Output Power Level Research Articles

Analyzing the Automatic Power Level Control Effect of a Signal Generator in RF Power Sensor Calibration by a Direct Comparison Transfer Method and a Millimeter Wave Application.

Most calibration laboratories prefer the Direct Comparison Transfer Method (DCTM) for a reliable and accurate calibration of power sensors in the radio frequency (RF) scope. Most studies suggest using this calibration method, with its automatic power level control (APLC) of RF signal generators. The APLC is preferred to keep the output power level of the signal generator the same, while the power sensor is calibrated and the reference power sensor is connected to the measurement system. The known APLC mechanisms are also explained for the DCTM, and a comparison of the calibration factor values carried out with and without the automatic power level control process in the DCTM is also given in this study. RF power sensor calibrations with coaxial and waveguide connector types are examined with DCTM in this study as well. This study shows that the DCTM, unless with APLC, should be applied for the waveguide power sensor's calibration at millimeter wave frequencies.

Slot-pole structure investigation for radial flux permanent magnet generator

Recently, Radial Flux Permanent Magnet Generator (RF-PMG) has been applied in various applications of generator. The configuration of the radial flux permanent magnet is the magnetic rotor arranged in a circle rotation while the inner core attached to the rotor’s center. However, various sizes and structure of RF-PMG can produce different output power levels, cogging torque and generator’s flux regulation capability. By investigating the output voltage and cogging torque value, this paper showed the suitable slot-pole combinations that can influence the output performance of the generator by using 2D-Finite Element Analysis. This investigation shows the comparison of the slot-pole that resulting the least cogging torque value and high output voltage, 0.1739Nm and 180.81V respectively. Hence, 36slots-30poles indicates as the best slot-pole combinations.

A new approach for ultra-wideband continuous class B/J power amplifier design and fabrication based on increasing efficiency in power loss-less case

A new theoretical approach to designing an ultra-wideband continuous class B/J power amplifier is presented. In the conventional design of continuous class J, the maximum accessible bandwidth is limited to one octave, which is equivalent to 66 % fractional bandwidth. In this paper, it will be shown by reforming the voltage expression of resistive-reactive class J, high efficiency continuous class B/J power amplifier design can be realized sothat the output power level maintains across more than one octave. Using a new defined correction factor in the output voltage of resistive-reactive class J while the third harmonic element with a proper coefficient is added to it, not only could help to decrease the compromise between the design space and efficiency but also improve the PA output power than conventional one. To check the feasibility of the suggested approach and validate the theoretical and simulation results, a broadband PA using CGH40010F GaN transistor in 0.5–2 GHz is designed and fabricated on RO4003c substrate with 20 mil thickness. The measured 39.8–42.2 dBm output power with 63.68 % average drain efficiency over more than 120 % fractional bandwidth confirmed both the theoretical and simulation results.

A 55 nm CMOS RF Transmitter Front-End with an Active Mixer and a Class-E Power Amplifier for 433 MHz ISM Band Applications

In order to meet the increasing demands of wireless communication for ISM bands, a 433 MHz transmitter RF front-end is designed using a 55 nm low-power CMOS technology. The circuits consist of an active mixer, a driver amplifier and a class-E power amplifier (PA). A double-balanced Gilbert active mixer is designed to realize binary phase-shift keying (BPSK) modulation. The driver is used to preamplify the modulated RF signals. The class-E PA adopts a parallel four-branch cascode structure to control the output power level. The load network of the PA is implemented through an off-chip circuit, in which a finite DC-feed inductance load network is selected to reduce the power loss. The mixer and driver are designed with a 1.2 V supply voltage, while the PA is operated at a 1.8 V supply voltage. The area of the chip is 0.206 mm × 0.089 mm, and the measured results show that it achieves a maximum output power of 2.7 dBm, with a total power consumption of 6.72 mW. At a drain efficiency (DE) of 34.5%, an S22 less than −10 dB over the frequency ranges from 393.79 MHz to 455.70 MHz can be measured for the PA. With 192 kbps BPSK data modulated at 433 MHz, the measured EVM is about 0.83% rms.

