Sinusoidal Current Excitation Research Articles

A three-dimensional numerical model for computing the actual voltage induced in a Barkhausen surface coil

This investigation presents a novel three-dimensional simulation model designed for the analysis of Magnetic Barkhausen Noise (MBN). The model’s formulation is directly deduced from Maxwell’s equations, establishing a Boundary Value Problem (BVP) with boundary conditions tailored to a specific configuration involving a lengthy steel rod encased within a solenoid, subjected to sinusoidal current excitation, all contained within an air enclosure. This chosen configuration holds physical equivalence to the majority of setups commonly utilized in Barkhausen experiments. Utilizing the proposed three-dimensional model, it became feasible, for the first time, to computationally assess the voltage induced in the coil by the flux emanating from all spatial directions. The findings indicate that the MBN signal is primarily generated by the flux rate aligned with the direction of the applied field. Nevertheless, simulations confirm additional contributions to the signal originating from magnetic flux in directions significantly deviating from the applied field direction. It is demonstrated that these contributions from lateral flux significantly influence the angular dependence of the Barkhausen signal energy, showcasing a notable alignment between the proposed model and experimental results. The results underscore the capability of the proposed model to facilitate the simulation of Barkhausen Noise.

Analytical Torque Ripple Reduction Strategy for Flux Modulated Doubly-Salient Reluctance Motor Drives Based on ZSC Harmonic Regulation

Compared to the conventional doubly-salient reluctance motor (DRM) drives, the novel flux modulated DRM (FMDRM) drives can achieve a better overall torque performance due to the dc-biased sinusoidal current excitation. However, previous investigations only focus on the dc-biased and fundamental current components, and the contributions of current harmonics to the torque production are not clear. This paper proposes an analytical torque ripple reduction strategy for open-winding FMDRM drives based on zero-sequence current (ZSC) harmonic regulation. Firstly, the contribution of third-order ZSC harmonic to the electromagnetic torque is investigated together with the dc-biased sinusoidal current components. Secondly, an alternative torque component cancellation method is put forward, where the additional third-order ZSC is utilized to counteract the dominating part of the alternative torque generated by the dc-biased sinusoidal current for torque ripple reduction. Both the amplitude and initial phase angle of the additional third-order ZSC are calculated by the analytical equation of electromagnetic torque. Moreover, the corresponding three-dimensional current distribution is investigated to achieve the desired ZSC regulation. With the proposed scheme, the torque ripple can be effectively suppressed while maintaining high output torque capability and efficiency. Furthermore, experimental results are presented on a three-phase FMDRM prototype to verify the proposed strategy. <fn fn-type="other" id="fn3" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> </fn>

A Novel Torque Ripple Suppression Scheme of Switched Reluctance Motors Based on Unipolar Sinusoidal Current Excitation

A Novel Torque Ripple Suppression Scheme of Switched Reluctance Motors Based on Unipolar Sinusoidal Current Excitation

A Simplified PWM Strategy for Open-Winding Flux Modulated Doubly-Salient Reluctance Motor Drives With Switching Action Minimization

In this article, a simplified pulsewidth modulation (PWM) strategy is proposed for open-winding flux modulated doubly-salient reluctance motor (FMDRM) drives for switching action minimization and common-mode voltage (CMV) reduction. Conventionally, the open-winding converter topology is utilized to achieve the zero-sequence current flow path and dc-biased sinusoidal current excitation for the FMDRM, where the switching actions of power switches are doubled compared to the conventional modular three-phase converter, leading to higher switching losses. Different from the conventional space vector PWM scheme, the reference voltages of converter legs are directly calculated by the reference phase voltages in the proposed PWM scheme. In addition, a rotor-position-based sector division method is proposed to deal with the sector imbalance caused by the distorted back electromotive force (back EMF). Furthermore, different leg voltage clamping methods are respectively developed in odd and even sectors for switching action minimization, which can achieve voltage stress balance and CMV reduction. With the proposed scheme, the switching actions in each switching cycle can be reduced by half, which effectively increases the system efficiency of the FMDRM drive. Experiments are carried out on a three-phase 12/8 FMDRM prototype to verify the effectiveness of the proposed scheme.

