CA2221667A1 - An electrically controlled solenoid valve driver with compensation for coil resistance changes - Google Patents
An electrically controlled solenoid valve driver with compensation for coil resistance changes Download PDFInfo
- Publication number
- CA2221667A1 CA2221667A1 CA 2221667 CA2221667A CA2221667A1 CA 2221667 A1 CA2221667 A1 CA 2221667A1 CA 2221667 CA2221667 CA 2221667 CA 2221667 A CA2221667 A CA 2221667A CA 2221667 A1 CA2221667 A1 CA 2221667A1
- Authority
- CA
- Canada
- Prior art keywords
- solenoid
- valve
- temperature
- coil
- voltage
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
- F16K31/00—Actuating devices; Operating means; Releasing devices
- F16K31/02—Actuating devices; Operating means; Releasing devices electric; magnetic
- F16K31/06—Actuating devices; Operating means; Releasing devices electric; magnetic using a magnet, e.g. diaphragm valves, cutting off by means of a liquid
- F16K31/0603—Multiple-way valves
- F16K31/061—Sliding valves
- F16K31/0613—Sliding valves with cylindrical slides
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B13/00—Details of servomotor systems ; Valves for servomotor systems
- F15B13/02—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors
- F15B13/04—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor
- F15B13/044—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor operated by electrically-controlled means, e.g. solenoids, torque-motors
- F15B13/0442—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor operated by electrically-controlled means, e.g. solenoids, torque-motors with proportional solenoid allowing stable intermediate positions
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
- F16K31/00—Actuating devices; Operating means; Releasing devices
- F16K31/02—Actuating devices; Operating means; Releasing devices electric; magnetic
- F16K31/06—Actuating devices; Operating means; Releasing devices electric; magnetic using a magnet, e.g. diaphragm valves, cutting off by means of a liquid
- F16K31/0675—Electromagnet aspects, e.g. electric supply therefor
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F7/00—Magnets
- H01F7/06—Electromagnets; Actuators including electromagnets
- H01F7/08—Electromagnets; Actuators including electromagnets with armatures
- H01F7/18—Circuit arrangements for obtaining desired operating characteristics, e.g. for slow operation, for sequential energisation of windings, for high-speed energisation of windings
- H01F7/1844—Monitoring or fail-safe circuits
Landscapes
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Fluid Mechanics (AREA)
- Magnetically Actuated Valves (AREA)
Abstract
To precisely control an electrically controlled solenoid valve, the resistance of the solenoid coil is measured either indirectly through measuring the temperature of the coil or directly by placing a known resistance in series with the solenoid or applying a known current source to the solenoid. Based on the measured coil resistance, the voltage applied to the coil is adjusted so that a desired current through the coil is achieved.
Description
AN ELECTRICALLY CONTROLLED SOLENOID VALVE DRIVER WITH
COMPENSATION FOR COIL RESISTANCE CHANGES
BACKGROUND OF THE INVENTION
This invention relates to a solenoid valve driver and a method of controlling 5 solenoid valves.
Many m~ inPs have parts which are moved by hydraulic or pneumatic cylinders. Such m~e,llin~s use valves to control the cylinders. These valves are often electrically operated. Where a m~ ine operator has a joystick to control each electrical valve, the valves are generally bang-bang (i.e. on-off) or proportional solenoid valves.
10 Solenoid valves are not known for a high degree of accuracy, but they are inexpensive and function satisfactorily in many applications. On the other hand, the inaccuracy of such valves can be problematic where m~e,11ines operated by the valves either move in envelopes having small tolerances or employ closed loop control schemes. For example, imprecise valve control may be satisfactory for a machine with a boom moved by three cylinders 15 where there is an equal number of joysticks such that one joystick controls the valve to each of these cylinders. On the other hand, such imprecision is generally not tolerable where the same boom is moved in three dimensions by a single joystick though a closed loop control scheme.
For precise control of a solenoid valve, a current source has been used to 20 drive the solenoid. Another approach has been to utilize a control system which feeds back actual valve position. A further known option is to dispense with a solenoid valve in favour of a servo controlled valve. However, all of these options are relatively expensive, especially when a machine has a great number of control valve drivers.
This invention seeks to overcome drawbacks of prior solenoid valve drivers.
