scholarly journals Wide-Range Operation of High Step-Up DC-DC Converters with Multimode Rectifiers

Electronics ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 914
Author(s):  
Andrii Chub ◽  
Dmitri Vinnikov ◽  
Oleksandr Korkh ◽  
Tanel Jalakas ◽  
Galina Demidova
Keyword(s):  
Duty Cycle ◽  
Input Voltage ◽  
Voltage Range ◽  
Front End ◽  
Wide Range ◽  
Theoretical Predictions

This paper discusses the essence and application specifics of the multimode rectifiers in high step-up DC-DC converters. It presents an overview of existing multimode rectifiers. Their use enables operation in the wide input voltage range needed in highly demanding applications. Owing to the rectifier mode changes, the converter duty cycle can be restricted to a range with a favorable efficiency. It is shown that the performance of such converters depends on the front-end inverter type. The study considers current- and impedance-source front-end topologies, as they are the most relevant in high step-up applications. It is explained why the full- and half-bridge implementations provide essentially different performances. Unlike the half-bridge, the full-bridge implementation shows step changes in efficiency during the rectifier mode changes, which could compromise the long-term reliability of the converter. The theoretical predictions are corroborated by experimental examples to compare performance with different boost front-end inverters.

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%.

scholarly journals Impact of Transformer Turns Ratio on the Power Losses and Efficiency of the Wide Range Isolated Buck–Boost Converter for Photovoltaic Applications

Energies ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5645
Author(s):  
Hamed Mashinchi Maheri ◽  
Dmitri Vinnikov ◽  
Andrii Chub ◽  
Vadim Sidorov ◽  
Elizaveta Liivik
Keyword(s):  
High Efficiency ◽  
Input Voltage ◽  
Power Losses ◽  
Efficient Operation ◽  
Wide Range ◽  
Photovoltaic Applications ◽  
Theoretical Predictions ◽  
Converter Topology ◽  
Isolation Transformer ◽  
The Impact

In this paper, the impact of transformer turns ratio on the performance of the quasi-Z-source galvanically isolated DC-DC converters is studied. Embedded buck–boost functionality enables these converters to regulate the input voltage and load in a wide range, which makes them suitable for such demanding application as photovoltaic microconverters. The isolation transformer here plays a central role as its turns ratio defines the point of transition between the boost and buck modes and overall capability of the converter to regulate the input voltage in a wide range at high efficiency. The studied quasi-Z-source galvanically isolated DC-DC converter is benchmarked in terms of power loss of components and weighted power conversion efficiency for three different turns ratios of isolation transformer to achieve the best and optimized turns ratio lead to the efficient operation. Operation in a wide range of input voltage at high efficiency is the main criterion for assessing the effect of turns ratio on the efficiency of the converter. The proposed loss model and theoretical predictions of the efficiency were validated with the help of a 300 W experimental prototype of the photovoltaic microconverter based on the quasi-Z-source galvanically isolated DC-DC converter topology.

A Stable Mode-Selectable Oscillator with Variable Duty Cycle and High-Efficiency

2015 ◽  
Vol 24 (09) ◽  
pp. 1550132 ◽  
Author(s):  
Li-Ye Cheng ◽  
Xin-Quan Lai
Keyword(s):  
Duty Cycle ◽  
High Efficiency ◽  
Dynamic Performance ◽  
Operation Mode ◽  
Charge Pump ◽  
Input Voltage ◽  
Cmos Process ◽  
Pump Efficiency ◽  
Stable Mode ◽  
Wide Range

A mode-selectable oscillator (OSC) with variable duty cycle for improved charge pump efficiency is proposed in this paper. The novel OSC adjusts its duty cycle according to the operation mode of the charge pump, thus improves the charge-pump efficiency and dynamic performance. The control of variable duty cycle is implemented in digital logic hence it provides robust noise immunity and instantaneous response. The OSC and the charge-pump have been implemented in a 0.6-μm 40-V CMOS process. Experimental results show that the peak efficiency is 92.7% at 200-mA load, the recovery time is less than 25 μs and load transient is 15 mV under 500-mA load variation. The system is able to work under a wide range of input voltage (V IN ) in all modes with low EMI.

