Low Voltage High Power Research Articles

Review of Cockcroft-Walton High Voltage Low Current DC Power Supplies

High-voltage power supplies are key for developing particle accelerators, neutron generators, x-ray systems, ion implantation, etc. This paper reviews various developed voltage low current power supplies based on Cockcroft-Walton voltage multiplier circuits for accelerator-based neutron sources and other industrial and medical applications. The paper presents a detailed review of the topology of the power supply used for the high voltage generation, the key design parameters, key active and passive components used in the High Voltage (HV) system, key experimental results, protection and measurement circuit used in the power supply and about the system performance. The improvement that occurred in the size and performance of the power supplies due to the development in the technology of the magnetic components, semiconductors and energy storage devices in successive years is apparent in the discussion. Finally challenges and possible solutions for the compact design and system performance are concluded for the development of high voltage low current power supplies.

A 380 V High Efficiency and High Power Density Switched-Capacitor Power Converter using Wide Band Gap Semiconductors

State-of-the-art switched-capacitor DC-DC power converters mainly focus on low voltage and/or high power applications. However, at high voltage and low power levels, new designs are anticipated to emerge and a power converter that has both high efficiency and high power density is highly desirable. This paper presents such a high voltage low power switched-capacitor DC-DC converter with an input voltage up to 380 V (compatible with rectified European mains) and an output power experimentally validated up to 21.3 W. The wide band gap semiconductor devices of GaN switches and SiC diodes are combined to compose the proposed power stage. Their switching and loss characteristics are analyzed with transient waveforms and thermal images. Different isolated driving circuits are compared and a compact isolated half bridge driving circuit is proposed. The full-load efficiencies of 98.3% and 97.6% are achieved for the power stage and the complete power converter, without heatsink or airflow. The corresponding power densities are 7.9 W/cm3 and 2.7 W/cm3, based on boxed volumes, respectively.

A Dual-Layer Receiver With Low Interlayer Voltage Stress and High Power Density for EVs Wireless Charging System

A Dual-Layer Receiver With Low Interlayer Voltage Stress and High Power Density for EVs Wireless Charging System

Study of Replacing Capacitors in the Electric Power Network of Indopintan Sukses Mandiri Semarang

This paper presents a study of the relocation of capacitors to the point of loading of the electrical network that has poor performance such as low voltage profiles and high power losses. This study takes the case of the electricity network of Indopintan Sukses Mandiri Semarang. The purpose of this study is to obtain an electrical system scenario that can reduce power losses that have an impact on the cost of electricity bills. There are two stages that need to be done, namely the load flow analysis process on the electricity network, followed by the fuzzy inference process to determine the optimal location of the capacitor. The results of the study indicate an increase in the average voltage profile of each main distribution panel from 0.982 pu to 0.987 pu as well as a decrease in total real power losses and total blind power by 3 KW and 7 KVAR. This reduction in power losses can save electricity bill costs of Rp. 29,295,367.2 per year.

Reduced Switch Voltage Stress Ultra-Gain DC-DC Converter for High Voltage Low Power Applications

An ultra-voltage gain dc-dc converter is proposed in this brief using an active impedance network with a single MOSFET switch. The proposed converter utilizes minimum components and achieves the ultra-gain with lower switch voltage stress. The general structure of an <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${n}$ </tex-math></inline-formula> -stage active switched impedance topology is presented, and the detailed operation of the basic converter configuration is discussed. The components of the converter are designed using proper mathematics, and a 200 W, 50 kHz, 650 V lab-scale hardware prototype is fabricated. The dynamic model of the converter is derived, and the transfer function <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${\hat {v}_{0} / \hat {d}} $ </tex-math></inline-formula> is presented. The testing of the 200 W prototype has been done, and the experimented waveforms are shown. Reduced components, lower voltage stress, ultra-voltage gain and single MOSFET are the major merits of the proposed converter; hence the converter has a potential application in high-voltage low power systems.

Analysis of a New Tripled Boost High Voltage Gain DC/DC Converter With Continuous Input Current

In this paper, a new dc to dc boost converter with triple voltage gain and single switch is proposed for low power high voltage applications, analyzed for both ideal and non‐ideal conditions, and compared with the existing topologies. The converter belongs to the family of single‐stage high‐gain non‐isolated dc to dc converter. The design of the inductor, capacitors and the power losses in the circuit are discussed in detail, the output voltage gain of the proposed converter is compared with the output voltage gain of the other recent topologies of high‐gain DC/DC converters. To verify the theoretical results, a laboratory hardware prototype is developed and tested. © 2021 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC.

