Performance In Different Operating Conditions Research Articles

A versatile plasma generation power supply featuring a multilevel converter for arbitrary waveforms generation

Purpose Plasma technology has become of great interest in a wide variety of industrial and domestic applications. Moreover, the application of plasma in the domestic field has increased in recent years due to its applications to surface treatment and disinfection. In this context, there is a significant need for versatile power generators able to generate a wide range of output voltage/current ranging from direct current (DC) to tens of kHz in the range of kVs. The purpose of this paper is to develop a highly versatile power converter for plasma generation based on a multilevel topology. Design/methodology/approach This paper proposes a versatile multilevel topology able to generate versatile output waveforms. The followed methodology includes simulation of the proposed architecture, design of the power electronics, control and magnetic elements and test laboratory tests after building an eight-level prototype. Findings The proposed converter has been designed and tested using an experimental prototype. The designed generator is able to operate at 10 kVpp output voltage and 10 kHz, proving the feasibility of the proposed approach. Originality/value The proposed converter enables versatile waveform generation, enabling advanced studies in plasma generation. Unlike previous proposals, the proposed converter features bidirectional operation, allowing to test complex reactive loads. Besides, complex waveforms can be generated, allowing testing complex patterns for optimized cold-plasma generation methods. Besides, unlike transformer- or resonant-network-based approaches, the proposed generator features very low output impedance regardless the operating point, exhibiting improved and reliable performance for different operating conditions.

Fuzzy-based collective pitch control for wind turbine via deep reinforcement learning

Wind turbines (WTs) have highly nonlinear and uncertain dynamics due to aerodynamic complexity, mechanical factors, and fluctuations in wind conditions. Turbulence and wind shear add complexity to modelling, especially in constant power region (region 3). Thus, an effective control design demands a deep understanding of the nonlinearities and uncertainties. This paper suggests a novel model-free reinforcement learning (RL) collective pitch angle controller to operate efficiently in region 3. The proposed controller stabilizes generator speed, maximizes power output, and minimizes fluctuations while accommodating system uncertainties, nonlinearity, and pitch limits. The disparity between WT dynamics due to wind speed perturbations and uncertainties is measured using a gap-metric criterion. The controller design adopts a deep deterministic policy gradient (DDPG) algorithm to train six agents in a medium-fidelity WT environment at different mean wind speeds to ensure the controller's robustness. Initially, imitation learning is used for efficient sample collection to fasten training convergence. Afterwards, the agent learns by interacting with the environment. After the training, the pitch control outputs from multi-trained agents are processed by a fuzzy system to have smooth transitions under different operating conditions. The resulting fuzzy DDPG (F-DDPG) controller is deployed to obtain the optimal pitch control action. The performance of the proposed F-DDPG controller is compared to the gain-scheduled PI (GSPI), Linear-Quadratic-Regulator (LQR), and single-DDPG-agent controllers. The controllers are simulated in high-fidelity onshore and offshore 5-MW WT environments using the OpenFAST/MATLAB simulation tools. The results reveal the superiority of the proposed controller in generalizing its optimal performance in different operating conditions.

Simulating Combustion-Induced Noise from a Gas-Fired Water Heater

Residential and commercial gas water heaters are designed for optimal performance for different operating conditions. These differences could arise from regional changes in fuel, local regulations for emissions, and the temperature preferences of the customer. From an engineering perspective apart from performance, other issues such as fire safety, longevity (thermo-mechanical durability) and though rarely, noise and vibration (N & V) need to be addressed. Unlike other appliances, there are almost no moving mechanical parts in an atmospheric gas water heater. This makes the N & V problem an interesting engineering challenge to diagnose and fix. In this paper, the authors consider different hypotheses for understanding the origins of combustion-induced noise. They propose a hybrid simulation methodology to predict noise and finally present the sound pressure level comparison with the physical test.

