Wide Speed Range Research Articles

Virtual Design and Analysis of the Balancing Element of an External Gear Machine Considering Cavitation and Mixed Lubrication Effects

This paper presents a simulation based approach for sizing the axial balance elements of a pressure compensated external gear machine. The reference hydraulic unit must be able to guarantee operation in two quadrants, as either a pump or a motor. It also needs to operate in a wide operating range of speed and pressure, as it is to be used as primary hydraulic unit for an electro-hydraulic actuator (EHA). The design procedure builds upon past work at the author’s center, but it extends it to the case of multiple quadrant units. Also, a unique method for modeling of both mixed lubrication and cavitation that might occur in the lubricating film is used. After describing the design procedure, the paper discusses the features of the balancing of a reference unit, along with the effects of both cavitation and mixed lubrication.

Circularly symmetric nanopores in 3D femtosecond laser nanolithography with burst control and the role of energy dose

Abstract The fabrication of three-dimensional (3D) nanostructures within optical materials is currently a highly sought-after capability. Achieving nanoscale structuring of media within its inner volume in 3D and with free design flexibility, high accuracy and precision is a development yet to be demonstrated. In this work, a 3D laser nanolithography technique is developed which allows producing mm-long hollow nanopores inside solid-state laser crystals and with a high degree of control of pore cross-sectional aspect ratio and size. We report an in-depth study on the formation of pores both within the non-thermal regime at which temperature is fast dissipated after each laser pulse, and for a thermally controlled regime using pulse-bursts which facilitate the formation of pores with highly circular shapes down to 1.1. We demonstrate this process for a wide range of speeds, pulse repetition rates and pulse energies, thus opening the door to a much more useful nanofabrication technique for nanophotonics. Finally, we also report the change in index of refraction that is produced at the nanoscale obtaining a positive index contrast of ∼3%. The work therefore provides a promising path towards reliable 3D nanostructuring of solid-state laser media for the flexible fabrication of large and complex structures with features sizes from the nanoscale up to the mm-scale. Moreover, due to the embedded, seamless, and monolithic nature of this technology, and since YAG crystals can sustain temperatures of up to 1900 °C and are highly chemically inert and erosion resistant, we anticipate its direct application in harsh environments.

Dynamically synergistic transition mechanism and modified nonlinear magnetic force modeling for multistable rotation energy harvester

Multistable energy harvesters with magnetic interaction have received increasing attention. However, the synergistic transition mechanism of the different oscillation states for rotation harvesters remains uninvestigated, and there is lack of precise magnetic force model for investigating the effect of the external magnetic force on dynamic characteristics and harvesting performance. This study proposes a synergistic transition and regulation mechanism for rotation energy harvesting and a modified model of the magnetic force is derived by taking the relative displacement and rotational angle into consideration. The transition mechanism of different oscillation states for the rotation system is studied under the guidance of static bifurcation, potential diagram, and dynamic behaviors, respectively. Based on the extended Hamilton’s principle, the theoretical model is established and the complexity dynamic characteristics are simulated. A prototype of multistable energy harvesters with magnetic interaction was fabricated and the effectiveness of the theoretical model was validated by experiments. The experimental results exhibit good agreement with the numerical results. The proposed harvester can harvest energy effectively in a wide rotation speed range of 280–500 rpm, and the output voltage and power can reach 6.4 V and 4 mW.

Effects of the Magnetic Model of Interior Permanent Magnet Machine on MTPA, Flux Weakening and MTPV Evaluation

Interior permanent-magnet synchronous machines are widely spreading in automotive and vehicle traction applications, because of their high efficiency over a wide speed range. This capability can be achieved by appropriated control strategies: Maximum Torque per Ampere (MTPA), Flux Weakening (FW) and Maximum Torque per Volt (MTPV). However, these control trajectories are often based on an simplified magnetic model of the electrical machine. In order to improve the evaluation of machine output capabilities, nonlinear magnetic behavior must be modeled. This is not only related to the final application with a given drive and control structure, but also during the design process of the electric machine. In the design process, the output torque Vs. speed characteristic must be calculated following MTPA, MTPV and FW in the most accurate way to avoid significant error. This paper proposes a set of algorithms to compute MTPA, FW and MTPV curves for interior permanent-magnet synchronous machines taking into account the machines’ nonlinearities caused by iron saturation and compares differed approaches to highlight the torque–speed capabilities for the same machine following different methods. The algorithms are based on the maps of the equivalent inductances of a reference interior permanent-magnet synchronous machine and inductances maps were obtained via 2-D Finite Element Analysis over the machine’s operating points in id−iq reference plane. The effects of different 2-D finite element methods are also computed by both standard nonlinear magnetostatic simulations and Frozen Permeability simulations. Results show that the nonlinear model computed via frozen permeability is more accurate than the conventional linear and nonlinear models computed via standard magnetostatic simulations; for this reason, during the electrical machine design, it is important to check the expected performance employing a complete inductance map and frozen permeability.