Low voltage high current modular DC power supply for solid state RF amplifiers

A low voltage, high current, modular 50 V, 700 A dc power supply has been developed to bias 35 number of 500 W, 505.8 MHz solid state RF amplifiers. This power supply incorporates 7 number of 50 V, 100 A ac-dc power modules, operating in parallel to share the load current. This power supply has two unique attributes namely modular hot swappability and active redundancy. Hot swappable feature incorporated in power modules enables isolation of faulty power modules and facilitates their online replacement without affecting the operation of RF amplifiers and remaining power modules. Active redundancy increases reliability of the power supply significantly. Both these features reduce the down time and increase the availability of the overall system significantly. This paper presents comparison of system reliability of this modular dc power supply with other modular dc power supplies of same output voltage and current rating and having different number of power modules. Suitable mathematical expressions for system reliability of these modular dc power supplies have been evaluated. This power supply also has a digital controller for monitoring the status of 35 number of RF amplifiers and 7 number of power modules as well as controls load current sharing among the power modules. This power supply achieves current THD ≤ 6.2%, input power factor ≥ 0.98, output voltage stability ≤ 0.4% and peak to peak output ripple ≤ 0.2% with overall system reliability and availability approaching near 100%.

Design and implementation of flyback converter as high voltage power supply for nanofibers production

Electrospinning is widely used method to produce nanofibers from the polymer solutions. Nanofibers are produced by loading polymer solutions into the syringe pump and applying a high voltage supply in the order of 5 kV–50 kV between the tip of needle and grounded collector. This paper presents the fabrication of low power high voltage power supply (HVPS) using flyback converter. It also demonstrates the mathematical modeling and simulation of flyback based low power HVPS. Mathematical modeling of flyback converter suggests that the output voltage depends on duty ratio, switching frequency and input supply voltage. Simulations are performed to visualise the behaviour of flyback based HVPS. From simulation results, a constant ripple free DC voltage of 5 kV is achieved. Flyback Converter is fabricated using 555 timer and TL494 IC as PWM generator. From 555 timer IC based HVPS, approximately 2 kV is achieved. High voltage of 5 kV is achieved using TL494 IC which varies non-linearly with increase in frequency for duty ratio above 40%. This work will be helpful to researchers for designing ripple free HVPS by appropriately selecting duty ratio and frequency.

Characteristic Analysis and Predictive Torque Control of the Modular Three-Phase PMSM for Low-Voltage High Power Application

In this study, a novel modular three-phase permanent magnet synchronous motor (PMSM) is proposed for low-voltage high power applications. The proposed modular three-phase PMSM has an independent segregated three-phase winding configuration, facilitating the implementation of the control algorithm. Firstly, on the basis of the electromagnetic properties, the mathematical model of the modular three-phase PMSM is established, considering the asymmetrical mutual inductances investigated by finite element analysis (FEA). Then, the predictive torque control (PTC) method combining the inductance characteristics of modular three-phase PMSM is developed, and excellent performance is obtained by adjusting the stator flux and torque. Finally, simulation and experiment are performed, and the results show that the proposed novel modular three-phase PMSM with the PTC method exhibits excellent control performance, and small stator current total harmonic distortion (THD).

Manufacture of High Current Low Voltage Power Supply with Using the Mot (Microwave Oven Transformer)

The manufacture of low voltage high current power supply using the MOT (Microwave Oven transformer) has been done. The purpose of this work is to convert low voltages into high currents by utilizing simple electrical equipment. This work use of varying voltages and different windings which are changed on the secondary winding section with a cable size of 240 mm 2, NYA cable type. The test is carried out with a series circuit, parallel circuit, and single circuit by utilizing a voltage of 30 V, 60 V, 90 V, 120 V and 5 different variations of winding. The results of this test provide knowledge of new methods that can be applied to iron smelting.

A Novel High Frequency Low Voltage Low Power Current Mode Analog to Digital Converter Pipeline

This paper introduces a novel structure for the realization of a low voltage, low power current-mode analog to the digital converter (ADC) pipeline (12 bits). The proposed structure of the ADC is based on a novel design of a current comparator and Digital to Analog Converter (DAC) structure. This modification allows us to reach a higher speed, lower voltage, and lower power dissipation. ELDO simulators using 0.18 μm, CMOS and TSMC parameters are performed to confirm the workability of this architecture. The proposed ADC is powered with a 1 V supply voltage. It is characterized by wide conversion frequency (350 MHz) and low power consumption that is 2.76 mW.