Evaluation of Tractor-Trailer Combination Braking Performance in Different Operating Conditions

In the trials of the present work, a double-axle trailer with a carrying capacity of 6 tons and a hydraulically effective mechanical brake were used as a tractor towed car. There is a hydraulic brake system on each axle of the agricultural trailer. In order to separate the brake system on the axles from each other, a hydraulic mechanically controlled 2/2 directional control valve was mounted on both hydraulic brake system inlets. The study was carried out at constant speed (25 km h-1), on stabilized road conditions, with 4 different braking modes and 4 different trailer loads. On stabilized ground, the braking acceleration (deceleration) of the tractor (without trailer) is 5.51 m s-2. The braking acceleration of the combination is 2.15 m s-2 under the condition that the trailer's carrying capacity was 30% more loaded and without brakes, and the braking acceleration of the combination was 3.26 m s-2 when braking on both axles (4 wheels). The deceleration of the combination was above 3.5 m s-2 under the condition of braking on both axles at the rated load of the agricultural trailer, while it was below the standard value in other braking approaches.

Comparison of Two Fractional-Order High-Order SMC Techniques for DFIG-Based Wind Turbines: Theory and Simulation Results

Two new nonlinear techniques are proposed in this study for improving the performance and efficiency of the doubly-fed induction generator (DFIG)-based wind turbine systems. Direct torque control (DTC) is among the most widely used strategies for controlling DFIGs due to its many advantages, such as robustness, simplicity, and fast response dynamics. However, this control causes big ripples in both torque and flux. Furthermore, it has significant total harmonic distortion (THD). Several solutions are proposed to overcome these problems, including nonlinear techniques and intelligent strategies such as genetic algorithms. In this work, two different controllers are proposed to improve the performance of the DTC technique. Firstly, the second-order continuous sliding mode (SOCSM) based on fractional-order (FO) control, and secondly, the super twisting algorithm (STA) based on the FO technique. The biggest advantages of the proposed strategies are their durability and ease of execution. Based on the proposed controls, the DTC strategy can greatly improve generator performance in different operating conditions. This paper also provides a comparative analysis of DTC-FOSOCSMC, DTC, and DTC-FOSTA in terms of reference tracking, robustness, chattering reduction, and computational complexity, using mathematical theory and simulation carried out in Matlab/Simulink using a 1.5 MW DFIG-based wind turbine. The simulation results demonstrate the effectiveness and high performance of the proposed DTC techniques.

Reliability Analysis of Power Tiller

Reliability analysis of a power tiller involves studying the probability of its performance and functionality over a given period. This analysis aims to identify the factors that affect the reliability of the power tiller and to determine ways to improve its performance. The reliability of a power tiller can be evaluated using different methods such as statistical analysis, probability theory, and simulation modelling. These methods enable the assessment of the power tiller's performance in different operating conditions and help to identify the critical components that contribute to its overall reliability. Some of the factors that affect the reliability of a power tiller include its design, manufacturing process, maintenance, and the environment in which it operates. The reliability analysis of a power tiller also involves identifying the failure modes and effects of different components and determining the probability of these failures occurring.

Optimal energy management of distributed generation in micro-grid to control the voltage and frequency based on PSO-adaptive virtual impedance method

Line impedance varies between distributed generation and load feeders due to the existence of different distances and the micro-grids complexity. Therefore, conventional droop control methods do not have the desired efficiency in the power distribution between DG units. Generally, due to simplification, the impedance of the lines is considered non-complex. The stated conditions greatly reduce the accuracy and dynamic response of the control system. In this paper, the voltage and frequency control of the micro-grid is presented by an adaptive virtual impedance control method based on the multi-objective particle swarm optimization (MOPSO) algorithm for the purpose of proportional power distribution. The control unit operation is based on the control of virtual resistance and inductance. The central control and the optimization unit are responsible for controlling the proportional power distribution by using the information of the local controllers. In the proposed method, in order to improve the stability and optimal operation of the micro-grid the reduction of the deviation related to active power, reactive power, voltage and frequency are presented. The proposed method has optimal performance in different operating conditions. Finally, the results are presented along with stability and sensitivity analysis based on the Bode diagram and Root locus.