A novel two‐stage solution for low‐power 48‐V voltage regulator module (VRM) using high step‐down hybrid LLC with integrated planar transformer

SummaryIn this paper, a novel two‐stage solution based on a 1‐MHz high step‐down hybrid LLC converter is proposed for low‐power 48 V voltage regulator modules (VRM). Since the hybrid LLC DCX converter with high step‐down ability is employed as the first‐stage, lower bus voltage can be obtained with the same transformer turns, which contributes to enhancing the duty cycle and efficiency of the second‐stage multi‐phase buck converter. Thus, an overall efficiency improvement can be achieved in the proposed two‐stage system, especially in low‐power applications. To further improve efficiency and power density, a novel integrated planar transformer is adopted for the double resonant tanks of the hybrid LLC converter. To validate the analysis, a 150‐W hardware prototype of the hybrid LLC converter is constructed in the laboratory. To ensure a fair comparison with existing LLC DCX designs, the output voltage is set at 6 V. The measured efficiency results of the first‐stage demonstrate an efficiency advantage at low power output levels compared to the similar full bridge LLC designs, especially at an output of around 100 W. Under the nominal 48‐V input, the first‐stage achieves a peak efficiency of 98.5% and a full load efficiency of 94.62%. Furthermore, a 4‐phase buck converter with nominal 6‐V input and 1.6‐V output is constructed to evaluate the efficiency performance of the overall system. When the second stage operates at 500 kHz, the proposed two‐stage system achieves a peak efficiency of 93.2% at 40A load, while maintaining an efficiency of 91.2% at 65A output. The calculated efficiency of the proposed two‐stage solution exhibits higher performance compared to the majority of single‐stage schemes.

Watt-level broadband PM Tm-doped fiber amplifier for the 1750–1910 nm window

We report broadband experimental and simulated performance of a single-clad polarization-maintaining (PM) thulium-doped fiber amplifier (TDFA) optimized for operation in the 1750–1910 nm wavelength band. With the two-stage amplifier architecture, a maximum output power of 2.4 W was obtained at 1850 nm for 7.0 W of launched pump power at 1567 nm, with a corresponding optical-to-optical efficiency of 31.4 %. The measured polarization extinction ratio (PER) was larger than 22.6 dB, and the long-term power stability exhibited a peak-to-peak variation of 2.4 %. By employing a tunable seed laser covering the 1750–1910 nm wavelength range, we measured a maximum output power level of 2.38 W with an optical signal-to-noise ratio (OSNR) greater than 53 dB/0.1 nm. Our simulations are in good agreement with the experimental data over the whole 160 nm operating spectral bandwidth.

Energy Conversion Optimization Method in Nano-Grids Using Variable Supply Voltage Adjustment Strategy Based on a Novel Inverse Maximum Power Point Tracking Technique (iMPPT)

This paper introduces a novel power supply voltage adjustment strategy that can determine the optimum voltage value based on the amount of absorbed power. The novel automatic voltage adjustment technique was called inverse maximum power point tracking (iMPPT). The proposed control strategy consists of a modified maximum power point tracking (MPPT) algorithm (more precisely the P&O method). In this case, the modified MPPT technique establishes the minimum value of the input absorbed power of a consumer load served by a switched-mode power supply (SMPS). The iMPPT adjusts the input power by modifying the input voltage of the main power supply. The served loads are connected to the variable power supply via an interfacing power electronics converter that performs the automatic voltage regulation function (AVR). The optimal value of the input voltage level can be achieved when the input power of the automatic voltage regulation converter is at a minimum. In that case, the energy conversion efficiency ratio is at a maximum, and the overall losses related to the front-end power stage are at a minimum. The proposed technique can also be considered a Maximum Efficiency Tracking (MET) method. By performing the inverse operation of a maximum power point tracking algorithm on the input demanded power of a switched mode power supply (SMPS), the optimum input voltage level can be determined when the maximum energy conversion ratio (related to a given load level) is achieved. The novel proposed iMPPT method can improve the energy conversion ratio from 85% up to approximately 10% in the case of an output power level of 800 W served by a synchronous buck converter at the input voltage level of 350 V. The total amount of recovered power in this situation can be approximately 100 W.

