High Input Voltage Research Articles

Study of RIN-Insulation Mechanical Properties for High Voltage Inputs

This paper presents the results of mechanical properties study for samples of RIN-insulation material (Resin Impregnated Nonwoven – non-woven resin impregnated fabric) for high-voltage inputs at various temperatures, determined by three-point bending tests, impact strength tests and tensile tests with registration of test diagrams. The mechanical properties of RIN-insulation, which ensure working ability of the whole construction of high-voltage inputs, operating in difficult climatic conditions, are determined.

Dual Piezoelectric Energy Investing and Harvesting Interface for High-Voltage Input.

A novel harvesting interface for multiple piezoelectric transducers (PZTs) is proposed for high-voltage energy harvesting. Pre-biasing a PZT prior to its mechanical deformation increases its damping force, resulting in higher energy extraction. Unlike the conventional harvesters where a PZT-generated output is assumed to be continuous sinusoidal and output polarity is assumed to be alternating every cycle, PZT-generated output from human motion is expected to be random. Therefore, in the proposed approach, energy is invested to the PZT only when PZT deformation is detected. Upon the motion detection, energy stored at a storage capacitor (CSTOR) from earlier energy harvesting cycle is invested to pre-bias PZT, enhancing energy extraction. The harvested energy is transferred to back CSTOR for energy investment on the next cycle and then excess energy is transferred to the battery. In addition, partial electric charge extraction (PECE) is adapted to extract a partial amount of charges from the PZT every time its voltage approaches the process limit of 40 V. Simulations with 0.35 µm BCD process show 7.61× (with PECE only) and 8.38× (with PECE and energy investment) improvement compared to the conventional rectifier-based harvesting scheme Proposed harvesting interface successfully harvests energy from excitations with open-circuit voltages up to 100 V.

Three-Phase Three-Level Isolated DC-DC Soft Switching Converter For Solar Applications

Three-level isolated DC-DC converter is an attractive topology in high input voltage applications, which can provide the voltage stress of the power devices to only a half of the dc voltage and also reduce the size of dc filter requirement. But major limitations in the existing three level ZVS converter topologies are brought out with an increased inductance in the primary side and it required to provide complete ZVS of all primary devices down to light loads. By employing an external inductance in the primary of the transformer, total leakage inductance of the transformer increases which is required for realization of soft switching of the converter switches but there are some disadvantages of connecting external inductance in the primary of the transformer. To overcome all these drawbacks, the three-phase three-level isolated DC-DC soft switching converter has been proposed in order to reduce voltage and current stresses. This converter topology requires less number of control switches and operates with an asymmetrical duty cycle control. The proposed three level DC-DC converters provide two- level voltage waveform before dc output filter, which significantly reduce the size of dc output filter. The proposed work has been implemented using MATLAB/SIMULINK and the performance of the proposed converter is verified through simulation results.

Snap-through of bistable variable stiffness laminates using MFC actuators

Unsymmetric composite laminates exhibit two or more stable equilibrium shapes with opposite curvature as a result of residual thermal stresses induced during the curing process. Surface bonded Macro Fibre Composite (MFC) actuators are generally employed to trigger snap-through between one stable shape to another by applying external voltages. However, these actuators require high actuation voltage input to change from one stable shape to another, especially when used in morphing applications. If the snap-through voltage is too high, morphing becomes infeasible or may require several actuators, which is contrary to the weight requirements. Variable Stiffness (VS) laminates provide the possibility for an enlarged design space with the possibility to tailor stiffness parameters, leading to lower snap-through loads and consequently reducing the size of the actuators.On the prediction of snap-through voltages, the existing semi-analytical models have shown reasonably high discrepancies between numerical and experimental results. An improved analytical model is proposed in this study to predict the snap-through of bistable VS laminates with MFC actuators. In the improved model, the equations resulting from the compatibility and the in-plane equilibrium are described equivalent to a standard plane elasticity problem which can be solved using a standard finite element (FE) approach. In addition, the total potential energy is written in terms of curvatures. The improved semi-analytical results are compared with a full geometrically nonlinear FE calculation.

