Patent Grant
9870888
This application is the national phase under 35 U.S.C. §371 of PCT International Application No. PCT/EP2015/057169 which has an International filing date of Apr. 1, 2015, which designated the United States of America and which claims priority to German patent application number DE 102014208014.2 filed Apr. 29, 2014, the entire contents of which are hereby incorporated herein by reference.
An embodiment of invention relates to a method having the features according to the preamble of claim 1.
A method is known from the German patent document DE 10 2011 083 282 B3. The patent document describes a method for operating an electric switch having at least one movable switch contact which is moved by a movable armature of an electromagnetic actuator in order switch the switch on and off, wherein a spring device is disposed between the movable switch contact and the armature. In order to move the armature from a predefined starting position, in which the switch contacts are open, into a predefined armature end position, in which the switch contacts are closed and spring energy is stored in the spring device, a magnetic flux is generated in an excitation winding of the actuator by way of an excitation current being fed into the excitation winding.
The German laid-open application DE 195 44 207 A1 describes a control method for an actuator. In this method, in order to control the movement of an armature of the actuator, the displacement variables, i.e., the acceleration, the speed, and the particular location of the armature, are ascertained during the movement of the armature, specifically, inter alia, while evaluating the magnetic flux which flows through an excitation winding of the actuator. Utilizing the calculated displacement variables, a control of the current through the excitation winding takes place with consideration for maintaining a predefined sequence of motions for the actuator.
An embodiment of the invention includes a method for operating an electric switch, in which the least possible amount of wear occurs.
An embodiment of the invention is directed to a method. Advantageous embodiments of the method according to the invention are described in the claims.
According to a method of an embodiment of the invention, the magnetic flux through the excitation winding, or a flux variable correlating to the magnetic flux through the excitation winding, is determined and a flux value Φist(t) is formed, the magnetomotive force in the excitation winding is determined with consideration for at least the excitation current flowing through the excitation winding and the number of turns of the excitation winding, a magnetomotive value Θ(t) is determined. And with consideration for a position data set which indicates the particular armature position as a function of magnetomotive values and flux values, an armature position, referred to in the following as the contact strike armature position, is determined at which the switch contacts meet each other during the closing operation, before the armature reaches the armature end position. In order to move the armature from the starting position into the end position, the magnetic flux through the excitation winding is regulated, specifically in such a way that the progression of the flux value Φist(t), in at least one time interval before the armature reaches the contact strike armature position, has a fixedly predefined setpoint flux progression.
An embodiment of the invention also relates to an electric switch having at least one movable switch contact which is moved by a movable armature of an electromagnetic actuator in order to switch the switch on and off, wherein a spring device is disposed between the movable switch contact and the armature and, in order to move the armature from a predefined starting position, in which the switch contacts are open, into a predefined armature end position, in which the switch contacts are closed and spring energy is stored in the spring device, a magnetic flux is generated in an excitation winding of the actuator by way of an excitation current being fed into the excitation winding.
According to a method of an embodiment of the invention, the magnetic flux through the excitation winding, or a flux variable correlating to the magnetic flux through the excitation winding, is determined and a flux value Φist(t) is formed, the magnetomotive force in the excitation winding is determined with consideration for at least the excitation current flowing through the excitation winding and the number of turns of the excitation winding, a magnetomotive value Θ(t) is determined. And with consideration for a position data set which indicates the particular armature position as a function of magnetomotive values and flux values, an armature position, referred to in the following as the contact strike armature position, is determined at which the switch contacts meet each other during the closing operation, before the armature reaches the armature end position. In order to move the armature from the starting position into the end position, the magnetic flux through the excitation winding is regulated, specifically in such a way that the progression of the flux value Φist(t), in at least one time interval before the armature reaches the contact strike armature position, has a fixedly predefined setpoint flux progression.
One advantage of the method according to an embodiment of the invention is considered to be that the contact strike armature position is determined in this method. This makes it possible to modify a setpoint flux progression, which is fixedly predefined before the contact strike armature position is reached, at the point in time when the contact strike armature position is reached, and to configure the further sequence of motions from the contact strike armature position up to the attainment of the armature end position so as to differ from the sequence of motions taking place before the contact strike armature position is reached. The sequence of motions taking place up to the armature end position may therefore be optimized.
The invention is explained in greater detail in the following with reference to example embodiments; by way of example
For the sake of clarity, the same reference numbers are always used for identical or comparable components in the figures.
The position data set is preferably determined in advance on the basis of calibration measurements, which are carried out at the particular specific switch, and are stored in a memory of the control device. Alternatively, the determination of the position data set can also take place using computer simulation methods which account for the mechanical and electromagnetic properties of the switch.
