Transformerless high step-up DC–DC converter with voltage multiplier concept (original) (raw)
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Jurnal Teknologi
A high dc voltage is commonly used in many process industries in testing, research laboratories and others. Currently, a high voltage dc is implemented using transformer. In this paper, a novel high voltage low current transformerless step-up dc-dc converter is presented. The proposed design consists of two step-up dc-dc converters with negative feedback signal and 15 stages of Cockcroft-Walton (C-W) voltage multiplier. The dc input voltage of 5 V triggers the first step-up dc-dc converter circuit to generate 30 V dc voltage and the second step-up dc-dc converter circuit boosts up to 100 V dc voltage. Further, diode-capacitor multiplier circuit is connected at the final stage to achieve 1.6 kV dc output voltages at 200 kHz switching frequency. The simulation results indicate that the proposed dc-dc converter can generate 1.548 kV dc voltage with a load current of 0.16 mA at 10 MΩ load resistor. Meanwhile, the experiment results show that the proposed dc-dc converter can generate 1.4...
High Gain DC-DC Converter Based on the Cockcroft-Walton Multiplier
IEEE Transactions on Power Electronics, 2016
Recent advancements in renewable energy have created a need for both high step-up and high efficiency dcdc converters. These needs have typically been addressed with converters using high frequency transformers to achieve the desired gain. The transformer design, however, is challenging. This paper presents a high step-up current fed converter based on the classical Cockcroft-Walton (CW) multiplier. The capacitor ladder allows for high voltage gains without a transformer. The cascaded structure limits the voltage stresses in the converter stages, even for high gains. Being current-fed, the converter (unlike traditional CW multipliers) allows the output voltage to be efficiently controlled. In addition, the converter supports multiple input operation without modifying the topology. This makes the converter especially suitable for photovoltaic applications where high gain, high efficiency, small converter size and maximum power point tracking are required. Design equations, a dynamic model, and possible control algorithms are presented. The converter operation was verified using digital simulation and a 450 W prototype converter.
Employing the Cascode Methods, A Transformer-Less High Voltage Gain Step-Up DC-DC Converter
Edison Journal for Electrical and Electronics Engineering, 2024
The goal of this research is to use the cascade approach to buck boost converters in order to produce high step-up voltage gain with a suitable duty ratio for an electric energy conversion system. Electronic equipment that demand electricity must convert AC voltage sources into DC power since they cannot be powered directly by the current electrical AC voltage. Significant voltage increases cannot be achieved by traditional boost converters because of the influence of power switches, parasitic resistive parts, and the diodes' reverse-recovery issue. The high voltage gains step-up (HVGSU) DC-DC converter, which combines two integrated buck-boost converters with a single switch, is proposed in this study. With the cascode technique, high voltage gain can be obtained without an extreme duty ratio; in this case, the switch's duty ratio is regulated by PWM technology. There is a thorough discussion of the suggested converter's equipment and modeling.
Digital control of high DC voltage converter based on cockcroft walton voltage multiplier circuit
TENCON 2005 - 2005 IEEE Region 10 Conference, 2007
A new method of controlling high DC voltage based on Cockcroft Walton Voltage Multiplier circuit by using digital controller is presented. The digital controller is developed using Complex Programmable Logic Devices (CPLD). The proposed system utilizes a single-phase AC as an input supply. The power switching devices in the controlled bridge are controlled by the multiple-pulse Pulse Width Modulation (PWM) switching technique so as to minimize the low order harmonic present on the AC side of the converter system. A low pass filter is incorporated in the circuit to filter out unwanted harmonics and to give a sinusoidal AC current. A high frequency transformer with 1:1 ratio is incorporated in the design to provide galvanic isolation for better circuit performance and protection. The optimum operation of transformer core in four quadrant of B-H curve is also considered in the proposed converter topology. The laboratory model of the converter is developed and tested. The experimental result is compared with the simulation result. http://ieeexplore.ieee.org/xpls/abs\_all.jsp?arnumber=4084880
High Voltage gain Transformer less Fly back Converter
2012
Conventional boost converters are unable to provide high step-up voltage gains due to the effect of power switches, rectifier diodes, and the equivalent series resistance of inductors and capacitors. This paper proposes high voltage gain transformer less Boost Converter without an extremely high duty ratio. Some dc-dc converters can provide high step-up voltage gain, but with the penalty of either an extreme duty ratio or a large amount of circulating energy. In the proposed converters, two inductors with the same level of inductance are charged in parallel during the switch-on period and are discharged in series during the switch-off period. The structures of the proposed converters are very simple. Only one power stage is used. Highefficiency, high step-up dc-dc converters with simple topologies are proposed in this paper.
