Adjustable Output Voltage Research Articles

Mechanism and application of lead-free KNN-based ceramics with superior piezoelectricity

Piezoelectric ultrasonic energy harvesters (PUEHs) have recently attracted increasing attention. For minimizing the energy losses during energy transfer, it is crucial for core piezoelectric materials to maintain high piezoelectric coefficient (d33), mechanical quality factor (Qm), and piezoelectric voltage coefficient (g33). Herein, a simple way of hardening strategy improves the piezoelectric properties of KNN-based ceramics, combined with optimizing grain growth. The enhanced d33 (∼340 pC/N), high Qm (∼211) and TC (∼305 °C) are obtained simultaneously in this system, accompanied by superior d33×g33=8770×10−15 m2/N. Through variable temperature resonance test, the polarization rotation diversity caused by phase structure difference is found to closely related to the temperature stability of Qm value. A prototype of PUEH device was further designed and fabricated, with adjustable ultrasound-induced output voltage up to 8.2 V. Our work exhibits an effective way to improve performance of PUEHs by optimizing piezoelectric materials, which is helpful for further developing PUEHs.

Disturbance observer-based fixed time control for bidirectional DC-DC converter with input voltage and load uncertainty

The bidirectional DC-DC converter serves a vital role in the energy recovery system of new energy vehicles. However, external interference and parameter uncertainty can easily affect its dynamic performance. A disturbance observer-based fixed time control strategy for bidirectional DC-DC is proposed to address the impact of input voltage and load uncertainty on bidirectional converters. Firstly, the bidirectional converter model undergoes coordinate transformation, and disturbance observers are designed to compensate for input voltage and load disturbances. Secondly, based on the fixed time control theory, a fixed-time controller is devised for the bidirectional DC-DC converter to facilitate fast tracking and adjustment of output voltage without requiring measurement of input voltage and load current. Finally, simulation and experiment evaluations are conducted to assess the proposed scheme’s effectiveness in output voltage regulation.

Swimmable Micro‐Battery for Targeted Power Delivery

AbstractThe boom of microelectronic devices and their diverse applications has heightened the demand for innovative and effective energy supply strategies. The longevity of contemporary microelectronic devices predominantly depends on direct human intervention power supply methods, encompassing battery replacement or recharging. However, these methods may falter in specific scenarios, such as when facing liquid conditions in vivo. Here, a concept of swimmable micro‐batteries (MBs) for targeted power delivery is presented. This is achieved through the design of a flexible polydimethylsiloxane/Fe3O4 soft‐magnetic substrate for actuation, polydimethylsiloxane/neodymium‐iron‐boron (NdFeB) hard‐magnetic tabs for precise targeting, and quasi‐solid‐state Zn//MnO2 battery for power generation. These swimmable MBs exhibit an impressive areal capacity of 102.3 µAh cm‐2, remarkable waterproofing, adjustable output voltage or capacity, rapid response, and accurate remote magnetic field manipulation, enabling targeted power supply available. This novel swimmable MB design broadens the function of MBs and may open a new avenue for their future development.

A High-Capacity Interleaved Parallel Full-Bridge LLC Converter for External Charging Applications

This paper explores innovative converter designs tailored to meet the evolving demands of modern electric vehicle (EV) charging and power conversion systems. The first investigation centres on an AC to DC converter featuring an input series inductor and an output capacitor, enhancing power factor correction, reducing harmonics, and optimizing voltage regulation through advanced simulation tools. Comparative analysis highlights its superior power factor maintenance and efficiency. The second proposal introduces an interleaved parallel LLC (Inductor-Inductor-Capacitor) DC/DC converter, incorporating hybrid pulse frequency modulation (PFM) and pulse width modulation (PWM) control. This design extends the adjustable output voltage range, ensuring precise voltage control. A meticulous analysis and parametric design demonstrate an output voltage range of 50–80 V and a maximum power of 20 kW through simulation results. These innovations hold promise for various applications, including renewable energy, electronic device power supplies, and EV charging, offering practical solutions to enhance energy efficiency and power quality across modern electrical systems and EV infrastructure.