A novel capacitor voltage fluctuation suppression method for the low-frequency operating stage of MMC driven pumped storage system

The pumped storage power plant, which has the energy conversion and storage capacity, is an important solution for improving the power grid absorption ability to the unstable and fluctuating new energy from wind farms, as well as photovoltaic power stations. The modular multilevel converter (MMC) is a competitive topology for driving the pumped storage motor due to the advantages of high output power level and low output current harmonics. However, the voltages of the sub-module capacitors fluctuate largely when the MMC is operating at low-frequency stage, which would lead to an abnormal start-up process or an unstable low-speed running state of the variable speed pumped storage system. In order to suppress the low-frequency voltage fluctuation of the MMC sub-module capacitors, this paper proposes a charge channel topology including in-phase and inter-phase channel between the sub-modules for transferring the capacitor charge. Then, the reverse fluctuating fundamental component and third harmonic circulating component, as well as the synchronizing fluctuating second harmonic component, of the sub-module capacitor voltages could be counteracted, respectively. Eventually, the start-up operation performance, as well as the low-speed operation performance of the variable speed pumped storage system are enhanced greatly. The effectiveness of the proposed low-frequency capacitor voltage fluctuation suppression method is verified through simulation results.

A simplified control method for a water heating load coupled to a hybrid energy system to improve inverter longevity

In this paper, the temperature characteristics of an inverter is determined through experimental validation. The experiment involves testing under two load scenarios. The first of which considers a low inverter load, which represents a baseload at approximately 18% of the maximum rated power of the inverter. The second includes an energy intensive water heater load, which increases the loading on the inverter to above 85%. The aim of this paper is to ensure that the operating limits with respect to the inverter temperature is maintained to at least 10% below the upper limit of the device. The experimental results indicated that the rate of change of the inverter temperature was 2.988 °C/min when loaded above 85% and −1.277 °C/min after returning to the 18% rated output power level. This indicated that if the inverter is subjected to a high load of above 85% for a certain amount of time and the operating temperature has reached its acceptable maximum limit, roughly twice the amount of time is necessary to cool the components down enough for another high loading event. A basic fuzzy logic control method is proposed to maintain the inverter temperature within acceptable limits to improve overall inverter longevity.

Intra-Articular Ultrasonography Probe for Minimally Invasive Upper Extremity Arthroscopic Surgery: A Phantom Study.

Upper extremity arthroscopic surgery is a highly technique-dependent procedure that requires the surgeon to assess difficult cartilage conditions and manage the risk of iatrogenic damage to nerves and vessels adjacent to the joint capsule in a confined joint space, and a device that can safely assist in this procedure has been in demand. In this study, we developed a small intra-articular ultrasound (AUS) probe for upper extremity joint surgery, evaluated its safety using underwater sound field measurement, and tested its visualization with a phantom in which nerves and blood vessels were embedded. Sound field measurement experiments confirmed the biological safety of the AUS probe's output, while confirming that sufficient output power level performance was obtained as an ultrasound measurement probe. In addition, images of blood vessels and nerves were reconstructed discriminatively using A-mode imaging of the agar phantom. This study provides proof-of-concept of the AUS probe in upper extremity surgery. Further studies are needed to obtain approval for use in future medical devices.