SUMMARY OF INVENTION
According to the present invention, there is provided a method of controlling a solenoid valve comprising the steps of: applying a control voltage to said valve;
measuring resistance of a solenoid coil of said solenoid valve; adjusting said control voltage based on said measured resistance.
According to another aspect of the present invention, there is provided a driver for an electrically controlled solenoid valve, comprising: a temperature sensor for measuring a temperature of a solenoid coil of said solenoid valve; a compensator responsive to said temperature sensor for adjusting a voltage supply providing a voltage across said coil.
BRIEF DESCRIPTION OF THE DRAWINGS
In the figures which illustrate plerelled embodiments of the invention, figure 1 is a schematic view of a m~chin~ incorporating a solenoid valve made in accordance with this invention, figure 2 is a schematic view of a solenoid valve with a driver made in accordance with this invention, figure 3 is a schem~tic view of one embodiment for the driver of figure 2, and figure 4 is a schematic view of an alternate embodiment for the driver of figure 2.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Turning to figure 1, a m~chine 100 has a boom 102 which is manipulated by hydraulic cylinders 104. Each cylinder is input with working fluid from a solenoid valve 10 associated with a valve manifold 106.
Turning to figure 2, each solenoid valve 10 comprises a valve body 12 and a valve spool 14. An oil inlet 16 and an oil outlet 18 extend through the valve body. The inlet receives oil from an oil pump and the outlet outputs oil to an hydraulic cylinder.
The valve spool has large diameter ends 22a, 22b and a narrow medial portion 24. The valve is biased to a closed position by spring 26 whereat the large diameter ends seal against the valve body.
A solenoid 30 has a solenoid core 32 which abuts end 22a of the valve spool and a coil 34. The coil is electrically connected to a driver 36. A temperature sensor 38 is inserted in the oil inlet 16 and is electrically connected to the driver. A requestor 39 is also electrically connected to the driver.
The driver 36 is detailed in figure 3. Turning to figure 3, the driver comprises a supply voltage source 40 which provides a voltage, Vbat, a pulse width modulator (PWM) 42 which comprises a controlled switch 44, and a controller 46. The temperature sensor 38 and requestor 39 are electrically connected to the controller of the driver. The controller has an internal clock 48 which has a clock period. The controller outputs to the PWM on control line 50 and senses voltage across the solenoid on sensing line 52. In figure 3, the solenoid is modelled as a resistor 130 which represents the coil resistance, Rc.
Referencing figures 2 and 3, in overview of the operation of the driver, a request to open the valve a precise amount may be received by the controller 46 from the requestor 39. (The requestor may comprise, for example, the output from a control algorithm for a joystick.) In response to this request and an input from temperature sensor 38, the controller selects a portion of each clock period (the "duty cycle") during which voltage should be applied to the solenoid coil. Based on this selection, the controller sends 5 comm~n-l~ to the PWM so that the PWM closes its switch 44 dllring the selected portion of each period. The controller measures the voltage applied to the solenoid by monitoring voltage on sensing line 52.
The force on the solenoid core 32 is a function of the average current flowing in the coil 34. The average current is directly proportional to the average voltage applied 10 across the solenoid, and the average voltage is dependent upon the duty cycle. As the force on the solenoid core increases, the solenoid core forces the valve spool 14 to open to a greater and greater extent against the force of spring 26.
The subject invention recognises that the resistance of the coil, Rc, is a variable. Since the average current flowing in the coil 34 is inversely proportional to the 15 actual resistance of the coil, Rc, it is therefore important to be able to determine the actual value of this resistance in order to precisely control valve 10. It is recognised that the variability of the coil resistance is primarily a function of temperature changes.
Temperature sensor 38 is inserted in the oil inlet 16 of valve 10. The temperature of the valve will approximate that of the oil which flows through it. This temperature will also 20 be conducted to the solenoid 30 such that the temperature measured by sensor 38 is a good approximation of the temperature of solenoid 30 and this temperature forms an input to controller 46. The controller uses the temperature information to adjust the average voltage so that the average current flowing through the solenoid is at a desired level.
The controller may adjust the average voltage in several dirrerell~ ways.