Solar Fed Ultra Lift Boost Converter for Induction Motor Drive Applications

Solar energy is one of the major contributors of electrical energy among renewable energy resources. But the low efficiency of solar PV output limits its applications in domestic and industrial field. Suitable MPPT techniques can be used to improve the efficiency of the solar PV cell and the low output voltage of the PV cell can be increased using boost converters. An Ultra lift boost converter is a voltage lift technique based converter, which lifts the input voltage in step by step manner to get high gain output voltage. Compared with conventional non isolated boost converter the voltage lift topology have high efficiency, high gain, low output voltage ripple and high power density. Maximum power from solar panel can be obtained using ICA method. The IMD based industrial and domestic applications are cost effective. The v/f method speed control is most common in case of IMD. In this paper a solar fed Ultra lift boost converter is designed for 3 phase, 1hp IMD. Speed of the induction motor is controlled by closed loop v/f control. For solar output voltage of 100V the results are verified by MATLAB simulink model.

Simple Designed of High Voltage Pulsed Electric Field Generator Based on Fly-back Transformer

The high pulse voltage low power supply can be built with fly-back transformer as a converter. Generation by using fly-back converter is a significant method which can be improved the circuits of the device to make it simpler, and occupies a smaller space, and cheaper. The study aimed to study and develop a device that will obtain a high pulse voltage low power supply. The results of the study obtained are, the high pulse voltage has reached 50 kV at the frequency of 100 kHz. In addition, when the high pulse voltage is fed to the plane parallel, then at the distance of 50 cm there is a spark, which means it is can generate high pulsed electric fields, it was 50kV/cm.

An Energy-Based Analysis for High Voltage Low Power Flyback Converter Feeding Capacitive Load

Generally, battery-fed capacitive loads are charged to high voltages in series of switching cycles with smaller fragments of energy delivered to the load in every cycle to ensure an efficient charging process. In high voltage low power (HVLP) flyback charging circuit, significant portion of input energy drawn from the source in a cycle is utilized by the effective parasitic capacitance of the HV transformer and semiconductor devices and circulated back to the source at the end of the cycle. This reduces the energy delivered to the load per cycle and hence the net energy delivered in the charging process. In this paper, an energy-based analysis and simplified energy-based model for HVLP charging circuits is derived. An energy-based approach is appropriate to describe and define the HVLP converter behavior in terms of load energy component and circulating energy component. The derived energy-based model is extended to obtain analytical closed-form expressions governing the essential parameters of the charging circuit. The proposed energy-based model and analytical formulation of essential parameters are experimentally validated on a 0–2.5 kV programmable high voltage charging circuit prototype fed from 12 V input battery source.

A Design With High Order Compensation and low Temperature Drift Bandgap Reference Voltage Source

Based on the analysis of the conventional bandgap reference circuitry and the current IC of reference voltage source in the design of low voltage low power consumption and high power supply rejection ratio, a bandgap voltage reference with startup circuit and current compensation circuit is presented. It has a low temperature coefficient(<20ppm/℃)，a temperature coefficient of 9.3ppm/℃ in the temperature range from-50℃ to 125℃, and a PSRR of-64dB at low frequency,which meets the requirements of bandgap reference for low voltage, low power and high PSRR.

A Novel Design of Static Electrostatic Generator for High Voltage Low Power Applications Based on Electric Field Manipulation by Area Geometric Difference

An electrostatic generator is an electromechanical device that produces static charges at high voltage and low current. This technology is mature enough, as it has existed for many centuries. Nevertheless, the working principle of most of the commonly used electrostatic generators is still based on typical mechanical methods, which consequently makes them bulky and limits their controllability on the generated charges, e.g., Van de Graaff generator that uses the friction between two different materials to generate electrostatic charges. In this paper, a novel design of a static electrostatic generator (SEG) is presented based on a completely different idea compared to existing electrostatic generators, which offers several potential benefits. The idea originates from the study of a parallel plates capacitor—for instance, if a voltage is applied to two plates of a capacitor, then according to Gauss’s law, both of the plates must have an equal and opposite charge. Suppose one of the plates has a different geometry, with a shorter length than the other, then the number of the charges on both plates will not be equal. Thus, by manipulating the geometrical area of the device, a different number of charges will be generated on both metal conductors. Therefore, a different number of charges are generated on both conductors; hence, by connecting both conductor plates of the capacitance, excess charges will remain on the device. The proposed idea was assessed with computer simulations using finite element and finite difference methods for a variety of different scenarios to determine the optimal design of the proposed device. The device offers several advantages over traditional electrostatic generators, such as that it can generate either positive or negative charges by merely reversing the polarity of the DC source; additionally, it is very simple, lightweight, and easy to manufacture. In particular, the principal advantage of the proposed device is that it is a static one, and no mechanical movement is required to produce charges. Further, the design is general enough and scalable. The simulation results demonstrate the performance of the proposed device.

