Research on the Principle and Characteristic of Compound Switch-Mode Hydraulic Power Supply

2006 ◽  
Author(s):  
Jianwei Cao ◽  
Linyi Gu ◽  
Feng Wang ◽  
Ying Chen
Keyword(s):  
Flow Rate ◽  
Power Supply ◽  
High Speed ◽  
Low Pressure ◽  
Power Supplies ◽  
Duty Ratio ◽  
Hydraulic Pressure ◽  
Hydraulic Power ◽  
Load Pressure ◽  
Switch Mode

Switch-mode hydraulic power supply is a hydraulic pressure converting unit made of some distributed hydraulic components, which can boost or buck hydraulic pressure steplessly, with low power loss (about 20%) and continuous flow-rate[1][2]. There are two types of switch-mode hydraulic power supply. One is pressure boost type and the other is pressure buck type. For the pressure boost power supply, changing of the pressure is realized through instantaneous braking of the large inertia load in the hydraulic inductor. For the buck power supply, changing of the pressure is realized through pulse flow-rate and low-pressure hydraulic complement (see "Switch-mode Hydraulic Power Supply Theory", 2005 ASME, IMECE-FPST No.79019)[2]. Because the output pressure is determined by the load, pressure buck is still requisite in pressure boost power supply. At the same time the system is unstable and with low efficiency. To deal with the problem that the pressure boost type switch mode hydraulic power supply is unfit for the low pressure load, the principle and the structure of a compounded switch-mode hydraulic power supply are proposed in this paper. In the compounded switch-mode hydraulic power supply, a pressure buck power supply is cascaded after a pressure boost power supply. At the same time, the output hydraulic capacitor of the pressure buck power supply and the input hydraulic capacitor of the pressure boost power supply are removed, which leads to the direct connection of the hydraulic inductors of the two power supplies Because of the same working principles of the two power supplies, one of the hydraulic inductors can be removed. Pressure boost and pressure buck are realized through the synchronically control of the two high - speed switch valves using PWM signal. No matter the outer load determined pressure is higher or lower than the pump pressure, compounded switch-mode hydraulic power supply can provide the proper power (not flow rate) matching actuators' consumption through regulating the duty ratio of the control signal. Therefore the optimal energy -saving is realized. Experimental research shows that the compounded switch-mode hydraulic power supply can realize a continuous bucking and boosting pressure with different duty ratio and the whole efficiency is at least 80%.

Switchmode Hydraulic Power Supply Theory

2005 ◽  
Author(s):  
Jianwei Cao ◽  
Linyi Gu ◽  
Feng Wang ◽  
Minxiu Qiu
Keyword(s):  
Flow Rate ◽  
Dynamic Characteristics ◽  
Power Supply ◽  
Power Loss ◽  
High Speed ◽  
Hydraulic Pressure ◽  
Hydraulic Systems ◽  
Hydraulic Pump ◽  
Hydraulic Power ◽  
Supply Pressure

Switchmode hydraulic power supply is a new kind of energy-saving pressure converting system, which is originally proposed by the authors. It is mainly applied in multiple-actuator hydraulic systems, and installed between hydraulic pump and actuators (one switchmode hydraulic power supply for one actuator). It can provide pressure or flow rate that is adapted to the consumption of each actuator in the system by boosting or bucking the pressure, with low power loss, and conveniently, through high-speed switch valves, just like a hydraulic pressure transformer. There are two basic types of switchmode hydraulic power supply: pressure boost and pressure buck. Their structures and working principles are introduced. The dynamic characteristics of two typical types of switchmode hydraulic power supply, the pressure boost type and the pressure buck type, were analyzed through simulations and experiments. The performances were evaluated, and improvements on the efficiency of switchmode hydraulic power supply were proposed.

Research on Electro-Hydraulic Control of Propellers of the Underwater Vehicles With Switch-Mode Hydraulic Power Supply

2006 ◽  
Author(s):  
Jianwei Cao ◽  
Linyi Gu ◽  
Feng Wang ◽  
Ying Chen
Keyword(s):  
Control System ◽  
Power Supply ◽  
High Speed ◽  
Weight Ratio ◽  
Pulse Frequency ◽  
Hydraulic Pressure ◽  
Hydraulic Control ◽  
Pulse Frequency Modulation ◽  
Hydraulic Power ◽  
Switch Mode

Switch-mode hydraulic power supply is a hydraulic pressure converting unit made of some distributed hydraulic components, which can boost or buck hydraulic pressure continuously with low power loss (about 20%)and continuous flow-rate. There are two types of switch-mode hydraulic power supply, pressure boost and pressure buck. (see "Switch-mode Hydraulic Power Supply Theory", 2005 ASME, IMECE-FPST No.79019)[1]. This paper introduces a new propeller driving system using the motor of the switch-mode hydraulic power supply for the underwater vehicle. And PFM (Pulse Frequency Modulation) control of high-speed switch-valves is applied to adjust the rotation speed of the propeller. The system has advantages over the widely used servo-valve valve-control system and pump-control system on the energy-weight ratio, anti-contamination performance and energy-saving capacity.