Improved Control Strategy of Triple-Voltage Three-Phase DAB (T2-DAB) Converter for Current Stress and Zero-Voltage-Switching Optimization

Three-phase triple-voltage dual-active-bridge (T <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> -DAB) converter possesses high input voltage and large output current capacity, which can be adopted to constitute a high-power-density dc transformer. However, when employing conventional phase-shifted (PS) control strategy, zero-voltage switching (ZVS) turn-on is easily lost under light-load and voltage-mismatching situations. Hence, this article presents an optimized asymmetrical duty-cycle modulation strategy for T <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> -DAB converter, ensuring ZVS for switches and reducing the current stress over wide power and voltage ranges. The detailed model is established with a time-domain analysis method, and ZVS constraints are given with the particular consideration of dead time and parasitic capacitances of switches. Then, the MATLAB optimization toolbox is adopted to calculate the optimum duty cycle and PS angle, and the specific control scheme is introduced. Finally, a 2-kW prototype is built to verify the theoretical analysis, whose input voltage ranges from 480 to 720 V and output voltage is 200 V. The experimental results show that the proposed optimized control scheme can realize ZVS turn-on for all switches over wide voltage and power ranges, and the efficiency is improved, especially under light-load and voltage-mismatching situation.

LLC LED Driver with Current-Sharing Capacitor Having Low Voltage Stress

In this paper, an LLC light-emitting diode (LLC LED) driver based on the current-sharing capacitor is presented. In the proposed LED driver, the LLC resonant converter is used to step down the high input voltage, to provide galvanic isolation, to offer a constant current for LEDs. Moreover, the current-sharing capacitor connected to the central-tapped point of the secondary-side winding is used to balance the currents in two LED strings. By doing so, the voltage stress on this capacitor is quite low. Above all, the equivalent forward voltages of the two LED strings are generally influenced by the temperature and the LED current, and this does not affect the current-sharing performance, as will be demonstrated by experiment on the difference in number of LEDs between the two LED strings. In addition, only the current in one LED string is sensed and controlled by negative feedback control, while the current in the other LED string is determined by the current-sharing capacitor. Moreover, this makes the current control so easy. Afterwards, the basic operating principles and analyses are given, particularly for how to derive the effective resistive load from the LED string. Eventually, some experimental results are provided to validate the effectiveness of the proposed LED driver.

A T‐type three‐level converter for wide‐range voltage application

AbstractFuel and solar cells are broadly used in Microgrids. However, their output varies widely when load and environment change extensively. Thus, DC‐DC converters are used for wide‐range voltage application. Nevertheless, output filter inductor is large and voltage stress of diodes is high in two‐level converters when input voltage varies widely. Therefore, a T‐type three‐level converter is proposed. A T‐type cell is added into the full‐bridge (FB) converter. The proposed converter can work in two‐ and three‐level modes, that is, 2L and 3L modes. It works in 2L mode in high input voltage. Thus, the output filter inductance and voltage stress of diodes in 2L mode decrease compared to the FB converter. Operating principle is illustrated. In addition, design guidelines and examples are shown. Finally, experimental results confirm the theoretical analysis.

High Performance Flexible Structure Three-Level DC-DC Converter: A Candidate DC Interface for Microgrids With Distributed Energy Resources

High-performance DC interfaces play a pivotal role in microgrids with distributed energy resources (DERs), which would significantly improve the utilization of DERs and the flexibility of the prosumers. For a candidate DC interface converter, how to maintain the performance over a wide operation range becomes the biggest challenge. This paper proposes a flexible structure soft-switching three-level (TL) dc-dc converter, which adds four high-speed MOSFETs and one low-speed electronic relay to achieve overall optimum performance over a wide range. Under high output or low input voltage conditions, the relay and the extra MOSFETs on the primary side are ON permanently. The proposed converter is a zero-voltage switching (ZVS) converter, which guarantees ZVS for all primary switches even under 0 load currents. Under low output or high input voltage conditions, the relay and the extra MOSFETs in the secondary side are OFF permanently. The proposed converter is a zero-voltage and zero-current switching (ZVZCS) converter, and two added MOSFETs provide ZVZCS operation not only for the main primary switches but also themselves over a wide range. Other advantages of the presented converter include reduced filter size, no primary side circulating currents, and reduced current stress of the clamping capacitor. Besides, the switching loss caused by the added power devices is low because of the full range of soft-switching operation and low on-state resistance of these devices. This paper discusses the circuit configuration, operation principle, soft switching characteristics, technical comparison, and experimental results from a 1-kW prototype prove the rightness of the presented converter.

Two-Mode Low-Voltage DC/DC Converter With High and Wide Input Voltage Range

It has been proposed that the main battery voltage of electric vehicles should be increased to increase the driving distance and decrease the charging time. Thus, a low-voltage dc/dc converter (LDC) with high and wide input voltage range is required for electronic loads. This article proposes a two-mode LDC and the entire input range is divided into two low and high input voltage ranges. The converter has two operating modes corresponding to these input voltage ranges. In the low input voltage range, it operates as a three-switch double-ended active clamp forward converter. In the high input voltage range, it operates as an asymmetric half-bridge converter. Changing the operating mode according to the input voltage, the proposed converter can have low-voltage stresses on the switches and a low dc offset current of the transformer resulting in high efficiency for the entire input voltage range. In order to confirm the validity of the proposed converter, a 600 W prototype is implemented and experimented.