Численный анализ взрывного формирования алюминиевых частиц в диапазоне скоростей 2…16 км/c

Explosive gun launchers are used to test rocket and space systems for their resistance to the impact of meteoroids and fragments of space debris. This work applies numerical simulation within the framework of the two-dimensional axisymmetric problem of continuum mechanics and substantiates design parameters of the shaped charges that form compact aluminum particles weighing up to 1 g and more in a wide range of speeds (from 2 km/s to 16 km/s). Simulation was carried out in relation to the shaped charges of different diameters (from 20 mm to 100 mm) using the ANSYS/AUTODYN, ERUDIT and KOLDUN computer systems. It is shown that charges of larger diameter are required to form faster particles identical in mass. Besides, it is necessary to use segmental cumulative liners of digressive thickness to form particles approaching the lower boundary of the indicated speed range. Wherein, to form faster particles moving at the speeds from 10 km/s to 16 km/s, it is necessary to implement the combined shaped charge liners, where the jet-forming part is shaped as a semi-ellipsoid or a semi-superellipsoid of rotation of the digressive thickness.

Performance of 7-level cascade H-bridge multi level inverter driven induction motor drive

In recent times, many of industrial applications require smooth control over a wide range of speeds or smooth torque control without effecting motor performance and efficiency. So, cascaded H-Bridge multilevel inverters convert the low or medium level voltage to medium or high level of output voltages. In this paper, a cascaded H-Bridge multilevel seven level inverter is operated by using sinusoidal pulse width modulation technique. This PWM technique will improves the smoothness of waveform by reducing the lower order harmonics. And analysed its performances like speed, torque, THD etc.

First-Order-Delay-Controlled Slip-Angular Frequency for the Dynamic Performance of an Indirect-Field-Orientation-Controlled Induction Motor-Driving Inertial Load

Sophisticated torque-current control is required in inertial load-drive applications, such as in electric vehicles and electric railway vehicles, over a wide speed range. However, the conventional indirect-field-orientation control (FOC) lacks the current response during the transient response because the conventional feedforward slip-angular-frequency control causes secondary flux fluctuation. Therefore, this article proposes FOC with first-order-delay slip-angular-frequency control, which reduces the secondary flux fluctuation and realizes high-performance torque-current control during transient response. The proposed method was verified through numerical simulation and small-scale model experiments with a 750 W induction motor and an inertial load.

Position sensorless field-oriented control of BLDC motor for EV applications

A brushless DC motor (known as BLDC) is a permanent magnet synchronous electric motor which is driven by direct current (DC) electricity, and it accomplishes an electronically controlled commutation system instead of a mechanical commutation system. Major of the BLDC applications are based on speed control like motors used in electric vehicles, washing machines, air conditioners, etc. For the speed regulation of BLDC, TMS320F2837xD and TMS320F28069M microcontrollers are used, which belong to the C2000 family. These microcontrollers are used to increase efficiency by reducing the system components and enabling a cost-effective design of intelligent controllers for three-phase motors. With these devices, digital vector control algorithms like field-oriented control (FOC) may be implemented with much more precision. By computing a dynamic model of the motor, the FOC algorithm maintains efficiency across a wide speed range and considers torque variations with transient phases. The ideas include strategies to get rid of the phase current sensors and switch to sensorless speed control with an observer. The proposed model simulations can be achieved using MATLAB simulation tools, Graphical User Interface (GUI) application and Code Composer Studio (CCS).

