Motor Windings Research Articles

Investment Strategy of Reactive Power Compensation Scheme in Wind Turbine Distribution Network Based on Optimal Allocation

The development and application of new energy have been paid more and more attention by governments of various countries since the 21st century. It is of practical engineering significance to study reactive power compensation of wind turbine distribution network. In view of the problems of poor grid quality and increased active power loss caused by a large amount of reactive power transmission during the operation of wind farms, based on the improved genetic algorithm, aiming at the minimum compensation capacity and the minimum voltage deviation of load nodes, a multiobjective optimization scheme of reactive power in wind farms is proposed, and an example is analyzed in Matlab. The results verify the effectiveness of the improved genetic algorithm in reactive power optimization of wind motor.

Design and Implementation of the New Sensorless Rotor Position Estimation in Homopolar Salient-Pole Brushless DC Motor

This article presents a novel method for indirect sensing of the rotor position in a homopolar salient-pole brushless dc (BLDC) motor and driving the motor smoothly from a standstill using an inductance bridge. Based on the characteristic of the phase inductance variation, the rotor position can be determined by using the inductance bridge to estimate the inductance of unknown phases. The proposed technique uses the motor winding in Hay’s bridge, and it is adjusted to achieve a balanced condition in an unaligned position when the minimum inductance occurs. In a running mode, by rotating the rotor, an idle phase inductance is changed and Hay’s bridge goes into an unbalanced condition. Then, by injecting extra voltage pulses into idle phases, the bridge output state changes. It then continues to sense the rotor position, while the motor is running by applying the same procedure. Moreover, the proposed method does not have problems like those in previous researches such as mutual inductance effects, need of large memory for locking up of the data, and losing of the estimation accuracy by the change in the sampling rate. As the main salient features of the proposed method, load independent, simplicity in implementation, and flexibility in tuning can be pointed out. Finally, experimental tests have been carried out to confirm the feasibility and practicability of the proposed method.

FREQUENCY-PARAMETRIC CONTROL SYSTEM OF AN ASYNCHRONOUS ELECTRIC DRIVE WITH AN OBSERVER OF THE ANGLE BETWEEN THE VECTORS OF THE STATOR CURRENT AND THE MAGNETIZATION CURRENT

In industry, especially metallurgy, a large number of previously installed electric drives based on an asynchronous motor with a phase rotor with uneconomical parametric control systems are used, the advantage of which is the possibility of removing part of the sliding energy from the rotor circuit, and the ability to obtain an increased inrush current multiplicity. The use of frequency converters in such an electric drive allows you to adjust the speed of rotation of the stator field and maintain sliding and losses in the rotor circuit at a minimum level. However, when the rotor windings are shorted, the multiplicity of the starting torque decreases. Additional possibilities for maintaining an increased starting torque of an asynchronous motor with a phase rotor with frequency control are provided by the inclusion of a frequency-dependent active-inductive resistance (IR) in the rotor circuit. In this case, the electric drive will be frequency-parametric. Using an observer of the mutual position of the stator and rotor current vectors, working on the basis of processing the measured signals of instantaneous values of the stator and rotor currents, allows you to build a scalar control system with stator current correction, bringing the operation of the electric drive to the mode with minimal losses in the motor windings.

Design of Wireless Individual-Drive System for Variable-Reluctance Stepping Motor

In this brief, a novel wireless individual-drive system for variable-reluctance (VR) stepping motor is proposed and implemented. The key is to use coil groups to drive each phase of the VR stepping motor individually through magnetic resonance coupling. Based on the proposed structure, the VR stepping motor can be driven wirelessly while the motor side is free of active components. Meanwhile, the constant current drive is achieved without a chopper. The proposed system enables the VR stepping motor to work with higher independence and robustness compared with the cable-powered motor. The system design is described at first. Then, the equivalent circuit model is derived and analysed. In addition, the operation principle is displayed. Finally, a system prototype is constructed in the laboratory to validate the effectiveness of the proposed system. The experimental results show that 87.5% efficiency from dc power source to motor winding is achieved with the transmission distance of 50 mm. Moreover, the motor speed can reach up to 150 r/min and the motor torque can be regulated with the duty-ratio modulation.

Short-circuit fault evaluation of SF6 circuit breaker energy storage motor coil based on high-frequency equivalent model

Abstract The capacitive inductance parameters of the energy storage motor windings were calculated by finite element method, and the high-frequency equivalent model of the winding was established based on ATP-EMTP. Square wave pulse voltage signal was applied to the input end of the model, and the response voltage curve at the end of the circuit model was measured. The wavelet packet-energy spectrum was calculated as the characteristic parameter of the response curve in different short-circuit positions, and the short-circuit position was evaluated by the random forest algorithm. The accuracy rate of short-circuit fault location in the test set was 75%, indicating that the method has certain feasibility.