РАЗРАБОТКА И ВЕРИФИКАЦИЯ ПОВЕДЕНЧЕСКИХ МОДЕЛЕЙ ЛИНЕЙНОГО СТАБИЛИЗАТОРА ОТРИЦАТЕЛЬНОГО НАПРЯЖЕНИЯ MC79L И ЕГО ФУНКЦИОНАЛЬНЫХ АНАЛОГОВ

The aim of the study is to develop and verify behavioural models of a linear negative voltage regulator. This paper presents the process of building behavioural models of a linear negative voltage regulator with 3.3 V fixed value of the output voltage and with an adjustable negative output voltage from the reference voltage value of 1.25 V to 20 V. As a prototype model, the MC79L stabilizer manufactured by OnSemiconductor and its closest functional analogues LM337L, LT1964, LT3032 are selected. Behavioural models of linear stabilizers are implemented in the SPICE language based on functional blocks that fulfil mathematical dependencies and constraints. Simulating integrated circuits is carried out in the time domain and in static modes using the OrCad end-to-end simulation software package. The simulation verification confirms the data result adequacy presented in the chip manufacturers’ technical specifications. The proposed behavioural model of a linear stabilizer can be applied in modern specialized CAD systems for circuit design and simulation in developing, designing and studying power supply devices for radio-electronic and industrial equipment.

A High Crosstalk Suppression SiC MOSFET Gate Driver

Fast switching speeds and high switching frequencies bring serious crosstalk problems in SiC MOSFET applications. In this paper, we design a SiC MOSFET gate driver with high crosstalk suppression capability by using a multi-level drive and active Miller clamp technology. In the design, an auxiliary branch is introduced to control the source potential of the SiC MOSFET to achieve multilevel driving. The branch has a simple structure, simple control logic, no external negative voltage supply, and adjustable negative output voltage. The proposed SiC MOSFET gate driver was designed using the Central Semiconductor Manufacturing Corporation (CSMC) 0.8 μm BCD high voltage process. The designed SiC MOSFET gate driver has an area of 2967 μm × 3180 μm. The simulation verification model is based on Wolfspeed’s SiC MOSFET product C3M0075120D. Post-layout simulation results show that a SiC MOSFET gate driver with a crosstalk suppression capability of over 150 V/ns is obtained, which can reliably drive SiC MOSFET power devices.

All-Solid-State Nanosecond Pulse Power Supply Based on BLTs and Pulse Transformer for DBD Application

Nanosecond(ns) pulses have been proven to drive DBD more efficiently. However, since the DBD device is a capacitive load, which will cause distortions in the pulse waveform of the power supply. To maintain the ns pulse waveform, a parallel resistor is normally set to overcome the influence of DBD loads in the traditional methods, which will cause extra energy loss. This paper proposed a bipolar ns pulse power supply for DBD based on Blumlein transmission lines (BLTs) and pulse transformer. It does not need to set a parallel resistor and can adapt well to the load characteristics of DBD. This topology can output bipolar ns pulses on DBD loads with a rise time of 100 ns, a pulse width of 300 ns, an adjustable amplitude of 0-5 kV, and a maximum repetition frequency of 20 kHz. In this context, the operating characteristics of the circuit are derived based on the lossless transmission line model and Laplace transform, and then the correctness of the theoretical derivation is verified by the prototype. The results showed that the proposed ns power supply can drive DBD loads with adjustable output voltage amplitude and frequency.

Design of a LDO with High PSRR

One of the common ways to increase the PSRR(power supply rejection ratio) of LDO (low dropout linear regulator) is increasing the gain of error amplifier, but the stability of LDO system will also be reduced. A new high gain error amplifier is designed to push the poles inside the amplifier away from the origin, which ensures the stability of LDO system and improves the PSRR of low frequency band. At the TT process corner, the range of adjustable output voltage of LDO is 1.361~1.860 V under the simulation condition of 27 °C. When power supply ranges from 2.3 V to 3.3 V, the linear regulation rate is 238.3 µV/V; When the load changes from 0 to 20 mA, the load regulation rate is 9.6 µV/mA; At load current of 20 µA, the power supply rejection ratio of LDO is -97 dB@dc, and the phase margin of the whole circuit is greater than 66 degrees. The chip is verified in a 0.18 µm CMOS process. Setting the power supply voltage in the range of 2.3 to 3.3 V, the output voltage is stable at 1.8 V, and the error is only 1.9 mV, which is less than 0.2%.

