Voltage Doubler Research Articles

High Efficiency and High Voltage Conversion Ratio Bidirectional Isolated DC–DC Converter for Energy Storage Systems

In this paper, a novel high-efficiency bidirectional isolated DC–DC converter that can be applied to an energy storage system for battery charging and discharging is proposed. By integrating a coupled inductor and switched-capacitor voltage doubler, the proposed converter can achieve isolation and bidirectional power flow. The proposed topology comprises five switches and a common core coupled inductor that uses only a set of complementary pulse-width-modulated signals to control and achieve high voltage gain without requiring high turn ratios or excessive duty cycles. Moreover, the proposed topology can recover the leakage inductance energy to improve the conversion efficiency. The main switches exhibit zero-voltage switching, which reduces the switching losses. A 500-W bidirectional converter is used to verify the feasibility of the proposed bidirectional converter through theoretical analysis and experiments. The experimental results indicate that the highest efficiency of the proposed converter in the step-up and step-down modes is 97.59% and 96.5%, respectively.

A CMOS Voltage Reference with Output Voltage Doubling Using Modified 2T Topology

This paper presents an ultra-low power CMOS voltage reference which operates in the subthreshold region. Modified from the conventional 2T circuit, the proposed circuit is capable of generating higher output voltage by using the resistor subdivision. The design comprises a negative-threshold native NMOS transistor as the current generator, a high-threshold PMOS transistor as the active load and an active voltage doubling network to generate the reference voltage. Implemented in TSMC 40 nm CMOS technology, the proposed circuit operates at a minimum supply of 0.65 V and consumes 5.5 nA. Under one sample simulation, the obtained T.C. is 16.64 ppm/°C and the nominal Vref is 489.6 mV (75.3% of Vddmin) for the temperature range from −20 °C to 80 °C. For Monte-Carlo simulation of 200 samples at room temperature, the average output voltage is 488 mV and the average T.C. is 29.6 ppm/°C whilst with the standard deviation of 13.26 ppm/°C. Finally, at room temperature, the proposed voltage reference has achieved a process sensitivity (σ/μ) of 3.9%, a line sensitivity of 0.51%/V and a power supply rejection of −45.5 dB and −76.3 dB at 100 kHz and 100 MHz. Compared to the representative prior-art works realized in the same technology and a similar supply current, the proposed circuit has offered the best 1-sampe T.C., the best average T.C. in multiple samples, the highest output voltage, the maximum output voltage per minimum supply voltage and the lowest process sensitivity in the output, Vref.

Novel Three and Four Switch Inverters With Wide Input and Output Voltage Range for Renewable Energy Systems

The proposed inverters receive input dc voltage in a wide range and generate output ac voltage in a wide range due to their buck–boost ability. They require only three or four active switches and two inductors. Therefore, the circuit topologies and their operation are simple, and control is easy. The output current of the proposed inverters is continuous, which lowers the output harmonics and filtering capacitor. In the proposed inverters, the output and input voltage sources or capacitors share the same ground, which results in a constant common-mode voltage and negligible leakage current. Of the proposed inverters, an inverter with four active switches and double input voltage sources is analyzed and tested in detail. The circuit operation is discussed, a control strategy is developed, a common-mode voltage analysis is presented, and design guidelines for circuit components selection are given. To verify the theoretical analysis, a 500-W, 40-kHz prototype of the proposed four-switch inverter is designed, fabricated, and tested. An output ac voltage of 110 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{V}_{\mathrm {rms}}$ </tex-math></inline-formula> is generated from an input dc voltage of 100–200 V. A peak efficiency of 97.5% is obtained. The proposed inverter obtains high efficiency due to simple circuit operation, few circuit components in the conduction path, and switching of only one switch at high frequency.