IoT-Based Automated Solar Panel Cleaning and Monitoring Technique

Aims: The objective of this research work is to design and develop an IoT-based automated solar panel cleaning and real-time monitoring system using a microcontroller to improve the output and efficiency of a solar module at a low cost.
 Study Design: Most of the time, dust over solar panels creates a barrier that obstructs the sun’s radiation and reduces their performance. As such, it is necessary to keep the solar panel clean to improve output power levels. We integrated the IoT technology along with a range of components, including a microcontroller, a NodeMCU, a servo motor, a DC motor-driven submersible pump, a Light Dependent Resistor (LDR), an LCD with driver IC, etc. to design the system. We developed the assembly language program for the microcontroller.
 Place and Duration of Study: The work was conducted individually under the supervisor of a faculty member as a part of the final project work of the Master of Engineering degree in Electrical and Electronic Engineering at American International University Bangladesh (AIUB), Dhaka, Bangladesh. The student conducted his research work at AIUB for two consecutive semesters from September 2022 to May 2023.
 Methodology: An LDR sensor detects the solar panel’s dirtiness and triggers the cleaning process through the microcontroller. The system monitors this continuously and real-time vital data is accessible to have some performance metrics, empowering timely maintenance actions to be triggered by the system and hence ensuring the maximum power output. The automated cleaning mechanism, driven by servo motors and mini submersible DC motor pumps, effectively removes dust and dirt from solar panels. An application was used to get real-time data through the internet to the user’s smartphone.
 Results: The server data is accessed to observe the system performance. The cost analysis shows that this system offers a cost-effective and sustainable solution for maintaining clean solar panels and optimizing power output.
 Conclusion: Such an automation system can contribute meaningfully to the progression of renewable power generation by significantly improving the efficiency and longevity of solar panels. Thus, we can have sustainable and efficient energy systems in the country by integrating IoT-based automation systems.

A static voltage stability index based on P-V curve for the medium-voltage distribution network with distributed PV

With the rapid increase of distributed photovoltaic (DPV) generations, the static voltage stability (SVS) of distribution network (DN) is faced with more and more challenges. Considering the characteristics of DPV and the network structure, an appropriate static voltage stability index (SVSI) in the medium-voltage DN with DPV is studied in this paper. In terms of the limitation of the traditional SVSI that only reflects the load change, based on P-V curve, a novel voltage change rate - network load change rate index (M-index) is proposed. The M-index considers the impacts of double changes in DPV power output and load level. The model of classic 33-node network with a DPV source is established to investigate the proposed M-index. By changing the DPV penetration percentage and the DPV access point, and comparing with the existing Load-index, the validity and superiority of M-index is verified. Comparing with the traditional SVSI, the M-index is more propitious to evaluate the SVS for the medium-voltage DN with DPV.

Demonstration of 3kW × 2 ports bidirectional output oscillating-amplifying integrated fiber laser employing chirped and tilted fiber Bragg gratings for co-SRS suppression.

Bidirectional output oscillating-amplifying integrated fiber laser (B-OAIFL) is a newly developed configuration with many advantages like compactness and good reliability. In this work, a B-OAIFL with a low time-stabilized threshold was constructed by employing a pair of side pump/signal combiner in the oscillating section, which demonstrates smooth temporal characteristics with no pulse detected by the photodetector at the output power level of only a few of tens Watts. We investigated the effect of side pumping on the Raman Stokes light and verified its contribution to mitigating the temporal-chaos-induced stimulated Raman scattering (SRS). The phenomenon of co-SRS caused by the mutual excitation of backward Stokes light from two amplifying sections under bidirectional pumping was first reported and studied. A pair of chirped and tilted fiber Bragg gratings (CTFBGs) were applied between the oscillating and amplifying sections to suppress the co-SRS, and the effect of the number of CTFBGs on the suppression of co-SRS was studied in detail experimentally. Finally, we successfully suppressed the co-SRS, and achieved a 3kW × 2 ports laser output, with a near-single-mode beam quality of M A 2∼1.3,M B 2∼1.4. In contrast, without the use of CTFBG, only a 2 kW-level output was obtained from each port, limited by co-SRS (with an SRS suppression ratio of less than 15 dB). The maximum output power of end A and end B is 3133 W and 3213 W, with the SRS suppression ratio of about 27.6 dB and 28.1 dB, respectively. No TMI features were observed under bidirectional pumping. The results demonstrate a significant potential for further power scaling based on this configuration. To the best of our knowledge, it is the highest output power achieved based on the B-OAIFL.