Field Oriented Control of AFPMSM for Electrical Vehicle Using Adaptive Neuro-Fuzzy Inference System (ANFIS)

Axial Flux Permanent Magnet Synchronous Motor (AFPMSM) are very attractive candidates for driving applications due to their high efficiency, high torque-to-weight ratio, high power density, small magnetic thickness, and simplicity of construction. On the other hand, AFPMSM produces undesirable torque ripple in the developed electromagnetic torque, affecting their output performance. An intelligent control method is proposed in this paper to reduce torque ripple and improve the dynamic performance of AFPMSM. The vector control, employing the Field Oriented Control (FOC) technique, was used to improve the dynamic performance of the AFPMSM. The speed and torque controllers are achieved using the decoupling method. The intelligent control was designed to improve the performance of AFPMSM obtained from PI-PSO. The Adaptive Neuro-Fuzzy Inference System (ANFIS) was used as an Intelligent controller to integrate both the speed and torque constraints in a single training procedure. Training data for ANFIS was obtained from PI-PSO with a multi-objective cost function that includes the torque ripple and speed response criteria. The approach gave great results in terms of speed performance in different operating conditions and in tracking the required speed in load and no-load. In addition, the torque ripple was reduced by 10.04% and 46.67% compared with PI-PSO and Multi-objective cost function of speed, respectively.

A Physics-Based Multidisciplinary Approach for the Preliminary Design and Performance Analysis of a Medium Range Aircraft with Box-Wing Architecture

The introduction of disruptive innovations in the transport aviation sector is becoming increasingly necessary. This is because there are many very demanding challenges that the transport aviation system will have to face in the years ahead. In particular, the reduction in pollutant emissions from air transport, and its impact on climate change, clearly must be addressed; moreover, sustainable solutions must be found to meet the constantly increasing demand for air traffic, and to reduce the problem of airport saturation at the same time. These three objectives seem to be in strong contrast with each other; in this paper, the introduction of a disruptive airframe configuration, called PrandtlPlane and based on a box-wing lifting system, is proposed as a solution to face these three challenges. This configuration is a more aerodynamically efficient alternative candidate to conventional aircraft, introducing benefits in terms of fuel consumption and providing the possibility to increase the payload without enlarging the overall aircraft wingspan. The development and analysis of this configuration, applied to a short-to-medium range transport aircraft, is carried out through a multi-fidelity physics-based approach. In particular, following an extensive design activity, the aerodynamic performance in different operating conditions is investigated in detail, the structural behaviour of the lifting system is assessed, and the operating missions of the aircraft are simulated. The same analysis methodologies are used to evaluate the performance of a benchmark aircraft with conventional architecture, with the aim of making direct comparisons with the box-wing aircraft and quantifying the performance differences between the two configurations. Namely, the CeRAS CSR-01, an open-access virtual representation of an A320-like aircraft, is selected as the conventional benchmark. Following such a comparative approach, the paper provides an assessment of the potential benefits of box-wing aircraft in terms of fuel consumption reduction and increase in payload capability. In particular, an increase in payload capability of 66% and a reduction in block fuel per pax km up to 22% is achieved for the PrandtlPlane with respect to the conventional benchmark, while maintaining the same maximum wingspan.

Experimental Determination of Equivalent Iron Loss Resistance for Prediction of Iron Losses in a Switched Reluctance Machine

Switched reluctance machine (SRM) has progressed as a suitable contender in the family of electrical machines for its high starting torque and better performance in different operating conditions. The need for accurate modeling of this machine is, therefore, dependent on the accurate determination of losses of which iron loss is exigent. This article aims to determine iron loss from the equivalent circuit parameters of the machine based on the input data tables that are directly obtained from the experiments carried out on an existing four-phase, bifilar wound SRM. The procedure and necessary steps for the loss separation method are well defined and supported by the theoretical and practical results. The experimental determination of the iron losses has been compared with the predicted results under the same operating conditions.