A novel experimental procedure for lock-in thermography on solar cells

&lt;abstract&gt; &lt;p&gt;The occurrence of defects in solar cells is intrinsically related to a reduction in the efficiency and reliability of these devices. Therefore, monitoring techniques, such as lock-in thermography, electroluminescence and the I-V characteristic curve are adopted in order to evaluate the integrity of the solar cells. In the present work, a novel experimental procedure for the lock-in thermography of solar cells is proposed, aiming to improve the detection capability of the assay. Conventional techniques use pulse width modulation to operate the cell at a fixed point on the I-V curve. Instead, we propose a methodology based on a sinusoidal electric current excitation in order to extend the range of operational points that are close to the maximum power point as the cell operates in the field. Some traditional image processing techniques (principal component analysis, the fast Fourier transform and the four-step phase-shifting method) have been used to analyze the thermal images captured by an infrared camera during steady-state operation mode of the solar cells using both sinusoidal electric current signal and standard pulse width modulation procedures. Comparison between the results of both procedures found that this novel approach provides smoother and clearer delimitation of the defects. Furthermore, the contrast of the phase images was found to exhibit significant changes between the defective and non-defective regions for different modulation frequencies and types of defects. From the achieved results, it was possible to obtain a satisfactory characterization of the existing defects.&lt;/p&gt; &lt;/abstract&gt;

Highly Integrated Online Multi-Channel Electrochemical Impedance Spectroscopy Measurement Device for Fuel Cell Stack

Electrochemical impedance spectroscopy (EIS) can provide information about the internal state of fuel cells, which makes EIS an important tool for fuel cell fault diagnosis. However, high cost, large volume, and poor scalability are limitations of existing EIS measurement equipment. In this study, a multi-channel online fuel cell EIS measurement device was designed. In this device, based on multi-phase interleaved Boost topology and average current control, an excitation source, which can output 1~500 Hz, 10 A sinusoidal excitation current was designed and verified by model simulation. Then, based on the quadrature vector digital lock-in amplifier (DLIA) algorithm, an impedance measuring module that can achieve precise online impedance measurement and calculation was designed. A prototype was then built for the experiment. According to the experiment test, the amplitude error of the excitation source is less than 1.8%, and the frequency error is less than 0.3%. Compared with the reference data, the impedance measured by the prototype has a modulus error of less than 3.5% and a phase angle error of less than 1.5°. Moreover, the waveform control and impedance extraction function of the EIS measurement device is implemented on an embedded controller, which can cut the price and reduce the volume.

Evaluation of cable and busbar system in multiconductor distribution systems in terms of current and magnetic field distributions

The selection of power distribution components is of great importance in electrical facilities. Cable and busbar systems are widely used applications, such as electric vehicle charge stations, microgrids and energy storage systems, for power distribution in the distribution grid. In this study, the current distribution on the parallel conductors and magnetic field distributions around cable and busbar structures is evaluated for studied application where the power is distributed using a cable system between a converter transformer and a converter. All modeling and analyzes are conducted using ANSYS Electronics Suite software, by applying balanced and pure sinusoidal current excitation. Obtained results show that, when the busbar system is installed for power distribution, current distribution between parallel conductors is decreased to the negligible level, and the calculated magnetic field density is about 73.7% lower than the cable system.

High-speed giant magnetostrictive actuator using laminated silicon steel core.

The high-frequency eddy current loss limits the output speed of the giant magnetostrictive actuator (GMA). This paper investigates a GMA using a laminated silicon steel core. Compared with the integral silicon steel core, the laminated silicon steel core can reduce the equivalent conductivity and eddy currents. The laminated structure reduces the magnetic reluctance of the core and increases the magnetic field intensity in the giant magnetostrictive material rod. Therefore, the actuator can output large vibration amplitude under high-frequency magnetic field. At the sinusoidal excitation current of 35A (rms) @ 2 kHz, the output vibration amplitude of the actuator using the laminated silicon steel core is 11.1 µm @ 4 kHz, which is 44.2% higher than that of the actuator with the integral silicon steel core. This indicates that the laminated structure of the magnetic core is beneficial to improve the output speed of GMA.