Optimal Power Sharing Control of Dual Winding Motor for Fuel Cell Vehicle

Optimal Power Sharing Control of Dual Winding Motor for Fuel Cell Vehicle

Estimation of energy characteristics of the asynchronous motor with a combined winding

PURPOSE. Asynchronous motors are the main consumers of the electrical energy. Increasing their energy performance can contribute to a significant reduction in energy consumption in general. Using a combined 12-zone winding instead of the standard 6-zone one theoretically can lead to a decrease in electrical losses in the stator winding of the asynchronous motor and to reduce additional losses caused by the higher spatial harmonics. The main purpose of the work is to assess the effect of using a combined winding stator on the energy characteristics of the induction motor.METHODS. The study was performed on two AIR71V4 electric motors, one of which had a standard winding and the other had a combined winding. In the experiment, the engines were rated voltage, and the load was carried out using an electromagnetic loading device. The engines were tested in the range of loads from idle to the nominal. The experiment was performed five times.RESULTS. The work under analysis shows the dependences of the current strength, consumed active and reactive power, efficiency, and power factor from engine load.CONCLUSION. The results of the study showed that an asynchronous motor with the combined winding over the entire investigated range of loads has a lower consumption of both active and reactive power, compared to a motor with a standard winding, while the power factors of these motors are practically the same. The greatest difference in efficiency was observed at loads lower than the nominal in favor of an improved engine model, but also at rated load, the motor with a combined winding has the higher efficiency of 3,1%.

Pulsewidth modulation method to balance the loss distribution of dual inverter to drive open-end winding motor

Pulsewidth modulation method to balance the loss distribution of dual inverter to drive open-end winding motor

A Three-Phase Electric Vehicle Charger Integrated With Dual-Inverter Drive

Lack of charging stations and long charge times are critical barriers to widespread electric vehicle (EV) adoption. High power off-board charging stations can address these issues but are expensive to implement. This article presents a three-phase EV charger integrated with the dual-inverter drive. Integrated charging can substantially reduce the charging station costs by reusing drivetrain components, such as power electronics and cooling systems, for charging when the EV is parked. The dual-inverter drive allows for significant current ripple reduction throughout the charger. Operation and control of the presented charger are discussed while functionality is experimentally verified with a 10- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$kW$ </tex-math></inline-formula> -rated prototype. The prototype is able to perform constant current, constant voltage (CCCV) charging of two isolated energy storage units (ESUs) from a three-phase grid with <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$&gt; 0.99$ </tex-math></inline-formula> power factor. Charging is performed with balanced dc current passing through the dual-inverter’s motor windings to prevent torque generation during charging. The prototype achieves a peak efficiency of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$&gt; 94\%$ </tex-math></inline-formula> while meeting grid current harmonic standards set by International Electrotechnical Commission (IEC)-61000-3-12.

Mathematical model of a vertical-axial wind motor in a viscous gas flow

The development of vertical axial wind turbines in Ukraine is in its infancy for many reasons: the lack of systematic theoretical and experimental studies of the aerodynamic characteristics of various schemes of wind turbines, the lack of an appropriate experimental base in technical universities, design organizations, insufficient number of available publications in foreign literature due to high competition between by monopoly firms. At present, various numerical methods are widely used to solve urgent problems of aero hydrodynamics, which are used for the approximate solution of boundary value problems in the form of differential forms of mathematical models. Their common disadvantages are the particularity and laboriousness of solutions, high requirements for computing resources, and, as a consequence, the complexity of solving optimization problems and economic feasibility. These problems can be avoided by using exact or approximate analytical dependences, which allow solving some urgent problems of studying the interaction of a viscous gas with the bearing elements of both aircraft and engineering structures. The existing methods for calculating the aerodynamic characteristics, based on the ideology of the mathematical model of the motion of an ideal medium without viscous interaction, do not correspond to the real processes and demands of practice. The article presents the ideology of determining the aerodynamic characteristics of the interacting system of solid profiles in the configuration of a vertical-axial wind turbine in a viscous gas flow. Based on generalized vector-tensor analysis, contour integral representations of solutions to the main problem of fluid and gas mechanics related to the determination of kinematic and dynamic characteristics of interaction have been constructed. In addition, the existence of a vector potential of the tensor of stresses and deformation velocities has been proved, reducing, in the simplest cases, the process of determining characteristics to integration. The limit values of these integral representations are a system of boundary integral equations, allow for elementary algorithmization, and lead to a system of linear algebraic equations having a single solution.

