Output Voltage Variation Research Articles

A DSP‐based implementation of fuzzy logic and predictive current control for a Sheppard–Taylor power factor correction converter

AbstractEnsuring a high electric power quality of power systems and electric machinery continues to be a major challenge for power engineers. The research on harmonic reduction and improvement of power factor in connection to alternating current (AC) networks has intensified. This paper focuses on the simulation and real‐time implementation of a single‐phase Sheppard–Taylor power factor correction (PFC) rectifier. Compared to conventional PFC rectifiers, this converter provides a better network current tracking and reduces voltage stresses. Furthermore, it proves an ability to control a detuning phenomenon from which most of the PFC circuits suffer. This yields a significant enhancement in the power quality (PQ). The proposed control scheme consists of two successive controllers: (1) a fuzzy logic controller (FLC) for the voltage loop, which ensures a good robustness to changes in parameters; and (2) a predictive current control (PCC), which allows to achieve a sinusoidal network current and improves the power factor. The proposed configuration is examined by simulation and implemented in real‐time using a dSPACE DS1104 controller board. The robustness of the proposed control is tested under different loading conditions and output voltage variations. The obtained results validate the superiority of the applied approach in terms of unity power factor (0.998), THD of the network current (3.7%, approximately), and fast dynamic response.

RANCANG BANGUN DC TO DC BUCK CONVERTER DENGAN SISTEM KENDALI PI PADA NI ELVIS II DAN ANTARMUKA BERBASIS LABVIEW

Understanding basic concepts is an important thing in electronics, especially regarding the teaching aid of power electronic components. Given the need for students to study the model of electronic schematic with feedback controller, a media that can support this is needed. One of the developments in component technology and electronic circuits that can be studied is the DC voltage conversion, namely the DC to DC buck converter. This teaching aid model uses software, namely LabVIEW and the control and data acquisition hardware, namely NI ELVIS II. DC to DC buck converter schematic that can reduce the variable output voltage with a value range of 6 - 18VDC from an input voltage of 24VDC. PI feedback controller testing in the system experiment resulted in a difference of 0.1567% error using the PI controller parameter of Kp = 3.00 and Ti = 0.01. The test results with the PI controller show the expected response and can be applied to the buck converter circuit system. Testing the interface of the buck type DC to DC converter system is considered feasible as a learning aid with an overall interface quality value of 83.8% with student responds.

Contact Doping as a Design Strategy for Compact TFT-Based Temperature Sensing

Contact-controlled devices, such as source-gated transistors (SGTs), deliberately use energy barriers at the source, and naturally, the positive temperature dependence (PTD) of drain current can be utilized for temperature sensing. We exploit the difference in drain current activation energy, which arises with contact doping in polysilicon n-type contact-controlled transistors, to demonstrate output current with either a PTD or negative temperature dependence (NTD). The range over which output current varies linearly with temperature, as well as the sensitivity, can be tailored by the choice of reference current magnitude and relative source contact properties within the current mirror. The sensing scheme simplifies the circuit design because it relies solely on thin-film transistors and it has inherent immunity to output voltage variation. This ability to tune the sign of temperature dependence allows facile integration in applications requiring homeostasis via feedback, e.g., electronic skin, in a minimal layout area and potentially with convenient reduction of patterning steps during fabrication.

An Explicit Discrete-Time Large- and Small-Signal Modeling of the Dual Active Bridge DC–DC Converter Based on the Time Scale Methodology

The conventional method to model a dc–dc converter is by averaging its state variable over a switching period. However, due to the dc–ac–dc structure of the dual active bridge converter (DABC), the average value of the inductor current over a switching cycle is zero. Therefore, the conventional methodology cannot be applied to the DABC. The time-scale discrete-time modeling of the DABC is proposed to mitigate the zero average state variable problem. The time-scale methodology simplifies the analysis of the DABC by segregating the fast state variable inductor current and slow state variable output voltage. The proposed model has the advantage of the explicit large signal in terms of the circuit parameter, like the average value model. The explicit steady-state circuit expression from the large-signal model helps in the study of the soft-switching range of the DABC. Moreover, the small-signal model from the proposed method results in an explicit small-signal model. The model incorporates semiconductor <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">on</small> -resistance, inductor equivalent series resistance, transformer resistance, and leakage inductance. The effect of the converter net equivalent resistance on the small-signal model is thoroughly studied. Finally, the model accuracy in the steady-state, open-loop, and the small-signal are verified in both the switching simulation model and experimental setup.