(Invited) Experimental Characterization and Modeling of Heat Generation Rates of Lithium-Ion Batteries with NMC/C Chemistries

The operating temperature of a battery strongly affects overall chemical reactions, ion transport, intercalation and deintercalation process and consequently efficiency, cycle life, and safety of battery systems. Therefore, battery thermal management system (BTMS) should be optimally designed to ensure a highly efficient and reliable operation of the battery system, which requires characterization and analysis of heat generated during operations rather than temperature.Characterization of heat generation rates of a battery requires a highly accurate and dynamic calorimeter that is not commercially available. Therefore, we designed a new multifunctional calorimeter for lithium-ion batteries using thermoelectric assemblies (TEA), which enables the measurement of heat generation rate as a function of C rates, state-of-charge (SOC) and temperatures. In addition, the calorimeter also works as a thermostat that is capable of tracking an alternating reference temperature, so that flexibility and accuracy of experiments are ensured. This capability enables to decouple the temperature fluctuation during charging and discharging operations and the measurement of the entropy coefficient.In this paper, the cells used as an example for the experiments are large format pouch type lithium ion batteries with LMO/NMC-Graphite chemistry. The lumped heat generation rate of the cell is measured at different C rates, state-of-charge (SOC) and temperatures. In addition, analysis of the data has shown that both the heat generation rate and the ratio of the total heat generation to the total energy stored or retrieved of the tested cells increase as the current increases or the temperature decreases.Characterization of the heat source terms includes measurement of reversible and irreversible heat sources that can be determined by calorimetric methods. Particularly, the entropy coefficient (dUOC/dT) in the reversible source is the key parameter that determines the amount of the reversible heat generated during operations. Currently, either potentiometric or calorimetric method is used to measure the value of the entropy coefficient, which drawbacks are long measurement time and inaccuracy. Thus, a new method is proposed based on the calorimeter that works as a thermostat in conjunction with an estimation technique. In order to reduce the measurement time, a time-domain background voltage offset correction and a frequency-domain entropy coefficient determination have been newly developed and applied. Comparison between the developed one and the classical methods has shown a drastic reduction of the measurement time and a similar accuracy to the potentiometric method. The proposed method is also used to investigate effects of temperatures and aging on the entropy coefficient. As a result, the reversible heat source term dependent upon the operating conditions such as SOC, temperature and cycle life can be characterized, which are the important factors for design of battery thermal management systems.Moreover, a calorimetric method for the characterization of the reversible and irreversible heat sources is also developed by applying a sinusoidal current excitation to the cell and analyzing the heat generation response in frequency domain. The determined parameters of both heat sources are compared with those measured by hybridized time frequency domain analysis method and EIS analysis, respectively, which shows a good match. Moreover, the calculated reversible and irreversible heat sources terms are compared with the experimental measurement. Results have shown improved performances in the characterization of irreversible and reversible heat with respect to measurement speed and accuracy.Finally, a thermal model that includes irreversible and reversible heat source terms is developed and then incorporated into a reduced-order electrochemical model (ROM). The electrochemical thermal model is validated against the heat generation rate of the cells measured by the developed calorimeter aforementioned. The model is capable of predicting heat generation rates up to 3C from -30°C to 35°C. Based on the validated thermal model, effects of C rates and temperatures on heat sources can be analyzed. The results have shown that the reversible heat is dominant at low C rates, while the irreversible one is dominant at high C rates because the Joule heating, which is the main irreversible heat source, is proportional to the square of the current. Besides, the reversible heat source is dominant at high temperatures, while the irreversible one is dominant at low C rates because battery internal resistance sources such as contact resistance and ionic resistivity rapidly increase at low temperatures.In addition, the lumped model is used to develop a two-dimensional electrochemical thermal model that is validated with temperature images captured by an Infrared thermal camera.Presented experimental characterization of heat generation and the associated theoretical analysis by electrochemical thermal models can provide basics and fundamentals for an optimal design of future battery thermal management systems.

