Dynamic Modeling and Design of a Radial Hydrostatic Piston Pump for Integrated Pump-Motor

2021 ◽  
Author(s):  
Md Minal Nahin ◽  
Garrett R. Bohach ◽  
F. N. U. Nishanth ◽  
Eric L. Severson ◽  
James D. Van de Ven
Keyword(s):  
Power Density ◽  
Electric Motor ◽  
Current Trend ◽  
Operating Conditions ◽  
Piston Pump ◽  
Critical Parameters ◽  
Electrical Machine ◽  
Hydraulic Pump ◽  
Frictional Loss ◽  
Detailed Model

Abstract There is a current trend towards the electrification of high force/torque density machines that have traditionally been dominated by diesel engine driven hydraulics. Power dense electric machines tend to favor high operating speeds whereas a hydraulic pump is more efficient at low speed and high torque conditions. The power density of a pump can be increased by decreasing the displacement and increasing the operating speed to provide the flow demand. This miniaturization of the pump allows it to be directly integrated into an electric motor inside a single casing. This integrated pump-motor is free of shaft seals and eliminates a set of bearings otherwise required when coupling an electric motor and pump with a shaft. Additionally, the leakage from the hydraulic pump can be used as coolant for the electrical machine, thereby improving the power density. In this paper, a hydrostatic radial piston pump has been evaluated for integration with an axial flux PM machine. The proposed hydrostatic piston pump uses a spherical head piston that can tilt while reciprocating inside the cylinder, eliminating the need for a joint at the slipper. To reduce the frictional loss between the slipper pad and the cam at high operating speeds, the cam freely rotates. A detailed model of the pump, with focus on the hydrostatic piston slipper, has been developed and a grid search approach has been utilized to select the critical parameters of the pump. Finally, an efficiency map has been presented for this pump at different operating conditions which shows around 86% efficiency at the 12500 rpm speed for 7 MPa pressure differentials.

scholarly journals Modeling and Optimization Study of a Tightly Integrated Rotary Electric Motor-Hydraulic Pump

2019 ◽  
Author(s):  
Garrett R. Bohach ◽  
Nishanth ◽  
Eric Severson ◽  
James D. Van de Ven
Keyword(s):  
Electric Motor ◽  
Piston Pump ◽  
Valve Timing ◽  
Hydraulic Pump ◽  
Detailed Model ◽  
Flow Rates ◽  
Design And Optimization ◽  
Piston Cylinder ◽  
Optimization Study ◽  
Four Quadrant

Abstract To meet the growing trend of electrification of mechanical systems, this paper presents a compactly integrated electric motor and hydraulic pump. The proposed application for this machine requires high flow rates at low pressure differentials and four quadrant operation. The hydraulic pump architecture selected for this machine is a radial ball piston pump. An inside impinged version of this architecture allows for efficient filling of the chambers and is radial balanced, both of which allow highspeed operation for increased power density. The radial ball piston pump is less expensive to manufacture and is radially more compact than a standard radial cylindrical piston pump. A model of the pump and the integrated electric motor have been created to study scaling relationships and drive detailed design and optimization. The scaling study considers how displacement is affected by pump diameter, and how the diameter and required torque change with angular velocity. The detailed model considers the effect of valve timing, piston-cylinder clearance, and pump geometry on the efficiency. The model is then exercised in an optimization of the machine parameters.

Cavitation Driven Impact in a Hydraulic Piston Pump: A Theoretical and Experimental Investigation

1997 ◽  
Author(s):  
Bernhard Manhartsgruber ◽  
R. Scheidl
Keyword(s):  
Basin Of Attraction ◽  
Supply System ◽  
Operating Conditions ◽  
Piston Pump ◽  
Strong Nonlinearity ◽  
Suction System ◽  
Detailed Model ◽  
Practical Examination ◽  
Axial Piston ◽  
The Basin Of Attraction

Abstract The occurrence of cavitation in a huge hydraulic supply system of a rolling mill which caused a severe defect in an axial piston pump is investigated by a mathematical model of the complex suction system. It comprises wave propagation in pipes and hoses, a detailed model of the pump including each of its nine cylinders, cavitation therein, the charge and discharge processes of these cylinders with the intake duct, and several accessories influencing the hydraulic processes. Results obtained by this model are compared with on-site experiments. Countermeasures which have been proposed are evaluated by our model and their practical examination is reported. Due to the strong nonlinearity of cavitation the dynamical system shows two attracting limit sets, one with and one without cavitation. The operating conditions of the original supply system cause startup conditions which do not lie in the basin of attraction of the non-cavitating attractor.

scholarly journals Reliability-Oriented Design of Inverter-Fed Low-Voltage Electrical Machines: Potential Solutions