Time–space–weight calibrated plastic optical fiber-based pressure sensing carpet

We demonstrate time-, space-, and weight-based calibration techniques for pressure monitoring in the low-cost plastic optical fiber (POF) sensor carpet. It is found that the POF-based pressure sensing platform has several limitations, such as output voltage variations and difference in the sensor response for horizontal and vertical fibers due to convex and concave shapes of bend. To surpass the these limitations, we have developed time-based calibration using time windowing technique to reduce the standard deviation of photodiode output voltage variations by 98%. We have also described space and weight calibration techniques based on the convex and concave shapes of fiber bend. These techniques help in improving the Landweber image reconstruction algorithm to obtain significant clarity and improvement in object pressure images. We also report an artificial intelligence-based algorithm to determine the accuracy of positioning of the load. Experimental results demonstrate that this algorithm gives a mean square error of 0.875 cm in position detection on the carpet. We discuss the potential for a compact and cost-effective pressure sensor carpet, which integrates with the living environment and the outside world.

Implementation of quasi Z-source inverter for renewable energy applications

This paper discusses the analysis of a Quasi Z source inverter with a trouble-free boost control tactic for renewable energy applications. The non-availability of uninterrupted renewable energy sources in atmosphere weather conditions raises variation in output voltage and currents. This may affects the performance of conventional inverters with potential source (VSI), current source connected (CSI) and impedance source inverter (ZSI). To overcome the drawback of VSI, CSI and ZSI a quasi-Z source inverters (QZSI) are used. The QZSI performs multiple operations such as DC-to-DC, AC-to-AC, AC-to-DC and DC- to-AC conversions. Also, it may be used for each buck and boost operation, using the shoot through state. The QZSI is derived from the ZSI topology, with a minor modification of the impedance network and overcomes the troubles facing in ZSI. The design construction and simulation study of quasi-Z source inverter is performed using MATLAB/Simulink environment.

IoT high-frequency electronic transformer with dimmable output voltage using PWM signals

This work presents the design, simulation, and implementation of a low-power electronic transformer, which output effective voltage can be controlled wirelessly through WIFI, via a user interface on a mobile phone. The methodology used in this project consists of 4 stages, a rectifier, an inverter, the inverter’s control system, and a ferrite reducer. The inverter has a full-bridge design and was implemented using MOSFET. The control system can vary the frequency and duty cycle of the output signals, by phase shifting the control signals, thus achieving the functionality of reducing the effective output voltage. Circuit design simulations were performed using PsPice Orcad. The implementation and the mathematical model of the built electronic transformer are carried out. The designed transformer operates with a maximum input voltage of 120 Vrms at 60 Hz at frequencies between 20 kHz and 30 kHz, which are controlled through the user interface; can reduce a 120 Vrms 60 Hz input signal to an effective voltage between 10 Vrms and 20 Vrms at a maximum power of 50 W. This project presents the feasibility of developing electronic transformers with variable output voltage, remotely controlled using IoT technology.

A Case Study: Influence of Circuit Impedance on the Performance of Class-E2 Resonant Power Converter for Capacitive Wireless Power Transfer

The evolution of power electronics led to rapid development in wireless charging technology; as a result, a single active switch topology was introduced. The present market utilizes inductive wireless power transfer (IPT); because of the disadvantages of cost, size, and safety concerns, research on wireless power transfer was diverted towards capacitive wireless power transfer (CPT). This paper studies the optimal impedance tracking of the capacitive wireless power transfer system for maximum power transfer. Compared to prior methods developed for maximum power point tracking in power control, this paper proposes a new approach by means of finding impedance characteristics of the CPT system for a certain range of frequencies. Considering the drone battery as an application, a single active switch Class-E2 resonant converter with circular coupling plates is utilized. Impedance characteristics are identified with the help of equations related to the input and resonant impedance. The impedance tracking is laid out for various resonant inductors, and the difference in current peak is observed for each case. Simulations verify and provide additional information on the reactive type. Additionally, hardware tests provide the variation of input current and output voltage for a range of frequencies from 70 kHz to 300 kHz. Efficiency at the optimal impedance points for a resonant inductor with 50 μH and 100 μH are tested and analyzed. It is noted that the efficiency for a resonant inductor with 50 μH is 8% higher compared to the CPT with a 100 μH resonant inductor. Further hardware tests were performed to investigate the impact of frequency and duty cycle variation. Zero-voltage-switching (ZVS) limits have been discussed with respect to both frequency and duty cycle.