Highly Efficient Full-Bridge Resonant AC/DC Converter Using T-Type Voltage Doubler

This article presents full-bridge resonant ac/dc converter that minimizes switching loss over entire grid voltage cycle. By using the voltage fluctuation at T-type voltage doubler, the existing hard-switched components are turned- <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</small> with almost zero-voltage switching at high instantaneous output power and with less than half of the output voltage at low instantaneous output power. Moreover, no instantaneous reactive current flows through the circuit under wide variations of grid voltages and loads. Furthermore, the proposed converter has balanced loss distribution over the primary-side and secondary-side switches, which ensures high power transfer capability with improved overall switch utilization. A 1-kW prototype is developed and tested to demonstrate the circuit functionality. Finally, the efficiency improvement is investigated; comparisons show the benefit of the proposed converter over conventional converters that use unfolders.

Compact antenna integrated with a Greinacher voltage multiplier for ambient energy harvesting applications

Radio frequency (RF) energy harvesting from freely available electromagnetic fields is a promising alternative for powering smart electronic devices. This article presents a compact and efficient rectenna for RF energy harvesting at an Industrial, Scientific, and Medical (ISM) band of 2.4 GHz. A compact microstrip antenna with opened-end slots and a full ground plane is designed. Moreover, a Greinacher voltage doubler topology-based rectifier was designed to sense small input power levels. The antenna and rectifier optimization were performed through the simulation software. The optimized prototypes were fabricated and measured individually and as well as an integrated system. Measured results were in good correlation with the simulations. A peak measured efficiency of 75% with a constant output voltage of 2.9 V was achieved for the proposed rectifier at a small input power of 10 dBm. Furthermore, for demonstration of the RF conversion efficiency and output voltage, the antenna was integrated with the rectifier of load resistance, which was later replaced by LED for WPT demonstration purposes. The demonstration verified that the proposed rectenna with achieved efficiency and sufficient output voltage is a promising candidate for powering smart electronic devices.

High step‐up DC–DC converter using coupled inductor voltage multiplier cell and differential connection method

This paper proposes a high step-up DC–DC converter using coupled inductor voltage multiplier cell and differential connection method. The proposed converter is obtained by differentially connecting a Cuk converter and a Buck-Boost converter and integrating a coupled inductor voltage multiplier cell. The control mode of the two switches adopts interleaved control and the proposed converter has higher voltage gain. The diode-capacitor branch in the shared topology is used as a passive clamping branch to reduce the maximum voltage stress of switches. The working principle of the proposed converter is analyzed and its performance parameters and boundary conditions are given. The voltage gain of the converter can be improved by adding different voltage doubling structures and the general topology of the proposed converter is given. The effect of leakage inductance on the performance of the proposed converter is analyzed. Finally, a 300-W prototype was built and verified the theoretical analysis.

Dynamic simulation of a reversible solid oxide cell system for efficient H2 production and power generation

Reversible solid oxide cell (rSOC) can flexibly switch between the electrolysis mode and the fuel cell mode for electrical energy storage and power generation. For practical application, sweeping gas is needed to bring in the reactants and take out the products timely. In this study, we use steam as anode sweeping gas in electrolysis to decrease the overpotential loss and collect pure O2, which is then used as the fuel cell cathode oxidant. The real fluctuating power generated from solar photovoltaic is used as the power supply, which allows rSOC to generate H2 from 6:45 a.m. to 5:45 p.m. and produce electricity in the night. Compared with the conventional strategy, the proposed system can utilize more than 35% electricity in electrolysis, and its efficiency and total H2 production can be increased by 8% and 50%, respectively. The total power generation and the power density are also increased by 290% and 160%, respectively. Overall, this new strategy results in a doubled round-trip voltage efficiency due to the much-decreased overpotential losses in the electrochemical processes. This study provides a guidance for the optimization of practical rSOC application with dynamic operating conditions.