A novel approach of high-voltage low-current electric energy input to synthesise cost-effective ultra-strong ductile material

ABSTRACT Adopting a unique electrical circuit design, here we treat a significant low-cost engineering material (eutectoid steel not containing costly alloying elements) with a high-voltage (100 kV) low-current (150 mA) energy input (energy level exceeding cohesive energy). A distinctive structural evolution is ascertained with treatment duration of only 5 min as an outcome of lamellar fragmentation and matrix supersaturation. This envisages an origin of dispersed nano-sized hard cementite spheroids embedded in nano-thick martensite crystals of stratified-tile-morphology along with distributed α-ferrite regions containing sub-microscopic cementite particles of various shapes. Apart from the conjoint effect of nano-scale dispersion strengthening and martensitic strengthening overhauling the effect of conventional lamellar strengthening on a gross scale; high dislocation density and systematically arranged dislocations of similar sign at incoherent cementite particle-matrix interface provides a unique combination of ultra-high strength (UTS ∼ 1.5 GPa), significantly high specific strength (188 MPa/g cm−3) and large ductility (%Elongation = 20). Therefore, in terms of the adopted synthesis route, structural evolution and mechanical property achieved, a new dimension is hereby added to the next-generation material development so as to meet the ever increasing demand for low-cost structural application. In turn, we elucidate a fundamental conceptualization for the first time which exemplifies disproportionate atomic migration at highly incoherent nano-sized cementite particle-martensite matrix interface in steel under high-voltage low-current energy input, resulting in accumulation of dislocations of similar sign so as to significantly enhance strength along with retention of substantial ductility.

A 2-MHz 9–45-V Input High-Efficiency Three-Switch ZVS Step-Up/-Down Hybrid Converter

This article presents a three-switch zero-voltage switching (ZVS) step-up/-down hybrid dc–dc converter with e-mode GaN transistors for wide-input-range applications. With a flying capacitor, the proposed hybrid converter saves one auxiliary branch for establishing ZVS and one power FET compared with the conventional buck–boost counterpart, thereby reducing the converter volume and power loss. The capability of having ZVS turn-ON of all power FETs enables the proposed converter to operate in the MHz range under high input voltages by removing the switching power loss. The flying capacitor in the proposed converter further lowers the main inductor current in the step-down mode, significantly decreasing the conduction loss of the inductor. The proposed converter was validated using three 100-V e-mode GaN HEMTs with the on-chip gate drivers implemented in a high-voltage 0.5- $\mu \text{m}$ process. The proposed converter supports a wide input range from 9 to 45 V with a maximum 48-W output power, operates at 2 MHz, and achieves peak power efficiencies of 97.6% and 96% in step-down and -up modes, respectively. The volume of the external components in the proposed converter is also reduced by at least three times compared with the prior art.

National Grid Connected 3-Phase Inverter based on Photovoltaic Solar System

In this paper, a national grid-connected photovoltaic (PV) system is proposed. It extracts the maximum power point (MPP) using three-incremental-steps perturb and observe (TISP&amp;O) maximum power point tracking (MPPT) method. It improves the classic P&amp;O by using three incremental duty ratio (ΔD) instead of a single one in the conventional P and O MPPT method. Therefore, the system's performance is improved to a higher speed and less power fluctuation around the MPP. The Boost converter controls the MPPT and then is connected to a three-phase voltage source inverter (VSI). This type of inverter needs a high and constant input voltage. A second-order low pass (LC) filter is connected to the output of VSI to reduce the total harmonic distortion (THD) of the output current. The LC filter is then connected to a step-up transformer to push up the low VSI output voltage to the high grid voltage level. The control strategy is based on the rotating reference frame (dq reference frame) and the grid phase shift angle extracted using a phase-locked loop (PLL) technique. The designed PV system supplies only active power with zero reactive power to the utility grid. The system is simulated using MATLAB / Simulink software.&#x0D;

A High Input Voltage Auxiliary Power Supply Utilizing Automatic Balanced MOSFET Stack

In order to deal with the challenges in establishing a high input voltage high step-down auxiliary power supply (APS) for modular converters, a flyback converter utilizing series-connected silicon carbide (SiC) MOSFETs is proposed in this article. With the aid of a novel snubber circuit structure, the used series-connected SiC MOSFETs can switch with nearly perfect dynamic voltage sharing. Besides, the snubber circuit acts as voltage clamping circuit for the flyback converter, so voltage overshoot caused by transformer leakage inductance can be effectively controlled. Furthermore, the snubber circuit helps to power the control, gate driver, and startup circuits of the APS, leading to a reduction in system complexity and improvement in efficiency. Detailed circuit analysis and design considerations of the APS are presented. Finally, hardware of a 4 kV/120 W APS is established and experimentally verified.