An Ultra High Gain Converter for Driving HASEL Actuator Used in Soft Mobile Robots

Soft robots have the potential to fundamentally change interactions between robots and the surrounding environment, and between robots and animals, and robots and humans in ways that today's hard robots are incapable of doing. However, to realize this potential, soft robot actuators require extremely high voltage supplies of more than 4 kV. The electronics that can satisfy this need currently are either too large and bulky or unable to achieve the high power efficiency required for mobile systems. To meet this challenge, this paper conceptualizes, analyzes, designs, and validates a hardware prototype of an ultra-high gain (UHG) converter that can support extremely large conversion ratios up to ∼1000× to provide up to 5 kV output voltage from an input voltage of ∼5-10 V. This converter is demonstrated to be able to drive HASEL (Hydraulically Amplified Self-Healing Electrostatic) actuators, a promising candidate to realize future soft mobile robotic fishes, from an input voltage range of a 1-cell battery pack. The circuit topology employs a unique hybrid combination of a high-gain switched magnetic element (HGSME) and a diode and capacitor-based voltage multiplier rectifier (DCVMR) to enable compact magnetic elements, efficient soft-charging in all flying capacitors, and adjustable output voltage capability with simple duty-cycle modulation. Achieving an efficiency of 78.2% at 15 W output power, while providing 3.85 kV output from 8.5 V input, the proposed UGH converter proves to be a promising candidate for future untethered soft robots.

Development of an efficient voltage regulation mechanism for switched capacitor converter with exponential gain

The compact switched-capacitor converter with exponential gain and modular design has been adopted in this paper. Two approaches have been applied to improve the efficiency by providing multiple no-load voltages. The first modifies the switching strategy to bypass the gain of one or more stages. The second introduces modified design that provide additional no-load voltages through alternative current paths. The voltage regulation is implemented by two control loops: The outer loop is designed to produce the minimum feasible no-load voltage and the inner loop adjusts the duty ratio of the switching signals to regulate the voltage to meet the desired reference. Switched capacitor converters have been used as voltage multipliers with constant voltage gain. The efficiency of a switched capacitor converter depends on the ratio between regulated to unregulated output voltage. Therefore, output voltage adjustment of these converters causes a significant efficiency reduction. By providing multiple no-load voltages within the output voltage range the efficiency of the switched capacitor converter can be improved. The proposed design has been applied to a three-stage converter to provide six no-load voltages. Simulation results demonstrate that the average efficiency over the entire output voltage range is more than 90 % of its maximum efficiency of the unregulated switched capacitor converter which reflects the effectiveness of the proposed scheme. This paper offers an efficient method to regulate the voltage of a modular switched capacitor converter with exponential gain. The advantages of the proposed design are small number of added components, does not require additional sources and suitable for higher power range

Mathematical model of a valve converter based on a parallel current inverter with an adjustable output voltage of an improved form

The results of development of mathematical model and structural diagram of transient processes calculation algorithm of the valve converter based on single-phase current inverter, operating both in continuous and intermittent mode of input current are given in the article. Mathematical model of DC-AC valve converter with adjustable output voltage on the basis of parallel autonomous current inverter with inductive-thyristor compensating device is made on the basis of the operator method. Instead of traditional approach related to making operator substitution diagram for each possible state of power circuit proposed to use universal substitution diagrams equivalent to several states of the power circuit involved in the development of electromagnetic processes. Analysis of possible power circuit structures, which can participate in development of transient processes has shown that six power circuit structures participate in formation of process, which can be brought to two universal operator substitution diagrams. Application of universal replacement schemes, preserving advantages of the operator method, makes it possible to reduce the size of the model, reduce the required volume and time of calculations, allows to perform necessary calculations of circuit parameters in a wide range, taking into account the excitation and regulation method and to carry out the appropriate selection of elements as a result. The proposed structural diagram of algorithm of calculation of transient process is made on the basis of performance of boundary conditions of stages of development of process and revealing of sequence of change of types of equivalent circuits on intervals of clocking. The algorithm allows making calculation of transients at change of an input voltage of the inverter, at change of loading, and also at simultaneous change of an input voltage and loading. The developed mathematical model and algorithm provide the procedure of parametric synthesis of inverter elements with high accuracy.