In terms of carrying out the flux regulation, it is considered to be advantageous when the magnetic flux through the excitation winding is regulated to a predefined constant setpoint flux Φconst1, by way of a constant flux regulation, in the at least one time interval before the armature reaches the contact strike armature position. In other words, it is considered to be advantageous when the fixedly predefined setpoint flux progression in the at least one time interval before the contact strike armature position is reached is a fixedly predefined, constant setpoint flux Φconst1.
The contact strike armature position can be detected particularly rapidly and easily when a magnetomotive value-armature position progression is read out of the position data set for the constant setpoint flux Φconst1, which progression indicates the armature position as a function of the particular magnetomotive force for the constant setpoint flux Φconst1, and the contact strike armature position is determined (at least also) on the basis of the magnetomotive value-armature position progression.
A strike magnetomotive value Θa(Xc), at which the armature reaches the contact strike armature position, is preferably read out of the position data set or the magnetomotive force-armature progression for the constant setpoint flux Φconst1. In this embodiment, the determination of the contact strike armature position preferably takes place on the basis of the strike electromotive value Θa(Xc).
Preferably, the constant flux regulation is terminated or is switched to another setpoint flux (Φconst2) as soon as the armature reaches the contact strike armature position. Preferably, the magnetic flux is reduced by reducing the excitation current flowing through the excitation winding.
In the case of a constant flux regulation before the contact strike armature position is reached, and in the case of accounting for the aforementioned strike magnetomotive value Θa(t), it is considered to be advantageous when the constant flux regulation is terminated or is switched to another setpoint flux (Φconst2) as soon as the magnetomotive value Θ(t) is equal to the strike magnetomotive value Θa(t).
Alternatively or additionally, the particular suitable or approximately suitable position value can be read out of the position data set for the particular determined magnetomotive value and for the particular determined flux value, and the contact strike armature position can be detected on the basis of the position values.
In the latter embodiment, it is considered to be advantageous when the progression of the armature movement is determined from the position data set and time-dependent position information is determined, the time-dependent position information is used for determining time-dependent acceleration information, and the attainment of the contact strike armature position is inferred when the absolute value of the time-dependent acceleration information exceeds or falls below a predefined threshold value.
An embodiment of the invention also relates to an electric switch having at least one movable switch contact which is moved by a movable armature of an electromagnetic actuator in order to switch the switch on and off, wherein a spring device is disposed between the movable switch contact and the armature and, in order to move the armature from a predefined starting position, in which the switch contacts are open, into a predefined armature end position, in which the switch contacts are closed and spring energy is stored in the spring device, a magnetic flux is generated in an excitation winding of the actuator by way of an excitation current being fed into the excitation winding.
In an embodiment of a switch, it is considered to be advantageous when the switch has a control device which determines an armature position—referred to in the following as the contact strike armature position—at which the switch contacts meet each other during the closing operation, before the armature reaches the armature end position, wherein the control device is designed in such a way that the control device determines the magnetic flux through the excitation winding or determines a flux variable correlating to the magnetic flux through the excitation winding, and a flux value Φist(t) is formed, wherein the control device is designed in such a way that the control device determines the magnetomotive force in the excitation winding with consideration for at least the excitation current flowing through the excitation winding and the number of turns of the excitation winding, and a magnetomotive value Θist(t) is formed, wherein the control device is designed in such a way that the control device determines the contact strike armature position with consideration for a position data set stored in a memory of the control device, which data set indicates the particular armature position as a function of magnetomotive values and flux values.
In respect of the advantages of the switch according to an embodiment of the invention, reference is made to the comments presented above in association with the method according to an embodiment of the invention, since the advantages of an embodiment of the method according to the invention correspond to those of the switch according to an embodiment of the invention.
It is considered to be particularly advantageous when the control device is designed such that, to move the armature from the starting position into the armature end position, the control device regulates the magnetic flux through the excitation winding to a constant setpoint flux by way of a constant flux regulation in at least one time interval, before the armature reaches the contact strike armature position.
Preferably, the control device is also designed in such a way that the control device shuts off the constant flux regulation or switches it to another setpoint flux Φconst2 as soon as the armature reaches the contact strike armature position, and reduces the magnetic flux by reducing the excitation current flowing through the excitation winding.
The control device preferably comprises a microprocessor or a microcontroller and the memory, in which the position data set is stored. The microprocessor or the microcontroller is preferably programmed in such a way that it can carry out an embodiment of the above-described method for operating the switch.
The movable switch contact 21 is connected to a drive rod 30 of the electromagnetic drive 10, which rod cooperates with a spring device 40. In addition, a further drive rod 50 is coupled to the spring device 40, which rod is connected to a movable armature 60 of the electromagnetic drive 10.
