Electromechanical Energy Conversion Research Articles

A Simulation and Experimental Study on Identification of an Electromechanical System

The current applications in electromechanical energy conversion demand highly accurate speed and position control. For this purpose, a better understanding of the motion characteristics and dynamic behavior of electromechanical systems including nonlinear effects is needed. In this paper, a suitable model of Permanent Magnet Direct Current (PMDC) motor rotating in two directions is developed for identification purposes. Model is parameterized and identified via simulation and using real experimental data. Linear and nonlinear models for the system are built for identification, and the effective nonlinearities in the system, which are Coulomb friction and dead zone, are integrated into the nonlinear model. A Weiner- Hammerstein nonlinear system description is used for identification of the model. MATLAB is selected as the investigating tool, and a simulation model is used to observe the error between the simulated and estimated outputs. Identification of the linear and nonlinear system models using experimental data is performed using the least squares (LS) and recursive least squares (RLS) methods. Performance of the model and identification method with the real time experiments are presented numerically and graphically, revealing the advantages of the proposed nonlinear identification approach.

To calculation of mechanical forces and power balance in electromechanical energy converter

To calculation of mechanical forces and power balance in electromechanical energy converter

PECULIARITIES OF MATHEMATICAL MODELING OF AN INDUCTION MOTOR TAKING INTO ACCOUNT ITS NONLINEARITIES

The choice of the mathematical description of the induction motor has been made. Modeling of an induction motor in threephase natural axes A, B, C is proposed, taking into account the nonlinearity of the parameters of an induction motor. The purpose of the study is aimed at improving the correspondence of the model of an induction motor to a real motor by taking into account the nonlinearities of its parameters. The mathematical model, obtained taking into account assumptions and idealization, is a system of differential, algebraic and logical equations that reflect the conditions of electrical and mechanical equilibrium and the conditions of electromechanical energy conversion. The electrical equilibrium equations are compiled according to Kirchhoff’s laws and Maxwell’s equations, and the mechanical ones – according to the d’Alembert and Lagrange equations. As state variables, the stator and rotor flux links are used, which are determined at each step of numerical integration. For the adequacy of the model in the calculations, it is necessary to take into account a number of nonlinearities of the IM – the effect of current displacement and machine saturation, losses in steel, changes in operating temperature. The choice of the parameter nonlinearity to be taken into account, as well as the accounting methods, are individual and are determined by the complexity of the tasks that are set for the model. The completeness of taking into account the non-linear parameters of the IM is determined by the requirements for the accuracy of the study and necessarily provides for taking into account the most influencing the performance of the machine

Enhanced piezoelectric properties of Sm3+-modified PMN-PT ceramics and their application in energy harvesting

Piezoelectric materials are widely used in electromechanical energy conversion, such as in sensors, transducers, and self-powered materials. In this paper, the influence of the Sm doping content on the microstructure and ferroelectric, piezoelectric, dielectric, and field-induced strain properties of 0.70Pb(Mg1/3Nb2/3)O3-0.30PbTiO3 (PMN-PT) ceramics was investigated. Sm-doped PMN-PT ceramics with both high piezoelectric properties (d33∼1406 pC/N) and a large electromechanical coupling coefficient (kp∼0.69) were synthesized. Based on their piezoelectric effect, a maximum output voltage of 31 V was achieved under external forces. The output voltages showed satisfactory stability, repeatability, and sensitivity under periodic external forces; hence, Sm-doped PMN-PT piezoelectric ceramics are potential candidates for energy conversion and signal monitoring.

Ways and Means of Calculating the Synchronous Mode of a Hysteresis Electromechanical Energy Converter with a Conical Design

Ways and Means of Calculating the Synchronous Mode of a Hysteresis Electromechanical Energy Converter with a Conical Design

Studying Processes inside the Rotor of a Hysteresis Electromechanical Energy Converter

Studying Processes inside the Rotor of a Hysteresis Electromechanical Energy Converter

Studying the Initial State and Starting Regime of a Hysteresis Electromechanical Energy Converter with a Conical Design

Studying the Initial State and Starting Regime of a Hysteresis Electromechanical Energy Converter with a Conical Design

Design and Finite Element Simulation Research on a Brushless Air-Core Compensated Pulse Alternator With One Equivalent Pole-Pair