Conventional DC Voltage Operating System for High Speeed Traction Power Supplies Using LLC-HPQC Control

2015 ◽  
Vol 4 (4) ◽  
pp. 118
Author(s):  
Ch. Lenin Babu ◽  
P. Harinath Reddy ◽  
T. Reddi Sekhar
Keyword(s):  
Power Supply ◽  
High Speed ◽  
Reactive Power ◽  
Design Procedure ◽  
Power Supplies ◽  
Parameter Design ◽  
Voltage Level ◽  
Harmonic Compensation ◽  
Traction Power Supply ◽  
Traction Power

<p>In this paper a hybrid power quality compensator (HPQC) is proposed for compensation in cophase traction power supply and minimum dc operation voltage is achievable for high-speed traction power supply. The parameter design procedure for minimum dc operation voltage in HPQC as well as minimum voltage rating with load PF is discussed. The detailed discussions of proposed circuit configurations of HPQC are provided in section II, together with comparison with conventional RPC. In comparison with conventional railway power compensator proposed HPQC can achieve reduced dc link voltage level. It is also verified through simulations results that the LLC-HPQC would operate at the minimum voltage with the proposed parameter design. HPQC is able to provide system unbalances, reactive power, and harmonic compensation in cophase traction power with reduced operation voltage. The cophase traction power supply with proposed HPQC is suitable for high-speed traction applications.</p>

Design of a Crank-Slider Spool Valve for Switch-Mode Circuits With Experimental Validation

2017 ◽  
Vol 140 (6) ◽  
Author(s):  
Shaun E. Koktavy ◽  
Alexander C. Yudell ◽  
James D. Van de Ven
Keyword(s):  
Flow Rate ◽  
High Speed ◽  
Experimental Validation ◽  
Viscous Friction ◽  
Transition Time ◽  
Switching Frequency ◽  
Experimental Demonstration ◽  
High Switching Frequency ◽  
Switch Mode ◽  
Spool Valve

A challenge in realizing switch-mode hydraulic circuits is the need for a high-speed valve with fast transition time and high switching frequency. The work presented includes the design and modeling of a suitable valve and experimental demonstration of the prototype in a hydraulic boost converter. The design consists of two spools driven by crank-sliders, designed for 120 Hz maximum switching frequency at a flow rate of 22.7 lpm. The fully open throttling loss is designed for <2% of the rated pressure of 34.5 MPa. The transition time is less than 5% (0.42 ms at 120 Hz) of the total cycle and the duty cycle is adjustable from 0 to 1. Leakage and viscous friction losses in the design are less than 2% of the rated hydraulic energy per cycle. The experimental results agreed well with the model resulting in a 3% variation in transition time. The use of the high-speed valve in a pressure boosts converter demonstrated boost ratio capabilities of 1.08–2.06.

Phase-Shift High-Speed Valve for Switch-Mode Control

2010 ◽  
Vol 133 (1) ◽  
Author(s):  
James D. Van de Ven ◽  
Allan Katz
Keyword(s):  
Phase Shift ◽  
High Speed ◽  
Viscous Friction ◽  
Duty Ratio ◽  
Switching Frequency ◽  
Full Potential ◽  
Hydraulic Actuator ◽  
Mode Control ◽  
Switch Mode ◽  
Variable Displacement

Hydraulic applications requiring a variation in the speed or torque of actuators have historically used throttling valve control or a variable displacement pump or motor. An alternative method is switch-mode control that uses a high-speed valve to rapidly switch between efficient on and off states, allowing any hydraulic actuator to have virtually variable displacement. An existing barrier to switch-mode control is a fast and efficient high-speed valve. A novel high-speed valve concept is proposed that uses a phase shift between two tiers of continuously rotating valve spools to achieve a pulse-width modulated flow with any desired duty ratio. An analysis of the major forms of energy loss, including throttling, compressibility, viscous friction, and internal leakage, is performed on a disk spool architecture. This analysis also explores the use of a hydrodynamic thrust bearing to maintain valve clearance. A nonoptimized design example of a phase-shift valve operating at 100 Hz switching frequency at 10 l/min demonstrates an efficiency of 73% at a duty ratio of 1 and 64% at 0.75 duty ratio. Numerous opportunities exist for improving this efficiency including design changes and formal optimization. The phase-shift valve has the potential to enable switch-mode hydraulic circuits. The valve has numerous benefits over existing technology yet requires further refinement to realize its full potential.

