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.

Crank-Slider Spool Valve for Switch-Mode Circuits

2015 ◽  
Author(s):  
Alexander C. Yudell ◽  
Shaun E. Koktavy ◽  
James D. Van de Ven
Keyword(s):  
Duty Cycle ◽  
High Speed ◽  
Volumetric Flow Rate ◽  
Viscous Friction ◽  
Total Power ◽  
Design Solution ◽  
Switching Frequency ◽  
Trade Offs ◽  
Switch Mode ◽  
Transition Times

A key component of switch-mode hydraulic circuits is a high-speed two-position three-way valve with a variable duty cycle. This paper presents a new valve architecture that consists of two valve spools that are axially driven by crank-slider mechanisms. By phase shifting the two crank links, which are on a common crankshaft, the duty cycle of the valve is adjusted. The two spools split and re-combine flow such that two switching cycles occur per revolution of the crankshaft. Because the spools move in a near-sinusoidal trajectory, the peak spool velocities are achieved at mid-stroke where the valve land transitions across the ports, resulting in short valve transition times. The spool velocity is lower during the remainder of the cycle, reducing viscous friction losses. A dynamic model is constructed of this new valve operating at 120 Hz switching frequency in a switch-mode circuit. The model is used to illustrate design trade-offs and minimize energy losses in the valve. The resulting design solution transitions to the on-state in 5% of the switching period and the combined leakage and viscous friction in the valve dissipate 1.7% of the total power at a pressure of 34.5MPa and volumetric flow rate of 22.8L/min.

Development of a High-Speed On-Off Valve for Switch-Mode Control of Hydraulic Circuits With Four-Quadrant Control

2010 ◽  
Author(s):  
Jeslin J. Wu ◽  
James D. Van de Ven
Keyword(s):  
High Speed ◽  
Average Power ◽  
Viscous Friction ◽  
Valve Design ◽  
Rotating Disc ◽  
Mode Control ◽  
Switch Mode ◽  
Variable Displacement ◽  
Four Quadrant ◽  
Hydraulic Circuits

Hydraulic circuits are typically controlled by throttling valves or variable displacement pump/motors. The first method throttles fluid for a desired pressure output and excess energy is lost through heat. While variable displacement pumps are more efficient, they are often large and expensive. An alternate method is the switch-mode control of hydraulic circuits through high-speed on-off valves. The proposed on-off valve design makes use of a continuously rotating disc to modulate flow between on and off states; the average power output or pulse duration is determined by the relative phase shift between the input and output ports. The addition of a directional valve to the the high-speed three-way valve allows any fixed displacement actuator to behave like a virtually variable displacement unit that is capable of four-quadrant control. In this paper a mathematical model focusing on the throttling, compressibility, internal leakage and viscous friction losses is developed and utilized to optimize the valve design for highest efficiency.

A Highly Integrated GaAs-based Module for DC-DC Regulators

2013 ◽  
Vol 2013 (1) ◽  
pp. 000604-000610 ◽  
Author(s):  
Greg J. Miller
Keyword(s):  
High Speed ◽  
Low Voltage ◽  
Field Effect Transistors ◽  
Cost Effective ◽  
Switching Frequency ◽  
Critical Element ◽  
High Current ◽  
High Switching Frequency ◽  
Gate Driver ◽  
High Level

There is a need and desire to push low voltage point-of-load voltage regulators (POL VRs) to higher switching frequencies. The main reason for this is to increase power density. Silicon MOSFET-based solutions are rapidly approaching their technology limits and are not capable of providing multi-MHz switching frequency for high current (&gt;10A) applications. Gallium Arsenide (GaAs) field effect transistors (FETs) can switch much faster, enabling cost-effective, high-current, high switching frequency POL VRs. Recent advances in GaAs technologies have enabled the demonstration of 5MHz VRs and provide a path to even higher frequency (&gt;50MHz) Power Supply in Package (PSiP) solutions. The high-speed GaAs power FETs are the “engine” to enable efficient high switching frequency POL VRs, but certain key elements must be designed appropriately to realize the desired performance. The gate driver and power path impedances must be minimized. To do this, a high level of integration is required, thus packaging is a critical element. New embedded die packaging solutions enable this high level of integration, dramatically reducing key parasitic impedances that can otherwise throttle performance, while also facilitating very compact multi-chip modules.

