87,346 research outputs found
Accurate Inverter Error Compensation and Related Self-Commissioning Scheme in Sensorless Induction Motor Drives
No full textThis paper presents a technique for accurately identifying and compensating the inverter nonlinear voltage errors that deteriorate the performance of sensorless field-oriented controlled drives at low speed. The inverter model is more accurate than the standard signum-based models that are common in the literature, and the self-identification method is based on the feedback signal of the closed-loop flux observer in dc current steady-state conditions. The inverter model can be identified directly by the digital controller at the drive startup with no extra measures other than the motor phase currents and dc-link voltage. After the commissioning session, the compensation does not require to be tuned furthermore and is robust against temperature detuning. The experimental results, presented here for a rotor-flux-oriented SFOC IM drive for home appliances, demonstrate the feasibility of the proposed solution
End effects in linear tubular motors and compensated position sensorless control based on pulsating voltage injection
No full textThe sensorless position control of permanent-magnet (PM) synchronous motors can be successfully implemented by superimposing a high-frequency voltage signal on the control voltage. In this paper, the position estimation is obtained by means of a high-frequency sinusoidal voltage signal injected along the estimated d-axis. Several methods proposed in the literature obtain the position estimation by tracking the zero condition of the high-frequency q current component. We propose a new approach that also exploits the d-axis high-frequency current component and allows working with injected voltage signal of reduced amplitude, thus reducing noise and additional losses. The main contribution of this paper relies in the compensation of the motor end effects due to the finite length of the tubular motor armature. These effects must be taken into account in the motor modeling because they cause an error in the position estimation that varies with the motor position. The modeling of the phenomenon and a proper compensation technique are proposed in this paper. Last, a simplified integral-type controller is used to estimate motor position instead of the commonly adopted proportional-integral controller plus integrator, and this requires a low-effort design. Experiments on a linear tubular PM synchronous-motor prototype are presented to validate the theoretical analysis and evidence the feasibility of the proposed sensorless technique
Position estimation delays in signal injection-based sensorless PMSM drives
No full textThe causes of position estimation delays and their effects on the sensorless control of permanent magnet synchronous motor drives are investigated. The position of a permanent magnet synchronous machine is estimated via the injection of high frequency voltage signals. The delays under investigation are due to the digital implementation of the control algorithm and to the digital filters adopted for decoupling the inspection signals from the fundamental components of the stator current measures. If not correctly modeled and compensated, such delays can reduce the performance of the control scheme. Experimental results are provided, proving the accuracy of the modeling approach and the effectiveness of the related compensation strateg
Experimental evaluation of current carrying capacity of printed circuit stator coils
No full textThis paper illustrates some results about the experimental characterization of current carrying capacity (CCC) of printed circuit board (PCB) stator coils. Thermometric tests have been carried out with both DC and AC power supply, in order to evaluate the relationship between flowing current and coils temperature rise and quantify with experiments the impact of frequency related parasitic phenomena on coils overheating. Temperature spatial distribution has been also investigated by means of thermal-imaging techniques. A comparison between experimental data and the most spread guideline for PCB traces sizing is provided
IPM motor rotor design by means of FEA-based multi-objective optimization
No full textThe design optimization of IPM motors for wide speed ranges is pursued by means of a FEA-based multi-objective genetic algorithm (MOGA). Respect to previous works in the literature, the proposed approach evaluates the motor performance with a very limited number of simulations, making FEA optimization more attractive. The 3 goal functions (motor torque, torque ripple and flux weakening capability) are evaluated by means of 7 static FEA runs, that means nearly 20 seconds per tentative motor with a laptop computer. The paper is focused on the rotor design, since it is the most controversial part of IPM design and the most difficult to be modeled due to magnetic saturation. Three different approaches are presented: a fast one, based on 2- objective optimization, a hybrid one, based on 2-objective optimization and 3-objective refinement, and actual 3-objective optimization. The results presented here will be the base for future, more comprehensive optimization