Firstly, given that:
ton is the time the waveform is at the supply voltage, Vbat (the rest of the time the waveform is typically at ground or O Volts or -0.7 Volts if a flyback diode is being used) 5 and T is the period of the clock then n = ton / T where n is the amount of time in each period the supply voltage is connected, thus, n is the "duty cycle"
10 and VO = n * Vbat where VO is the nominal average output voltage Based on the temperature indication from sensor 38, the controller may access a look-up table to look up the coil resistance, RneW~ for that temperature. Then, assuming the desired current through the solenoid is idesired and that this current is achieved 15 using VO when the solenoid is at 25~C -- at which temperature the resistance of the coil is Rnominal~ to m~int~in current constant as coil resistance changes to RneW~ the average output voltage is adjusted to match the change in resistance, i.e.:
Vactual = Vo * (RneW/Rnominal) then iactual = Vactual / Rnew = [VO * Rnew / Rnominal] / Rnew = VO / Rnominal ~ idesired 2 5 Therefore, to compensate for the change in solenoid resistance, the controller multiplies the nominal output voltage, VO, by the correction factor (RneW / Rnominal) to obtain the desired output current, idesired Instead of looking up RneW~ based on the temperature, the controller could access a look-up table cont~ining voltage correction factors as a function of temperature.
10 Then:
Vac~ual = Vo * k where k is a correction factor While the temperature sensor 38 has been shown as inserted into the oil inlet, it may equally be inserted into the oil outlet or valve body. Further, a m~rlline often has a considerable number of hydraulic cylinders, each with a controlling valve. In such 15 instance, the valves are normally attached to a common valve manifold as is depicted for machine 100 of figure 1. With this configuration, a single temperature sensor may be inserted in the manifold and the temperature reading used by the controller for each solenoid valve as representative of the temperature of the solenoid.
Figure 4 illustrates an alternate driver. Turning to figure 4 where like parts have been given like reference numerals, a controlled switch 56 having switches 56a and 56b and a reference resistor 58, R,~ l,CC, are connected in series with the solenoid coil resistance 130. The reference resistor is fabricated of a temperature insensitive material.
Controller 146 has a control output 60 to the controlled switch, voltage sensing line 62a to sense the voltage, VreferenCe across the solenoid and voltage sensing line 62b to sense the battery voltage, Vbat In operation of the embodiment of figure 4, controller 146 switches the solenoid off for a brief period of time by sending a control signal to PWM 42, then the controller switches in the reference resistor by sending a control signal to controlled switch 56 resulting in the closing of switch 56. The controller may then sense VreferenCe and estimate the coil resistance, RneW as:
Rnew = R~crc~nce * Vreference / (Vbat~ Vreference) Once RneW is known, a corrected average voltage may be determined utili~ing expressions 1 and 2 set forth hereinbefore.
In this embodiment, the solenoid must be switched off for a sufficiently long time to allow transients to pass.
In another embodiment, the controller first switches the solenoid off then applies a current source onto the solenoid coil. The controller measures the voltage across the coil and then estimates the actual coil resistance using Ohm's law. With the coil resistance known, expression 1 and 2 set forth above are utilised to obtain a corrected average voltage which may be applied to the solenoid.
Although this embodiment uses a testing current source, the output of the testing current source may be m~gnit~1des smaller than the requisite output of a current source which is used to precisely control a solenoid valve. Therefore, the testing current source is much less expensive and smaller than a current source used to control a solenoid 5 valve.
To further enhance the accuracy of the control of the solenoid valve, the controller may be modified to also measure the voltage output by the voltage source. If this voltage is not at its nominal value, the controller may adjust the average voltage to compensate.
Other modifications will be a~parelll to those skilled in the art and, therefore, the invention is defined in the claims.
COMPENSATION FOR COIL RESISTANCE CHANGES
BACKGROUND OF THE INVENTION
This invention relates to a solenoid valve driver and a method of controlling 5 solenoid valves.
Many m~ inPs have parts which are moved by hydraulic or pneumatic cylinders. Such m~e,llin~s use valves to control the cylinders. These valves are often electrically operated. Where a m~ ine operator has a joystick to control each electrical valve, the valves are generally bang-bang (i.e. on-off) or proportional solenoid valves.
10 Solenoid valves are not known for a high degree of accuracy, but they are inexpensive and function satisfactorily in many applications. On the other hand, the inaccuracy of such valves can be problematic where m~e,11ines operated by the valves either move in envelopes having small tolerances or employ closed loop control schemes. For example, imprecise valve control may be satisfactory for a machine with a boom moved by three cylinders 15 where there is an equal number of joysticks such that one joystick controls the valve to each of these cylinders. On the other hand, such imprecision is generally not tolerable where the same boom is moved in three dimensions by a single joystick though a closed loop control scheme.