New Dual-Input Zero-Voltage Switching DC–DC Boost Converter for Low-Power Clean Energy Applications

This article introduces a new dual-input nonisolated zero-voltage switching (ZVS) dc–dc boost converter. The proposed converter hybridizes two bidirectional and unidirectional boost converters to harvest energy from a rechargeable energy storage element and a clean energy dc generator, respectively. Hence, the proposed circuit utilizes three power switches, one power diode, two inductors, and an output filtering capacitor. The ZVS of all the power switches and zero-current switching (ZCS) for the power diode are realized without any auxiliary circuit. The soft-switching performance is designed to be valid for the whole power ranges of the converter input sources and the output load. The converter power switches are switched in pulsewidth modulation manner with two individual duty ratios, allowing to regulate the converter output voltage and control the extracted power from the input unidirectional port through a simple and useful control system. Depending on the converter duty ratios, its basic operation principle is analyzed in two different operation cases. The proposed converter benefits from a simple and compact structure, minimum numbers of power switches and magnetic elements, and high efficiency. The behavior of the proposed converter is analytically investigated, and a low-power laboratory prototype is designed and fabricated to evaluate the converter performance in different operating conditions.

Thermal analysis of non‐isolated conventional PWM‐based DC–DC converters with reliability consideration

This paper proposes analytics for reliability assessment of non-isolated conventional pulse width modulation DC-DC (NIDC-DC) converters. This class of converters consists of conventional Buck, Boost, Buck–Boost, Cuk, Sepic and Zeta topologies. The proposed analytics are founded based on the Markov process principles and can effectively capture the effects of duty cycle, input voltage, output power, voltage gain, components characteristics and aging on the overall reliability performance and mean time to failure of the NIDC-DC converters. Furthermore, the suggested framework takes both continuous and discontinuous conduction modes of each converter into account, with which the open and short circuit faults in the components are analysed. As an important outcome, the most reliable operation region of the NIDC-DC converters are obtained with respect to different operational parameters, which is useful in design procedure. Eventually, extensive thermal experiments with an appropriate reflection of reliability metric are conducted to measure the components’ temperatures and verify their performance in different operating conditions.

Investigation of power split schemes for modern hybrid cars transmissions

The modes of operation of the transmissions for hybrid cars are studied in this work, using planetary gears for connecting the internal combustion engine (ICE) and the electric machines (motor-generators). The peculiarities of the two-stream variants with an electric branch – a closing block consisting of two electric machines is analysed. This achieves a stepless gear change and an increase in overall efficiency with respect to the efficiency of electrical machines. The theoretical formulation is based on the dependences between the losses of a two-stream circuit, which proves that this increase is a function of the relative share of power transmitted through the electrical branch. The characteristics of typical two-stream circuits with input differential and output differential with one mechanical and one electrical branch are determined. The aim is to evaluate not only the change in the total efficiency, but also the kinematic gear ratio and the ratio of the torques and their ranges for the whole circuit, as a function of the parameters of the electrical branch. The development of the schemes in order to improve their performance in different operating conditions is considered, which allows for combining the variants and modes of operation – serial hybrid and parallel hybrid in two variants, at low speed and high speed. Analytical and graphical methods are used to analyse and illustrate the results, which are more visual and suitable for composite planetary gears with more units. It is expected that cars with such transmissions will have better dynamics compared to conventional automatic transmissions and lower energy consumption or do less damage to the atmosphere, as a result of the optimal combination of the operating modes and dimensions of ICE and electric machines.