The armature 60 can carry out a reciprocating motion along a predefined sliding direction P and thereby move in the direction of a yoke 70 of the drive 10.
The function of the spring device 40 consists of, inter alia, providing a predefined contact pressure in the closed state of the switch 20; in the example embodiment according to
Due to the spring device 40, the armature 60 will reach an intermediate position—referred to in the following as the contact strike armature position—during the movement from the starting position into the armature end position, in which the intermediate position the switch contacts meet each other during the closing operation, but the armature has not yet reached the armature end position. The starting position of the armature 60 is labeled in
In order to close the electric switch 20 using the electromagnetic drive 10, a current I(t) is fed into the excitation winding 80 via a control device 100, which current induces a magnetic flux within the excitation winding and brings the armature 60 into its closed position in opposition to the spring force of the spring device 40. The control device 100 preferably comprises a microprocessor or a microcontroller 110 which regulates the current I(t), specifically in such a way that the progression of the flux value Φist(t) of the magnetic flux corresponds to a fixedly predefined setpoint flux curve, but only up to the point in time at which the armature 60 reaches the contact strike armature position Xc; this point in time is referred to in the following as the strike instant. Particularly preferably, the magnetic flux through the excitation winding 80 is regulated to a constant setpoint flux Φconst1, by way of a constant flux regulation, in the time interval directly before the strike instant.
In order to make this regulation of the magnetic flux possible, the control device 100 is connected to an auxiliary coil 200 which encloses the magnetic yoke 70 and through which the same magnetic flux flows as flows through the excitation winding 80. The control device 100 or its microcontroller 110 measures the electric voltage Uh(t) dropping at the auxiliary coil 200, and forms a measured coil voltage value and, on the basis thereof and with consideration for the law of induction:
Uh(t)=N·dΦist(t)/dt
determines the magnetic flux which permeates the excitation winding 80 and the auxiliary coil 200; in the formula, N represents the number of turns of the auxiliary coil 200, Uh(t) represents the voltage dropping at the auxiliary coil 200, and t represents time.
With consideration for the particular flux value Φist(t), the microcontroller 110 of the control device 100 controls the current I(t) through the excitation winding 80 in such a way that the flux value Φist(t) of the magnetic flux has a predefined progression over time, before the armature reaches the contact strike armature position. In other words, the regulation of the actuator movement or the regulation of the movement of the armature 60 initially takes place independently of its actual movement parameters, and, in fact, exclusively on the basis of the flux value Φist(t) of the magnetic flux which permeates the excitation winding 80 and the auxiliary coil 200, specifically for the period of time until the armature 60 reaches the contact strike armature position.
In order to provide for a shutoff of the setpoint flux regulation or a switchover of the setpoint flux regulation to a setpoint flux other than the setpoint flux Φconst1 when or as soon as the armature 60 reaches the contact strike armature position Xc, the control device 100 additionally determines the magnetomotive force in the excitation winding 80 during the movement of the armature, for example, with consideration for the excitation current I(t) flowing through the excitation winding and the number of turns W of the excitation winding 80, and forms a magnetomotive value Θ(t), preferably according to
Θ(t)=W·I(t)
The magnetomotive force therefore corresponds to the magnetic voltage as a line integral of the magnetic field strength in a closed magnetic circuit.
With consideration for a position data set POS which is stored in a memory 120 of the control device 100 and indicates the particular armature position X as a function of magnetomotive values Θ(t) and the magnetic flux values Φist(t), the microcontroller 110 can determine the contact strike armature position Xc at which the switch contacts meet each other during the closing operation, before the armature 60 reaches the armature end position.
One example embodiment of a family of characteristics which can form the position data set POS in the memory 120 of the control device 100 is shown in
Φ=f(Θ)
for different armature positions X, wherein the starting position, in which the switch contacts are open, is labeled with the reference character Xa, and the armature end position, in which the switch contacts are closed and the spring energy is stored in the spring device 40, is labeled with the reference character Xe. The curve X(t) shows, by way of example, one possible armature progression over time through the family of characteristics during the movement from the starting position Xa through the contact strike armature position Xc into the armature end position Xe.
If a constant flux regulation takes place by way of the control device 80 in such a way that the flux value Φist(t) has the constant setpoint flux Φconst1 before the contact strike armature position Xc is reached, the control device 80 or its microcontroller 110 can read out, from the position data set POS for the constant setpoint flux Φconst1, or form a magnetomotive value-armature position progression Θa(X) which indicates the armature position X as a function of the particular magnetomotive value Θ(t) for the constant setpoint flux Φconst1. On the basis of this magnetomotive value-armature position progression Θa(X), the control device 80 or its microcontroller 110 can therefore read out the strike magnetomotive value Θa(Xc) for which the armature 60 reaches the contact strike armature position Xc.