For precise control of a solenoid valve, a current source has been used to 20 drive the solenoid. Another approach has been to utilize a control system which feeds back actual valve position. A further known option is to dispense with a solenoid valve in favour of a servo controlled valve. However, all of these options are relatively expensive, especially when a machine has a great number of control valve drivers.
This invention seeks to overcome drawbacks of prior solenoid valve drivers.
SUMMARY OF INVENTION
According to the present invention, there is provided a method of controlling a solenoid valve comprising the steps of: applying a control voltage to said valve;
measuring resistance of a solenoid coil of said solenoid valve; adjusting said control voltage based on said measured resistance.
According to another aspect of the present invention, there is provided a driver for an electrically controlled solenoid valve, comprising: a temperature sensor for measuring a temperature of a solenoid coil of said solenoid valve; a compensator responsive to said temperature sensor for adjusting a voltage supply providing a voltage across said coil.
BRIEF DESCRIPTION OF THE DRAWINGS
In the figures which illustrate plerelled embodiments of the invention, figure 1 is a schematic view of a m~chin~ incorporating a solenoid valve made in accordance with this invention, figure 2 is a schematic view of a solenoid valve with a driver made in accordance with this invention, figure 3 is a schem~tic view of one embodiment for the driver of figure 2, and figure 4 is a schematic view of an alternate embodiment for the driver of figure 2.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Turning to figure 1, a m~chine 100 has a boom 102 which is manipulated by hydraulic cylinders 104. Each cylinder is input with working fluid from a solenoid valve 10 associated with a valve manifold 106.
Turning to figure 2, each solenoid valve 10 comprises a valve body 12 and a valve spool 14. An oil inlet 16 and an oil outlet 18 extend through the valve body. The inlet receives oil from an oil pump and the outlet outputs oil to an hydraulic cylinder.
The valve spool has large diameter ends 22a, 22b and a narrow medial portion 24. The valve is biased to a closed position by spring 26 whereat the large diameter ends seal against the valve body.
A solenoid 30 has a solenoid core 32 which abuts end 22a of the valve spool and a coil 34. The coil is electrically connected to a driver 36. A temperature sensor 38 is inserted in the oil inlet 16 and is electrically connected to the driver. A requestor 39 is also electrically connected to the driver.
The driver 36 is detailed in figure 3. Turning to figure 3, the driver comprises a supply voltage source 40 which provides a voltage, Vbat, a pulse width modulator (PWM) 42 which comprises a controlled switch 44, and a controller 46. The temperature sensor 38 and requestor 39 are electrically connected to the controller of the driver. The controller has an internal clock 48 which has a clock period. The controller outputs to the PWM on control line 50 and senses voltage across the solenoid on sensing line 52. In figure 3, the solenoid is modelled as a resistor 130 which represents the coil resistance, Rc.
Referencing figures 2 and 3, in overview of the operation of the driver, a request to open the valve a precise amount may be received by the controller 46 from the requestor 39. (The requestor may comprise, for example, the output from a control algorithm for a joystick.) In response to this request and an input from temperature sensor 38, the controller selects a portion of each clock period (the "duty cycle") during which voltage should be applied to the solenoid coil. Based on this selection, the controller sends 5 comm~n-l~ to the PWM so that the PWM closes its switch 44 dllring the selected portion of each period. The controller measures the voltage applied to the solenoid by monitoring voltage on sensing line 52.
The force on the solenoid core 32 is a function of the average current flowing in the coil 34. The average current is directly proportional to the average voltage applied 10 across the solenoid, and the average voltage is dependent upon the duty cycle. As the force on the solenoid core increases, the solenoid core forces the valve spool 14 to open to a greater and greater extent against the force of spring 26.
The subject invention recognises that the resistance of the coil, Rc, is a variable. Since the average current flowing in the coil 34 is inversely proportional to the 15 actual resistance of the coil, Rc, it is therefore important to be able to determine the actual value of this resistance in order to precisely control valve 10. It is recognised that the variability of the coil resistance is primarily a function of temperature changes.