As a kind of high power pulse power supply, the air-core compensated pulse alternator (CPA) is widely used in electromagnetic emission, laser weapon, pulse capacitor charging, and other fields. A brush structure or a brushless structure can be used in the air-core CPA. Because the brushless structure is more suitable for high-speed operation and has higher reliability, more and more scholars have studied the brushless structure air-core CPA. In this article, an electric excitation brushless air-core CPA which the equivalent pole-pairs number is one is proposed. The CPA adopts a brushless rotor winding designed based on the principle of magnetic field differential modulation, which can simultaneously produce two and three pole-pair magnetic fields rotating in the same direction. The rotor winding can couple the field winding and the armature winding at the same time, thus realize electromechanical energy conversion. Under the same conditions, the pulsewidth of pulse discharge current can be significantly increased by reducing the number of pole pairs of the CPA and the output energy of a single pulse can be improved. In this article, a detailed design method of the differential modulation rotor winding of the CPA is presented, and the harmonic content of the CPA is calculated by analytical and numerical methods. Finally, the finite element model is used to analyze the related performance of the CPA, and the analysis results verify the effectiveness of the design scheme.

Toward Less Rare-Earth Permanent Magnet in Electric Machines: A Review

Many electric traction drive systems (ETDSs) are driven by electric motors primarily composed of high-energy rare-earth (RE) permanent magnets (PMs), such as neodymium-iron-boron (NdFeB) and samarium-cobalt (SmCo). Given the high cost of RE materials, there is a great interest among various industry sectors in searching for breakthrough technologies that reduce the consumption of high-energy RE magnets in their electromechanical energy conversion systems. The reduction of the magnetic volume is typically realized either by replacing a portion of the high-energy RE magnet with the low-energy ferrite magnet (knows as hybrid structure) or by modifying the magnetic arrangement of the machine itself, where a portion of the physical RE magnets is removed and replaced by induced magnets (known as consequent-magnetic pole structure). For this purpose, this article presents a review of the current state-of-the-art motor typologies with less-RE PMs and their key design challenges, followed up by a series of recommended guidelines to overcome related design challenges.

MECHATRONIC CLAMPING MECHANISM WITH ELECTRO-HYDRAULIC ACTUATOR FOR MACHINE SPINDLE UNITS

The design of the clamping mechanism for fixing workpieces and tools in the spindle assemblies of machines that is equipped with an additional subsystem to provide the possibility of programmable settings to the required clamping force is presented. The electronic unit and electromechanical energy converters provide the possibility of reconfiguration by reprogramming the clamping mechanism according to the different tasks comparatively easily. The obtained results help to expand the functionality of clamping mechanisms, and consequently the functionality of machine tools and their technological flexibility.

High performance of polycrystalline piezoelectric ceramic-based magneto-mechano-electric energy generators

ABSTRACT The cantilever-structured magneto-mechano-electric (MME) energy generator with smaller volume exhibits excellent magnetic energy conversion performance than electro-magnetic current induction type energy harvesters. An anisotropic single crystal is an ideal piezoelectric constituent of a high-performance MME generator owing to its superior electromechanical properties and high electromechanical energy conversion efficiency. However, the complicated synthesis and high cost of piezoelectric single crystals limit the wide deployment of the MME generator. Alternatively, the implementation of the polycrystalline ceramic piezoelectric can largely reduce the device fabrication cost. In this work, the PMN-PZT single crystal fiber composites (SFC) were replaced by high-performance polycrystalline ceramic (MnO2-doped 25PMN-PZT) fiber composites (PCFC) for MME generator. The magnetoelectric response and harvested electrical power of SFC- and PCFC-based MME generators were measured. Interestingly, the electrical output power of the PCFC-based MME generator at 10 Oe magnetic field tuned at 60 Hz was found to be ~90% of that of its SFC-based counterpart, in addition to the superior thermal stability. The presented MME energy generator has excellent potential for applications as low cost and efficient power source for wireless sensor networks deployable to the internet of things (IoTs), low power consumption electronic devices, etc., by harvesting the stray magnetic energy.

Hydrodynamic constraints on the energy efficiency of droplet electricity generators

Electric energy generation from falling droplets has seen a hundred-fold rise in efficiency over the past few years. However, even these newest devices can only extract a small portion of the droplet energy. In this paper, we theoretically investigate the contributions of hydrodynamic and electric losses in limiting the efficiency of droplet electricity generators (DEG). We restrict our analysis to cases where the droplet contacts the electrode at maximum spread, which was observed to maximize the DEG efficiency. Herein, the electro-mechanical energy conversion occurs during the recoil that immediately follows droplet impact. We then identify three limits on existing droplet electric generators: (i) the impingement velocity is limited in order to maintain the droplet integrity; (ii) much of droplet mechanical energy is squandered in overcoming viscous shear force with the substrate; (iii) insufficient electrical charge of the substrate. Of all these effects, we found that up to 83% of the total energy available was lost by viscous dissipation during spreading. Minimizing this loss by using cascaded DEG devices to reduce the droplet kinetic energy may increase future devices efficiency beyond 10%.