Design of a high-voltage resistant and highly reliable LDO for automotive applications

This paper presents a high reliability low dropout linear regulator with high voltage tolerance, which uses an open loop structure and is applied to the feedforward response portion of the power tube gate to enhance the transient response of the LDO. The proposed LDO is simulated using a 0.18um DTI isolated BCD process with a 3.3V-14V supply voltage, a maximum input voltage of 40V and an adjustable output voltage of 3.1V/5V. The line regulation is 0.086% at 40V high voltage input and the supply voltage rejection ratio of the circuit can be maintained at around 60dB.

A 5 V-to-32 V Input PVT-Robust Charge-Pump Circuit with Adjustable Output in a 0.18 μm BCD Process

In this paper, a new closed-loop charge-pump circuit with adjustable output voltage and an on-chip compensation technique is proposed. The environmental temperature and process corner can be detected with an on-chip detection circuit and automatically feedback an adjusted reference voltage. With this, the magnitude of the charge-pump output voltage with Pulse-Width Modulation (PWM) can be compensated. The charge-pump circuit is designed and verified with a 180 nm Bipolar-CMOS-DMOS (BCD) process, and its output voltage at different process, voltage, and temperature (PVT) is controllable with low ripple. There are three selections for adjusting the output voltage: +5 V/+7 V/+10 V shifts, with the supply voltage ranging from 5 V to 32 V. It can remain tunable and stable at any shifts. The maximum deviation is ±0.265%, and the maximum load current can reach 30 mA. The ripple voltage is less than 0.3% (Δ Vripple/Vout) underthe maximum load. The Monte Carlo simulation results show that the worst case of the process sensitivity (σ/μ) is 0.1%. The charge-pump core area is 0.308 mm2, and the power consumption is 4.753 mW. The circuit can produce high-precision output and is suitable for high-side driving IC applications.

An Input-Oriented Power Sharing Control Scheme With Fast-Dynamic Response for ISOP DAB DC–DC Converter

With some advantages, such as electric isolation, high efficiency, and fast dynamic response, the input-series output-parallel (ISOP) dual-active-bridge (DAB) dc–dc converter has been regarded as one of the most promising candidates for connecting the medium voltage terminal and the low voltage terminal. For the ISOP DAB dc–dc converter, the existing control strategies are mainly focusing on the equivalent power sharing control, but the fast-dynamic response is not included and the decoupling between the regulation of input voltage and the adjustment of output voltage is not eliminated significantly. In this article, the average model of this ISOP DAB dc–dc converter is presented first, which can be employed to analyze the power distributions of this modular topology clearly. Then, an input-oriented power sharing control scheme with fast-dynamic response is proposed for ensuring both the power sharing ability and the fast-dynamic performance of the ISOP DAB dc–dc converter in this article. Compared with the existing methods, this proposed scheme can also significantly reduce the coupling between the power sharing control and the output voltage regulation. In addition, an inductance-estimating method is proposed for ensuring the power sharing performance of the ISOP DAB dc–dc converter. Finally, the experimental results are provided to verify the effectiveness of the proposed input-oriented power sharing control with fast-dynamic response for the ISOP DAB dc–dc converter system.

A Novel LLC Resonant Converter With Configurable Capacitors in Output Stage for Wide Output Voltage Range Operation

The traditional <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LLC</i> converter with variable switching frequency achieves wide output voltage range operation, but it is companied by the issues of reduced efficiency and difficult magnetic component design. To overcome these issues, a novel <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LLC</i> converter with configurable capacitors in the output stage is proposed. It realizes two-times adjustment of output voltage by simply arranging the configurable capacitors in parallel or series in pulsewidth modulation manner. As compared to prior art, it reduces the output inductor, power losses, and switch capacity by 50%, 15.6%, and 5.7%, respectively. The experimental results obtained from a 100-V 1.5-kW setup verify the feasibility of the proposed converter.

