Ohmic Load Research Articles

Design and implementation of Type-3 intuitionistic fuzzy logic MPPT controller for PV solar system: Comparative study

The performance of a photovoltaic (PV) solar system is affected by partial shading conditions (PSC) and environmental conditions, such as solar irradiance and ambient temperature, which vary throughout the day. This results in variations in the maximum power point (MPP) on the solar PV output characteristic curve. Therefore, various classical MPP tracking (MPPT) techniques have been used to track the MPP and extract maximum power from PV systems. However, these techniques have drawbacks such as lower stability, increased oscillation around the steady state, and slower convergence to the MPP. To overcome this problem, the newly proposed interval Type-3 intuitionistic fuzzy logic (T3IFL) controller has been proposed. The T3IFL MPPT controller combines the uncertainty of Type-3 fuzzy logic (T3FL) controller with intuitionistic concepts. The T3IFL controller is more accurate and offers faster convergence to the MPP under changing climatic and steady-state conditions than classical techniques and T3FL controller. The T3IFL algorithm provides better performance with excellent MPP tracking by controlling the duty cycle of the DC-DC buck converter. Four cases studied were investigated: uniform radiation conditions, a step change in solar radiation with constant temperature, replacing the battery load with the ohmic load with constant radiation and temperature, and partial shading conditions. Experimental validation of the T3IFL was performed on a DC-DC buck converter using real-time hardware-in-the-loop (HIL). Finally, the simulation and experimental results with comparative studies verified the accuracy of the proposed method in tracking the desired value and disturbance/uncertainty attenuation with better response.

An Inverted Doherty Power Amplifier Insensitive to Load Variation With an Embedded Impedance Sensor in Its Output Power-Combining Network

This article presents an inverted Doherty power amplifier (IDPA) made load insensitive up to 2:1 voltage standing wave ratio (VSWR) across its fractional bandwidth with a very compact wideband impedance sensor embedded in its output power-combining network (OPCN). To correct for load variation, a low-loss tunable resonator (TR) is used to ensure ohmic loads to the main and peaking stages at the center frequency of operation. At off-center frequencies, TR is used to present an ohmic load for the main stage, while a digitally adjustable phase shifter is used to (re)align the main and peaking stage’s current summation in the OPCN. For ohmic load deviations, the main and peaking stage supply voltages and input drives are adjusted to maintain the ideal Doherty’s output power and efficiency profile related to nominal 50 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${\Omega}$</tex-math> </inline-formula> loading across the bandwidth. To implement the control of the formerly mentioned technique, a wideband impedance sensor is proposed, which uses the orthogonality of incident and reflected waves and requires only four peak detectors. As proof of principle, a prototype 850–950-MHz IDPA featuring the proposed correction technique, the impedance sensor, and the control loop has been implemented as a printed circuit board (PCB) demonstrator. Measurement results show that the IDPA can maintain constant output power with a tolerance of only <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${\pm}$</tex-math> </inline-formula> 0.2 dB while improving the drain efficiency and linearity across the entire fractional bandwidth (11 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${\%}$</tex-math> </inline-formula> ) for a VSWR range of 2:1.

Maximum Power Point Tracking with Incremental Conductance and Fuzzy Logic Controller in Solar Energy Systems

Energy benefits both individuals and nations. Humanity's reliance on fossil fuels an inability to respond increases depletion. Energy supplies are rapidly decreasing. Electricity use causes the energy crisis. Sustainable energy largely meets the energy demand of the growing population. In addition, it benefits the environment by reducing carbon emissions. This situation sustainable energy sources have supplemented traditional energy sources and promoted sustainable energy use. Solar, wind, and fuel cell energy are given example of sustainable energy. Power generating facilities are employed nowadays because of their extended lifespan, inexpensive maintenance, no hazardous waste, and independence from dwindling energy sources. Solar power generation depends on environmental circumstances, hence MPP generation must be observed. MPPT follow solar panel highest MPP. This study involves a system is comprised by a DC-DC boost converter, PV panel, and a ohmic load. The duty ratio is generated by the IC and FLC MPPT algorithms, and the PWM signal is generated by comparing it with the triangle wave. This generated signal is applied to the DC-DC boost converter. The aim of this research is to investigate the effectiveness, variability, and duration required to attain the MPP of the implemented MPPT methods. The system has been developed within the MATLAB/Simulink framework. Based on the findings of the simulation, it has been determined that the FLC MPPT algorithm achieves the MPP at a faster rate compared to the IC MPPT algorithm. Consequently, the level of fluctuation is minimum and the efficiency is high.