Parametric optimization of magnetoelectric generator with double stator

A methodology for the optimization-parametric calculation of geometric parameters of the design of an axial-flux permanent magnet generator has been developed. The developed methodology can be used to calculate and optimize geometric parameters in an automated mode for almost any type of electromechanical energy converter. The operation of the developed system is based on the interconnections between the computer-aided design system, software package, and numerical calculation of the electromagnetic field with the possibility of feedback and parameterization and a computing environment such as Matlab. The parameterized geometric model is constructed on the example of an axial-flux permanent magnet generator with a double stator. Subsequently, parametric optimization of geometric parameters was performed using the developed algorithm. The use of the developed solution reduces the time spent by the researcher on the calculation of geometry and optimization. Parameterization is performed at all stages of construction of a single part, the geometry of which is planned to change, and in each part of the assemblies if any in a particular case. That is, with the help of the developed model, it is possible to program the optimization of both a separate structural element of the studied system and the object as a whole. In the process of optimization, the main geometrical parameters of the investigated end generator with double side changed: stator yoke, air gap, gear-groove zone of the stator, housing elements. As a result of parametric optimization of the geometry of the prototype, it was possible to reduce the geometric dimensions by optimizing the magnitude of the magnetic induction in some areas of the magnetic core of the studied generator. Due to the application of the developed algorithm, it was possible to reduce the cost of the generator, as well as the volume of the magnetic circuit by 18.1% and 24.3%, respectively. This indicates the effectiveness of the developed algorithm and the possibility of using this algorithm in further research

Bases of calculation and design of asynchronous diesel generators for autonomous system of power supply

The article discusses the characteristics of diesel generator sets currently used in autonomous power supply systems. The modes of operation of synchronous generators and their overload capacity are analyzed. The overloading capacity of diesel generator sets (DGS) can be significantly increased when used as an electromechanical energy converter of asynchronous generators (AG). The initial algorithm for their selection involves calculating the optimal value of the rotor speed and choosing the range of rotation frequency. The value of the optimal value of the rotational speed is determined depending on the method of maintaining the constancy of the current frequency when calculating the parameters of an autonomous asynchronous semiconductor cascade, which is understood as an AG together with its excitation and control system. The dependences of individual terms of electrical power losses on the operating mode of an autonomous asynchronous semiconductor stage are considered. After determining the optimal speed, the possible AG power is selected. Then, from a number of powers, its nominal power is selected. After determining the rated power, the minimum and maximum values of the rotational speed, it is possible to determine the optimal operating modes of the diesel generator set with the AG. As a criterion of optimality, the specific effective fuel consumption of the diesel generator set is taken. This approach to the choice of the type of diesel generator set when designing autonomous power supply systems requires a detailed consideration of the technical and economic characteristics of the units. The proposed design principles can ensure the most complete use of the positive properties of a diesel engine and an electromechanical energy conversion system, as a result of which to improve the technical and economic characteristics of autonomous power supply systems.

Analytical model of the inductor system of the device to prevent ice formation on power lines

The article describes the analytical model of the magnetic-pulsed electromechanical energy converter in relation to the device for preventing ice formation on power lines. The inductor system of the device is a flat inductor and a firing pin made of electrically conductive material. The mobility of both the firing pin, and also the inductor is due to the attachment of the device to the pair of power line wires. This feature, in contrast to the fixed position of the inductor traditionally used, required the development of the universal design scheme for the electrodynamic interaction of the inductor and the firing pin. The proposed analytical model takes into account the forces of resistance to the motion of the inductor system caused by the presence of the elastic return mechanisms in the device and attachment to the power line wire, which is a body with a distributed mass. The developed analytical model was tested. The calculation of the device parameters for the transmission line span with the specified mass-dimensional characteristics was performed.