Development of fast and hybrid charger for lithium ion batteries in light weight electric vehicles

This paper introduces a battery charging circuit, which utilizes solar and grid power for charging lightweight electric vehicles. The novelty of the proposed approach is the development of hybrid charger with control algorithm that charges the electric vehicle battery using dual input power. This hybrid charging provides electricity to start the electrically powered vehicle and also powers the additional vehicle. The controller can act as fast charger by closed loop operation with battery parameters as input. The speed of the charge level is varied based on the state of charge (SOC) of battery and parameters detected from battery side. Battery state estimation is defined through adopted battery model and their precision affects the accuracy of state estimation. Micro controller acts as a smart charger that controls the parameter of voltage and current level for battery charging. Battery output performance, voltage, and current variation in battery simulator during stage 1 to 2 charging level, current variation during stage 1 to 2 and stage 2 to 3 charging level by simulation and experimental results are also exhibited in the proposed work. Average power usage for conventional charger with proposed one during day and night time was compared. Time taken to reach 100% SOC for conventional charger with proposed system, probability of battery capacity, energy demand of charging station, effects of charging and discharging of battery, and charging capacity and temperature of battery is also further studied. The result analysis part proves that the proposed strategy shown to be superior to its existing methodologies.

A Cuk Converter and Resonant LLC Converter Based E-Bike Charger for Wide Output Voltage Variations

In this article, an e-bike charging solution for two wheelers, is presented. This e-bike charger is realized by a Cuk converter followed by a <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LLC</i> resonant converter with an improved power quality (PQ) input current indices. The pulsewidth modulated Cuk converter is operated in discontinuous conduction mode of its output side inductor, which leads to a voltage follower approach for input current shaping. Thus, the control loop is greatly simplified as it consists of a single voltage loop. The e-bike battery charging algorithm is implemented in variable frequency controlled HB <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LLC</i> resonant converter followed by a diode rectification at its output stage. Furthermore, a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\text{550}\;\text{W}$</tex-math></inline-formula> , constant current/constant voltage charger with a maximum current rating of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\text{10}\;\text{A}$</tex-math></inline-formula> is developed to charge a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$20AH$</tex-math></inline-formula> e-bike battery. A variable dc link reference voltage estimator is presented, which varies the dc link voltage and extends the output voltage range for charging e-bike battery of varying voltage rating from 42– <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\text{80}\;\text{V}$</tex-math></inline-formula> . Moreover, a resonant frequency optimizer loop is also proposed, which reduces the turn-off losses during charging a deeply discharged battery. The behavior of this charger is exhaustively analyzed under steady state and transient conditions and the PQ at the input, is found to comply the international standard of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$IEC-61\,000-3-2$</tex-math></inline-formula> .

Design, Simulation and Application of Buck Converter with Digital PI Controller

In this paper, a dc-dc buck converter with digital PI-controlled is analyzed and designed considering all design parameters such as inductance current variation, output voltage ripple etc. The designed dc-dc buck converter provides stable output voltage against to load changes and output voltage variations. Buck converter control method relies on voltage mode controlled PWM (Pulse width Modulation) with digital PI (Proportional Integral) controller. The design criteria, operating mode selection, suitable material selection, etc. of low cost and high-performance buck converter are explained in detail. Finally, the designed converter is carried out experimentally and the experimental results shows the effectiveness of designed converter under different load profiles.

On the controlled adhesive contact and electrical performance of vertical contact-separation mode triboelectric nanogenerators with micro-grooved surfaces

The triboelectric nanogenerator (TENG) is a new energy technology to convert mechanical energy into electricity based on contact electrification and electrostatic induction. Altering the alignment state of TENG with two micro-grooved surfaces is a simple way to achieve controlled electrical output. To guide the output regulation of TENG with micro-grooved surfaces and avoid causing interface separation failure, comprehensive analysis based on adhesive contact mechanics is essential. In this paper, the relation between charge density and contact stress is measured. Numerical adhesive contact and electrical models of TENG with grooved surfaces considering the charge density-contact stress relation and material properties are established to quantitatively analyze the effects of alignment angle, applied pressure and loading time on adhesive contact and electrical performance. It is shown that there exists an exponential relation between charge density and contact stress. Alignment angle of grooved surfaces in TENG significantly affects the adhesive contact and electrical performance. Under low and high applied pressures, the variations of output voltage with alignment angle are 630.5% and 301.1%, respectively, while same pull-off force variation of 532.6% is exhibited. Large pull-off force usually comes along with high voltage output, except for alignment angle of 10°, at which relative high voltage and low pull-off force are exhibited. Strategies for the output regulation of TENG with grooved surfaces without causing interface separation difficulty are presented.