Wideband Chebyshev Impedance Transformer Set with Very Low Reflection Coefficient

In various electronic and electrical devices for communication systems, impedance transformers with wide bandwidths are important. In this article, Chebyshev impedance transformers for ohmic loads with order 3 are presented at different frequencies and load impedance values using Duroid and FR4 substrates (εr = 2.2 and εr = 4.4 respectively). Simulated results are shown using the software Advanced Design System (ADS). The thickness of the substrate for FR4 dielectric material is 1.544 mm and for Duroid material is 1.27mm. The matching transformers were performed at 1 GHz, 1.5 GHz, 2 GHz, and 1.5 GHz for two load impedance 100 Ohms and 75 Ohms from 50 Ohms showing a reflection coefficient Γm = 0.05. The S11 scattering parameter was obtained.

Inductive Power Line Harvester With Flux Guidance for Self-Powered Sensors

Self-powered sensors are expected to enable new large-scale deployment and location access capabilities for sensor systems. Energy harvesting devices have been shown to provide adequate power densities but their dependence on very specific environmental conditions restricts their applicability. Energy harvesting from power line infrastructure offers an architecture for addressing this challenge, because such infrastructure is widely available. In this paper an inductive power line harvester concept is presented, based on a flux concentration approach adapted to a closed-loop core geometry. Flux concentration is studied by simulation, showing a 26% flux increase using a 1:3 geometrical concentration ratio in a closed-loop core. A 20×20×25 mm prototype with a U-shaped soft-core sheet and a 200-turn Cu coil around a 5 mm diameter, 20 mm long soft-core rod is introduced. The total device volume is 9.1 cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> . Characterization results on a power line evaluation setup for currents up to 35 A RMS and a 50 Hz – 1 kHz range are presented. Power between 2.2 mW (50 Hz) and 233 mW (1 kHz) is demonstrated on an ohmic load, from a 10 A RMS power line current, employing impedance matching with reactance cancellation. The corresponding power densities are 0.24 mW/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> and 25 mW/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> respectively, per total device volume. This performance is adequate for enabling self-powered wireless sensor networks installed along power distribution lines.

Operating the Induction Motor as a Generator Mode by Supplying DC Voltage and Investigation of the End Voltage Depending on the Excitation Current and RPM

Asynchronous or induction machines are among the leading devices in the electrical industry. They are well suited for motor and production applications with power ratings from a few kilowatts to megawatts. In addition, their use in renewable energy systems, especially in wind conversion systems, is increasing daily due to their advantages, such as low cost, brushless, and robust structure. In this work, the operation of a three-phase asynchronous motor with a winding rotor as an alternator, the variation of the voltage produced depending on the excitation current by keeping the number of revolutions constant, and the interpretation of the voltage produced according to the number of revolutions by keeping the excitation current constant have been investigated. The variation of the terminal voltage in ohmic, inductive, and capacitive loads has been experimentally investigated by observing the source voltage providing the rotational speed and excitation current constant.