Comprehensive Analysis and Optimized Control of Torque Ripple and Power Factor in a Three-Phase Mutually Coupled Switched Reluctance Motor With Sinusoidal Current Excitation

This article presents a comprehensive analysis of torque ripple and power factor for three-phase mutually coupled switched reluctance motors (MCSRMs) with sinusoidal current excitation. MCSRMs controlled by sinusoidal currents have the advantage of using the conventional voltage source inverter and the conventional vector control. However, MCSRMs are characterized by high torque ripple and low power factor. The torque harmonics due to the sinusoidal current excitation are investigated, and the effect of the current excitation angle on the motor saturation level and the power factor is analyzed. These analyses are then used in the development of an optimized control method to reduce torque ripple and to increase power factor and average torque. In the proposed control method, the power factor and phase voltage are calculated by the knowledge of the phase flux linkage and phase current. The phase flux linkage is represented in terms of Fourier coefficients, where these coefficients are functions of direct- and quadrature-axis currents. Hence, they are estimated from 2-D lookup tables (LUTs), which are independent of rotor position. Similarly, the Fourier coefficients of the torque harmonics are also estimated from the 2-D LUTs. The independence of the LUTs from rotor position reduces the size of the LUTs significantly. The proposed control method is validated by experiments on a 2-kW 12/8 MCSRM.

A novel method for estimating the fractional Cole impedance model using single-frequency DC-biased sinusoidal excitation.

The Cole model is a widely used fractional circuit model in electrical bioimpedance applications for evaluating the content and status of biological tissues and fluids. Existing methods for estimating the Cole impedance parameters are often based on multi-frequency data obtained from stepped-sine measurements fitted using a complex non-linear least square (CNLS) algorithm. Newly emerged numerical methods from the magnitude of electrical bio-impedance data-only do not need CNLS fitting, but they still require multi-frequency stepped-sine data. This study proposes a novel approach to estimating the Cole impedance parameters that combines a numerical and time-domain fitting method based on a single-frequency DC-biased sinusoidal current excitation. First, the transient and steady-state voltage response along with the current excitation are acquired in electrical bio-impedance measurement. From the sampled data, a numerical method is applied to provide the initial estimation of the Cole impedance parameters, which are then used in a time-domain iterative fitting algorithm. The accuracy of the algorithm proposed is tested with noisy electrical bio-impedance simulations. The maximum relative error of the estimated Cole impedance parameters is 1% considering 2% (34 dB) additive Gaussian noise. Experimental measurements performed on a 2R-1C circuit and some fruit samples show a mean difference less than 1% and 5% respectively compared to the Cole impedance parameters estimated from a commercial electrical bio-impedance analyzer performing stepped-sine measurements and CNLS fitting. This is the first method that allows estimating the Cole impedance parameters from single-frequency electrical bio-impedance data. The approach presented could find broad use in many applications, including single-frequency body impedance analysis.

Stator Inductance Identification Based on Low-Speed Tests for Three-Level NPC Inverter-Fed Induction Motor Drives

This paper proposes a stator inductance identification process for three-level neutral point clamped (NPC), inverter-fed Induction Motor (IM) drives based on a low-speed test drive. Conventionally, the stator inductance of an IM is identified by methods based on standstill or rotational tests. Since conventional standstill test-based methods have several practical problems when used with three-level inverters because of their nonlinearity, an identification method based on rotational tests is superior in such applications. However, conventional rotational tests cause unintended behavior because of the high speeds used during the test. In the proposed stator inductance identification process, the stator inductance is identified based on a low-speed test drive. In the proposed method, the stator flux is estimated using the instantaneous reactive power of the IM during low-frequency sinusoidal current excitation, and the stator inductance is then identified based upon this. Therefore, the proposed identification process is safer than conventional approaches, as it uses only a low-speed test. The accuracy and reliability of this method are verified by simulation and experiment using three motors with different rated voltage and power.

Model-Based Spatial Harmonics Vector Compensation Method for Three-Phase Mutually Coupled Switched Reluctance Machine With Sinusoidal Current Excitation

This paper presents a spatial harmonics compensation method for mutually coupled switched reluctance machines (MCSRMs) with sinusoidal current excitation. The regulation by linear controllers to achieve sinusoidal currents in MCSRMs is challenging due to the substantial presence of spatial harmonics. The standard vector control with using Proportional-Integral controllers cannot effectively suppress the spatial harmonics of the current waveform due to the bandwidth limitations. In the proposed method, the essential voltage harmonics are added to the fundamental voltage component to create sinusoidal currents. The voltage harmonics are calculated from the flux linkage harmonics where voltage and flux linkage harmonics are represented as vectors in terms of Fourier coefficients. The Fourier coefficients of the flux linkage are function of direct-and quadrature-axis currents. Hence, they are in the form of two-dimensional look-up tables (LUTs). The used LUTs in the proposed method are independent of rotor position and they are obtained from the finite element analysis (FEA) model. The proposed spatial harmonics compensation method is validated using FEA and experiments for a 3-phase 12/8 MCSRM at generating and motoring modes of operation.