scholarly journals A Self-Powered and Low Pressure Loss Gas Flowmeter Based on Fluid-Elastic Flutter Driven Triboelectric Nanogenerator

Sensors ◽  
2020 ◽  
Vol 20 (3) ◽  
pp. 729 ◽  
Author(s):  
Trung Kien Phan ◽  
Song Wang ◽  
Yan Wang ◽  
He Wang ◽  
Xiu Xiao ◽  
...  
Keyword(s):  
Flow Rate ◽  
Pipe Flow ◽  
Pressure Loss ◽  
High Speed ◽  
Volume Flow Rate ◽  
Low Pressure ◽  
Triboelectric Nanogenerator ◽  
Mean Velocity ◽  
Electric Voltage ◽  
Self Powered

A self-powered and low pressure loss gas flowmeter is presently proposed and developed based on a membrane’s flutter driven triboelectric nanogenerator (TENG). Such a flowmeter, herein named “TENG flowmeter”, is made of a circular pipe in which two copper electrodes are symmetrically fixed and a nonconductive, thin membrane is placed in the middle plane of the pipe. When a gas flows through the pipe at a sufficiently high speed, the membrane will continuously oscillate between the two electrodes, generating a periodically fluctuating electric voltage whose frequency can be easily measured. As demonstrated experimentally, the fluctuation frequency (fF) relates linearly with the pipe flow mean velocity (Um), i.e., fF ∝ Um; therefore, the volume flow rate Q (=Um × A) = C1fF + C2, where C1 and C2 are experimental constants and A is the pipe cross-sectional area. That is, by the TENG flowmeter, the pipe flow rate Q can be obtained by measuring the frequency fF. Notably, the TENG flowmeter has several advantages over some commercial flowmeters (e.g., vortex flowmeter), such as considerable lower pressure loss, higher sensitiveness of the measured flow rate, and self-powering. In addition, the effects of membrane material and geometry as well as flow moisture on the flowmeter are investigated. Finally, the performance of the TENG flowmeter is demonstrated.

The Modern Direct-Hydraulic System

1946 ◽  
Vol 154 (1) ◽  
pp. 178-208 ◽  
Author(s):  
F. H. Towler
Keyword(s):  
Hydraulic System ◽  
High Speed ◽  
Hydraulic Press ◽  
Hydraulic Pressure ◽  
Hydraulic Pump ◽  
Hydraulic Power ◽  
The Press ◽  
Hydraulic Accumulator ◽  
Work Done ◽  
Full Pressure

The first hydraulic press invented by Joseph Bramah in 1795 employed the direct-hydraulic system; i.e. hydraulic pressure was directly supplied to the press cylinder by a hydraulic pump and, therefore, the pressure exerted by the press ram was directly proportional to the pressure supplied by the pump, and the speed of the press ram was directly proportional to the delivery of the pump. Later developments in the use of hydraulic power resulted in the invention of the hydraulic accumulator to store liquid under pressure. With the accumulator system the speed and pressure exerted by the press ram are not controlled by the pump, and in fact they cannot be controlled with any precision; also there is considerable wastage of power when the press ram is operating at less than full pressure. The advent of the high-speed reciprocating ram pump has produced the modern direct-hydraulic system in which the press and pump form one self-contained unit. The power to drive the pump is in direct proportion to the work done by the press, and the speed and pressure exerted by the press ram can be precisely controlled. The author considers that a saving of at least 75 per cent in electric power can be made by conversion from the accumulator system to the direct-hydraulic system. Indicator diagrams are reproduced in the paper to show the saving in power which can be achieved by the direct-hydraulic system, and a comparison is made between the power consumption, in kilowatt-hours, of a direct-hydraulic cartridge-drawing press and a mechanical double-rack press doing the same operation. The paper includes a number of illustrations of direct-hydraulic presses, ranging from those of Bramah to present-day types.

Decentralized Compact Hydraulic Power Supply by High Speed Components

2019 ◽  
Vol 12 (1) ◽  
pp. 66-71
Author(s):  
David Roth ◽  
Georg Jacobs ◽  
Tobias Pietrzyk ◽  
Katharina Schmitz
Keyword(s):  
Power Supply ◽  
High Speed ◽  
Hydraulic Power
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