High Performance Nonsalient Sensorless BLDC Motor Control Strategy From Standstill to High Speed

2018 ◽  
Vol 14 (10) ◽  
pp. 4365-4375 ◽  
Author(s):  
Xinxiu Zhou ◽  
Xi Chen ◽  
Cong Peng ◽  
Yongping Zhou
Author(s):  
Ye Yuan ◽  
Douglas Thomson ◽  
Renliang Chen

The coaxial compound configuration has been proposed as a concept for future high-performance rotorcraft. The co-axial rotor system does not require an anti-torque device, and a propeller provides axial thrust. A well-designed control strategy for the propeller is necessary to improve the performance and the flight dynamics characteristics. A flight dynamics model of coaxial compound helicopter is developed to analyze these influences. The performance and the flight dynamics characteristics in different propeller strategies were first investigated. The results show that there is an improvement in the performance in high-speed flight when the propeller provides more propulsive forces. It also illustrates that a reasonable allocation of the rotor and the propeller in providing thrust can further reduce the power consumption in the mid speed range. In other words, the propeller control strategy can be an effective method to improve the cruise-efficiency. The flight dynamics analysis in this paper includes trim and handling qualities. The trim results prove that the propeller strategy can affect the collective pitch, longitudinal cyclic pitch, and the pitch attitude. If the control strategy is designed only to decrease the required power, it will result in a discontinuity in the trim characteristics. Handling qualities are investigated based on the ADS-33E-PRF requirement. The result demonstrates that the bandwidth and phase delay results and eigenvalue results in various speed at different propeller strategies are all satisfied. However, some propeller control strategies lead to severe inter-axis coupling in high-speed flight. Based on these results, this paper proposes the propeller control strategy for the coaxial compound helicopter. This strategy ensures good trim characteristics and handling qualities, which satisfy the related requirements, and improves the flight range or the performance in high-speed flight.


2014 ◽  
Vol 494-495 ◽  
pp. 1253-1256
Author(s):  
Hui Wang

In this thesis , the control strategy based on sensorless BLDCM(Brushless DC Motor) has been researched.A control system for BLDCM operating on ADSP-BF548 has been given. we focus on studying the control strategy of sensorless BLDC motor based on back-EMF detection, and present a control system for BLDC motor based on ADSP-BF548 special for motor control. The calculation method of back EMF in BLDC motor was deduced and the hardware circuit of line voltage detecting was designed. A pre-position starting tactics based on back EMF detection and a tactics of phase converting by postponing back-emf-zero-crossing detecting was designed. The signal wave was filtered by postponing back-emf-zero-crossing detecting when back-emf-zero-crossing had been detected. To release the phase delay caused by hardware filtering, a phase compensation algorithm has been designed. The PID adjusting algorithm and other strategy are designed in this program. Experimental results show that the control system has good speed adjusting performance and runs stably.


2021 ◽  
Vol 12 (4) ◽  
pp. 195
Author(s):  
Mengyuan Dong ◽  
Yuezhen Fan ◽  
Donglei Yu ◽  
Qingchun Wang

Vehicle driving safety is an important performance indicator for vehicles, and there is still much room for development in the active safety control of electric vehicles. A vehicle rollover is an important road traffic safety problem, as rollover accidents cause serious casualties and huge economic losses. It is very easy for vehicles in high-speed sharp turns or high-speed overtaking to roll over; in order to improve the vehicle in these conditions with the anti-rollover stability, this study proposed a real-time motor control strategy, mainly through the acquisition of vehicle attitude data and the use of multi-sensor fusion on the vehicle running state for real time. The lateral load transfer rate was used as the vehicle rollover evaluation index, and the test results indicate that when the real-time rollover index exceeds the set limit safety threshold, the motor speed is reduced through active control so that the vehicle avoids rollover accidents, or the risk of rollover is reduced. The STM32F103RET6 was used as the main chip for hardware design, control board fabrication, control program software design, and joint testing of software and hardware. The tests and data analysis prove that the motor control strategy is reliable in real time and can significantly improve the active safety of electric vehicles.


Author(s):  
Werachet Khan-Ngern ◽  
Wiwat Keyoonwong ◽  
Narongrit Chatsiriwech ◽  
Pongsakorn Sangnopparat ◽  
Ponghiran Mattayaboon ◽  
...  

Author(s):  
N. Yoshimura ◽  
K. Shirota ◽  
T. Etoh

One of the most important requirements for a high-performance EM, especially an analytical EM using a fine beam probe, is to prevent specimen contamination by providing a clean high vacuum in the vicinity of the specimen. However, in almost all commercial EMs, the pressure in the vicinity of the specimen under observation is usually more than ten times higher than the pressure measured at the punping line. The EM column inevitably requires the use of greased Viton O-rings for fine movement, and specimens and films need to be exchanged frequently and several attachments may also be exchanged. For these reasons, a high speed pumping system, as well as a clean vacuum system, is now required. A newly developed electron microscope, the JEM-100CX features clean high vacuum in the vicinity of the specimen, realized by the use of a CASCADE type diffusion pump system which has been essentially improved over its predeces- sorD employed on the JEM-100C.


Author(s):  
Marc H. Peeters ◽  
Max T. Otten

Over the past decades, the combination of energy-dispersive analysis of X-rays and scanning electron microscopy has proved to be a powerful tool for fast and reliable elemental characterization of a large variety of specimens. The technique has evolved rapidly from a purely qualitative characterization method to a reliable quantitative way of analysis. In the last 5 years, an increasing need for automation is observed, whereby energy-dispersive analysers control the beam and stage movement of the scanning electron microscope in order to collect digital X-ray images and perform unattended point analysis over multiple locations.The Philips High-speed Analysis of X-rays system (PHAX-Scan) makes use of the high performance dual-processor structure of the EDAX PV9900 analyser and the databus structure of the Philips series 500 scanning electron microscope to provide a highly automated, user-friendly and extremely fast microanalysis system. The software that runs on the hardware described above was specifically designed to provide the ultimate attainable speed on the system.


Author(s):  
M. T. Postek ◽  
A. E. Vladar

One of the major advancements applied to scanning electron microscopy (SEM) during the past 10 years has been the development and application of digital imaging technology. Advancements in technology, notably the availability of less expensive, high-density memory chips and the development of high speed analog-to-digital converters, mass storage and high performance central processing units have fostered this revolution. Today, most modern SEM instruments have digital electronics as a standard feature. These instruments, generally have 8 bit or 256 gray levels with, at least, 512 × 512 pixel density operating at TV rate. In addition, current slow-scan commercial frame-grabber cards, directly applicable to the SEM, can have upwards of 12-14 bit lateral resolution permitting image acquisition at 4096 × 4096 resolution or greater. The two major categories of SEM systems to which digital technology have been applied are:In the analog SEM system the scan generator is normally operated in an analog manner and the image is displayed in an analog or "slow scan" mode.


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