Single-phase single-stage high DC voltage multiplier converter
2005 IEEE International Conference on Industrial Technology, ICIT 2005, 2005
This paper proposed a single-phase single-stage high DC voltage Multiplier converter. The convertion of high DC voltage converter without a DC-link is involved. A high frequency transformer using ETD 59 ferrite core with ratio 1:1 is used as energy storage and also providing isolation. Cockcroft-Walton circuit is connected at secondary side of the transformer. AC input is controlled by IGBT switch which the current flow in both directions of the transformer to fully utilize the transformer core. The current flow is controlled by the IGBTs using PWM technique. Experimental and simulation results are provided to show the effectives of the proposed technique.
Multiple output dc-dc converter derived from Cock-Croft Walton voltage multiplier and SIMO converter
This paper proposes a high step-up dc-dc converter based on the Cockcroft-Walton (CW) voltage multiplier without a step-up transformer with a high-efficiency single-input multiple-output (SIMO) dc-dc converter. Increased voltage dependent on number of stages is obtained using Cockcroft Walton voltage multiplier, which acts as an input voltage source for SIMO converter. Providing continuous input current with low ripple, high voltage ratio, and low voltage stress on the switches, diodes, and capacitors, this converter is quite suitable for applying to low-input-level dc generation systems plus this converter can boost the voltage of a lowvoltage input power source to a controllable high-voltage dc bus and middle-voltage output terminals. The high-voltage dc bus can take as the main power for a high-voltage dc load or the front terminal of a dc-ac inverter. Moreover, middle-voltage output terminals can supply powers for individual middle-voltage dc loads or for charging auxiliary power sources (e.g., battery modules). Moreover, based on the n-stage CW voltage multiplier, this converter can provide a suitable dc source for an n + 1-level inverter. The Cockcroft-Walton voltage multiplier circuit is designed from a series of rectifiers to obtain high DC voltage. In the presented model, the DC voltage, which is generated in the present stage, contributes to a higher value in the next stage. Every stage produces a higher DC output voltage Cockcroft-Walton multiplier constructed by ladder network of capacitor and diode for generation of high voltage. When number of stages of multiplier increases output of the Cockcroft-Walton Multiplier also increases. In this paper 3 stages Cockcroft-Walton multiplier are used for simulation purpose and for practical implementation to generate high voltage. Also in this paper transformer method are eliminated therefore cost and size of propose converter are reduced. The control strategy employs three independent frequencies, one of which operates at high frequency to minimize the size of the inductor while the other one operates at relatively low frequency according to the desired output voltage ripple. In this study, a coupled-inductor based dc-dc converter scheme utilizes only one power switch with the properties of voltage clamping and soft switching, and the corresponding device specifications are adequately designed. As a result, the objectives of high-efficiency power conversion, high step up ratio, and various output voltages with different levels can be obtained. This converter does not require any other circuit components in order to achieve good cross regulation. So that it again reduces the cost which will be an attractive feature in modern market. In order to check the behavior of the converter simulation is carried out in MATLAB environment. The simulation results validate the operation of the converter.
A Novel Techniques for Step down converter implemented by High Voltage Operational
— This paper introduces techniques which can be used to step down input voltage. It is different from traditional idea which use duty cycle concept. By using frequency domain concept low pass active filter can be used to step down input voltage. While high pass active filter can be used to step up output voltage. High precision supply voltage at 1mV step can be generated by the proposed techniques without the series resistor and switches more than 1000 pieces if the cut off frequency of the filter is accurate enough. If the input voltage is not as high as 15 volt, op-amp model LF353 can be used to implement step down converter. Keywords— Cuk converter, Buck-Boost converter, ac to dc converter, step up and down converter
A new step-up high voltage gain dc-dc converter
2010 9th IEEE/IAS International Conference on Industry Applications - INDUSCON 2010, 2010
A new high voltage gain dc-dc converter is proposed on this work as a viable solution to step-up a low battery voltage into a high voltage dc link. This converter is suitable for non-isolated on-line UPS systems with common neutral connection, that improves bypass circuit installation. Furthermore, smaller size, higher efficiency, and increased reliability are features that spread the transformerless products. The adopted control strategy uses a hybrid control that implements both analog and digital controllers, that implements the average current mode control. It presents characteristic of continuous input current through the batteries that improve its lifetime, the maximum voltage across the controlled switches is equal to one fourth of the total output voltage, and voltage equalization across the dc-link capacitors is intrinsic. In order to verify the feasibility of this topology, principle of operation, theoretical analysis, and experimental waveforms are shown for a 1.55 kW assembled prototype.