Design of Current Regulator for Induction Machines at Low Sampling-to-Fundamental Frequency Ratios with Improved Current Observer

2019 ◽  
Author(s):  
Yang Xu ◽  
Chikara Morito ◽  
Robert D. Lorenz
Keyword(s):  
Fundamental Frequency ◽  
Induction Machines ◽  
Frequency Ratios

Operation of an induction motor supplied by voltage with interharmonics

2018 ◽  
Vol 2 (1) ◽  
pp. 47-53 ◽  
Author(s):  
Tomasz Drabek
Keyword(s):  
Induction Motor ◽  
Fundamental Frequency ◽  
Skin Effect ◽  
Induction Machines ◽  
Positive Sequence ◽  
Rotor Speed ◽  
Negative Sequence ◽  
Three Phase ◽  
Total Multiplicity ◽  
Rotor Cage

The paper discusses the effects of interharmonics, i.e. frequencies higher than the fundamental frequency, not being its total multiplicity, in the voltage supplying the induction motor. The emergence of interharmonics in a three-phase grid is mainly the result of the swinging of peak mains voltages. In induction machines, this results in the occurrence of currents with interharmonic and subharmonic frequencies, the generation of alternating moments, the swinging of the rotor speed and the change in the RMS value of the current of the fundamental frequency. The paper explores these phenomena simulation, taking into account the skin effect of currents in the rotor cage. The research was carried out both for interharmonics with a positive sequence of phases as well as for the negative sequence. The paper is a continuation of work [1].

scholarly journals Miniaturized substrate-integrated coaxial line bandpass filter with improved upper stopband

2017 ◽  
Vol 9 (7) ◽  
pp. 1441-1445 ◽  
Author(s):  
Yunlong Lu ◽  
Yi Wang ◽  
Taijun Liu ◽  
Bo Yu ◽  
Kai Li
Keyword(s):  
Theoretical Analysis ◽  
Fundamental Frequency ◽  
Bandpass Filter ◽  
Spiral Structure ◽  
Coaxial Line ◽  
Space Filling ◽  
Resonance Property ◽  
Circuit Structure ◽  
Frequency Ratios ◽  
Rejection Band

A miniaturized substrate-integrated coaxial line (SICL) bandpass filter with improved upper stopband using asymmetrical spiral stub-loaded resonators is presented in this paper. Owing to the space-filling feature of the spiral structure, the size of the proposed filter is significantly reduced. A theoretical analysis is carried out to examine the resonance property of the proposed resonator. It is found that the frequency ratios of the second and third harmonics to the fundamental frequency can be extended to 2.86 and 4.4. Benefiting from the circuit structure and SICL technology, the designed filter has a small size, wide stopband, low crosstalk, and high-density integration ability. The measured results show that the proposed filter, with dimensions of 0.051λ0 × 0.044λ0, operates at 1.056 GHz and the 20-dB rejection band is extended to 3.94f0.

Theory of Helmholtz-Beat Frequencies

1984 ◽  
Vol 1 (3) ◽  
pp. 308-322 ◽  
Author(s):  
Rudolf A. Rasch
Keyword(s):  
Fundamental Frequency ◽  
Beat Frequency ◽  
Numerical Data ◽  
Fundamental Frequencies ◽  
The Absolute ◽  
Frequency Ratios

In musical tuning, deviations from the simple frequency ratios of pure consonant intervals are often necessary. These deviations are called temperings. They result in beats in the sounding interval. Rules are developed according to which the beat frequencies can be determined, both exactly and by way of easy integer approximations. Beat frequencies of consonant intervals are most easily expressed as relative beat frequencies, the quotient of the beat frequency and the lower fundamental frequency of the interval. The relative beat frequency is a constant for a certain interval in a certain tuning, whereas the absolute beat frequencies vary with fundamental frequencies. Also described are the relationships between the beat frequencies of the three intervals that make up a consonant triad. Numerical data are given for five model tunings: Pythagorean, equal, Silbermann, meantone, and Salinas.

Music Training and Vocal Production of Speech and Song

2008 ◽  
Vol 25 (5) ◽  
pp. 419-428 ◽  
Author(s):  
Elizabeth L. Stegemööller ◽  
Erika Skoe ◽  
Trent Nicol ◽  
Catherine M. Warrier ◽  
Nina Kraus
Keyword(s):  
Statistical Analysis ◽  
Fundamental Frequency ◽  
Musical Experience ◽  
Music Listening ◽  
Vocal Production ◽  
Music Training ◽  
Listening Experience ◽  
Similarities And Differences ◽  
Frequency Ratios ◽  
Fine Tune

Studying similarities and differences between speech and song provides an opportunity to examine music's role in human culture. Forty participants divided into groups of musicians and nonmusicians spoke and sang lyrics to two familiar songs. The spectral structures of speech and song were analyzed using a statistical analysis of frequency ratios. Results showed that speech and song have similar spectral structures, with song having more energy present at frequency ratios corresponding to those ratios associated with the 12-tone scale. This difference may be attributed to greater fundamental frequency variability in speech, and was not affected by musical experience.Higher levels of musical experience were associated with decreased energy at frequency ratios not corresponding to the 12-tone scale in both speech and song. Thus, musicians may invoke multisensory (auditory/vocal-motor) mechanisms to fine-tune their vocal production to more closely align their speaking and singing voices according to their vast music listening experience.

scholarly journals An Accurate Discrete Current Controller for High-Speed PMSMs/Gs in Flywheel Applications

Energies ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1458
Author(s):  
Xiang Zhang ◽  
Yunlong Chen ◽  
Yves Mollet ◽  
Jiaqiang Yang ◽  
Johan Gyselinck
Keyword(s):  
Fundamental Frequency ◽  
High Speed ◽  
Controller Design ◽  
Storage System ◽  
Cross Coupling ◽  
Sampling Period ◽  
Energy Storage System ◽  
Current Loop ◽  
Current Controller ◽  
Frequency Ratios

High-speed Permanent-Magnet Synchronous Motors/Generators (PMSMs/Gs) in a Flywheel Energy Storage System (FESS) are faced with high cross-coupling voltages and low switching-to-fundamental frequency ratios. High cross-coupling voltages between d-q axis current loops lead to transient current errors, which is more serious at lower switching-to-fundamental-frequency ratios. If the delays are not properly considered during the current controller design in a digital control system, the low switching-to-fundamental-frequency ratios may result in oscillatory or unstable responses. In this study, an accurate discrete current controller for high-speed PMSMs/Gs is proposed based on an accurate discrete model that takes the phase and magnitude errors generated during the sampling period into consideration, and an Extended State Observer (ESO) is applied to estimate and compensate the back EMF error. The cross-coupling problem is well settled, and the current loop dynamic at lower switching-to-fundamental frequency ratios is improved. Finally, the proposed discrete controller is validated on a 12,000 rpm PMSM/G prototype.

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