Experimental study on hybridization of a PV–TEG system for electrical performance enhancement using heat exchangers, energy, exergy and economic levelized cost of energy (LCOE) analysis

Abstract The concept of employing thermoelectric generators (TEGs) to recover energy from waste heat has gained popularity, with applications that range from milliwatt to kilowatt levels of output power. In this study, a hybrid photovoltaic panel and thermoelectric generator (HPVTEG) system consisting of an integrated heat exchanger, a commercial polycrystalline silicon photovoltaic (PV) panel and a commercial bismuth telluride TEG was proposed. Here, TE components can be used to cool PV modules, increasing their output power via the Seebeck effect. The main finding is that the hybrid system has a reduced average temperature of 16.01°C. The average power of the stand-alone PV panel is 28.06 W, but that of the HPVTEG system is 32.76 W, which is an increase of 4.7 W. The conversion efficiency and power of the hybrid system increased by 16.7% and 16.4%, respectively, compared with a stand-alone PV panel. The HPVTEG system achieved an average exergy efficiency of 12.79% compared with 10.98% for a stand-alone PV panel. According to the calculation results, the levelized cost of energy (LCOE) of the stand-alone PV panel can range from 0.06741 to 0.10251 US$/kWh depending on how many days it is in operation, while the LCOE of the HPVTEG system can range from 0.06681 to 0.10160 US$/kWh.

A Multi-Inverter Multi-Rectifier Wireless Power Transfer System for Charging Stations With Power Loss Optimized Control

Electric vehicles (EVs) with different output power levels can use wireless power transfer (WPT) systems. Different vehicle assemblies (VAs) may be charged by different ground assemblies (GAs) in charging stations. However, the overall efficiency of the WPT system may drop significantly when the power class difference between GA and VA is large. To address this issue this paper proposes a DC-link parallel AC-link series (DPAS) multi-inverter multi-rectifier (MIMR) architecture for high-power WPT systems. Modulation, power transfer capability, and power sharing from the design aspects are investigated. A detailed power loss analysis and an easy-to-implemented power loss optimized control method based on mutual inductance identification are presented in this paper. Finally, experimental results are obtained from a 20-kW LCC-LCC WPT system to validate the analysis and proposed system operation.

Enhanced-efficiency Capacitive Coupling Intra-body Power Transfer Systems with 1.8 V Output for Neural Interfaces.

Traditional wireless power transfer methods for powering neural interfaces have many restrictions such as short transmission distance and strict device alignment. The recently proposed capacitive coupling intra-body power transfer (CC-IBPT) which utilizes human body as the medium supports flexible placements of the transmitter electrode. In this paper, we established two prototype systems based on CC-IBPT with different power sources of a grounded signal generator and a battery-powered board to explore the maximum output power levels with 1.8 V load voltage. To improve the power transmission efficiency, LC impedance matching (IM) and backward compensation (BC) are conducted at the transmitter (TX) and receiver (RX) respectively. Measured results show that 2.5 and 7.4 times load power is enhanced in the two prototype systems. Moreover, the maximum power transfer efficiency (PTE) of 11.16% can be obtained with the TX-RX distance of 16 cm. Therefore, our work verifies CC-IBPT's capability of achieving a high PTE in long-distance wireless power supply for neural interfaces and promotes its widespread application.