Numerical estimation of Fricke–Morse impedance model parameters using single-frequency sinusoidal excitation

Objective: The Fricke–Morse impedance model is widely used in bioelectrical impedance analysis (BIA), which is usually fitted by multi-frequency electrical impedance data. Here, we propose a novel numerical method for estimating the model parameters using single-frequency sinusoidal excitation. Approach: A single-frequency sinusoidal signal is used as the current excitation, from which the initial transient, the steady-state and the ending transient voltage responses along with the current excitation are recorded. The model parameters can be then estimated with numerical calculations from the acquired signals. Main results: Simulation and experimental measurements are verified on a 2R1C circuit by using a 50 kHz sinusoidal current excitation. The results show that the maximum relative errors of the estimated model parameters are <1% in simulation with 2% noise and <2% in experimental measurement. Significance: The proposed method could extend the applications of wideband BIA by using single-frequency excitation, rather than multi-frequency excitation as is done today.

Gene-sensor on the basis of bioimpedance measurements assisted with nanotechnology: an instrumentation proposal

In this study, we propose basic instrumentation for a new gene-sensor based on Polymerase Chain Reaction (PCR) product and its multifrequency bioimpedance relative measurements assisted with nanotechnology. The instrumentation proposal is split into four basic blocks: A) Control. - The fundament is a microcontroller (µC) for wide bandwidth current excitation, as well as data acquisition and registration. B) Digital Synthesizer. - A wide bandwidth digital synthesizer will provide a sinusoidal excitation current. C) Bioimpedance measurement.- this section will detect relative multifrequency bioimpedance by comparison of a reference signal with the signal of the Analyte Under Test (AUT). Comparison is on the basis of magnitude ratio and phase shift. D) Electrical-Ionic Interphase. – This is based on gold electrodes in contact with the AUT for current injection and relative bioimpedance measurements. Deoxyribonucleic Acid (DNA) fragments as PCR products will be functionalized by magnetic nanoparticles-DNA biding and its magnetic DNA insulation. The specific electronic components for every section are out of the range of this study, and the general instrumentation structure proposed is intended to show tentative low cost technology for gene detection and obtain academic discussion and feedback.

Cannula Tip With Integrated Volume Sensor for Rotary Blood Pump Control: Early-Stage Development.

The lack of direct measurement of left ventricular unloading is a significant impediment to the development of an automatic speed control system for continuous-flow left ventricular assist devices (cf-LVADs). We have developed an inlet cannula tip for cf-LVADs with integrated electrodes for volume sensing based on conductance. Four platinum-iridium ring electrodes were installed into grooves on a cannula body constructed from polyetheretherketone (PEEK). A sinusoidal current excitation waveform (250 μA pk-pk, 50 kHz) was applied across one pair of electrodes, and the conductance-dependent voltage was sensed across the second pair of electrodes. The conductance catheter was tested in an acute ovine model (n = 3) in conjunction with the HeartMate II rotary blood pump to provide circulatory support and unload the ventricle. Echocardiography was used to measure ventricular size during pump support for verification for the conductance measurements. The conductance measurements correlated linearly with the echocardiography dimension measurements more than the full range of pump support from minimum support to suction. This cannula tip will enable the development of automatic control systems to optimize pump support based on a real-time measurement of ventricular size.

Two-Dimensional Exact Subdomain Technique of Switched Reluctance Machines with Sinusoidal Current Excitation

