. The method sacrifices input power factor adjustment, but enables the use of an indirect module construction leading to significantly reduced device count and complexity. Strategy for reducing additional switchings caused by input voltage ripples is also implemented and explained. In addition to simulation verifications, all the proposed schemes are further tested experimentally on a low-voltage prototype built in the lab. Details about the prototype implementation are introduced.

scholarly journals Hybrid DC-DC Converter with Low Switching Loss, Low Primary Current and Wide Voltage Operation

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2536
Author(s):  
Bor-Ren Lin ◽  
Yi-Kuan Lin
Keyword(s):  
Pulse Width ◽  
Pulse Width Modulation ◽  
Input Voltage ◽  
Resonant Circuit ◽  
Switching Loss ◽  
Voltage Range ◽  
Current Loss ◽  
Zero Voltage Switching ◽  
Energy Applications ◽  
Multi Stage

A full-bridge converter with an additional resonant circuit and variable secondary turns is presented and achieved to have soft-switching operation on active devices, wide voltage input operation and low freewheeling current loss. The resonant tank is linked to the lagging-leg of the full bridge pulse-width modulation converter to realize zero-voltage switching (ZVS) characteristic on the power switches. Therefore, the wide ZVS operation can be accomplished in the presented circuit over the whole input voltage range and output load. To overcome the wide voltage variation on renewable energy applications such as DC wind power and solar power conversion, two winding sets are used on the output-side of the proposed converter to obtain the different voltage gains. Therefore, the wide voltage input from 90 to 450 V (Vin,max = 5Vin,min) is implemented in the presented circuit. To further improve the freewheeling current loss issue in the conventional phase-shift pulse-width modulation converter, an auxiliary DC voltage generated from the resonant circuit is adopted to reduce this freewheeling current loss. Compared to the multi-stage DC converters with wide input voltage range operation, the proposed circuit has a low freewheeling current loss, low switching loss and a simple control algorithm. The studied circuit is tested and the experimental results are demonstrated to testify the performance of the resented circuit.

A Novel Soft Switching Based Fuzzy Logic Control for Single Phase Inverter

2014 ◽  
Vol 573 ◽  
pp. 143-149
Author(s):  
N. Ismayil Kani ◽  
B.V. Manikandan ◽  
Prabakar Perciyal
Keyword(s):  
Fuzzy Logic ◽  
Pulse Width ◽  
Pulse Width Modulation ◽  
Soft Switching ◽  
Switching Frequency ◽  
Pwm Inverter ◽  
Zero Voltage Switching ◽  
Control Scheme ◽  
Zero Voltage ◽  
Voltage Switching

—This The Pulse Width Modulation (PWM) DC-to-AC inverter has been widely used in many applications due to its circuit simplicity and rugged control scheme. It is however driven by a hard-switching pulse width modulation (PWM) inverter, which has low switching frequency, high switching loss, high electro-magnetic interference (EMI), high acoustic noise and low efficiency, etc. To solve these problems of the hard-switching inverter, many soft-switching inverters have been designed in the past. Unfortunately, high device voltage stress, large dc link voltage ripples, complex control scheme and so on are noticed in the existing soft-switching inverters. This proposed work overcomes the above problems with simple circuit topology and all switches work in zero-voltage switching condition. Comparative analysis between conventional open loop, PI and fuzzy logic based soft switching inverter is also presented and discussed. Keywords—Zero voltage switching, Inverter, Dc link, PI controller, Fuzzy logic system control ,Modulation strategy, Soft switching

Development of Serial-Connected High Step-Up DC-DC Converter with Single Switch

2013 ◽  
Vol 479-480 ◽  
pp. 535-539
Author(s):  
Van Tsai Liu ◽  
Chien Hao Hsu
Keyword(s):  
Electric Vehicles ◽  
Pulse Width Modulation ◽  
Hybrid Electric Vehicles ◽  
Single Pulse ◽  
Input Voltage ◽  
Duty Ratio ◽  
Leakage Inductance ◽  
High Voltage Gain ◽  
Output Capacitor ◽  
Voltage Spike

In this paper, a novel high step-up DC-DC converter has been designed for fuel cell applications. The proposed high step-up converter can be used for various portable energy storage components such as fuel cells which are used for hybrid electric vehicles (HEV), and light electric vehicles (LEV).The proposed converter is integrated by boost circuit, voltage lift capacitor, and coupled-inductor techniques to achieve high step-up voltage and has several advantages. First, the circuit is controlled by one single pulse width modulation (PWM). Second, the converter consists of active clamp circuit to recycle the leakage inductance and send to output capacitor so that the voltage spike on active switch is suppressed and efficiency is also improved. Third, by using the winding of secondary boost circuit, and voltage lift capacitor techniques, the high voltage gain can be achieved without more than 50% duty ratio, and the slope compensation circuit can also be simplified.Finally, a 1k W prototype converter is implemented, to verify the performance of the proposed converter with input voltage 48V, output voltage 400V, and output power 1k W is also achieved. The highest efficiency is 92.96% at 400W, and the full-load efficiency is up to 90.48%.