Comparison of ANFIS and FLC as Charging Battery Based on Zeta Converter

Solar energy is an unlimited source of energyand its availability will never run out. It can be converted into asupply of electrical energy. And saved into battery throughconverter. There are many people who convert solar energy intoelectrical energy. Unfortunately, when stored in the battery, it isstill necessary to adjust the output voltage of the converter. So, itis need a controller to do it. To solve the problem, we proposeFuzzy Logic Controller (FLC) and Adaptive Neuro FuzzyInference System (ANFIS) control to adjust output voltage whilethe input voltage is fluctuative. We will compare which twocontrollers are better. We used the constant voltage method, andafter we ran the simulation, we got ANFIZ better than FLC.Because we get setting point faster when using ANFIZ. Theresult, it need time 0,04s to get setting point on output voltage

Analysis and Design of a Modular Switched Capacitor Converter With Adjustable Output Voltage in DC Microgrid

A high conversion ratio, high efficiency and miniaturized switching power supply converter is an important part of DC microgrid. Switched capacitors have been widely used in low-power voltage conversion applications, for small size, light weight, high efficiency, etc. Due to the structural characteristics of the switched capacitor topology, the transformation ratio of the circuit cannot be adjusted continuously. In response to this need, some control methods are proposed, most of which require more complicated control circuits or parameter design. A modular switched capacitor converter with adjustable output voltage is proposed in this paper. The topology can be modularized as required. More switched capacitor module provides higher output power and higher efficiency. More voltage regulating module provides wider output adjustment range. Its control method is simple and can be expanded to a high-power power supply as needed. The advantages of small size and high efficiency of switched capacitor topology are also retained. A 4 to 1 prototype with 12V output is built to verify the proposed topology. The peak efficiency of the prototype is 95.34% and the full load efficiency is 93.82%.

Long term performance of reference electrodes for cathodic protection of steel in concrete

This paper will report on long term behaviour of potential sensors used in cathodic protection of steel reinforcement in concrete. Cathodic protection (CP) systems, both impressed current CP (ICCP) and galvanic CP (GCP), need regular testing to establish the quality of protection. In addition, ICCP may require adjustment of output voltage or current. Various types of potential sensors have been used in relatively large numbers, comprised of true reference electrodes (RE) based on silver/silver chloride or Mn/MnO2 and decay probes (DP) based on a.o. activated titanium. Failures may occur due to loss of contact, drying out or cable defects. Test methods for potential sensors are discussed. Monitoring of about one hundred CP systems with several thousands of potential sensors over more than ten years allows to analyse their performance and failures. It appears that limited numbers of potential sensors fail over time, but in some cases an insufficient number of working potential sensors are left to properly monitor a CP system or zone. It is recommended to install more potential sensors than strictly needed in order to allow for failures and to maintain testability and save the high cost of installing new potential sensors later.

A new switching look-up table for direct power control of grid connected 3L-NPC PWM rectifier

This paper presents a comprehensive and systematic approach in developing a new switching look-up table for direct power control (DPC) strategy applied to the three-phase grid connected three-level neutral-point clamped (3L-NPC) pulse width modulated (PWM) rectifier. The term of PWM rectifier used in this paper is also known as AC-DC converter. The approach provides detailed information regarding the effects of each multilevel converter space vector to the distribution of input active and reactive power in the converter system. Thus, the most optimal converter space vectors are able to be selected by the switching look-up table, allowing smooth control of the active and reactive powers for each sector. In addition, the proposed DPC utilizes an NPC capacitor balanced strategy to enhance the performance of front-end AC-DC converter during load and supply voltage disturbances. The steady state as well as the dynamic performances of the proposed DPC are presented and analyzed by using MATLAB/Simulink software. The results show that the AC-DC converter utilizing the new look-up table is able to produce almost sinusoidal line currents with lower current total harmonic distortion, unity power factor operation, adjustable DC-link output voltage and good dynamic response during load disturbance.

Design of PID Controller Based on ELM and Its Implementation for Buck Converters

Buck converter is a kind of converter device with high efficiency, wide adjustable output voltage, small loss, small size and light weight. Its circuit has nonlinearity and will exhibit abundant nonlinear phenomena with the change of circuit parameters, resulting in unstable output voltage and being susceptible to load and external disturbances. Therefore, a control method based on Extreme Learning Machine (ELM) combined with a proportionalintegral-derivative (PID) controller is proposed in this paper and used for output voltage control of buck converter. Firstly, the mathematical model of buck converter in Continuous Conduction Mode (CCM) is established by the state space averaging method. Then the PID tuning algorithm is designed in combination with ELM, and the stability analysis of the model is carried out. Finally, the simulation experiment is carried out under different disturbances. By comparing with the open-loop control strategy, the effectiveness of the proposed ELM-PID control strategy is verified, indicating that the proposed method can achieve the stability of output voltage and good dynamic response.