scholarly journals Flux States of Active Galactic Nuclei

Galaxies ◽  
2019 ◽  
Vol 7 (2) ◽  
pp. 57
Author(s):  
Daniela Dorner ◽  
Axel Arbet-Engels ◽  
Dominik Baack ◽  
Matteo Balbo ◽  
Adrian Biland ◽  
...  
Keyword(s):  
Active Galactic Nuclei ◽  
Time Scales ◽  
Duty Cycle ◽  
Main Part ◽  
Flux Distribution ◽  
Galactic Nuclei ◽  
Quiescent State ◽  
Wide Range ◽  
Multi Wavelength

Blazars are known to show variability on time scales from minutes to years covering a wide range of flux states. Studying the flux distribution of a source allows for various insights. The shape of the flux distribution can provide information on the nature of the underlying variability processes. The level of a possible quiescent state can be derived from the main part of the distribution that can be described by a Gaussian distribution. Dividing the flux states into quiescent and active, the duty cycle of a source can be calculated. Finally, this allows alerting the multi-wavelength and multi-messenger community in case a source is in an active state. To get consistent and conclusive results from flux distributions, unbiased long-term observations are crucial. Only like this is a complete picture of the variability and flux states, e.g., an all-time quiescent state, possible. In seven years of monitoring of bright TeV blazars, the first G-APD Cherenkov telescope (FACT) has collected a total of more than 11,700 hours of physics data with 1500 hours to 3000 hours per source for Mrk 421, Mrk 501, 1ES 1959+650, and 1ES 2344+51.

scholarly journals Photovoltaic Energy Yield Improvement in Two-Stage Solar Microinverters

Energies ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3774 ◽  
Author(s):  
Chub ◽  
Vinnikov ◽  
Stepenko ◽  
Liivik ◽  
Blaabjerg
Keyword(s):  
Energy Production ◽  
Input Voltage ◽  
Energy Yield ◽  
Control Methods ◽  
Maximum Power Point ◽  
Two Stage ◽  
Voltage Range ◽  
Front End ◽  
Power Point ◽  
Geographical Locations

The focus in this paper is on the two-stage photovoltaic (PV) microinverters using a buck-boost dc/dc front-end converter. Wide input voltage range of the front-end converter enables operation under shaded conditions but results in mediocre performance in the typical voltage range. These microinverters can be controlled with either fixed or variable dc-link voltage control methods. The latter improves the converter efficiency considerably in the range of the most probable maximum power point (MPP) locations. However, the buck-boost operation of the front-end converter results in noticeable variations of the efficiency across the input voltage range. As a result, conventional weighted efficiency metrics cannot be used to predict annual energy productions by the microinverters. This paper proposes a new methodology for the estimation of annual energy production based on annual profiles of the solar irradiance and ambient temperature. Using this methodology, quantification of the annual energy production is provided for two geographical locations.

A Wide-Range Charge Controller for Solar Sensor

2015 ◽  
Vol 24 (07) ◽  
pp. 1550108 ◽  
Author(s):  
Cihun-Siyong Alex Gong ◽  
Long-Xi Chang
Keyword(s):  
Pulse Width Modulation ◽  
Input Voltage ◽  
Active System ◽  
Fully Integrated ◽  
Voltage Range ◽  
Point Tracking ◽  
Error Amplifier ◽  
Wide Range ◽  
Solar Powered ◽  
Power Point

The solar energy conversion driven by the solar sensor (or the so-called solar cell) has become an important and feasible way to solve global energy crisis while at the same time minimizing environmental pollution. The solar charge controller is the key of its active system for the signal processing circuits involved. In this paper, a fully integrated solar charge controller is presented. The charger has wide input voltage range about 10–28 V for the solar-powered panel. The input loop regulation is used here as the maximum power point tracking protection. This charger also provides different kinds of battery voltages about 4–12 V. The controller system uses just one error amplifier (EA) and no external compensation components is needed. Besides, this controller has 600-kHz pulse-width modulation (PWM) and offers the over-current/over-voltage protection. Other components like bandgap, reference generator, saw-tooth generator, register controller and driver circuits are all implemented in this circuit. This chip is fabricated in a 0.4-μm 5 V/40 V 2P4M process. The power consumption of this full-integrated solar charge controller IC is about 10 mA.

Sign in / Sign up

Export Citation Format

Share Document