Design Space Exploration of Antenna Impedance and On-Chip Rectifier for Microwave Wireless Power Transfer

This paper discusses a design methodology to efficiently determine the best combination of rectenna (rectifier and antenna) to minimize the input power under a given output condition for microwave wireless power transfer (MWPT) without any other external components, such as a matching network, for cost reduction. A linearized equivalent circuit model is expanded upon to include the microstrip line connecting the antenna and rectifier. Based on the model, the design flow is presented that has mainly three steps: (1) Determination of the equivalent rectifier input impedance and the amplitude of input voltage by running SPICE simulation, (2) Drawing contour plots of input power by rectifier candidate on the antenna impedance plane by conducting model calculation and impedance loci of antenna candidates on the contour plots, and (3) Selecting the combination of antenna and rectifier which gives the minimum input power for all the combinations. To validate the equivalent circuit model and design flow, a single-diode (SD) rectifier and a voltage-doubler (VD) rectifier were fabricated in 65 nm CMOS. The input power to generate 100 μA at 1 Vdc was measured and compared. The model, SPICE and measurement are in good agreement with each other that VD has 30–50% lower input power than SD does. In addition, the sensitivity of the parasitic elements, such as the microstrip line and the bonding wires and pads on the input power, are investigated to explore the design space for rectenna.

An Intra-Body Power Transfer System With 1-mW Power Delivered to the Load and 3.3-V DC Output at 160-cm of on-Body Distance.

This paper presents an intra-body power transfer (IBPT) system that can deliver power greater than 1 mW across an on-body distance of 160 cm. A system simulation model is built for the characterization of the channel and optimization of the power transfer. Our system analysis and experimental validation demonstrate that 1 MHz is an optimal carrier frequency for IBPT in terms of power delivered to the load (PDL) and power efficiency (PE). Prototype TX and RX boards were built, and an IC was fabricated in a 180-nm CMOS process for the RX. The proposed RX IC consists of a voltage doubler (VD) and a charge pump (CP) to obtain a sufficiently high voltage conversion ratio (VCR). Among various rectifier topologies, the VD is the optimal topology for the power receiver front-end because the parasitic ground coupling capacitances, which inevitably exist in the IBPT system, act as an inherent input-coupling capacitance for the VD. The implemented VD utilizes a dynamic VTH compensation (DVC) for its diode components. Compared to the conventional static VTH compensation (SVC), DVC in the VD reduces the reverse leakage current of the diode, thus maximizing the power conversion efficiency (PCE) and VCR. In addition, the PDL is enhanced by inserting an inductor on the TX board. It reduces the backward-path impedance without increasing the RX volume, boosting the PDL by up to 9.9 times compared to the PDL without the inductor insertion. The proposed IBPT system delivers up to 178.8 μW of power at 11.7% of maximum power efficiency with 3.3-V DC output voltage and even 1.385 mW of power with the inductor insertion, supporting various biomedical wearable sensors, such as ECG sensor modules.

Comprehensive Analysis of Voltage Step-Up Techniques for Isolated SEPIC

High step-up converters are often used in photovoltaic applications due to low voltage of photovoltaic modules. In this paper, a study of several voltage step-up cells added on primary and secondary sides of an isolated dc-dc SEPIC (single ended primary inductor converter) is made, in order to increase its static gain and synthesize a family of converters. To perform this study and select the most appropriate resulting converter, theoretical and comparative analyzes are accomplished. They include a brief description of each converter, tables and curves with relevant information, such as voltage gain, voltage stresses and component count, and the identification of the use of coupled inductor or transformer based on the analysis of dc magnetizing current. Moreover, theoretical analysis and experimental results on a 50 kHz and 200 W prototype of selected isolated SEPIC with voltage doubler cell are presented to validate the proposed topology and concept.

A high step‐up isolated DC–DC converter based on voltage multiplier cell

AbstractGenerating sources of renewable systems, like photovoltaic module or fuel cell, have a low‐output voltage that has to be boosted for most of applications, such as grid‐tie inverters. To accomplish this, an isolated DC–DC high step‐up single‐ended primary‐inductor converter (SEPIC) with a Greinacher voltage doubler cell is presented. It has the advantage of continuous input current, high efficiency, and high‐voltage gain and isolation and demands a single switch, being suitable for low‐power grid‐tie photovoltaic systems. The operating principles and steady‐state analysis are presented, including the detailed analysis of resonant stage, and the effects of transformer winding capacitances on converter operation are investigated. Moreover, the effects of resonance frequency variations on converter efficiency are experimentally investigated. Experimental results on a 50 kHz and 200 W prototype are presented to validate the proposed concept.