Application of Frequency Response Analysis Method to Detect Short-Circuit Faults in Three-Phase Induction Motors

The industry has widely accepted Frequency Response Analysis (FRA) as a reliable method to detect power transformers mechanical deformations. While the FRA technique has been recommended in recent literature as a potential diagnostic method to detect internal faults within rotating machines, detailed feasibility studies have not been fully addressed yet. This paper investigates the feasibility of using the FRA technique to detect several short circuit faults in the stator winding of three-phase induction motors (TPIMs). In this regard, FRA testing is conducted on two sets of induction motors with various short circuit faults. Investigated faults include short circuits between two phases, short circuit turns within the same phase, phase-to-ground, and phase-to-neutral short circuit. The measured FRA signatures are divided into three frequency ranges: low, medium, and high. Several statistical indicators are employed to quantify the variation between faulty and healthy signatures in each frequency range. Experimental results attest the feasibility of the FRA technique as a diagnostic tool to detect internal faults in rotating machines, such as induction motors.

Harmonic and Vibration Analysis of Dual Three-Phase PMSM with One-Phase Open Circuit Fault

This paper analyzes the harmonics and vibration under different fault-tolerant current control when one-phase winding of dual three-phase permanent magnet synchronous motor (PMSM) is an open circuit fault. Firstly, the dual three-phase load condition subdomain model of breadloaf surface-mounted permanent magnet (PM) PMSM is established. Secondly, the working conditions of an open circuit fault of one-phase winding are set from the perspectives of no fault-tolerant (NFT) control, maximum torque (MT) control, minimum copper loss (MCL) control and single three-phase mode (STPM) control. The torque harmonics and electromagnetic force harmonics of the four working conditions are analyzed. Then, considering the multi-physical field of electromagnetic and structural coupling, the electromagnetic force in the motor air gap acts on the stator core, and the vibration under four different working conditions is calculated and analyzed. Through the comparison between the analytical method and finite element method, the accuracy of the established model is verified. The calculation method is effective and accurate, it can quickly predict the motor performance in case of one-phase open circuit fault of dual three-phase PMSM.

Running State Monitoring of Induction Motor Windings Using Near Infra-red Sensor Residual Signal and Q Factor Analysis

Running State Monitoring of Induction Motor Windings Using Near Infra-red Sensor Residual Signal and Q Factor Analysis

PV Generator-Fed Water Pumping System Based on a SRM with a Multilevel Fault-Tolerant Converter

This paper presents a pumping system supplied by a PV generator that is based on a switched reluctance machine (SRM). Water pumping systems are fundamental in many applications. Most of them can be used only during the day; therefore, they are highly recommended for use with PV generators. For the interface between the PV panels and the motor, a new multilevel converter is proposed. This converter is designed in order to ensure fault-tolerant capability for open switch faults. The converter is based on two three-level inverters, with some extra switches. Moreover, to reduce the number of switches, the converter is designed to provide inverse currents in the motor windings. Due to the characteristics of this motor, the inverse currents do not change the torque direction. In this way, it was possible to obtain an SRM drive with fault-tolerant capability for transistor faults; it is also a low-cost solution, due to the reduced number of switches and drives. These characteristics of fault-tolerant capability and low cost are important in applications such as water pumping systems supplied by PV generators. The proposed system was verified by several tests that were carried out by a simulation program. The experimental results, obtained from a laboratory prototype, are also presented, with the purpose of validating the simulation tests.

Reduced DC sensor based grid-interactive operation of single-stage solar photovoltaic water pumping system

ABSTRACT The grid-interactive operation of a single-stage solar photovoltaic water pumping system (SPVWPS) requires additional power electronic interface and a number of sensors. This paper realizes the grid-interactive operation of the single-stage SPVWPS with reduced sensor and without adding to the cost of the grid-interface converter. The single-phase grid is connected directly with the SPVWPS and the three-phase inverter is controlled as a single-phase grid-interactive inverter. The motor winding inductance is utilized as a current filter. This arrangement functions as a photovoltaic-static synchronous compensator (PV-STATCOM) with voltage-oriented current control by feeding the peak solar photovoltaic (SPV) power to the grid and supporting the reactive power to alleviate steady-state grid voltage variations. The modified adaptive second-order generalized integrator (SOGI) is utilized for effective grid-angle estimation under the presence of DC-bias in the input signal. The modified perturb and observed maximum power point tracking (MPPT) technique is implemented using grid-side quantities, which curtails the requirement of the SPV current sensor. Extensive experiments are performed on the developed prototype under the variable atmospheric and the variable grid voltage conditions. The presented grid-interactive SPVWPS is realized with single power electronics device and three sensors. The cost of power electronics interface is reduced in presented single-stage grid-interactive SPVWPS by 22% compared to two-stage grid-interactive SPVWPS. Abbreviations: FLL: Frequency Looked Loop; PFC: Power Factor Correction; FFT: Fast Fourier Transform; PV: Photovoltaic; SPVWPS: Solar Photovoltaic Water Pumping System; MPPT: Maximum Power Point Tracking; P & O: Perturb and Observe; SPV: Solar Photovoltaic; OSG: Orthogonal Signal Generator; PWM: Pulse Width Modulation; SOGI: Second-order Generalized Integrator; PEC: Power Electronic Converter; RMS: Root Mean Square; VSI: Voltage Source Inverter; PF: Power Factor; RMF: Rotating Magnetic Field; VSC: Voltage Source Converter; PI: Proportional Integral; SySPWM: Synchronous Sine Pulse Width Modulation