ANALISIS STABILITAS MULTI MACHINE PADA ISLAND MODE SISTEM KELISTRIKAN BALI

Modern electrical systems are characterized by extensive interconnection systemswith the need for electrical energy and control depending on the control system. Oneelectricity system that has been widely interconnected is the Bali electricity system. The Balisystem using island mode has four generating units that can supply electrical energy needsincluding UP Pesanggaran, UP Celukan Bawang, UP Gilimanuk and UP Pemaron. But itmust be remembered in supplying electrical energy needs are also affected by the constantchange in load, resulting in instability in the electrical system. So the need for a controlsystem that can increase the value of damper such as the Power System Stabilizer (PSS). PSScan be used to reduce frequency oscillations when interference occurs, but for PSS design itgives less good performance in different operating conditions. Problems with PSS occur dueto errors in modeling, input value input, and topology variations. Efforts are made to reduceerrors in PSS by using methods that are expected to overcome this problem, namely the fuzzylogic controller.The results of the analysis show that the system performance index usingfuzzy logic is 78.6064. Fuzzy logic has the ability to damp better and reduce errors better.

WASTE HEAT RECOVERY FOR HYBRID ELECTRIC VEHICLES USING THERMOELECTRIC GENERATION SYSTEM

Thermal energy can be easily converted to electrical energy using the thermal electric generator (TEG). This paper is aimed to developing a model of TEG array for Hybrid Electric Vehicle (HEV) system. The proposed system is implemented experimentally by increasing the temperature difference between the two sides of TEG array. To achieve the high temperature difference between these sides, the hot side is putting on the exhaust manifold of car, and the other side is colded by using the air-condition system in the car. The voltage generated from TEG is used for achieving maximum energy to recharge a battery car. Simulation results are carried out using MATLAB/Simulink software package to investigate the system performance. The experimental results are presented to demonstrate the effectiveness of the proposed array of TEG for HEV system. Also, the obtained results prove that the designed array of TEG gives good performance for different operating conditions.

Experimental verification of monitoring techniques for metal‐oxide surge arrester

Monitoring and diagnostics of metal-oxide surge arresters (MOSAs) have been a research topic for decades. During these years, many monitoring and diagnostic methods have been developed. However, only a few studies perform a comparative analysis of these methods with respect to their performance in different operating conditions. This study briefly explains the most commonly analysed MOSA monitoring techniques and performs a comparative analysis of these techniques on an experimental basis, considering different operating conditions of the arrester. The experimental setting is made to simulate different operating conditions regarding operating voltage root mean square value, voltage harmonics, and temperature conditions. The results show the reliability of MOSA indicators in the analysed conditions, suggesting which indicators and methods should be used for the purpose of MOSA diagnostics.

Robust operation of microgrid energy system under uncertainties and demand response program

<span>Microgrid energy systems are one of suitable solutions to the available problems in power systems such as energy losses, and resiliency issues. Local generation by these energy systems can reduce the role of the upstream network, which is a challenge in risky conditions. Also, uncertain behavior of electricity consumers and generating units can make the optimization problems sophisticated. So, uncertainty modeling seems to be necessary. In this paper, in order to model the uncertainty of generation of photovoltaic systems, a scenario-based model is used, while the robust optimization method is used to study the uncertainty of load. Moreover, the stochastic scheduling is performed to model the uncertain nature of renewable generation units. Time-of–use rates of demand response program (DRP) is also utilized to improve the system economic performance in different operating conditions. Studied problem is modeled using a mixed-integer linear programming (MILP). The general algebraic modeling system (GAMS) package is used to solve the proposed problem. A sample microgrid is studied and the results with DRP and without DRP are compared. It is shown that same robustness is achieved with a lower increase in the operation cost using DRP.</span>

Test and Modelling of Commercial V2G CHAdeMO Chargers to Assess the Suitability for Grid Services

Aggregation and control of electric vehicles (EVs) via vehicle-to-grid (V2G) technologies is seen as a valid option for providing ancillary power system services. This work presents results from V2G-ready equipment tests and modelling. The technical capabilities of an EV connected to a commercial V2G charger are investigated when controlled either locally or remotely. The charger is characterized in terms of efficiency characteristics, activation time, response granularity, ramping-up/down time, accuracy and precision. Test results show the performance for different operating conditions, highlighting the importance of a good calibration and knowledge of the employed hardware when providing standard-compliant grid regulation services via V2G technology. Ultimately, a set of simulations demonstrates that the designed EV charger model replicates accurately the operating conditions of the real hardware.