Analysis and comparison of high step‐up converters based on Greinacher voltage multiplier cells

AbstractHigh step‐up converters are often used in photovoltaic applications due to low voltage of photovoltaic modules. In this paper, two new topologies, obtained with the insertion of voltage multiplier cells on secondary side of isolated SEPIC, are proposed. They have the advantages of continuous input current, isolation, high efficiency, and high voltage gain, being suitable for low power applications. To perform this study, theoretical and comparative analyses are accomplished. They include a description of each converter, tables, and curves with relevant information, such as voltage gain, total voltage stress, and total current stress. Moreover, the identification of the use of coupled inductor or transformer based on the analysis of DC magnetizing current is presented. Theoretical analysis and experimental results on 37.4/400 V, 50 kHz, and 200 W prototypes of selected isolated SEPIC with voltage doubler cell and voltage quadrupler cell are presented to validate the proposed topology and concept, where the maximum efficiency obtained for the converter with doubler cell is 96.85%, while for the converter with quadrupler cell is 97.75%.

Sphere-Shaped Receiver Coil for Misalignment-Resilient Wireless Power Transfer Systems for Implantable Devices

Positional misalignments of coils cause a sharp drop in the power transfer efficiency (PTE) of wireless power transfer (WPT) systems. To minimize this deterioration of the PTE, this study introduces a sphere-shaped (Rxs) to a three-coil magnetic resonance-coupled WPT system for implantable devices. To assess the significance of Rxs, its performance was compared to the well-known circular planar (Rxf), half-sphere-shaped (Rxhs), and solenoid (Rsl) coils. Moreover, a small and efficient voltage doubler as a rectifier was designed. This voltage doubler has a high conversion efficiency of 89% with an output voltage of >3 V at 15 dBm. To validate the concept, prototypes of the coils and voltage doubler were fabricated and measured in saline and minced pork. The PTEs of the Rxf, Rxhs, Rsl, and Rxs coils-based WPT systems were studied under different lateral and angular misalignments in both simulations and measurements. In perfect alignment conditions, the measured PTEs of Rxf, Rxhs, Rsl, and Rxs WPT systems were 7.68%, 10.18%, 25.01%, and 22.38%, respectively; however, when the (Rx) receiver coils rotated by 90°, the PTEs were 0%, < 0.2%, 0.15%, and 5.4%, respectively. Under lateral misalignments of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$dx =25$ </tex-math></inline-formula> mm, the PTEs were 0.82%, 1.91%, 2.4%, and 4.87%, respectively. Furthermore, the PTE for the Rxs-based WPT system was measured in saline- and minced-pork-filled boxes and a saline-filled American Society for Testing and Materials (ASTM) model under different misalignment conditions to expand its applicability range to deep-body non-static implants. Both the simulated and remeasured results show that the proposed Rxs-based WPT system presented an improved and stabilized PTE under positional misalignments.

An Isolated Multilevel DC–DC Converter Topology With Hybrid Resonant Switching for EV Fast Charging Application