Simulation of turn-to-turn short circuit in the rotor winding of an induction motor

Simulation of turn-to-turn short circuit in the rotor winding of an induction motor

TRANSFER OF AN ASYNCHRONOUS ELECTRIC MOTOR TO GENERATOR FOR PARALLEL OPERATION WITH MICROGRID

One of the issues of the energy sector is to increase the efficiency of energy supply to remote or isolated territories by creating microgrids based on renewable energy sources. The requirements for generators are design simplicity and high operational reliability, as well as the parameters of the generated electricity. (Research purpose) The research purpose is converting an asynchronous motor into an asynchronous generator. The technical solution for the transfer of an asynchronous electric motor to the generator has two directions: the creation of reactive energy in the electric motor and the excitation control. We took the first direction as a basis. (Materials and methods) The article presents a semi-automatic synchronization scheme for the operation of an asynchronous electric motor in generator mode, when one part of the operations is performed automatically and the other is performed manually. A test stand was made. The characteristics of an asynchronous generator when working in parallel with the grid are presented. (Results and discussion) During the analysis of the data obtained, the dependence of the power transmitted by the generator to the grid on the rotating frequency of the asynchronous electric motor was drawn. Using experimental studies, capacitor banks included in the stator winding of an asynchronous motor according to the «triangle» scheme allow it to be used as an asynchronous generator. (Conclusions) The parameters of the asynchronous generator depend on the rotation speed and the power transmitted by the micro-gas turbine engine; the semi-automatic synchronization scheme, in which one part of the operations is carried out automatically and the other manually, makes it possible to turn on the asynchronous generator to work with the distribution grid without equalizing current.

Model of the heat flow of the stator winding of an induction traction electric motor

Model of the heat flow of the stator winding of an induction traction electric motor

The Insulation Resilience of Inverter-Fed Low Voltage Traction Machines: Review, Challenges, and Opportunities

The use of wide bandgap (WBG) semiconductor devices, which enable higher switching slew rates, and the increase in DC link voltage, which provides system-wide advantages, exposes the winding system of traction machines to enhanced electrical stress. The resulting nonlinear voltage distribution along the motor winding favors partial discharges (PD), which in low voltage (LV) machines causes excessive damage to the insulation system, and premature failure can occur. A simple solution by increasing the enamel thickness of the wires leads on the one hand to a lower copper fill factor. On the other hand, this measure is not necessarily accompanied by an increase in electrical resilience in the case of pulsed voltage. It is therefore essential to understand the phenomenon of partial discharges, which is composed of a large number of processes and mechanisms, to be able to make an estimation of aging. The ultimate goal is to derive a lifetime model that links the dynamic load collectives – ideally in conjunction with the environmental stress influences – of a traction application to a usage-dependent and realistic prediction of the residual lifetime. To this end, this paper provides an overview of the current state of science and technology in this interdisciplinary topic by describing, with reference to high voltage (HV) technology/engineering, the design of the insulation system, the discharge physics, the degradation mechanisms, the statistical effects to be considered, and the partial discharge measurement methods.

Radial force cancellation of bearingless brushless direct current motor using integrated winding configuration

A bearingless brushless direct current (BLDC) motor incorporates the function of magnetic bearings into a BLDC motor, making it a new type of high-performance motor. In this paper, the main motor windings are used to generate the radial force cancellation by injecting the required dc current, “integrated winding configuration”. The bearingless BLDC motor, direct current (DC) cancellation system model is established with the aid of (ANSYS/MAXWELL) software. The simulation results confirm that the rotor radial force is approximately zero and results from a balanced distribution of the magnetic flux density. The proposed DC excitation system is suitable to realize the rotor radial force cancellation in the bearingless BLDC motor. The simulation results of the proposed configuration show the approach of integrating winding configuration at different active pole positions to find the more efficient suspension performance and reduce the suspensions system current.