Maximum Power Point Tracking for Solar Photovoltaic System Based on Interval Type-3 Fuzzy Logic: Practical Validation

Maximum power point tracking (MPPT) is a technique that allows photovoltaic (PV) arrays to operate at or near their maximum power point (MPP) under all weather conditions. Fuzzy logic controller (FLC) is the most popular method to monitor the MPPT, such as Type-1 fuzzy logic (T1FL), Type-2 fuzzy logic (T2FL), and Type-3 fuzzy logic (T3FL) controllers. This article proposes a new T3FL algorithm that improves tracking efficiency and tracking speed because it is better equipped to deal with uncertainty arising from disturbances. The proposed system consists of a PV module, a DC-DC buck converter controlled by the MPPT algorithm, a resistive load, and a battery. The PV solar panel is directly connected to the DC-DC buck converter, which operates based on the proposed controller’s output pulse width to ensure that the PV system works at MPP. The T3FL algorithm has the advantage of extracting the maximum power from the PV panel while preventing battery damage caused by variable MPPT voltage and thus extending battery lifetime. The maximum power and voltage of T3FL are compared with the existing T1FL and T2FL of battery and ohmic load. The MPPT performance of the proposed different algorithms was applied to a PV module and a DC-DC buck converter to be evaluated via simulation studies and experimental studies. MATLAB/Simulink is used to implement different algorithms. Several weather conditions are simulated: (i) uniform irradiation, (ii) sudden changing, and (iii) partial shading. A real-time implementation of the three MPPT algorithms by using Arduino Uno and spatial Simulink package known as the “support package for Arduino hardware”. Finally, the simulation and experimental results demonstrate that the T3FL controller of an ohmic load provides accurate maximum power, high levels of stability, and robust performance against uncertainties arising from disturbances to the PV system’s inputs

A GaN–Si hybrid integrated driver for narrow-pulse and high-current LiDAR applications

Light detection and ranging (LiDAR) is the most important active remote sensing tool and is widely used in civilian and military fields. There are a number of methods to drive laser diodes; the most common circuit topologies are capacitor-discharge resonant circuits. However, the performance of the silicon (Si)-based switching device limits the development of Light detection and ranging, such as the large figure of merit (FOM) and the stray inductance. Although different methods have been reported to resolve these problems, there are still great challenges in reducing the pressure on Light detection and ranging driver design. Hence, this work presents a gallium nitride (GaN)–Si hybrid integrated driver for a Light detection and ranging system. In the circuit, the switching power device uses GaN instead of a Si-based device, because GaN enables much better performance for pulsed-laser operation due to its near-ideal switching performance. Furthermore, a GaN push–pull driver stage between the GaN power device and the Si-based driver integrated circuit (IC) was innovatively introduced, which is integrated in the same chip with the GaN power device, thereby effectively reducing the parasitic parameters of the signal chain and enhancing the system reliability. The design and implementation of the Si-based IC and GaN IC are based on 0.18 µm 80–120 V Bipolar-CMOS-DMOS (BCD) technology and 0.5 µm p-GaN technology, respectively. The experimental results suggest that the proposed driver circuit output pulse width is 12.6 ns, and it can normally operate at 10 MHz with turn-on/turn-off delay is 11.94 ns. In addition, the driver was capable of generating approximately 8.25 A current pulses through a low ohmic load with a pulse width of approximately 12.4 ns. This work plays a vital role in promoting the development of information equipment and aerospace equipment such as precise ranging, high-efficiency power supplies, and high-speed motors.

Optimization of a Multilevel Inverter Design Used for Photovoltaic Systems under Variable Switching Controllers

Among multilevel inverters (MLIs), two-level inverters are the most common. However, this inverter type cannot maintain total harmonic distortion (THD) due to its limited number of levels. Reductions in THD are inversely proportional to the number of levels where increased output occurs in diverse ways, and the use of fewer components with low harmonic distortion is necessary for such reductions. This work proposes a seven-level (7L) MLI design with a small number of components and low harmonic distortion. The proposed MLI is combined with switched capacitor (SC) cells to promote output levels and at the same time to boost the input voltage. The connections between the capacitor and the source are based on the series to parallel topology, where the charging and discharging of the SC cells are caused by fluctuations in their connection. The output of the SC cell is combined with an H-bridge inverter controlled by a proposed PWM controller. The simulation result of the SC 7L inverter was completed using LTspice software. A comparison of the proposed topology with that of other current MLI led to better validation results. The proposed design shows a reduction in the THD with fewer components. The cost and size of the proposed inverter is minimal due to the smaller number of components. Ohmic load and inductive ohmic load were used as loads for the system.