This paper presents a two-dimensional (2D) exact subdomain technique in polar coordinates considering the iron relative permeability in 6/4 switched reluctance machines (SRM) supplied by sinusoidal waveform of current (aka, variable flux reluctance machines). In non-periodic regions (e.g., rotor and/or stator slots/teeth), magnetostatic Maxwell’s equations are solved considering non-homogeneous Neumann boundary conditions (BCs). The general solutions of magnetic vector potential in all subdomains are obtained by applying the interface conditions (ICs) in both directions (i.e., r- and θ-edges ICs). The global saturation effect is taken into account, with a constant magnetic permeability corresponding to the linear zone of the nonlinear B(H) curve. In this investigation, the magnetic flux density distribution inside the electrical machine, the static/dynamic electromagnetic torques, the magnetic flux linkage, the self-/mutual inductances, the magnetic pressures, and the unbalanced magnetic forces (UMFs) have been calculated for 6/4 SRM with two various non-overlapping (or concentrated) windings. One of the case studies is a M1 with a non-overlapping all teeth wound winding (double-layer winding with left and right layer) and the other is a M2 with a non-overlapping alternate teeth wound winding (single-layer winding). It is important to note that the developed semi-analytical model based on the 2D exact subdomain technique is also valid for any number of slot/pole combinations and for non-overlapping teeth wound windings with a single/double layer. Finally, the semi-analytical results have been performed for different values of iron core relative permeability (viz., 100 and 800), and compared with those obtained by the 2D finite-element method (FEM). The comparisons with FEM show good results for the proposed approach.

Ion shot noise in Hodgkin–Huxley neurons

Ion shot noise, the noise associated to the random passage of ions across the cell membrane, is studied by means of a stochastic model based on the Hodgkin–Huxley equations, which includes gating channels for sodium and potassium cations and leakage channels through the biological membrane. Apart from shot noise, other sources such as extrinsic and channel noise are taken into account. Ion shot noise, of increasing influence for smaller membrane patch sizes S, can lead to the emergence of action potentials in the membrane voltage in the presence of sinusoidal excitation currents below the threshold for the onset of spikes. The spiking activity in the presence of noise has been analyzed in terms of the coefficient of variation CV, the inter-spike interval histogram, the spectrum of membrane voltage fluctuations and the signal-to-noise ratio SNR. CV shows improved coherence in the sequence of randomly generated spikes due to the presence of shot noise. The voltage noise spectra show a common signature of the presence of spikes under different operating conditions, even in the absence of excitation. The SNR exhibits intrinsic stochastic resonance when varying S. For a sinusoidal excitation current with amplitude 1.5 μA/cm2 and frequency 50 Hz, the SNR presents optimal values around 0.2 μm2. When considering the presence of ambient noise in the excitation current, extrinsic stochastic resonance is found for S > 0.6 μm2.

Exchange biased spin valve-based gating flux sensor

A hybrid type of magnetic sensor, combining the advantages of both fluxgate sensors and giant magnetoresistance sensors (GMR), was developed in this work by applying the fluxgate principle into the GMR sensors. The well-known measuring principle of the fluxgate sensor is based on the offset of the hysteresis curve and the second harmonic characteristic using the phase sensitive detection technique. The GMR spin valve was used as the soft magnetic core and the pickup coil of the fluxgate. Based on the harmonic analysis using Fourier series, the second harmonic component of the hybrid GMR-fluxgate sensor output was found to be dominated. The sensitivity of the device was maximized by turning the amplitude and the phase of the sinusoidal excitation current. The obtained sensitivity was 1.52 mV/mT and the field noise was found to be 5.7 nT/√Hz@1Hz. The non-hysteresis of the transfer V-B curve was achieved, and the nonlinearity was about 2.5% within the operation range of ±0.2 mT. The proposed sensor is an appropriate design for low field measurements and geomagnetic applications.

One-axis hysteresis motor driven magnetically suspended reaction sphere

This paper presents the design, modeling, control, and experimental results for a one-axis magnetically suspended reaction sphere (1D-MSRS) driven by a hysteresis motor. The goal of this work is twofold: (a) to conduct a preliminary study for magnetically suspended reaction sphere for three-axis spacecraft attitude control, and (b) study the potential of hysteresis motors for the reaction wheel/sphere drives. The 1D-MSRS uses a hysteresis motor with a spherical rotor made of solid steel. The rotor sphere is magnetically suspended in all translational directions, and is driven about the vertical axis by a bearingless hysteresis motor. We present the modeling and control of the magnetic suspension of the bearingless motor in the 1D-MSRS, and the hysteresis motor dynamics are analyzed by a hysteresis motor equivalent circuit model. The 1D-MSRS system has experimentally demonstrated a starting torque of 8.9 mNm under 0.7 A peak sinusoidal excitation current. With this excitation the sphere can run up to 12,000 rpm synchronously in the presence of air drag. This study demonstrates that the hysteresis motor has strong potential for use in high-speed, low-vibration reaction wheels.