Temperature sensor 38 is inserted in the oil inlet 16 of valve 10. The temperature of the valve will approximate that of the oil which flows through it. This temperature will also 20 be conducted to the solenoid 30 such that the temperature measured by sensor 38 is a good approximation of the temperature of solenoid 30 and this temperature forms an input to controller 46. The controller uses the temperature information to adjust the average voltage so that the average current flowing through the solenoid is at a desired level.
The controller may adjust the average voltage in several dirrerell~ ways.
Firstly, given that:
ton is the time the waveform is at the supply voltage, Vbat (the rest of the time the waveform is typically at ground or O Volts or -0.7 Volts if a flyback diode is being used) 5 and T is the period of the clock then n = ton / T where n is the amount of time in each period the supply voltage is connected, thus, n is the "duty cycle"
10 and VO = n * Vbat where VO is the nominal average output voltage Based on the temperature indication from sensor 38, the controller may access a look-up table to look up the coil resistance, RneW~ for that temperature. Then, assuming the desired current through the solenoid is idesired and that this current is achieved 15 using VO when the solenoid is at 25~C -- at which temperature the resistance of the coil is Rnominal~ to m~int~in current constant as coil resistance changes to RneW~ the average output voltage is adjusted to match the change in resistance, i.e.:
Vactual = Vo * (RneW/Rnominal) then iactual = Vactual / Rnew = [VO * Rnew / Rnominal] / Rnew = VO / Rnominal ~ idesired 2 5 Therefore, to compensate for the change in solenoid resistance, the controller multiplies the nominal output voltage, VO, by the correction factor (RneW / Rnominal) to obtain the desired output current, idesired Instead of looking up RneW~ based on the temperature, the controller could access a look-up table cont~ining voltage correction factors as a function of temperature.
10 Then:
Vac~ual = Vo * k where k is a correction factor While the temperature sensor 38 has been shown as inserted into the oil inlet, it may equally be inserted into the oil outlet or valve body. Further, a m~rlline often has a considerable number of hydraulic cylinders, each with a controlling valve. In such 15 instance, the valves are normally attached to a common valve manifold as is depicted for machine 100 of figure 1. With this configuration, a single temperature sensor may be inserted in the manifold and the temperature reading used by the controller for each solenoid valve as representative of the temperature of the solenoid.
Figure 4 illustrates an alternate driver. Turning to figure 4 where like parts have been given like reference numerals, a controlled switch 56 having switches 56a and 56b and a reference resistor 58, R,~ l,CC, are connected in series with the solenoid coil resistance 130. The reference resistor is fabricated of a temperature insensitive material.
Controller 146 has a control output 60 to the controlled switch, voltage sensing line 62a to sense the voltage, VreferenCe across the solenoid and voltage sensing line 62b to sense the battery voltage, Vbat In operation of the embodiment of figure 4, controller 146 switches the solenoid off for a brief period of time by sending a control signal to PWM 42, then the controller switches in the reference resistor by sending a control signal to controlled switch 56 resulting in the closing of switch 56. The controller may then sense VreferenCe and estimate the coil resistance, RneW as:
Rnew = R~crc~nce * Vreference / (Vbat~ Vreference) Once RneW is known, a corrected average voltage may be determined utili~ing expressions 1 and 2 set forth hereinbefore.
In this embodiment, the solenoid must be switched off for a sufficiently long time to allow transients to pass.
In another embodiment, the controller first switches the solenoid off then applies a current source onto the solenoid coil. The controller measures the voltage across the coil and then estimates the actual coil resistance using Ohm's law. With the coil resistance known, expression 1 and 2 set forth above are utilised to obtain a corrected average voltage which may be applied to the solenoid.
Although this embodiment uses a testing current source, the output of the testing current source may be m~gnit~1des smaller than the requisite output of a current source which is used to precisely control a solenoid valve. Therefore, the testing current source is much less expensive and smaller than a current source used to control a solenoid 5 valve.
To further enhance the accuracy of the control of the solenoid valve, the controller may be modified to also measure the voltage output by the voltage source. If this voltage is not at its nominal value, the controller may adjust the average voltage to compensate.
Other modifications will be a~parelll to those skilled in the art and, therefore, the invention is defined in the claims.
Claims (8)
1. A method of controlling a solenoid valve comprising the steps of:
applying a control voltage to said valve;
measuring resistance of a solenoid coil of said solenoid valve;
adjusting said control voltage based on said measured resistance.
applying a control voltage to said valve;
measuring resistance of a solenoid coil of said solenoid valve;
adjusting said control voltage based on said measured resistance.