A Dynamic Threshold Cancellation Technique for a High-Power Conversion Efficiency CMOS Rectifier.

Power conversion efficiency (PCE) has been one of the key concerns for power management circuits (PMC) due to the low output power of the vibrational energy harvesters. This work reports a dynamic threshold cancellation technique for a high-power conversion efficiency CMOS rectifier. The proposed rectifier consists of two stages, one passive stage with a negative voltage converter, and another stage with an active diode controlled by a threshold cancellation circuit. The former stage conducts the signal full-wave rectification with a voltage drop of 1 mV, whereas the latter reduces the reverse leakage current, consequently enhancing the output power delivered to the ohmic load. As a result, the rectifier can achieve a voltage and power conversion efficiency of over 99% and 90%, respectively, for an input voltage of 0.45 V and for low ohmic loads. The proposed circuit is designed in a standard 130 nm CMOS process and works for an operating frequency range from 800 Hz to 51.2 kHz, which is promising for practical applications.

A Low-Loss Load Correction Technique for Self-Healing Power Amplifiers Using a Modified Two-Tap Six-Port Network

This article presents a low-loss correction technique for a self-healing load-insensitive power amplifier (PA) using a modified two-tap six-port network, wherein the varying (complex) load is first compensated for its unwanted susceptance part, followed by adjustment of the transistor output stage to the ohmic load variation, by modifying its supply voltage and drive level. This two-step approach avoids the high-Q conditions that occur in tunable matching network solutions, which aims to correct for both the real and imaginary load deviations, such as providing lower insertion loss and voltage stress. Next, to facilitate a fully automated load mismatch correction without the need for calibration, a modified two-tap six-port network for impedance detection and control loop approach is proposed. As proof of principle, a prototype 900-MHz class-AB PA featuring the proposed correction technique, as well as, the six-port reflectometer and the control loop, has been implemented as a PCB demonstrator. Measurement results show that the self-healing load-insensitive PA in the events of load mismatch significantly improves the performance and approaches the 50- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Omega $ </tex-math></inline-formula> performance. On a 2:1 VSWR 360° mismatch trajectory and driven by a 64-QAM 3.86-MHz signal, the PA achieves a linear output power of 22 dBm with only ±0.1-dB variation and better than −45-dBc adjacent channel power ratio (ACPR).

Current-voltage characteristics of a discharge in a supersonic flow of ionized air in permanent magnets field

The work is devoted to the development of direct conversion devices of energy of high-enthalpy hypersonic gas flow into electrical energy. The experiments were carried out to study the electrical characteristics of the gap between two electrodes filled with weakly ionized plasma of the airflow at the wind tunnel with a magnetogasdynamic accelerator SMGDU. The voltages induced in the field of permanent magnets and the corresponding induction currents were measured with an ohmic load in the external circuit. The current-voltage characteristics of the discharge are constructed for the case of an additional supply of a current pulse from an external source to the interelectrode gap. The conductivity of the medium in the gas flow and the MHD interaction parameter were estimated. The results obtained can be used in the design of surface MHD generators for the autonomous production of electrical power on board of a hypersonic aircraft.