This article proposes a multilevel dc–dc converter topology for fast charging of electric and plug-in hybrid electric vehicles (EVs and PHEVs). The proposed dc–dc converter topology converts the front end ac–dc converter output and provides regulated supply to the EV propulsion battery. The proposed topology consists of full-bridge converter at the primary, while the secondary side consists of voltage doubler rectifier units and combination of diodes and <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">mosfet</small> for reconfiguration of the voltage doubler rectifiers to generate the multilevel voltage. The multilevel voltage at the output helps in reducing the output filter size and increases the power density of the converter. The topology utilizes the resonance between leakage inductor of high frequency transformer, parasitic output capacitors of full-bridge <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">mosfet</small> s and voltage doubler capacitors to achieve soft switching (ZVS turn- <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">on</small> ) for all the full-bridge devices and soft turn- <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</small> for the rectifier diodes. The load limited ZVS turn <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">on</small> capability of conventional full-bridge topologies is mitigated through the use of resonance between magnetizing inductance of transformer and <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">mosfet</small> output capacitors. The converter is designed for 650 V dc bus input and 200–400 V EV battery output at 100 kW rated charging power. The analysis of the proposed converter in continuous and discontinuous modes of operation, soft switching operation, and the component design guidelines are presented in this article. The proposed converter is validated through detailed PLECS simulation results for 100 kW charging power. Experimental results from laboratory prototype of 500 W power are also presented to validate the design methodology and converter performance.

Bimodal Transformerless Inverter With Three Switches

The semi-Z-source inverter (SZSI) with least switch count (only two switches) eliminates the leakage current due to the doubly grounded structure. However, the main disadvantage is the high voltage stresses of the switches (the sum of double photovoltaic output voltages and the grid voltage amplitude). This article proposed an improved inverter based on the SZSI. It inherits the advantage of less leakage current and owns another merit of lower switch voltage stress. Besides, the operation principle of the proposed inverter is bimodal and only two switches operate at high frequency in each mode. First, the circuit structure and the operation principle are introduced in detail. Then, the grid current controllers in both modes are designed. Two comparisons are investigated for better clarification of the pros and cons of the proposed inverter. Finally, experimental results, obtained with a 500-W laboratory prototype, are presented to validate its performance.

Accurate Steady-State Modeling and Design Based on State Trajectory Analysis for LCC Resonant Converter With Voltage Doubler Rectifier

The <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LCC</i> series–parallel resonant converter with a voltage doubler rectifier, widely used in X-ray machines, is required to meet an extremely wide output range. However, state-of-the-art models are based on fundamental harmonic approximation and cannot maintain good accuracy over the entire output range. The state trajectory method has the potential to achieve a full range of high accuracy without high complexity, but it only applies to simple topologies, like <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LCC</i> with a full-bridge rectifier. For <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LCC</i> with a voltage multiplier, the capacitors in the multiplier are involved in the resonance, which can be modeled as a five-element resonant circuit. Moreover, the conduction sequence of components in the minor mode is different from that in the major mode, which is usually ignored in the steady-state model. The influence of the output capacitance of power transistors on the state trajectory is so unclear that the model accuracy decreases considerably at high frequencies. In this article, the equivalent parallel resonant capacitance is derived through the current distribution. The steady-state model of the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LCC</i> converter with a voltage doubler rectifier is developed for both major mode and minor mode. The deviation of the state trajectory and modeling accuracy induced by the output capacitor is investigated. Based on the proposed model and device stress analysis, the design procedure for <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LCC</i> under a wide operation range is presented. The simulations and experiments verify the accuracy of the model and the validity of the design method. The simulation mismatches are less than 2.3% over the entire output range. The maximum experimental mismatch is 15%.

Self-Powered and Self-Configurable Active Rectifier Using Low Voltage Controller for Wide Output Range Energy Harvesters

This article presents a self-configurable and self-poweredactive rectifier that operates from 0.25–20 V for energy harvesting applications. The proposed circuit self-startups from a low voltage using a charge pump and amplifies the voltage with a voltage doubler topology to provide succeeding circuits such as boost converters with a higher voltage. When the voltage of the energy harvester reaches a high threshold, the circuit switches its topology to a full-wave rectifier that does not amplify the voltage. The start-up circuit can limit its voltage intake to prevent boosting the high voltage, which may damage the whole circuit. Comparators with a maximum operating voltage of 5.5 V used in the implementation of the rectifier are protected by a diode and resistor based circuit. A piezoelectric energy harvester (PEH) that has a wide open-circuit voltage of 0.4–15 V under the acceleration of 0.04–0.3 g was used to test the circuit. The experiment results showed the rectifier can startup from 0.25 V and switch its topology according to the PEH voltage. The voltage and power conversion efficiencies are over 90% in most cases.

