The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Based on in-depth research on the structure of train operation dispatching command system (TDCS) and its operation maintenance status, a TDCS integrated operation and maintenance platform is designed in this paper. This platform realizes real-time monitoring of the computers, network equipment, databases, software and hardware and other infrastructure based on the businesses, effective pre-alarm for...
Based on in-depth research on the characteristics of the current train receiving and departure operations of China's railway stations, the urgent need of traffic standardization, automation and safety control and the status quo of the construction of the traffic command system in China, the overall scheme for the establishment of a TDCS/CTC-based train receiving and departure operation management-control...
A second-order integral flux observer (SOIFO-FLL) with dc component and harmonics attenuation capability is proposed for PMSM sensorless control in this paper. Due to the nonzero integral initial value, parameter mismatch, converter nonlinearities and detection errors, the estimated rotor flux by the conventional methods, pure integrator and low-pass filter (LPF) suffer the dc component and harmonics...
The ship shaft power generation system based on a stand-alone brushless doubly-fed induction generator (BDFIG) have demonstrated excellent saving-energy performance. This paper presents a new control scheme of the stand-alone BDFIG for supplying unbalanced loads in the ship shaft power generation system. The positive-and negative-sequence components of the unbalanced power winding (PW) voltage caused...
In this paper, one improved speed estimation method of linear induction motor (LIM) based on stator current observer is developed, of which the observer is deeply investigated and fully optimized. Then it discusses the estimation accuracy of observer influenced by different disturbances, and the effect of observer parameters on dynamic response is analyzed. Through comprehensive simulation, the speed...
Due to the current constraint of linear induction machine (LIM) and voltage constraint of inverter, the output thrust of LIM is limited. So, in order to make LIM output thrust as large as possible within current and voltage limit, firstly, the maximum thrust per ampere (MTPA) is used to achieve maximum thrust with limited current in low speed. Secondly, with the speed of LIM increasing, the voltage...
The linear induction machine (LIM) suffers heavily from low efficiency due to its large air-gap length, the influence of end-effects, and the partial load conditions. Several loss minimization control (LMC) techniques have been developed for LIM to adjust the flux to an optimal level to reduce the losses in the steady state. However, these methods are not applicable during dynamic process, since it...
Brushless doubly-fed induction generator (BDFIG) is a new type of ac induction machine and can be used for both grid-connected and stand-alone power generation. The conventional control methods for the BDFIG almost all rely on the encoder, which brings many limitations in terms of cost, complexity, reliability, and so on. This paper presents a new rotor speed observer (RSO) for the encoderless operation...
A novel 4/4 stator/rotor single-phase doubly salient permanent magnet machine (DSPMM) with asymmetric stator poles is proposed in this paper. The stator poles of proposed machine are distributed non-uniformly along the circumference of the stator yoke. Firstly, it investigates the new topology and operation principle based on diagram description and mathematical derivation. Then, the dimension equation,...
By means of studying on impacting pricing of ancient ceramic artworks, and auction prices unified according to the auction-year inflation rate and conversion rate; thereby, ancient ceramic artworks' price is only connected with pricing factors. In addition, in order to overcome influence of the six factors: glaze, pattern decoration, craft, dynasties, type of ware and kiln to fluctuations in the price...
In order to meet the current requirement of low voltage apparatus protection function test, a design of three phase high current generator based on virtual instrument technology is proposed. The coarse-fine tuning voltage regulator with the compensation transformer structure is used in the main circuit of the current generator, which not only could extend the range of current regulation, improve current...
To maximize the efficiency of wave attenuation of anti-wave forest with low cost, a multi-objective optimal layout selection model using improved fuzzy entropy was proposed. A new entropy weight calculation formula was introduced in the fuzzy entropy to improve the reliability of entropy weight. The effect of each vegetation factor was quantified and analyzed. The law of wave attenuation was revealed...
To achieve good steady-state performance and quick dynamic response, one model predictive current control (MPCC) method is proposed in this paper to replace the traditional proportional-integral (PI) controller to regulate the control winding (CW) current of brushless doubly-fed machine (BDFM) for stand-alone power generation system. The MPCC is developed based on the unified reference frame dq model...
This paper considers a multiuser massive multiple-input multiple-output (MIMO) uplink transmission with the help of an Nr-antenna amplify-and-forward (AF) relay. Assume that the base station (BS) is equipped with a large array of Nd antennas but supported by a far smaller number, K, of radio-frequency (RF) chains, which greatly reduce hardware complexity and cost. A hybrid processing is proposed to...
The utilization of millimeter wave (mmWave) frequency has shown great potential in developing the next-generation wireless systems. Conventional fully digital precoding which needs one radio frequency (RF) chain per antenna is impractical in large-scale mmWave systems because of the high hardware complexity, power consumption and cost. In this paper, we propose a scheme with hybrid precoding at the...
We report an innovative magnetron sputtering deposition process to continuously fabricate long metal-coated optical fiber for distributed sensing applications. A 60-meter long optical fiber coated with titanium and palladium was made for distributed hydrogen sensing. Fabrication details and sensing performance are presented.
To solve the complexity and difficulty of tree species selection of wavebreak forest in a certain area effectively, an improved fuzzy optimum selection model (FOSM) using the tree species suitability multi-index system is proposed for wavebreak forest in flood control planning. And a new relative membership degree formula is introduced in the FOSM. Through the improved FOSM, the tree species recommended...
The brushless doubly-fed induction generator (BDFIG) shows commercial potential for the wind-power generation and ship shaft power generation due to its brushless operation as compared with doubly-fed induction generator. This paper proposes an improved vector control scheme oriented on the power winding flux reference frame to achieve stable stand-alone operation. To improve the dynamic performance...
In order to satisfy rate requirement in the enhanced mobile broadband (eMBB) application group, wireless technologies as Air Interfaces (AI) are widely studied, including non-orthogonal multiple access (NOMA) and massive multiple-input multiple-output (mMIMO). In this paper, we propose a Minorization-Maximization (MM) based hybrid precoding scheme in NOMA-mMIMO system. Firstly, we introduce a user...
The distributed solving algorithms and experiments of the rendezvous problem for multiple quadrotors system are discussed in this paper. Firstly, the mathematical model of rendezvous problem is established and the distributed solution strategy based on coordinate variable is given. Secondly, the optimal control protocol based on consensus algorithm is derived. The cost function is defined, and the...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.