scholarly journals A Review of High-Speed Electro-Hydrostatic Actuator Pumps in Aerospace Applications: Challenges and Solutions

2019 ◽  
Vol 141 (5) ◽  
Author(s):  
Qun Chao ◽  
Junhui Zhang ◽  
Bing Xu ◽  
Hsinpu Huang ◽  
Min Pan
Keyword(s):  
Power Density ◽  
High Power ◽  
High Speed ◽  
Operating Conditions ◽  
Future Research ◽  
High Power Density ◽  
Pump Design ◽  
Aerospace Applications ◽  
Delivery Pressure ◽  
Increasing Demand

The continued development of electro-hydrostatic actuators (EHAs) in aerospace applications has put forward an increasing demand upon EHA pumps for their high power density. Besides raising the delivery pressure, increasing the rotational speed is another effective way to achieve high power density of the pump, especially when the delivery pressure is limited by the strength of materials. However, high-speed operating conditions can lead to several challenges to the pump design. This paper reviews the current challenges including the cavitation, flow and pressure ripples, tilting motion of rotating group and heat problem, associated with a high-speed rotation. In addition, potential solutions to the challenges are summarized, and their advantages and limitations are analyzed in detail. Finally, future research trends in EHA pumps are suggested. It is hoped that this review can provide a full understanding of the speed limitations for EHA pumps and offer possible solutions to overcome them.

Design and Characteristics of Microfocus X-ray Source with Sealed Tube and Transmissive Target on Diamond Window

2021 ◽  
Vol 79 (6) ◽  
pp. 631-640
Author(s):  
Takaaki Tsunoda ◽  
Takeo Tsukamoto ◽  
Yoichi Ando ◽  
Yasuhiro Hamamoto ◽  
Yoichi Ikarashi ◽  
...  
Keyword(s):  
Power Density ◽  
High Power ◽  
High Speed ◽  
Electronic Device ◽  
High Reliability ◽  
Electronic Devices ◽  
Lithium Ion ◽  
High Power Density ◽  
High Magnification ◽  
X Ray

Electronic devices such as medical instruments implanted in the human body and electronic control units installed in automobiles have a large impact on human life. The electronic circuits in these devices require highly reliable operation. Radiographic testing has recently been in strong demand as a nondestructive way to help ensure high reliability. Companies that use high-density micrometer-scale circuits or lithium-ion batteries require high speed and high magnification inspection of all parts. The authors have developed a new X-ray source supporting these requirements. The X-ray source has a sealed tube with a transmissive target on a diamond window that offers advantages over X-ray sources having a sealed tube with a reflective target. The X-ray source provides high-power-density X-ray with no anode degradation and a longer shelf life. In this paper, the authors will summarize X-ray source classification relevant to electronic device inspection and will detail X-ray source performance requirements and challenges. The paper will also elaborate on technologies employed in the X-ray source including tube design implementations for high-power-density X-ray, high resolution, and high magnification simultaneously; reduced system downtime for automated X-ray inspection; and reduced dosages utilizing quick X-ray on-and-off emission control for protection of sensitive electronic devices.

Research on a high power density mechanical-electrical-hydraulic regenerative suspension system for high-speed tracked vehicles

2021 ◽  
pp. 095440702110610
Author(s):  
Chao Wang ◽  
Weijie Zhang ◽  
Guosheng Wang ◽  
Yong Guo
Keyword(s):  
Power Density ◽  
High Power ◽  
High Speed ◽  
Excitation Amplitude ◽  
Suspension System ◽  
Level Energy ◽  
High Power Density ◽  
Damping Force ◽  
Tracked Vehicles ◽  
Energy Regeneration

High power density energy regeneration is one of the effective solutions to solve the contradiction between improving the damping performance and energy consumption of active suspension. The hydraulic commutator is used to realize hydraulic rectification and hydraulic variable speed/pump/motor with few teeth difference gear pairs is used to match the speed, combined with permanent magnet motor power generation and power supply to put forward kilowatt level high power density mechanical-electrical-hydraulic regenerative suspension system for high-speed tracked vehicles. The mathematical model and fluid-solid-thermo-magnetic multiphysics coupling model are built to analyze the damping performance and regenerative characteristics of the system under passive and semi-active working conditions. The simulation results show that the damping force of the system increases with the increase of the road excitation amplitude and the semi-active control can be realized by adjusting the duty cycle with the PWM control rectifier module. The high power density mechanical-electrical-hydraulic regenerative suspension system can realize kilowatt level energy regeneration, and the regenerative efficiency is more than 50% under low-frequency excitation. The temperature rise of the system is low during operation, which is helpful to improve the reliability and service life.

scholarly journals Design and Analysis of a Dual Rotor Multiphase Brushless DC Motor for its Application in Electric Vehicles

2021 ◽  
Vol 11 (6) ◽  
pp. 7846-7852
Author(s):  
M. Hussain ◽  
A. Ulasyar ◽  
H. Sheh Zad ◽  
A. Khattak ◽  
S. Nisar ◽  
...  
Keyword(s):  
Fault Tolerance ◽  
Power Density ◽  
Electric Vehicles ◽  
High Power ◽  
Operating Conditions ◽  
Design Parameters ◽  
High Power Density ◽  
Bldc Motor ◽  
Brushless Dc ◽  
Stator Current

The main objective of this paper is to study the effect of phase numbers in the dual rotor Brushless DC (BLDC) motor for its application in Electric Vehicles (EVs). The performance of two novel 5-, and 7-phase dual rotor BLDC motors is compared against the standard 3-phase dual rotor BLDC motor. The proposed motors combine the positive characteristics of multiphase BLDC motor and the dual rotor BLDC motor thus achieving better fault tolerance capability, high power density, and less per phase stator current. Finite Element Method (FEM) was used to design the 3-, 5-, and 7-phase dual-rotor BLDC motors. The design parameters and operating conditions are kept the same for a fair comparison. The stator current and torque performance of the proposed motors were obtained with FEM simulation and were compared with the standard 3-phase dual rotor BLDC motor. It is possible to use low power rating power electronics switches for the proposed motor. The simulation results also validate low torque ripples and high-power density in the proposed motors. Finally, the fault analysis of the designed motors shows that the fault tolerance capability increases as the phase number increases.

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