As soon as the control device 80 establishes that the magnetomotive value Θ(t) is equal to the strike magnetomotive value Θa(Xc), the device infers that the armature 60 has reached the contact strike armature position Xc and reduces the magnetic flux ΦIst(t) by reducing the excitation current I(t) flowing through the excitation winding. Such a reduction of the magnetic flux can take place, for example, by switching the constant flux regulation to another, i.e., lower, setpoint flux Φconst2.
Adjoining the rising ramp section 300 is a first constant flux section 310, in which the magnetic flux has a first constant setpoint flux Φconst1 due to constant flux regulation. The first constant flux section 310 is used for inducing particularly great acceleration forces in the initial phase of the acceleration of the movable armature 60, in order to particularly rapidly increase the speed of the armature 60 in the initial phase.
As soon as the armature 60 has reached the contact strike armature position Xc at the point in time tc, the setpoint flux regulation is switched, specifically to a constant second setpoint flux Φconst2 which is suitable for holding the armature 60 in the armature end position. A second constant flux section results, which is labeled in
The second constant flux section 420 functions as a brake section and is chronologically situated between the first constant flux section 410 functioning as the acceleration section and the third constant flux section 430 which is suitable for holding the armature 60 in the armature end position. The second constant flux section 420 is used for allowing the speed of the armature 60 to decrease—before the impact on the magnetic yoke 70—to a value which ensures the least possible amount of wear of the actuator parts of the actuator 10. In the second constant flux section 420, the constant setpoint flux Φconst2 is preferably less than the third constant setpoint flux Φconst3, with which the armature 60 can be held in its end position against the yoke 70.
The switchover of the constant flux regulation for the transition from the first constant flux section 410 into the second constant flux section 420 preferably takes place when the armature 60 has reached the contact strike armature position Xc at the point in time te. The contact strike armature position Xc is detected by the microcontroller 110 preferably on the basis of the position data set POS.
The switchover of the constant flux regulation for the transition from the second constant flux section 420 into the third constant flux section 430 preferably takes place when the armature has reached the armature end position Xe at the point in time te. The armature end position Xe is detected by the microcontroller 110 preferably on the basis of the position data set POS, which is stored in the memory 120 of the control device 100, as a function of the magnetomotive values Θ(t) and the magnetic flux values Φist(t), i.e., for example, in the same way that the microcontroller determines the contact strike armature position Xc as a function of the magnetomotive values Θ(t) and the magnetic flux values Φist(t). The aforementioned comments apply similarly in respect of the detection of the armature end position Xe.
Alternatively, the control device 100 or its microcontroller 110 can also determine the contact strike armature position Xc and/or the armature end position Xe as follows:
Initially, the particular suitable or approximately suitable position value X(t) of the armature 60 is read out of the position data set POS for the particular determined magnetomotive value Θ(t) and for the particular determined flux value ΦIst(t). On the basis of the time-dependent position information, time-dependent acceleration information a(t) is determined according to
and it is inferred that the contact strike armature position Xc or the armature end position Xe has been reached when the absolute value |a(t)| of the time-dependent acceleration information a(t) reaches or exceeds a predefined threshold value M, i.e., when the following applies:
|a(t)|≧M
Moreover, the aforementioned comments apply similarly in respect of the mode of operation of the control device 100 and its microcontroller 110.
In summary, the example embodiment according to
Although the invention was illustrated and described in greater detail by way of preferred example embodiments, the invention is not restricted by the disclosed examples, and other variations can be derived therefrom by a person skilled in the art, without departing from the scope of protection of the invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2014 208 014 | Apr 2014 | DE | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2015/057169 | 4/1/2015 | WO | 00 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2015/165684 | 11/5/2015 | WO | A |
| Number | Name | Date | Kind |
|---|---|---|---|
| 8159807 | Pohl | Apr 2012 | B2 |
| 20100019581 | Pantke et al. | Jan 2010 | A1 |
| Number | Date | Country |
|---|---|---|
| 19544207 | Jun 1997 | DE |
| 102008040668 | Jan 2010 | DE |
| 102009042777 | Apr 2011 | DE |
| 102011083282 | Feb 2013 | DE |
| WO-2007079767 | Jul 2007 | WO |
| Entry |
|---|
| International Search Report PCT/ISA/210 for International Application No. PCT/EP2015/057169 dated Sep. 25, 2015. |
| Written Opinion of the International Searching Authority PCT/ISA/237 for International Application No. PCT/EP2015/057169 dated Sep. 25, 2015. |
| Office Action for German Application No. 10 2014 208 014.2 dated Feb. 2, 2015. |
| Number | Date | Country | |
|---|---|---|---|
| 20170110274 A1 | Apr 2017 | US |