Single-Stage SECS Interfaced With Grid Using ISOGI-FLL-Based Control Algorithm

This paper proposes an improved second-order generalized integrator with frequency-locked loop (ISOGI-FLL) based control scheme for a grid-connected solar photovoltaic (PV) array fed voltage source converter (VSC) to mitigate the power quality problems. The steepest descent algorithm based maximum power point tracking is used to achieve the crest power from a solar PV array to improve solar power generation (SPG) into the grid as well as to maintain dc bus voltage of the VSC. The ISOGI-FLL-based control scheme is very effective for grid currents balancing and harmonics mitigation, at a variation of SPG and unity power factor operation. Simulated results are demonstrated using MATLAB/Simulink for load unbalancing and variation in solar insolation. The effectiveness of the proposed algorithm is demonstrated based on comparative performance with conventional algorithms. Test results of a developed prototype show satisfactory performance for different operating conditions like grid currents balancing, photovoltaic-distribution static compensator (PV-DSTATCOM) mode, and DSTATCOM-PV mode at variable solar insolation. Moreover, total harmonic distortions of grid voltages–currents are achieved within the limit of the IEEE-519 standard.

Investigating the Effects of Interaction of Single-Tine and Rotating-Tine Mechanisms with Soil on Weeding Performance Using Simulated Weeds

Abstract. Mechanical weeding augmented with automation technology should result in highly effective weeding systems. However, the interaction between weeding mechanisms and soil is not well understood. Moreover, soil is highly variable, which makes studying this interaction challenging. The main objective of this research was to develop a method to investigate the effects of mechanical tool-soil interaction on weeding performance for different operating conditions in a controlled environment. Experiments were conducted in an indoor soil bin with loam soil, and the weeding performance was studied using small wooden cylinders as simulated weed plants. The investigations featured a single cylindrical tine and a rotating tine mechanism, vertically oriented and inserted into the soil. The total width of soil disturbance and potential weeding rate were evaluated for the single cylindrical tine at different levels of three operating parameters: tine diameter (6.35, 7.94, and 9.53 mm), working soil depth (25.4, 50.8, and 76.2 mm), and tine speed (0.23 and 0.45 m s-1). Potential weeding rate was examined for the rotating tine mechanism with two operating parameters: working soil depth (25.4 and 76.2 mm) and rotational speed (25, 50, and 100 rpm). Statistical analysis was performed using ANOVA at p < 0.05. A simulation of the rotating tine mechanism was developed that estimated the disturbed area. For the single tine, soil disturbance width was independent of tine speed; however, tine diameter and depth had significant effects, as the width increased with increased levels of these two parameters. All three parameters had significant effects on the potential weeding rate of the single tine, and the rates were observed to increase with higher levels of the parameters. For the rotating tine mechanism, both depth and rotational speed were significant. The potential weeding rate for the rotating tine mechanism was found to increase with higher levels of these parameters. The results showed that although the width of soil disturbance due to a cylindrical tine was affected by the tine diameter and working soil depth, operating parameters such as increased longitudinal and rotational speeds also affected plant disturbance. The percentage of disturbed soil area in the simulation followed similar patterns as the percentage of disturbed plants observed in the experiments. Keywords: Inter-row weeding, Intra-row weeding, Mechanical weeding, Rotating tine mechanism, Soil disturbance, Tine.