2. The method of claim 1 wherein said step of measuring resistance comprises measuring temperature of said solenoid coil and determining resistance based on said measured temperature.
3. The method of claim 2 wherein said solenoid valve controls hydraulic fluid flowing to an hydraulic cylinder and wherein said step of measuring temperature comprises measuring a temperature of hydraulic fluid flowing through said valve.
4. The method of claim 2 wherein said solenoid valve is associated with a valve manifold and wherein said step of measuring temperature comprises measuring a temperature of said valve manifold.
5. A machine with a plurality of hydraulic cylinders, comprising:
a control valve associated with each of said hydraulic cylinders to control the flow of hydraulic fluid to each hydraulic cylinder;
an electrically operated solenoid to control a position of said control valve;
a voltage supply to provide a voltage across a coil of said solenoid;
a temperature sensor for measuring a temperature of said solenoid coil;
a compensator responsive to said temperature sensor for adjusting said voltage supply.
a control valve associated with each of said hydraulic cylinders to control the flow of hydraulic fluid to each hydraulic cylinder;
an electrically operated solenoid to control a position of said control valve;
a voltage supply to provide a voltage across a coil of said solenoid;
a temperature sensor for measuring a temperature of said solenoid coil;
a compensator responsive to said temperature sensor for adjusting said voltage supply.
6. The machine of claim 5 wherein said temperature sensor is positioned in sensing relation with hydraulic fluid passing through said control valve.
7. The machine of claim 5 including a valve manifold for each said control valve and wherein said temperature sensor is in sensing relation with said manifold.
8. A driver for an electrically controlled solenoid valve, comprising:
a temperature sensor for measuring a temperature of a solenoid coil of said solenoid valve;
a compensator responsive to said temperature sensor for adjusting a voltage supply providing a voltage across said coil.
a temperature sensor for measuring a temperature of a solenoid coil of said solenoid valve;
a compensator responsive to said temperature sensor for adjusting a voltage supply providing a voltage across said coil.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2221667 CA2221667A1 (en) | 1997-11-20 | 1997-11-20 | An electrically controlled solenoid valve driver with compensation for coil resistance changes |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2221667 CA2221667A1 (en) | 1997-11-20 | 1997-11-20 | An electrically controlled solenoid valve driver with compensation for coil resistance changes |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2221667A1 true CA2221667A1 (en) | 1999-05-20 |
Family
ID=29275248
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2221667 Abandoned CA2221667A1 (en) | 1997-11-20 | 1997-11-20 | An electrically controlled solenoid valve driver with compensation for coil resistance changes |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2221667A1 (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1233428A1 (en) * | 2001-02-19 | 2002-08-21 | Max Co., Ltd. | Solenoid driver circuit |
| US9684310B2 (en) | 2015-07-17 | 2017-06-20 | Automatic Switch Company | Compensated performance of a solenoid valve based on environmental conditions and product life |
| EP3597939A1 (en) * | 2018-07-20 | 2020-01-22 | Hamilton Sundstrand Corporation | Servo valve |
| EP3715644A1 (en) * | 2019-03-29 | 2020-09-30 | Hamilton Sundstrand Corporation | Spool servo valve |
-
1997
- 1997-11-20 CA CA 2221667 patent/CA2221667A1/en not_active Abandoned
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1233428A1 (en) * | 2001-02-19 | 2002-08-21 | Max Co., Ltd. | Solenoid driver circuit |
| US9684310B2 (en) | 2015-07-17 | 2017-06-20 | Automatic Switch Company | Compensated performance of a solenoid valve based on environmental conditions and product life |
| EP3325863A4 (en) * | 2015-07-17 | 2019-03-27 | Automatic Switch Company | Compensated performance of a solenoid valve based on environmental conditions and product life |
| EP3597939A1 (en) * | 2018-07-20 | 2020-01-22 | Hamilton Sundstrand Corporation | Servo valve |
| US11078931B2 (en) | 2018-07-20 | 2021-08-03 | Hamilton Sunstrand Corporation | Servo valve |
| EP3715644A1 (en) * | 2019-03-29 | 2020-09-30 | Hamilton Sundstrand Corporation | Spool servo valve |
| US11060536B2 (en) | 2019-03-29 | 2021-07-13 | Hamilton Sunstrand Corporation | Spool servo valve |
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