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4144
Author(s):  
Yatai Ji ◽  
Paolo Giangrande ◽  
Vincenzo Madonna ◽  
Weiduo Zhao ◽  
Michael Galea
Keyword(s):  
Power Density ◽  
High Speed ◽  
High Performance ◽  
Low Voltage ◽  
Electrical Machines ◽  
Design Stage ◽  
Switching Frequency ◽  
Special Focus ◽  
Electrical Machine ◽  
Engineering Approach

Transportation electrification has kept pushing low-voltage inverter-fed electrical machines to reach a higher power density while guaranteeing appropriate reliability levels. Methods commonly adopted to boost power density (i.e., higher current density, faster switching frequency for high speed, and higher DC link voltage) will unavoidably increase the stress to the insulation system which leads to a decrease in reliability. Thus, a trade-off is required between power density and reliability during the machine design. Currently, it is a challenging task to evaluate reliability during the design stage and the over-engineering approach is applied. To solve this problem, physics of failure (POF) is introduced and its feasibility for electrical machine (EM) design is discussed through reviewing past work on insulation investigation. Then the special focus is given to partial discharge (PD) whose occurrence means the end-of-life of low-voltage EMs. The PD-free design methodology based on understanding the physics of PD is presented to substitute the over-engineering approach. Finally, a comprehensive reliability-oriented design (ROD) approach adopting POF and PD-free design strategy is given as a potential solution for reliable and high-performance inverter-fed low-voltage EM design.

The influences of operating conditions and design configurations on the performance of symmetric electrochemical capacitors

2016 ◽  
Vol 18 (41) ◽  
pp. 28626-28647 ◽  
Author(s):  
Innocent S. Ike ◽  
Iakovos Sigalas ◽  
Sunny E. Iyuke
Keyword(s):  
Energy Density ◽  
Power Density ◽  
Electrochemical Capacitors ◽  
Electrochemical Capacitor ◽  
Operating Conditions ◽  
Modelling And Simulation ◽  
Charging Current ◽  
Current Densities

The influence of different charging current densities, charging times and several structural designs on symmetric electrochemical capacitor (EC) performance, including capacitance, energy density and power density, has been investigated via modelling and simulation.

The Performance Analysis and Experimental Research of Multiple Oil Ports Axial Piston Pump which Able to Control the Movement of Differential Cylinder Directly in the Closed Circuit

2011 ◽  
Vol 308-310 ◽  
pp. 388-400
Author(s):  
Xiao Gang Zhang ◽  
Long Quan
Keyword(s):  
Digital Simulation ◽  
Flow Distribution ◽  
Closed Circuit ◽  
Piston Pump ◽  
Distribution Area ◽  
Axial Piston Pump ◽  
Hydraulic Pump ◽  
Asymmetric Flow ◽  
New Type ◽  
Axial Piston

In order to realize that an asymmetric flow piston pump can control an asymmetric differential cylinder, a proposal about the application of an asymmetric flow-distributing axial piston pump is put forward. The new type of piston pump can output the flows with two different values to control the movement of the differential cylinder directly in the closed circuit and realize much ideal result of the control of the differential cylinder by a single pump. Also a simulation model of the hydraulic pump is established under the circumstance of SimulationX software, considering the characteristics of the movement of an individual piston, the oil compressibility, and the flow distribution area changed with the rotation angle. The key data of the pump is defined by means of digital simulation. In particular, an analysis is made on the dimension of the unloading groove of the port plate and the characteristics of the flow pulse of the pump. Furthermore, an experimental model pump is manufactured, the basic performances of the pump is tested on the experimental platform at various rotatory speeds such as pressure, flow and noise, in the end the accuracy of the principle is verified.

Improving the Volumetric Efficiency of the Axial Piston Pump

2012 ◽  
Vol 134 (11) ◽  
Author(s):  
Shu Wang
Keyword(s):  
Operating Conditions ◽  
Volumetric Efficiency ◽  
Valve Plate ◽  
Piston Pump ◽  
Efficient Design ◽  
Axial Piston Pumps ◽  
Definition Of ◽  
Engineering Practices ◽  
First Time ◽  
Axial Piston

The volumetric efficiency is one of the most important aspects of system performance in the design of axial piston pumps. From the standpoint of engineering practices, the geometric complexities of the valve plate (VP) and its multiple interactions with pump dynamics pose difficult obstacles for optimization of the design. This research uses the significant concept of pressure carryover to develop the mathematical relationship between the geometry of the valve plate and the volumetric efficiency of the piston pump. For the first time, the resulting expression presents the theoretical considerations of the fluid operating conditions, the efficiency of axial piston pumps, and the valve plate designs. New terminology, such as discrepancy of pressure carryover (DPC) and carryover cross-porting (CoCp), is introduced to explain the fundamental principles. The important results derived from this study can provide clear recommendations for the definition of the geometries required to achieve an efficient design, especially for the valve plate timings. The theoretical results are validated by simulations and experiments conducted by testing multiple valve plates under various operating conditions.

scholarly journals Measurements and Analysis of AC Losses in HTS Windings of Electrical Machine for Different Operation Modes