Dispersion effects in on‐state resistance of lateral Ga 2 O 3 MOSFETs at 300 V switching

Static characterisation and fast switching processes of lateral β-Ga2O3 metal oxide semiconductor field-effect transistors (MOSFETs) are presented. The investigated transistors with 10 mm gate width and 6 µm gate drain distance achieve on-state resistances of 5 Ω and saturation currents above 2.4 A. Hard switching in a double pulse test setup with an inductive load results in voltage slopes up to 65 V/ns at 300 V input voltage. After longer blocking times and higher DC voltages, a strong dynamic increase in on-state resistance occurs. Switching with an ohmic load and different load currents reveals only minor influence of the hot electron mechanism during the hard turn on. However, a clear influence of the turn-on gate drive voltage on the dynamic increase is observed, indicating a shift of the transfer characteristic due to charge trapping in the gate region.

A Nanosecond High-Voltage Pulse Generator Based on Artificial Double Forming Lines

The results of experimental studies of a compact high-voltage pulse generator are presented. The generator is based on two artificial double forming lines in a collapsed circuit, which are switched by gas spark gaps; it also contains a peaking gas spark gap, transmission lines filled with a liquid dielectric, and a load equivalent. The characteristics of this generator were studied in the charging-voltage range of up to 100 kV. When the voltage pulse duration from the forming line was 100 ns, current pulses with an amplitude of 18 kA and a rise time of ~18 ns were obtained across an ohmic load.

Modelling of SiPM Performance for Detection of Cherenkov Radiation from Extensive Air Showers in UV and Visible Ranges for Application at the TAIGA-IACT Telescope

Abstract A novel cluster of sensitive detectors based on silicon photomultipliers (SiPM) is being developed for the Cherenkov gamma-ray telescope TAIGA-IACT (Tunka valley, Republic of Buryatia, Russia). The cluster will be able to detect Cherenkov radiation from extensive air showers in two wide bands: 250–300 nm (UV) and 250–700 nm (visible and UV). Each pixel consists of a Winston cone, 4 SiPMs with the total sensitive area of 144 mm2, and readout electronics based on fast analogue memory. During operation in the UV band, a UV-bandpass filter is used to suppress cluster sensitivity in the visible range. In order to evaluate the detection efficiency of the selected SiPMs, a specific software simulator of SiPM output signal has been developed. This simulator takes into account such inherent parameters of SiPMs as total number of microcells, their recharge time, the dark count rate, the effective detection area, the quantum efficiency, the crosstalk between microcells, as well as conditions of SiPM operation, namely, the background noise and the Ohmic load in the readout (front-end) electronics. With this simulator it is possible to determine the expected trigger threshold under given conditions and parameters of selected detectors. Based on preliminary simulations, OnSemi MicroFJ-60035 SiPM chips have been chosen for the novel cluster of TAIGA-IACT. These SiPMs have sensible efficiency in the ultraviolet range (5–20% in the 250–300 nm band) and are distinguished by the presence of a fast output, which allows one to capture a low amplitude signal above a relatively high background noise.

Design Validation of a Single Semiconductor-Based Marx-Generator Stage for Fast Step-Wise Arbitrary Output Waveforms

A new modular pulsed-power source with fast rise time and step-wise arbitrary output waveform generation is currently under development to drive the Gepulste Elektronenstrahlanlage device investigated at the Institute for Pulsed Power and Microwave Technology (IHM). Acknowledging the complex design procedures necessary to set up a modular pulsed-power source for voltages of up to 120 kV, this paper focuses on the circuit design for a single stage and its validation prior to the generator assembly. Using a semiconductor-based Marx generator topology, the stages are designed to have an output voltage of 1 kV with a pulse current of up to 600 A. When connected to an ohmic load, the measured current rise times are in the order of 46 ns resulting in the current rise rates of up to 10 kA/μs using the commercial devices. The step-wise arbitrary output waveform is created by generating the switching commands on the stage using a microprocessor and a fast optical synchronization unit. Effective stage shielding is verified by operating the stage in a 100-kV, 2.5-kA electromagnetic interference test bed. This paper presents the design considerations and the corresponding measurements.