A Common-Mode Voltage Suppression Strategy Based on Double Zero-Sequence Injection PWM for Two-Level Six-Phase VSIs

A common-mode voltage (CMV) suppression strategy, namely double zero-sequence injection common-mode voltage (DZICMV), is proposed in this paper for an asymmetrical six-phase induction motor fed by two-level dual three-phase voltage source inverters (VSIs). In this strategy, the sinusoidal waveforms injected by double zero-sequence signals are employed as modulation signals, and two opposite triangular waveforms are used as carriers. The fundamental period is divided into 24 sectors. In each sector, the carrier used by the medium amplitude phase is distinct from the carriers used by the other two phases in each set of three-phase windings. Using this method, the zero vectors (000) and (111) in each set of three-phase windings can be eliminated, and the peak values of sub-CMV and total CMV can be reduced from ±Udc/2 to ±Udc/6. The experiment results show that the root mean square (RMS) value of common-mode leakage current in DZICMV can be reduced by 51.83% compared with the double zero-sequence injection PWM (DZIPWM) strategy. It is also found in the other four existing benchmark CMV suppression strategies that the peak values of sub-CMV therein are nearly all ±Udc/2, and only in the low linear modulation region could one of these strategies suppress sub-CMV peak values to ±Udc/6. However, the proposed DZICMV can suppress the sub-CMV peak values to ±Udc/6 in the whole linear modulation range. Moreover, the maximum linear modulation index of the DZICMV is 1.15, which is larger than that of the four benchmark strategies, whose maximum modulation index is 1.

Patch antenna with multi-cell EBG for RF energy harvesting applications

AbstractIn this paper, a ring patch antenna with 1 GHz of bandwidth and three resonances is designed for the RF energy harvesting application. Two complementary split-ring resonators (CSRR) is etched out from the patch, designed at 6.8 GHz, near feed to enhance the bandwidth from 267 MHz to 1 GHz. Due to the introduction of CSRR, two additional resonances at 6.4 and 7.4 GHz are obtained with gain 5.5 and 0.2 dB respectively. The gains at 6.8 and 7.4 GHz are enhanced to 8.3 and 2 dB respectively by cascaded circular mushroom electromagnetic bandgap structures (EBGs) with circular symmetry designed around the antenna. This ring patch antenna with cascaded EBG is integrated with a rectifier circuit based on voltage doubler topology (rectenna). The results of the rectenna show that, for an input power of 7 dBm to the rectifier circuit, a DC output voltage of 1.2 V with a power conversion efficiency of 40% is achieved.

РОЗВИТОК ПРИНЦИПІВ ПОБУДОВИ ТА ВДОСКОНАЛЕННЯ МАГНІТНО- НАПІВПРОВІДНИКОВИХ ІМПУЛЬСНИХ ПРИСТРОЇВ СИЛОВОЇ ПЕРЕТВОРЮВАЛЬНОЇ ТЕХНІКИ

The principles of construction and improvement of magnetic-semiconductor devices of power converter technology using a complex synthesis of their elements, keys, nodes, and structures are considered in specific examples. The advan-tages are presented: synthesized semiconductor, magnetic and magnetic-semiconductor switches; combined single-phase power supply rectifiers; autotransformer multilevel voltage inverters; voltage converters with input current buffer node; pulse compression units with voltage doubling and generating special output pulses; the structure of a magnetic-semiconductor pulse generator assembled from the indicated components. It is shown that these advantages in comparison with known analogs include improved efficiency, quality of input electricity, efficient use of pulsed power supply by loads, simplification, and expansion of the functionality of the synthesized objects. As a result, materials were obtained. It was determined that it would be expedient to use and develop the presented complex synthesis concerning other objects of research of magnetic-semiconductor pulse devices of power converter technology. Ref. 9, fig. 8.