2021 ◽  
Vol 11 (6) ◽  
pp. 2741
Author(s):  
Sergey Zanegin ◽  
Nikolay Ivanov ◽  
Vasily Zubko ◽  
Konstantin Kovalev ◽  
Ivan Shishov ◽  
...  
Keyword(s):  
Magnetic Field ◽  
High Temperature ◽  
High Temperature Superconductor ◽  
High Temperature Superconductors ◽  
Transport Current ◽  
Operating Conditions ◽  
Ac Losses ◽  
Electrical Machine ◽  
2Nd Generation ◽  
Motor Mode

The article is devoted to the study of losses in devices based on high-temperature superconductors of the 2nd generation. The complexity of the devices under study increases from a single rack coil to a winding assembled from several coils, and finally to an electric machine operating in generator mode. This is the way to experimentally study the behavior of 2nd generation high temperature superconductor (2G HTS) carrying a transport current in various conditions: self-field, external DC, and AC magnetic field. Attention is also paid to the losses in the winding during its operation from the inverter, which simulates the operating conditions in the motor mode of a propulsion system.

Characteristics Analyses of Energy Consumption for Boom Closed Circuit of Hydraulic Excavators

2012 ◽  
Vol 170-173 ◽  
pp. 3491-3494
Author(s):  
Ming Dong Chen ◽  
Ding Xuan Zhao
Keyword(s):  
Energy Consumption ◽  
Mathematical Models ◽  
Operating Conditions ◽  
Closed Circuit ◽  
Load Drop ◽  
Hydraulic Pump ◽  
Full Load ◽  
Power Characteristics ◽  
Hydraulic Excavators ◽  
Power And Energy

The boom with closed circuit in Hydraulic Excavators, which is made up of motor, hydraulic pump and accumulator, was put forward based on analysis of the operating condition of ordinary hydraulic excavators and mathematical models of system were built. Power characteristics of main power elements were obtained under typical operating conditions, and then the energy consumption characteristics were analyzed. The results show that the installed power and energy consumption will be reduced using boom with closed circuit, and no-load drop and full load rise of boom are the worst operating conditions.

Pressure Transients in an Axial Piston Hydraulic Pump

1974 ◽  
Vol 188 (1) ◽  
pp. 189-199 ◽  
Author(s):  
B. O. Helgestad ◽  
K. Foster ◽  
F. K. Bannister
Keyword(s):  
Noise Reduction ◽  
Operating Conditions ◽  
Valve Plate ◽  
Hydraulic Pump ◽  
Noise Emission ◽  
Relief Valve ◽  
Pressure Transients ◽  
Theoretical Predictions ◽  
Axial Piston

A method is given for calculating pressure transients in an axial piston hydraulic pump. Some theoretical predictions are given of the effect of port timing and the effect of introducing restricting grooves at the ends of the kidney ports in the valve plate and suggestions are made of the effects of these parameters on noise emission; comparative measurements of noise are then quoted that support the general arguments. A parallel shot is recommended as the best compromise for the restrictor groove geometry to give good results over the widest range of operating conditions, including reverse rotation. Finally, mention is made of the use of a relief valve in the port plate for noise reduction.

scholarly journals Optimized Thermal Efficiency of Rotor and Stator Using CFD

2020 ◽  
Vol 6 (6) ◽  
pp. 29-37
Author(s):  
Md. Shahwaz Hussain ◽  
Sujata Pouranik
Keyword(s):  
Temperature Distribution ◽  
Air Flow ◽  
Operating Conditions ◽  
Electrical Machine ◽  
Total Efficiency ◽  
Transfer Pattern ◽  
Turbulence Effect ◽  
Total Temperature ◽  
Simulation Results ◽  
And Performance

The space between rotor and stator plays a very important role in the design and performance of rotating machinery. The thickness of the gap can vary considerably depending on the size and operating conditions for the different types of rotating machines. Analysis the air velocity and temperature distribution over the air flow gap in stator and motor. Changing the design of rotor to develop turbulence in air flow gap. Compare the velocity and temperature distribution of proposed design with previous studies. The simulation results pinpoint also the periodic heat transfer pattern from the rotor surface and this provides useful information for the prediction of the temperature distribution inside the rotating electrical machine. The simulation results of case-1 show about 117°C temperature inside the rotor machine. Then increase the number of slot inside the rotor machine the total temperature of the rotor machine decreases up to 76°C. Due to low temperature total efficiency of the system increases. And also reduces the loss due to heat. The turbulence effect inside the rotor increase in third case. Due to turbulence effect the air cover large amount of area inside the rotor. So total temperature of the rotor casing decreases. In a system where volume is held constant, there is a direct relationship between Pressure and Temperature. For this case, when the pressure increases then the temperature also increases. When the pressure decreases, then the temperature decreases. So pressure in third case decrease upto1.26Pa and temperature 76 °C.

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