A control strategy for improved efficiency in direct-coupled photovoltaic systems through load management

Nearly all photovoltaic (PV) systems involve power management and/or conversion devices. Each of these devices introduces a power loss and has an associated monetary cost. In this paper, a direct-coupled load-managing PV system is proposed that promises both a lower cost and a higher efficiency than conventional systems. Against the prevailing wisdom that the PV power must be managed, the proposed system varies the power demand of the loads by controlling the number of loads connected to the PV array to extract the maximum available power throughout a day without a conventional maximum power point tracker. This system can also regulate its operating voltage to less than ±3% of its target voltage without a DC/DC converter. The proposed control strategy can be applied to many direct-coupled PV systems for improved efficiency. A simulation program was developed for the load-managing system that can simulate its performance with a PV array of any size and any number of loads. The theoretical system efficiency was found to increase with the number of loads being managed and reaches above 99% for a direct-coupled system with just eight ohmic loads. Experimentally, a prototype system with equal and unequal ohmic loads was demonstrated in an outdoor environment that responds to changes in solar irradiance. The control strategy also allows direct-coupled PV systems to be backed up by a secondary power source, e.g. the electric grid, to eliminate their intermittency for applications such as electric vehicle charging. The cost of the control electronics for the load-managing system is less than 1% of the commercial-scale PV system cost. Several challenges in implementing and optimizing the proposed system are discussed.

Human motion energy harvesting: numerical analysis of electromagnetic swing-excited structures

Energy harvesting from human motion has constantly attracted scientific interest over recent years. A location where a harvesting device can easily and unobtrusively be integrated is the shoe sole, which also protects the device from exterior influences. In this work a numerical system model is developed, which can be used to simulate different inductive harvester geometries and predict their power output. Real world acceleration data is used as a model input. The model is implemented in Matlab/Simulink and subdivided into a mechanical and an electromagnetic model. The key features including the motion model and the calculation of the electromagnetic coupling coefficient are explained in detail and the model is briefly evaluated experimentally. A total of six inductive architectures, i.e. different cylindrical and rectangular magnet-coil arrangements, are then investigated in detail. The geometrical parameters are optimized for each architecture to find the best geometry within the size of 71 mm × 37.5 mm × 12.5 mm, which can be integrated into the sole. With the best overall design an average power output of 42.7 mW is simulated across an ohmic load of 41 Ohms. In addition to the respective best designs, the (dis-)advantages of each architecture are explained.

Optimization study on a 0.6 kW PMSG for VAWTs and determination of open and short circuit performances by using external circuit method

As is known, machine design is a time-consuming and complicated process. And consequently, the verification of the designs and machine performances with known optimization methods prior fabrication are becoming more complex and expensive. Relating to this issue, many studies have been achieved to realize optimization and analyze dynamic performance of the designed machines. In this paper, optimization and short/open circuit fault analysis along with transient performance of a designed 0.6 kW radial flux permanent magnet synchronous generator (RFPMSG) for a stand alone wind turbine was studied. The main feature of this study is to use RMxprt dynamic generator model which is linked with the ANSYS Simplorer external circuit simulator. The co-simulation method has been used to analyze the performance of the generator considered for feeding an ohmic load. This method also yields the waveforms of load voltages and load currents for different load and wind speed conditions along with experimental studies.

Preliminary studies of a new permanent magnet generator (PMG) with the axial and radial flux morphology

In this work, a new axial and radial flux permanent magnet generator (PMG) is introduced. The machine has multiple cores in its stator, which has double sides, coils in these sides. It operates in 3 phases and uses disc type magnets in two rotors at each side. PMG has 24 circular coils and 12 laminated cores. Each rotor has 16 magnets and the stator is stable at the middle of the rotors. The simulations include magnetostatics and magnetodynamics analyzes via finite element method (FEM). After the determination of optimal physical, electrical and magnetic parameters, a prototype machine is constructed for the experiments. The rated values of the machine are measured experimentally for different rotor speeds and different ohmic loads. According to the experimental and theoretical analyzes, the rated power is found as 250 W with the efficiency ratio of 92% for the testing values of airgap 5 mm.