An Improved and Integrated Design of Segmented Dynamic Wireless Power Transfer for Electric Vehicles

This paper describes improvements in a segmented dynamic wireless power transfer (DWPT) system for electric vehicles (EVs), and aims to offer a stable charging method for high-power applications. An integrated design is presented, including the modified switching sequence, the size of segmented transmitters, and parallel inverter technology for high-power applications. Three consecutive transmitters mounted on the rail track are energized according to the position of the pickups. This three-consecutive-transmitter group is comprised of a Q-shaped coil, a DD-shaped coil, and a Q-shaped coil again (QDDQ). QDDQ is used as an elementary energized group to optimize the number of energized transmitters and mitigate the output voltage variation. The entire DWPT system is designed with finite element analysis (FEA) and studied with circuit topologies. Overall, an experimental prototype for dynamic charging is built to verify the overall performance, which shows a great agreement with the theoretical analysis. In this prototype, there are five transmitters and one receiver. All dimensions are 500 mm × 500 mm. The proposed system has been validated to realize 500 V constant output voltage with approximately 85% dc-dc efficiency from the 100 Ω to 200 Ω load conditions. A 2.5 kW maximum output power occurs at the 100 Ω load condition.

Electromagnetic Transformer With a Continuously and Quickly Adjustable Voltage Ratio

This article presents a new electromagnetic transformer with a continuously and quickly adjustable voltage ratio between the output and input. The transformer uses a voltage-controlled magnetic device called magnetic flux valve to control the magnetic flux through the secondary winding. In this way, the amplitude of the output voltage induced across the secondary winding of the transformer can be regulated continuously and fast when the turn ratio and input voltage amplitude of the transformer are fixed. The configuration and working principle of the proposed transformer are elaborated. A prototype of the proposed transformer was designed and constructed. The experimental tests are performed on the prototype to validate the proposed transformer concept and demonstrate its superior performance, including continuous and nearly instantaneous output voltage regulation capability, wide output voltage variation range, and high efficiency.

Piezoelectric Energy Harvesting for Flapping Wing Micro Air Vehicle and Flapping Wing Sensing Based on Flexible Polyvinylidene Fluoride

The flapping wing micro air vehicle (FWMAV) has been attracting lots of interest since the 1990s and is one of the research hotspots in microminiaturization design. However, along with the miniaturization of FWMAV development, flight endurance becomes the bottleneck that significantly impedes the rapid development for these aircrafts because of the critical limit in energy supply due to the limited overall size and weight. In this paper, energy recovery technology was developed for FWMAV with the new type polyvinylidene fluoride (PVDF) piezoelectric wing which could generate the electric potential energy caused by the wing deformation due to the characteristics of the PVDF material. A single crank double rocker mechanism flapping platform was designed to test the deformation energy collection effect and aerodynamic lift. The PVDF wing surface was divided into 16 grid areas to be measured respectively. The lift, output voltage and output power variations for the different flapping frequency was successfully obtained in tests. By analyzing test data, if could be found that the output power could reflect the flutter condition without equipping other sensors and adding extra weight to the aircraft. Moreover, when the flapping frequency was accelerated to 12 Hz, the output power and root mean square (RMS) voltage could increase to 21 μW and 6 V respectively, which is enough to power micro electronic devices such as LED lights.

A Novel Loss-of-Excitation Protection Strategy Based on Reactive Power Increment of Synchronous Generators

This paper outlines a novel loss of excitation (LOE) protection scheme for synchronous generators (SGs) based on reactive power increment (RPI) strategy and tracking the variation of SG output voltage (<i>V_SG</i>). When variation of the <i>V_SG</i> exceeds lesser than a specified threshold value, the proposed RPI strategy is triggered and <i>V_SG</i> deviation is analyzed. For RPI execution, generated reactive power by SG (<i>Q_SG</i>) is shifted in increment direction. Following the applying RPI strategy, the <i>V_SG</i> does not have any increasing changes during LOE events due to lack of excitation system to provide the required field current; while for Non-LOE (NLOE) events, <i>V_SG</i> will be increased. Therefore, this provided feature by RPI strategy can properly and immediately cluster all LOE&#x002F;NLOE events even under worst-scenarios. Due to power quality issues, the value of the shifted reactive power (<i>&#x0394;Q_SG</i>) is considered small as much as possible. Meanwhile, it does not require any extra devices for execution. The exhaustive simulation studies on the power system prove that, the proposed scheme is quite reliable for clustering all LOE&#x002F;NLOE events, and is much faster than other available methods.