Novel rotor design of dual‐stator brushless doubly fed generator based on surrogate model

Dual-stator brushless doubly fed generator (DSBDFG) is a novel generator applied for wind power generation, and the electromechanical energy conversion between the stator and rotor is realised by the magnetic field modulation of the special rotor structure. Therefore, the rotor design is critical to improve the performance of DSBDFG. In this study, the different rotor structures are compared and analysed, and the position of the non-magnetic ring is determined. In order to reduce the computational cost and improve the optimisation efficiency, the surrogate model coupled with the multi-island geometric algorithm is applied for the optimisation of the magnetic barrier layer of the cage barrier rotor. In addition, in order to reduce the effect of skin effect on the copper loss of cage bars of the rotor, the different simulation models, whose cage bars have different layer number, are simulated and analysed. Finally, the simulation and experimental results verify the correctness of the theoretical analysis and the effectiveness of surrogate model used for the rotor optimisation design of DSBDFG.

Speed control and quantum vibration reduction of Brushless DC Motor using FPGA based Dynamic Power Containment Technique

In modern industrial field Brushless DC Motor (BLDC) is important component of electromechanical energy conversion. The BLDC is used in many application like high power traction, high end pumps etc. In this BLDC motor have a drive to operate in a constant operation but some noise and losses are create, so the various control technique is used to reduce the noise although some harmonic loss is occur in existing system. In that reason a new Dynamic Power Containment Technique (DPCT) algorithm is developed to reduce the harmonic loss and increase the system efficiency. The inverter is used to drive the Brushless DC Motor (BLDC) in a constant speed operation. This proposed control system is replace to classical cascaded method in speed and current control of BLDC motor. The inverter input current is directly control with help of the proposed FPGA based DPCT control system. The proposed system performance is analysis through the MATLAB simulation software. This proposed DPCT model is given the solution of delay issue. Afterward, another immediate pay technique was proposed to foresee the adjustment in current inside the defer time. The existing comparison of two-step predictive strategy, the new method is also easier to develop and can be used for optimized control to choose the best switch state in each cycle.

Определение периода повторяемости электромагнитных процессов в аварийных режимах работы многофазных вентильных двигателей малой мощности

Increasing requirements for the reliability indicators of technical systems lead to the need to apply new approaches to the design of electric machines and electric drives as an electrical complex, one of which is a systematic approach. To provide a set of increased reliability indicators, it is proposed to use multiphase AC converter-fed motors that differ in structural and algorithmic redundancy It is shown in order to implement variants of AC converter-fed motor circuit, in addition to reliability indicators, a quantitative assessment of its energy capabilities in normal and emergency operating modes is necessary. The most important stage of the practical implementation of the numerical process in the quantitative assessment of energy capabilities is to determine the period of repeatability of electromagnetic processes. The main issues of determining the period of repeatability of quasi-steady-state electromagnetic processes of an electromechanical energy converter of low-power multiphase AC converter-fed motors in the design of systems of increased reliability are considered. This made it possible to implement the numerical solution of systems of differential equations describing the physical processes in AC converter-fed motors with a variable structure of the electromechanical converter in normal and emergency operating modes.

Methodological problems of replacing low-voltage AC networks with DC networks

The paper discusses the prospects for replacing low-voltage AC power grids of industrial frequency with DC power grids in order to introduce energy-saving equipment and technologies. The modern achievements in the field of energy-saving electric drives are analyzed in detail, which make it possible to introduce constant voltage electric networks attractive for investments. The generalized analysis can be performed using the synergetic criterion of the technical and economic efficiency of innovation. To use such a criterion, all indicators to be analyzed must be presented in dimensionless form. We propose to consider separately the technical and operational groups of the generalized technical characteristics of AC and DC electric drives. The selected subset of groups of parameters of electric drives is justified from the point of view of regulatory and technical documents currently in force. This methodology seems to be more objective than the existing industry methodology for assessing product quality based on functional analogues of products being developed. With a synergetic approach, any characteristic is invariant relative to the others, which confirms the objectivity and reliability of the comparison method. The system of indicators is necessary and sufficient, both for technical assessment and for the creation of new designs and the development of directions for the design of electric drives. In conclusion of this work, we give examples of the implementation of such an approach by comparing the achieved indicators of quality and operational reliability of electromechanical energy converters produced by domestic enterprises.

An approach combining additive manufacturing and dielectrophoresis for 3D-structured flexible lead-free piezoelectric composites for electromechanical energy conversion

Additive manufacturing technology has promoted the development of piezoelectric devices, from the one-step moulding of micro-miniature devices to large-scale devices.