High-Linearity Self-Biased CMOS Current Buffer

A highly linear fully self-biased class AB current buffer designed in a standard 0.18 μ m CMOS process with 1.8 V power supply is presented in this paper. It is a simple structure that, with a static power consumption of 48 μ W, features an input resistance as low as 89 Ω , high accuracy in the input–output current ratio and total harmonic distortion (THD) figures lower than −60 dB at 30 μ A amplitude signal and 1 kHz frequency. Robustness was proved through Monte Carlo and corner simulations, and finally validated through experimental measurements, showing that the proposed configuration is a suitable choice for high performance low voltage low power applications.

Modeling, Analysis, and Implementation of High Voltage Low Power Flyback Converter Feeding Resistive Loads

In High Voltage flyback converters, the dominant factor that influences a converter operation is the parasitic capacitance. A significant portion of input energy is utilized in charging the parasitic capacitances of the circuit, which is circulated back to the source at the end of every switching cycle. The circulating energy is a function of output voltage, load power, and parasitic capacitances and remains significant in High Voltage Low Power (HVLP) applications. This energy transfer phenomenon involving parasitic capacitances results in a reduced fraction of input energy reaching the load in every cycle, thereby resulting in an apparent deviation in the converter operating point compared to ideal flyback in case of resistive loads. An analytical energy-based model is derived, which includes the effect of parasitic capacitances, and is valid for steady state and dynamics of HVLP flyback converters feeding resistive loads. The influence of parasitic capacitances on the switch voltage of the converter is exploited to achieve Zero Voltage Switching (ZVS), thereby minimizing the turn- on loss. The proposed analytical model is verified through simulation and experimental results on 1.5 kV/ 5 W and 1.5 kV/ 200 mW resistive loads.

Hollow cobalt oxide nanoparticles embedded in nitrogen-doped carbon nanosheets as an efficient bifunctional catalyst for Zn–air battery

Rational design of low-cost, highly electrocatalytic activity, and stable bifunctional electrocatalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) has been a great significant for metal–air batteries. Herein, an efficient bifunctional electrocatalyst based on hollow cobalt oxide nanoparticles embedded in nitrogen-doped carbon nanosheets (Co/N-Pg) is fabricated for Zn–air batteries. A low-cost biomass peach gum, consisting of carbon, oxygen, and hydrogen without other heteroatoms, was used as carbon source to form carbon matrix hosting hollow cobalt oxide nanoparticles. Meanwhile, the melamine was applied as nitrogen source and template precursor, which can convert to carbon-based template graphitic carbon nitride by polycondensation process. Owing to the unique structure and synergistic effect between hollow cobalt oxide nanoparticles and Co-N-C species, the proposal Co/N-Pg catalyst displays not only prominent bifunctional electrocatalytic activities for ORR and OER, but also excellent durability. Remarkably, the assembled Zn–air battery with Co/N-Pg air electrode exhibited a low discharge-charge voltage gap (0.81 V at 50 mA cm–2) and high peak power density (119 mW cm–2) with long-term cycling stability. This work presents an effective approach for engineering transition metal oxides and nitrogen modified carbon nanosheets to boost the performance of bifunctional electrocatalysts for Zn–air battery.

Application of modular multilevel converter in medium voltage high power permanent magnet synchronous generator wind energy conversion systems

Traditional low voltage high power wind energy conversion system (WECS) requires heavy cables and large step-up grid interfacing transformers. In recent years, power rating of offshore wind turbines already exceeds 10 MW, and medium voltage (MV) converters have become strongly demanded. Modular multilevel converter (MMC) is suitable for MV high power applications. However, there are two technical difficulties for MMC when applied in MV permanent magnet synchronous generator (PMSG) WECS. The first one is the large sub module (SM) voltage fluctuation caused by low frequency and high amplitude PMSG phase current. The other one is the low voltage ride through (LVRT) problem. Overall control strategy based on carrier-phase-shifted -sinusoidal pulse width modulation technique of the MMC WECS is proposed. For the first difficulty mentioned, a second-order circulating current injection method based on closed-loop control is proposed. For the LVRT problem, a distributed braking chopper solution is provided. The effectiveness of the injection method and the distributed braking chopper solution are validated by simulation of a 5 MW/3.3 kV MMC WECS. Influences of the current injection amplitude on SM voltages and arm currents are discussed and a trade-off method is given to optimise system design, which is also verified by simulation.