Dual-Loop Continuous Control Set Model Predictive Control for a Three-phase Unity Power Factor Rectifier

In this article, a novel cascade model-predictive control for a three-phase unity power factor rectifier is presented. Unlike the traditional control techniques for rectifiers, the proposed method uses a cascade dual-model-predictive control for the inner and outer control loops. The three-phase currents of the rectifier are controlled with the inner control loop, while the desired output voltage is achieved with the outer control loop. In this proposal, the output power is used as a feedforward to enhance the transient dynamics of the output dc voltage. Several advantages can be highlighted such as a fixed switching frequency, and output voltage variations are avoided when a sudden change in the load or a voltage sag appears. The overall control proposal has been fully integrated into a digital signal processor. Selected experimental results are introduced to validate the theoretical contributions of this article.

Efficient and Optimized Methods for Alleviating the Impacts of IR-Drop and Fault in RRAM Based Neural Computing Systems

Resistive switching random access memory (RRAM) shows its potential to be a promising candidate as the basic in-memory computing unit for deep neural networks (DNN) accelerator design due to its non-volatile, low power, and small footprint properties. The RRAM based crossbar array (RRAM CBA) is usually employed to accelerate DNN because of its intrinsic characteristic of executing multiplication-and-accumulation (MAC) operation according to Kirchhoffs' law. However, some major non-ideal effects including IR-drop and Stuck-at-Faults (SAF) in real RRAM CBA are typically ignored in the DNN accelerator design because of the considerations of training speed and design closure. Such non-ideal effects will conduct the variations of output column current and voltage and further cause serious degradation in computing accuracy. Thus, direct mapping from the weights of DNN model without considering the IR-drop and SAF to RRAM CBA is unrealistic. In this work, two efficient and optimized methods including adding additional tunable RRAM row and Trans-impedance amplifier (TIA) based RRAM are proposed to recover the computation accuracy with a view to reducing variation of the output column current of the RRAM CBA and output voltage of the TIA in each column respectively. The two optimized methods are evaluated in different sizes of RRAM CBA and different resistance levels of RRAM cell. The simulation results show that the two optimized methods can further suppress the degradation of computing accuracy induced by IR-drop and SAF for LeNet-5 with the MNIST dataset and VGG16 with the CIFAR-10 dataset.

Integrated buck and boost converter for a universal battery charger of an Electric Vehicle

A two-stage converter connects the input grid voltage to a pack of batteries with the voltage varying between 48-400 V, depending on the size and the range of the vehicle, with battery-operated electric and Plug-in Hybrid Electric Vehicles (PHEVs). This article offers a unique built-in converter that can interface with both high voltage (HV) and low voltage (LV) batteries. For all car architectures a universal charger that can accommodate this wide range of battery pack voltages is suitable. The novel integrated buck and boost converter (IBBC) is the proposed converter supplied using AC-DC driver at the front end mode. The main objective of this paper is to show a universal battery charger for an EV with a high power factor (PFC) and a small total harmonic distortion (THD) in addition to the high power density. A PFC converter is formed without any auxiliary circuit to balance the output voltage dependence of the battery against fluctuations in the ac grid input voltage, which in turn reduces the cost of additional circuit. A closed loop controller scheme is used to adjust for variations in the broad range output voltage and load. The proposed topology’s detailed operation is simulated using the MATLAB/Simulink software and achieved a THD of 1.18%.

The extended model predictive-sliding mode control of three-level AC/DC power converters with output voltage and load resistance variations

In the proposed approach, an Extended Model Predictive Sliding Mode Controller (EMPSMC) is designed to control Three-Level Ac/Dc Power Converters to achieve improved dynamic performance and better. Steady-state stability. The traditional proportional-integral (PI) controller is used in the Model Predictive PI controller (MPPIC) technique to produce active power reference. However, this technique results in a significant overshoot/undershoot and steady-state error. Instead of PI, sliding mode control (SMC) is used to overcome these shortcomings. The performances of EMPSMC and MPPIC are compared and analyzed with and without disturbance. The results show that the system’s settling time is minimized by introducing SMC, and the overshoot is also reduced. Moreover, it also provided better steady-state stability. Similarly, dynamic improvements are achieved with EMPSMC for tracking the desired dc reference voltage demand. The simulation results validate the performance of the designed model.