Analysis, Monitoring and Control of Speed Variations for Various Applications of SRM Motor with ESP32 and Thing speak

Due to the growing demand for and growth in the electric vehicle (EV) market in a future civilization with advanced technology. Electric vehicles outperform traditional ones in terms of performance. Because they are environmentally friendly, EVs can help create a green and sustainable environment. They provide convenience with eco-friendliness that conventional cars cannot. Over the past 20 years, the switching reluctance motor (SRM) drive has been created and researched as a revolutionary electrical drive. The brushless switching reluctance motor drive has developed to the point that it may be used in the industrial sector as a reliable, durable, and cost- effective brushless drive with a wide speed range. In this paper, artificial intelligent controllers like Fuzzy Logic Controllers (FLC), and PID are discussed where SRM speed fluctuations are monitored and controlled by a controller using simulation analysis. Experimental analysis is carried out with prototype model. Here various speed variations are controlled and monitored using the ESP32 and Thing Speak cloud platform.

Modified Primary Flux Linkage for Enhancing the Linear Induction Motor Performance Based on Sliding Mode Control and Model Predictive Flux Control

This paper proposes a modified primary flux linkage and an improved weighting less model predictive control for linear induction motors (LIMs) to enhance the drive system in terms of linear speed response, wide speed range, efficiency, and computation time. Sliding mode controller is presented in this work to get quick response instead of the use of the PI controller. A weighting less model predictive flux control (MPFC) is employed to eliminate the weighting factor and reduce the computation time. Furthermore, the optimum value of the primary flux linkage is calculated to guarantee higher efficiency under the operation of maximum thrust per ampere, loss minimization control and wider speed range in the field weakening region. The FCS-MPFC uses only the primary flux in the cost function independent on the weighting factor. Moreover, simplified calculation process can be executed greatly in the αβ-coordinates without transformation matrix, where the end-effect is fully taken into consideration. In comparison with the PI controller under different conditions, the proposed control method can achieve faster dynamics with lower thrust ripple, computation time, and so on. Comprehensive simulation and experimental results based on one prototype with 3 kW linear induction machine have verified the advantages of the proposed strategy in this work.

Combustion and Performance Evaluation of Methanol (M15)-Fueled BS-VI Compliant Light-Duty Spark-Ignition Engine

Abstract This study investigated the effect of the methanol–gasoline blend (M15) on the combustion and performance characteristics of a commercial light-duty Bharat Stage-VI (BS-VI) 2020 spark-ignition (SI) engine. The M15 and baseline gasoline (G100) engine tests were performed at a wide range of engine loads and speeds. For the M15 operation, it was ensured that the lambda values matched with the baseline gasoline operation at each engine operating point by changing fuel quantity manually. The combustion characteristics of M15 were quite similar to gasoline at all operating points. Alcohol addition improves octane number and flame speed, which changes the combustion characteristics of the engine, but in this study, the combustion characteristics of M15 fuel were almost identical. It may be due to blending a small fraction of methanol and the engine's high compression ratio, which improved the combustion kinetics. The coefficient of variance of indicated mean effective pressure was slightly lower for M15 than gasoline, except at 1000 rpm, where the charge mixing might not be adequate at low engine speed for M15 due to lower methanol volatility. Engine's brake thermal efficiency improved with M15 fueling by ∼1%, compared to baseline gasoline, though brake-specific fuel consumption deteriorated by ∼6% due to the lower calorific value of M15. Higher combustion stability and possibly lower heat transfer losses, as observed from slightly higher exhaust gas temperature (EGT), might have improved the engine's performance for M15. This study demonstrated that M15 fueling exhibited identical combustion characteristics and higher thermal efficiency than baseline gasoline fueling at similar lambda values in a commercial light-duty BS-VI SI engine.

Opportunistic Routing with Multi-Channel Cooperative Neighbour Discovery

Due to the scattered nature of the network, data transmission in a distributed Mobile Ad-hoc Network (MANET) consumes more energy resources (ER) than in a centralized network, resulting in a shorter network lifespan (NL). As a result, we build an Enhanced Opportunistic Routing (EORP) protocol architecture in order to address the issues raised before. This proposed routing protocol goal is to manage the routing cost by employing power, load, and delay to manage the routing energy consumption based on the flooding of control packets from the target node. According to the goal of the proposed protocol technique, it is possible to manage the routing cost by applying power, load, and delay. The proposed technique also manage the routing energy consumption based on the flooding of control packets from the destination node in order to reduce the routing cost. Control packet exchange between the target and all the nodes, on the other hand, is capable of having an influence on the overall efficiency of the system. The EORP protocol and the Multi-channel Cooperative Neighbour Discovery (MCCND) protocol have been designed to detect the cooperative adjacent nodes for each node in the routing route as part of the routing path discovery process, which occurs during control packet transmission. While control packet transmission is taking place during the routing path discovery process, the EORP protocol and the Multi-channel Cooperative Neighbour Discovery (MCCND) protocol have been designed to detect the cooperative adjacent nodes for each node in the routing. Also included is a simulation of these protocols in order to evaluate their performance across a wide range of packet speeds using Constant Bit Rate (CBR). When the packet rate of the CBR is 20 packets per second, the results reveal that the EORP-MCCND is 0.6 s quicker than the state-of-the-art protocols, according to the findings. Assuming that the CBR packet rate is 20 packets per second, the EORP-MCCND achieves 0.6 s of End 2 End Delay, 0.05 s of Routing Overhead Delay, 120 s of Network Lifetime, and 20 J of Energy Consumption efficiency, which is much better than that of the state-of-the-art protocols.