Hybrid LLC Converter with Wide Range of Zero-Voltage Switching and Wide Input Voltage Operation

A new hybrid inductor-inductor-capacitor (LLC) converter is investigated to have wide voltage input operation capability and zero-voltage turn-on characteristics. The presented circuit topology can be applied for consumer power units without power factor correction or with long hold-up time requirement, photovoltaic energy conversion and renewable energy power transfer. To overcome the weakness of narrow voltage gain of resonant converter, the hybrid LLC converter with different turns ratio of transformer is presented and the experimental investigation is provided to achieve wide voltage input capability (400 V–50 V). On the input-side, the converter can operate as full bridge resonant circuit or half bridge resonant circuit with input split capacitors for high or low voltage input region. On the output-side, the less or more winding turns is selected to overcome wide voltage input operation. According to the circuit structures and transformer turns ratio, the single stage LLC converter with wide voltage input operation capability (400 V–50 V) is accomplished. The laboratory prototype has been developed and the experimental waveforms are measured and demonstrated to investigate the effectiveness of the presented hybrid LLC converter.

Design of class‐E M amplifier with consideration of parasitic non‐linear capacitances and on‐state resistance

In this study, the design of the class-E M­ power amplifier is presented. In this design, the effects of on-state resistance and non-linear parasitic capacitances of the transistors are investigated. Two metal oxide semiconductor field-effect transistors (MOSFETs) of IRFZ24N and IRF510 with different drain-source resistances are used in the presented circuits. In the given design, the values of the operational frequency and duty ratio are 3.5 MHz and 0.5, respectively. This study shows the importance of considering non-linear parasitic elements of MOSFET, especially drain-source resistance in the designing of the class-E M power amplifiers. It is shown that the class-E M power amplifier with high MOSFET drain-source resistance needs high DC input voltage for both the primary and auxiliary circuits. In the previous works, non-linear on-state resistance and non-linear drain-source and gate-drain capacitances have not been included at the same time in the analyses. Two class-E M amplifiers contain IRF510 and IRFZ24N are designed, simulated, and measured. The efficiency equal to 96.6% with 11.851 W output power at 3.5 MHz and the efficiency equal to 88.4% with 12.361 W output power are achieved for presented class-E M amplifiers contain IRFZ24N and IRF510, respectively.

Novel multi‐level inverters with flyback high frequency link

A novel topological family of multi-level inverters with flyback high frequency link is proposed in this study. The inverters can transfer high DC voltage into regulated sinusoidal voltage with low total harmonic distortion (THD). The circuit configuration consists of high DC input voltage, DC-link capacitors, novel multi-level conversion unit, high frequency flyback transformer, cyclo-converter, output filter capacitor and AC load. This topological family includes diode-clamp type full-wave mode, hybrid-clamp half-bridge mode, multi-end mode and improved multi-end mode. To achieve reliable multi-level inversion and overcome DC-link capacitor voltages unbalance, multi-carrier modulation and DC-link capacitor voltage balancing strategy are presented. In addition, steady principle and AC small-signal model are analysed. Simulation and experimental results are given to prove that the novel flyback high frequency isolated multi-level inverters have the following advantages such as the high frequency electrical isolation, the bi-directional power flow, the two-stage power conversion (DC-high frequency AC (HFAC) - low frequency AC (LFAC)), the lower voltage stress of power switches and the low THD of output voltage.