scholarly journals Resonant Hybrid Flyback, a New Topology for High Density Power Adaptors

Electronics ◽  
2018 ◽  
Vol 7 (12) ◽  
pp. 363 ◽  
Author(s):  
Alfredo Medina-Garcia ◽  
Manfred Schlenk ◽  
Diego Morales ◽  
Noel Rodriguez
Keyword(s):  
Power Density ◽  
Pulse Width Modulation ◽  
High Efficiency ◽  
Full Range ◽  
Input Voltage ◽  
Zero Voltage Switching ◽  
Zero Current Switching ◽  
Zero Current ◽  
Class Power ◽  
World Class

In this article, an innovative power adaptor based on the asymmetrical pulse width modulation (PWM) flyback topology will be presented. Its benefits compared to other state-of-the-art topologies, such as the active clamp flyback, are analyzed in detail. It will also describe the control methods to achieve high efficiency and power density using zero-voltage switching (ZVS) and zero-current switching (ZCS) techniques over the full range of the input voltage and the output load, providing comprehensive guidelines for the practical design. Finally, we demonstrate the convenience of the proposed design methods with a 65 W adaptor prototype achieving a peak efficiency of close to 95% and a minimum efficiency of 93.4% at full load over the range of the input voltage, as well as a world-class power density of 22 W/inch3 cased.

scholarly journals Step-Up Series Resonant DC–DC Converter with Bidirectional-Switch-Based Boost Rectifier for Wide Input Voltage Range Photovoltaic Applications

Energies ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3747 ◽  
Author(s):  
Abualkasim Bakeer ◽  
Andrii Chub ◽  
Dmitri Vinnikov
Keyword(s):  
Theoretical Analysis ◽  
Duty Cycle ◽  
Input Voltage ◽  
Voltage Regulation ◽  
Switching Frequency ◽  
Voltage Gain ◽  
Voltage Range ◽  
Dc Voltage ◽  
Wide Range ◽  
Series Resonant

This paper proposes a high gain DC–DC converter based on the series resonant converter (SRC) for photovoltaic (PV) applications. This study considers low power applications, where the resonant inductance is usually relatively small to reduce the cost of the converter realization, which results in low-quality factor values. On the other hand, these SRCs can be controlled at a fixed switching frequency. The proposed topology utilizes a bidirectional switch (AC switch) to regulate the input voltage in a wide range. This study shows that the existing topology with a bidirectional switch has a limited input voltage regulation range. To avoid this issue, the resonant tank is rearranged in the proposed converter to the resonance capacitor before the bidirectional switch. By this rearrangement, the dependence of the DC voltage gain on the duty cycle is changed, so the proposed converter requires a smaller duty cycle than that of the existing counterpart at the same gain. Theoretical analysis shows that the input voltage regulation range is extended to the region of high DC voltage gain values at the maximum input current. Contrary to the existing counterpart, the proposed converter can be realized with a wide range of the resonant inductance values without compromising the input voltage regulation range. Nevertheless, the proposed converter maintains advantages of the SRC, such as zero voltage switching (ZVS) turn-on of the primary-side semiconductor switches. In addition, the output-side diodes are turned off at zero current. The proposed converter is analyzed and compared with the existing counterpart theoretically and experimentally. A 300 W experimental prototype is used to validate the theoretical analysis of the proposed converter. The peak efficiency of the converter is 96.5%.

Low Input Current Ripple Quasi-Single-Stage Power Supply Based on Double Resonant Tank LLC Converter for Maglev Control System Applications

2016 ◽  
Vol 25 (06) ◽  
pp. 1650064 ◽  
Author(s):  
Hongbo Ma ◽  
Junhong Yi ◽  
Jie Shuai ◽  
Jie Yang
Keyword(s):  
Power Supply ◽  
Low Voltage ◽  
Magnetic Levitation ◽  
High Reliability ◽  
Input Voltage ◽  
Single Stage ◽  
Input Current ◽  
Duty Ratio ◽  
Low Input ◽  
Current Ripple

High input voltage, multiple low voltage outputs and high working temperature are the main design challenges for magnetic levitation (maglev) control power supply. The traditional solutions have several problems, such as the uncontrolled duty ratio, the poor cross-regulation capability and low reliability. In order to solve these problems, a quasi-single-stage solution employing the double resonant tank LLC topology is proposed and developed in this paper. The proposed solution can increase significantly the overall conversion efficiency because of the achieved soft-switching over the entire operation range. Moreover, the low input current ripple, high magnetic utilization and high reliability can be achieved. Experimental results of a 210-W laboratory prototype with 220–380[Formula: see text]V input and four outputs are presented to demonstrate the declared features.

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