The relevance of the use of an intelligent mechanism in the drive of modern agricultural machines

The article analyzes theoretical and experimental studies of intelligent mechanism designs, considers the advantages of using intelligent mechanisms for agricultural machines in comparison with traditional structural schemes. The principle of operation of an intelligent mechanism presented in the form of two differential drives for agricultural machines is considered. Planetary mechanisms of this type are systems with two or more degrees of freedom in terms of the number of structural connections, therefore, with one leading link, the movement of their driven links is determined by additional external links that may have different physical origins. The paper presents a description and also considers the main advantages of using the developed kinematic scheme of an intelligent mechanism for agricultural machines, which allows for automatic regulation in a wide range of movement speed depending on the load on the working body, the weight of grain on the conveyor belt, the type of soil on which the agricultural machine moves, etc., overload protection, increased productivity due to full engine load. The proposed intelligent mechanism for agricultural machines allows the distribution of torque from a single engine, and there is also no need to install a set of sensors and a control unit.

Small-scale Magnetic Flux Ropes in Stream Interaction Regions from Parker Solar Probe and Wind Spacecraft Observations

Using in situ measurements from the Parker Solar Probe and Wind spacecraft, we investigate the small-scale magnetic flux ropes (SFRs) and their properties inside stream interaction regions (SIRs). Within SIRs from ∼0.15 to 1 au, SFRs are found to exist in a wide range of solar wind speeds with more frequent occurrences after the stream interface, and the Alfvénicity of these structures decreases significantly with increasing heliocentric distances. Furthermore, we examine the variation of five corresponding SIRs from the same solar sources. The enhancements of suprathermal electrons within these SIRs persist at 1 au and are observed multiple times. An SFR appears to occur repeatedly with the recurring SIRs and is traversed by the Wind spacecraft at least twice. This set of SFRs has similarities in variations of the magnetic field components, plasma bulk properties, density ratio of solar wind alpha and proton particles, and unidirectional suprathermal electrons. We also show, through the detailed time-series plots and Grad–Shafranov reconstruction results, that they possess the same chirality and carry comparable amounts of magnetic flux. Lastly, we discuss the possibility for these recurring SFRs to be formed via interchange reconnection, maintain the connection with the Sun, and survive up to 1 au.

Comparative Study of Induction and Wound Rotor Synchronous Motors for the Traction Drive of a Mining Dump Truck Operating in Wide Constant Power Speed Range

Comparative Study of Induction and Wound Rotor Synchronous Motors for the Traction Drive of a Mining Dump Truck Operating in Wide Constant Power Speed Range

Model Predictive Controlled IM Drive based on IT2FNN Controller

Abstract In this paper, the predictive torque control (PTC) based induction motor (IM) drive using an interval type-2 fuzzy neural network (IT2FNN) controller in the speed control loop is designed and tested in simulations. The states required for the proposed motor drive are estimated by extended complex Kalman filter (ECKF). The ECKF performs online estimations of stator currents, rotor fluxes, rotor mechanical speed, and rotor resistance. Compared to conventional extended Kalman filter (EKF), which estimates the same states/parameters, the designed ECKF has less computational burden because it does not contain matrix inverse and the matrix dimensions have been reduced. In addition, the rotor resistance estimated by ECKF is updated online to the PTC system. Thus, the performance of the PTC-based IM drive is improved against variations in the rotor resistance, whose value changes with operating conditions such as frequency and temperature. In order to force both the ECKF observer and the proposed IM drive, a challenging scenario containing the wide speed range operation of the IM is designed. Simulation results confirm the performance of the proposed speed-sensorless PTC-based drive that uses an IT2FNN controller in the speed control loop and the estimation performance of the ECKF observer.