Design of a High-Speed On-Off Valve

2009 ◽  
Author(s):  
Allan A. Katz ◽  
James D. Van de Ven
Keyword(s):  
High Speed ◽  
First Generation ◽  
Viscous Friction ◽  
Input Power ◽  
Future Research ◽  
Switching Frequency ◽  
Efficient Design ◽  
Output Pressure ◽  
Parameter Values ◽  
Valve Control

On-off control of hydraulic circuits enables significant improvements in efficiency compared with throttling valve control. A key enabling technology to on-off control is an efficient high-speed on-off valve. This paper documents the design of an on-off hydraulic valve that minimizes input power requirements and increases operating frequency over existing technology by utilizing a continuously rotating valve design. This is accomplished through use of spinning port discs, which divides the flow into pulses, with the relative phase between these discs determining the pulse duration. A mathematical model for determining system efficiency is developed with a focus on the throttling, leakage, compressibility, and viscous friction power losses of the valve. Parameters affecting these losses were optimized to produce the most efficient design under the chosen disc-style architecture. Using these optimum parameter values, a first generation prototype valve was developed and experimental data collected. The experimental valve matched predicted output pressure and flows well, but suffered from larger than expected torque requirements and leakage. In addition, due to motor limitations, the valve was only able to achieve a 64Hz switching frequency versus the designed 100Hz frequency. Future research will focus on improving the prototype valve and improving the analytical model based on the experimental results.

Digital Feed-Forward Control of Gas Mixture With High-Speed Valve Switching

2018 ◽  
Author(s):  
Christopher R. Martin ◽  
Todd D. Batzel
Keyword(s):  
Flow Rate ◽  
High Speed ◽  
Gas Flow ◽  
Pulse Width Modulation ◽  
Modulation Scheme ◽  
Switching Frequency ◽  
Gas Mixture ◽  
Constant Flow Rate ◽  
Feed Forward Control ◽  
Flow Rate Control

To address a need for digital gas mixture control, this paper presents a valve design for digital gas flow rate control without a feedback measurement. This design uses a transonic nozzle to regulate a constant flow rate with partial pressure recovery and a pulse-width modulation scheme to actuate flow rate without needing precise location of a throttle body. Experimental results from a prototype are presented showing linear variation of flow with respect to duty cycle and switching frequency consistent with the valve’s theory of operation. Outliers are especially prominant as frequency is varied, and are believed to be due to acoustic effects in the supply line.

Experimental Investigation of a Switched Inertance Hydraulic System

2014 ◽  
Author(s):  
Min Pan ◽  
James Robertson ◽  
Nigel Johnston ◽  
Andrew Plummer ◽  
Andrew Hillis
Keyword(s):  
Hydraulic System ◽  
High Speed ◽  
Small Diameter ◽  
Switched System ◽  
Experimental Results ◽  
Experimental Investigations ◽  
Switching Frequency ◽  
Rotary Valve ◽  
High Switching Frequency ◽  
Flow Loss

This article reports on experimental investigations of a switched inertance hydraulic system (SIHS), which is designed to control the flow and pressure of a hydraulic supply. The switched system basically consists of a switching element, an inductance and a capacitance. Two basic modes, a flow booster and a pressure booster, can be configured in a three-port SIHS. It is capable of boosting the pressure or flow with a corresponding drop in flow or pressure respectively. This technique makes use of the inherent reactive behaviour of hydraulic components. A high-speed rotary valve is used to provide sufficiently high switching frequency and minimise the pressure and flow loss at the valve orifice, and a small diameter tube is used to provide an inductive effect. In this article, a flow booster is introduced as the switched system for investigation. The measured steady state and dynamic characteristics of the rotary valve are presented, and the dynamics characteristics of the flow booster are investigated in terms of pressure loss, flow loss and system efficiency. The speed of sound is measured by analysis of the measured dynamic pressures in the inertance tube. A detailed analytical model of a SIHS is applied to analyse the experimental results. Experimental results on a flow booster rig show a very promising performance for the SIHS.

scholarly journals 40 kW/L High Switching Frequency Three-Phase AC 400 V All-SiC Inverter

2013 ◽  
Vol 740-742 ◽  
pp. 1081-1084 ◽  
Author(s):  
Kensuke Sasaki ◽  
Shinji Sato ◽  
Kohei Matsui ◽  
Yoshinori Murakami ◽  
Satoshi Tanimoto ◽  
...  
Keyword(s):  
Equivalent Circuit ◽  
Output Power ◽  
High Speed ◽  
Switching Frequency ◽  
Test Results ◽  
Circuit Boards ◽  
High Switching Frequency ◽  
Three Phase ◽  
Drive Circuit ◽  
Forced Air

We, the R&D Partnership for Future Power Electronics Technology (FUPET), have reported a forced-air-cooled DC 600 V three-phase AC 400 V inverter built with SiC-JFETs and SiC-SBDs and designed to attain an output power density (OPD) of 40 kW/L with a switching frequency (fSW) of 50 kHz. This paper reports the test results of this inverter attaining an OPD of 40 kW/L in operating a 3-phase motor with fSW = 50 kHz, and an OPD of more than 60 kW/L in operating an equivalent circuit with fSW = 20 kHz by adopting specialized high speed drive circuit boards.

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