Hand-generated piezoelectric mechanical-to-electrical energy conversion plasma

A transient spark discharge is an atmospheric pressure plasma that has applications in pollutant removal, medicine, water treatment, agriculture, bactericides, and nanomaterial synthesis. Conventional methods of generating transient sparks at atmospheric pressure usually require a high voltage input at nanosecond pulses. Piezoelectric crystals offer a path to creating plasma devices that do not require a high voltage power supply to generate high voltage outputs; they directly transform mechanical energy into electrical energy. This work examines a manually-operated piezoelectric mechanical-to-electrical energy conversion plasma device. Electrical characterization of the plasma discharge generated by this device shows that it behaves as a transient spark, discharging 0.96 mJ over approximately 30 ns, with consistent behavior across multiple consecutive discharges. Although this specific device had a low mechanical-to-plasma energy conversion efficiency of 1.54%, the piezoelectric crystal resets to an equilibrium condition after approximately 8 μs, which suggests that it could be operated with a mechanical input of up to nearly 125 kHz. This work shows the potential of generating plasma in off-the-grid situations using piezoelectric crystals. One particular application of a piezoelectric plasma device is for in situ pollution mitigation or plasma-enhanced combustion, embedding such a device on the high-frequency oscillating or rotating components of internal combustion engines and turbomachinery.

Performance analysis of multi-scaling voltage level shifter for low-power applications

Purpose In complementary metal-oxide-semiconductor (CMOS) logic circuits, there is a direct square proportion of supply voltage on dynamic power. If the supply voltage is high, then more amount of energy will be consumed. Therefore, if a low voltage supply is used, then dynamic power will also be reduced. In a mixed signal circuit, there can be a situation when lower voltage circuitry has to drive large voltage circuitry. In such a case, P-type metal-oxide-semiconductor of high-voltage circuitry may not be switched off completely by applying a low voltage as input. Therefore, there is a need for level shifter where low-voltage and high-voltage circuits are connected. In this paper the multi-scaling voltage level shifter is presented which overcomes the contention problems and suitable for low-power applications. Design/methodology/approach The voltage level shifter circuit is essential for digital and analog circuits in the on-chip integrated circuits. The modified voltage level shifter and reported energy-efficient voltage level shifter have been optimally designed to be functional in all process voltage and temperature corners for VDDH = 5V, VDDL = 2V and the input frequency of 5 MHz. The modified voltage level shifter and reported shifter circuits are implemented using Cadence Virtuoso at 90 nm CMOS technology and the comparison is made based on speed and power consumed by the circuit. Findings The voltage level shifter circuit discussed in this paper removes the contention problem that is present in conventional voltage level shifter. Moreover, it has the capability for up and down conversion and reduced power and delay as compared to conventional voltage level shifter. The efficiency of the circuit is improved in two ways, first, the current of the pull-up device is reduced and second, the strength of the pull-down device is increased. Originality/value The modified level shifter is faster for switching low input voltage to high output voltage and also high input voltage to low output voltage. The average power consumption for the multi-scaling voltage level shifter is 259.445 µW. The power consumption is very less in this technique and it is best suitable for low-power applications.

A High-Voltage Dual-Input Buck Converter With Bidirectional Inductor Current for Triboelectric Energy-Harvesting Applications

This article presents a high-voltage (HV) dual-input buck converter with a bidirectional inductor current (IL) and a fully integrated maximum power point tracking circuit for triboelectric (TE) energy-harvesting applications. The proposed converter regulates HV inputs through a single shared inductor, and HV inputs can be isolated without using an additional HV protection circuit. In addition, the proposed diode-based HV sampling circuit can accomplish high ac voltage sampling and peak detection to perform the fractional open-circuit voltage method without any external components. Fabricated using a 180-nm bipolar-CMOS-DMOS (BCD) process, the proposed system with a self-manufactured polytetrafluroethylene (PTFE)based TE nanogenerator can regulate two HV inputs up to 70 V and achieve a power conversion efficiency of 84.7% and an endto-end efficiency of 75.6%, which are 30.2% and 22.7% better than prior work, respectively.

A VHF Wide-Input Range CMOS Passive Rectifier With Active Bias Tuning

Tiny implantable medical devices in millimeter size demand advanced wireless power solutions that operate at hundreds of megahertz and mainly use passive rectifiers for ac–dc power conversion. A conventional cross-connected (CC) rectifier can operate with high frequency and low input voltage but only achieves good efficiencies in a very narrow input power range, due to the shoot-through and reverse currents. This work presents a CMOS passive rectifier with active bias tuning (ABT), allowing a widely extended input range with high power conversion efficiency (PCE). In addition, we compensate for the process, voltage, and temperature variations with the ABT scheme that leads to a robust design for very-high-frequency (VHF) operation. Meanwhile, we propose a peak $V_{\mathrm {OUT}}$ searching scheme to indicate the charging/discharging directions for the ABT. We obtain a bias-voltage balancing among stacked rectifier stages with a switched-capacitor network. The proposed rectifier is fabricated in a 65-nm CMOS process. Measurement results of three chips show that the proposed rectifier improves the PCE over a wide input range, with an average maximum PCE of 64.4%.