Determining the Control Objectives of a Switched Reluctance Machine for Performance Improvement in Generating Mode

This paper presents a methodology to determine the control objectives of conduction angle control in generating mode of operation in a switched reluctance machine. First, the performance in motoring mode of control is compared with generating mode for different operating points. Then, the key optimization objectives are established to improve a switched reluctancemachine's performanceingenerating mode. A multi-objective optimizer is used to select the conduction angles. The proposed generating-specific objectives are maximizing source current per torque and minimizing torque ripple. These objectives are then compared with the motoring-specific objectives, such as maximizing average torque and minimizing torque ripple for a wide speed range. Finally, the proposed generating objectives have been validated experimentally using a three-phase 12/8 SRM.

Sensorless Speed Control of a Brushless DC Motor Using Particle Filter (PF)

The equivalent of electricity has recently been used to replace all the wear-prone moving mechanical components that produce faults. The electronic unit that substitutes the mechanical commutation unit in Brushless Direct Current (BLDC) motors improves dynamic properties, noise level, and efficiency. This work describes a method for estimating the BLDC machine's rotor speed and position by using Extended Kalman Filter (EKF) and Particle Filter (PF). The BLDC is a non-linear system with nonlinear measurements. To perform the EKF, Jacobian linearization of the motor model and the observation are needed. Linearization leads to a decrease in the accuracy of filter estimation. In PF, the relative likelihood of each particle is computed according to the measurements. Resampling gives set particles are distributed according to power density function (pdf). Then the PF can compute any desired statistical measure of this pdf. A sensorless drive has an accurate good throughout a wide speed range and with varied load torque, according to the simulation's results. The results show that the velocity inaccuracy rate at PF is approximately 0.01% and that at EKF it is approximately 1%. According to the findings, the PF outperformed the EKF in a comparison between them.

Wide-Speed Range Sensorless Control of Five-Phase PMSM Drive under Healthy and Open Phase Fault Conditions for Aerospace Applications

This paper presents a speed sensorless control of a five-phase PMSM in healthy operation and under the Open-Phase Fault on any phase of the machine. The solution is recommended for mission-critical applications requiring high reliability capacities, such as Aerospace applications. An adapted Active Fault Tolerant Control is proposed with the aim of obtaining electromechanical torque as close as possible to that normally developed by a machine working in healthy condition. In instances of a loss of power to one phase of the machine, a reconfiguration of the control law is performed to ensure the continuity of service and to maintain acceptable control performances without requiring a hardware rearrangement of the power architecture. The motor rotation speed and position, required for the Field Oriented Control (FOC) of the stator currents, are estimated using a Back-Electromotive Forces (Back-EMF) observer based on a mathematical model of the motor and implemented in the stator diphase reference frame. Different electrical models that describe the behavior of the five-phase machine in the normal and degraded operations are given. Experimental results on a 1.25 kW synchronous PM machine are shown to confirm the effectiveness of the motor control.

Neck-embedded acoustic meta-liner for the broadband sound-absorbing under the grazing flow with a wide speed range

Acoustic liners are the most commonly used dissipative muffler for aero-engines but remain a challenge to design a broadband acoustic liner under the grazing flow. In this work, a novel neck-embedded meta-liner is proposed for the broadband sound-absorbing under the grazing flow with a wide speed range. The meta-liner is composed of many neck-embedded Helmholtz Resonators, and the idea of bending the subsequent cavity is introduced to improve low-frequency sound absorption performance. The acoustic impedance model of the meta-liner with neck-embedded slit is first detailly established by analyzing the acoustic characteristics of the equivalent elliptical pipe and using the matrix transfer method. Then by designing the local coupling between channels, efficient broadband impedance modulation and broadband matching with air impedance under grazing flow conditions are realized. The proposed meta-liner exhibits the excellent sound attenuation capacity in the frequency domain of 500–3000 Hz under the grazing flow speeds from 0 m s−1 to 98 m s−1 and the sound absorption performance is greatly boosted compared with the traditional Double- Degree-Of-Freedom liner. Features mentioned above have been verified numerically and in a series of comparative experiments. Besides, the thickness of the meta-liner is only 50 mm. Our work provides a possible design reference for the new generation of acoustic liners and has potential applications in noise reduction engineering.