Optimal traces arrangement in planar magnetic based slotless PMSM
No full textThis paper presents an automated procedure for coils conductors’ arrangement. The procedure has been applied to slotless permanent magnet machines having planar magnetic stator windings, such as printed circuit board (PCB) coils. The proposed method is driven by optimization techniques whose goal is to find a proper arrangement of PCB traces, which make up stator windings in order to find some
trade-off solutions, optimal respect to some objective functions. A time-efficient numerical model has been developed to reduce computational load and thus make the optimization based
design attractive. The paper shows results of numerical simulations of an annular permanent magnet synchronous
machine having 200 poles and PCB windings
FEA-based multi-objective optimization of IPM motor design including rotor losses
No full textThe design optimization of IPM motors for wide speed ranges is considered in this paper by means of a FEAbased multi-objective genetic algorithm (MOGA). The minimum number of simulations is pursued for the fast evaluation of four goal functions: maximum torque, minimum torque ripple, maximum flux weakening capability and minimum rotor harmonic losses. The paper is focused on the rotor design, that is the most controversial aspect of IPM design due to the difficult modeling dominated by magnetic saturation. Three original results are presented: the elimination of higher order torque ripple harmonics and the minimization of FEA evaluations by means of a random rotor position offset and the evaluation, by means of the same static FEA runs, of the eddy current losses in the rotor core
Competitive learning applied to detect broken rotor bars in induction motors
No full textThis paper describes an automatic, load independent procedure for the detection of broken bars in squirrel cage induction machines based on the analysis of the space-vector of voltages induced in the stator windings after supply disconnection. In this condition, no current flows in the stator windings and the voltages measurable at its terminals are due to flux produced by rotor current. If there are some broken bars and the rotor symmetry is compromised, the voltages induced in the stator windings results distorted and some particular harmonics increase their amplitudes. The diagnostic technique is based on monitoring these voltage harmonics by analyzing the space vector of the voltages induced in the stator windings via Short-Time MUSIC: (STMUSIC) time-frequency pseudo-representation. The output data of MUSIC processing are fed into an unsupervised self-organizing neural network (NN) with an ABCL training algorithm that is able to successfully discriminate between data measured on healthy and faulty motors
Comparison between Permanent Magnet Assisted Synchronous Reluctance Motors Considering Electric Vehicle Driving Cycle
No full textPermanent magnet assisted synchronous reluctance motors are becoming a promising solution for electric vehicles, thanks to their high power density, efficiency and increased constant power speed range. The design of the rotor geometry, in terms of amount of PM to be inserted within the machine rotor slots, constitutes a challenging task which has to considered the requirements in terms of speed and torque during a typical electric vehicle driving cycle. This paper presents a comparison among different permanent magnet assisted synchronous reluctance motors for electric vehicles, by also investigating the influence of the number of pole pairs on the main performance indicators. The selected machines are therefore compared in terms of overall efficiency and operating limits, thus leading to some design insights for a given outer envelope
LIVING HISTORY FOR THE CUPERTINO HISTORICAL MUSEUM: A FEASIBILITY STUDY
No full textThis study had the purpose of determining the feasibility of establishing a living history program at McClellan Ranch Park for The Cupertino Historical Museum. The results of the study will be integrated into the long-range planning scheduled for the fall.
The primary objectives of the study were: To assess the need for expanded history programs, especially living history, in Cupertino. To recommend preliminary program activities based on the results of the community needs assessment. To evaluate McClellan Ranch Park as the site for the new program. To project the capital and operating costs of expanding the programs of the Museum to include living history. To identify possible funding sources for the program.
In addition, the study provides The Cupertino Historical Society and Museum with a preliminary assessment of the market and the needs of the community as they relate to local history programs, which can be used for other program planning, a basis for projecting costs for2 future projects, and a document useful when presenting museum planning concepts to the City of Cupertino or other organizations and individuals, including those approached for funding assistance. Not within the scope of this study were considerations of major restoration costs or costs associated with collections management for new programs
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