Design, implementation, and analysis of an asymmetrically configured DK-type multilevel inverter

ABSTRACT This work proposes a new configuration of asymmetrical MLI which is called a dual kite type (DK-type) multilevel inverter. Its special features include the low total standing voltage (TSV) along with less number of total components. The basic module of the proposed structure is able to generate 15 levels without the use of h-bridge. This results in decreasing the voltage stress considerably. The extension of the proposed circuit can be done in order to increase the levels. The operation of proposed MLI has been discussed in detail, and its comparison with some recently proposed topologies has been done in the paper. Moreover, the simulation results for different constant and dynamic loading conditions have been presented and experimental verification of the same has been done and results have been shown. Fundamental frequency-based switching strategy, also called nearest level control (NLC) modulation technique, is used for providing the switching signals. Further, loss evaluation in the proposed structure has been completed with the help of PLECS software. 5.5% THD is present in the output voltage. The proposed MLI has the maximum efficiency of 98.68% at the output power level of 0.5 kW. The results and analysis presented in the paper describe the improved performance of the proposed MLI.

Optimal Allocation of Curtailment Level of PV Power Output in Different Regions in Consideration of the Reduction in Aggregated PV Power

Due to the extremely high penetration of photovoltaic power generation system (PV), the power output curtailment (Cr) of PV is necessary not only to maintain supply-demand balance but also to preserve enough capacity for the frequency control. Although the Cr level for the aggregated PV in the power system service area is determined in a day-ahead unit commitment (UC) scheduling, the Cr for individual PV with different weather conditions should be allocated so that the fluctuation of aggregated PV power output is minimized. Assuming that the short-term forecasting of individual PV power output fluctuations characteristics is available, the objective of this study is to propose methods for optimal short-term allocation of Cr level among each region. The proposed methods have proven their effectiveness in meeting the predetermined average PV power ouput as well as reducing the fluctuations of the overall system.

Analytical Approach to Improve the Performance of a Fully Integrated Class-F Power Amplifier with 0.13 µm BiCMOS Technology Using Drain–Bulk Capacitor Modulation

This article reports a novel technique based on drain–bulk capacitor modulation to improve the performance design of a class-F power amplifier (PA) used in low-power transceivers based on the I-Q amplitude modulation technique considering linearity–efficiency–miniaturization trade-offs. This idea is carried out by implementing a tuned capacitor in parallel with a cascode transistor on the output of the power stage to enhance the shape of the voltage–current amplitudes of the class-F PA by creating a new harmonic current component. Simulated results were obtained for the power back-off region of the proposed configuration, with an output power, power gain and power-added efficiency of 8 dBm (+ 5 dBm)B, 19 dB (+ 5 dB)B and 45% (+ 5% to 10%)B, respectively. In addition, post-layout simulations revealed a similar level of output power, a power gain of a 20 dB and a 28% power-added efficiency for an added capacitance equal to 1.3 pF. Class-F PA is implemented on a 732×605 μm2 chip’s surface. (B: indicates the improved values in the power back-off region).

Single-mode quasi PT-symmetric laser with high power emission

Large-area lasers are practical for generating high output powers. However, this often comes at the expense of lower beam quality due to the introduction of higher-order modes. Here, we experimentally demonstrate a new type of electrically pumped, large-area edge-emitting lasers that exhibit a high power emission (∼0.4 W) and a high-quality beam (M2∼1.25). These favorable operational characteristics are enabled by establishing a quasi PT-symmetry between the second-order mode of a large area two-mode laser cavity and that of a single-mode auxiliary partner cavity, i.e., by implementing a partial isospectrality between the two coupled cavities. This in turn enlarges the effective volume of the higher-order modes. As a result, a selective pump applied via current injection into the main laser cavity can provide a stronger modal gain to the fundamental mode, and thus lead to lasing in the single mode regime after filtering out higher order transverse modes. The reported experimental results confirm this intuitive picture and are in good agreement with both theoretical and numerical analysis. Above all, the employed material platform and fabrication process are compatible with the industrial standards of semiconductor lasers. This work provides the first clear demonstration, beyond previous proof-of-concept studies, of the utility of PT-symmetry in building laser geometries with enhanced performance and, at the same time, useful output power levels and emission characteristics.