The specific embodiment
First embodiment
Fig. 1 shows the structure of the whole brake system of elevator.The car 1 of elevator is hanging by the well-bucket mode by the main rope 3 that is wound on the driving wheel 2 with counterweight portion 4.
The brake rotor (as brake wheel or brake disc) 6 that drives by hoist motor 5 be installed in usually hoist motor 5 and driving wheel 2 be connected to each other spool on.Brake block 8 is forced to brake rotor 6 under the effect of the elastic force of spring 7 and engages, and the braking force that causes because of friction is provided thus.When utilizing the 9 pairs of brake coils of being made up of electromagnet 10 of driving circuit that provided by constant pressure source 11 to energize, the armature 12 that is engaged to brake block 8 overcomes the elastic force of spring 7 and is attracted to brake coil 10.Drg release portion comprises electromagnet, and this electromagnet comprises brake coil 10 and armature 12.
The voltage that current probe 13 and piezoelectric detector 14 detect electric current and apply on brake coil 10 (electromagnet).Voltage variation detectors 15 detects the abnormal electrical pressure drop of constant pressure source 11.When voltage level is below or above the threshold value that clearly limits, be set as zero (VD=0) at this monitor signal of representing by VD (logical signal).For the situation of normal running, the value of monitor signal is set as 1 (VD=1).
Carrying out armature movement according to the threshold level that appointment in the portion 17 is set at threshold level in motion detector and motion indicator unit 16 detects.Discharge the period at drg and be illustrated in the threshold level setting that threshold level is provided with appointment in the portion 17, and be illustrated in the threshold level setting that threshold level is provided with appointment in the portion 17 with TH3 and TH4 at the brake application period with TH1 and TH2.
Fig. 2 shows when electromagnet energising and outage, applies the typical relation of voltage (u) and time (t) ((a) among Fig. 2), armature displacement (x) and time (t) ((b) among Fig. 2) and coil current (i) and time (t) ((c) among Fig. 2).
When electric current is connected at first (the time point A on the time point T1 on (a) figure among Fig. 2 and (c) figure among Fig. 2), the electric current gradual change increases, up to the intensity in the magnetic field that coil generates become be enough to the pull-up armature till.At this time point place, because armature movement causes the instantaneous decline of electric current (i) (the some B on (c) figure among Fig. 2) of flowing through coil.Finally, electric current reaches its steady-state value (the time point T2 on (a) figure among Fig. 2, some C on (c) figure among Fig. 2) during armature keeps.
When electric current cuts off at first (the some D on the time point T3 on (a) figure among Fig. 2 and (c) figure among Fig. 2), the electric current gradual change reduces, and the power that generates up to the magnetic field of coil becomes till the power less than spring, thereby discharges armature.At this time point place, because armature movement, cause the instantaneous increase of electric current (i) (the some E on (c) figure among Fig. 2) of flowing through coil, finally reach its steady-state value (the time point T4 on (a) figure among Fig. 2, the some F on (c) figure among Fig. 2) at the armature deenergized period.
Armature movement based on induced electromotive force (E.M.F.) estimation and monitoring detects
Below, the example based on the armature movement method of inspection of electro-motive force estimation and monitoring according to first embodiment of the invention is described.
Fig. 3 is the exemplary view according to the basic operation of the armature movement detecting device of first embodiment of the invention.(a) among Fig. 3 shows the voltage that imposes on brake coil 10, and (b) among Fig. 3 shows the displacement of armature 12, and (c) among Fig. 3 shows induced electromotive force.In Fig. 3, when releasing the brake, applied pick-up voltage to brake coil 10, so that be provided with the electromagnet adhesive armature 12 of brake coil 10 at time point T1.At F/s, induced electromotive force ((c) among Fig. 3) is because of the steady state value that sensor bias causes (being zero in theory), and when electromagnetic attraction overcomes the power that is generated by spring 7, armature 12 setting in motions, and induced electromotive force increases.After motion armature 12 was run into fixed armature, induced electromotive force began to reduce.Armature movement finishes at time point T2.
When the brake application device, the voltage that is applied on the brake coil 10 becomes zero at time point T3 from pick-up voltage, the result, the drg electric current begins to reduce, and when electromagnetic attraction becomes less than elastic force, armature 12 begins to descend or moves towards brake rotor 6, and induced electromotive force reduces as shown in (c) among Fig. 3.At time point T4, armature 12 finishes its step-down operation, as shown in (b) among Fig. 3.
Fig. 4 is the constructional drawing that illustrates according to an example of the armature movement detecting device based on electro-motive force (E.M.F.) estimation and monitoring of the present invention.
Apply voltage (u) and electric current (i) by utilizing piezoelectric detector 14 and current probe 13 to measure, in EMF estimation portion 18, estimate induced electromotive force.According to the signal VD that threshold level is provided with portion 17 and considers to be provided by voltage variation detectors 15, detect armature movement by motion detection algorithm A portion 19.
Motion indicator 20 is used the signal indication armature movement with visual means (for example, if armature 12 moves or do not move then connects or cut out LED) and/or in electronics mode (sending digital signal to monitor unit).
Below, (shown in Fig. 5) electro-motive force (E.M.F.) estimation according to first embodiment of the invention is described.
The voltage equation of electromagnetic actuators can be write as:
u=Ri+dΨ/dt (1)
Wherein, be to apply voltage (u), (i) be electric current, R is a coil resistance, and Ψ is a total magnetic flux.(i x) depends on electric current (i) and armature displacement (x) to total magnetic flux Ψ=Ψ.
Therefore, according to above-mentioned formula, can obtain:
Above-mentioned formula can be approximated to be:
u≈Ri+L(i)di/dt+e (3)
Wherein e is an induced electromotive force:
And
If there is no magnetic saturation, then L (i)=L=constant.
According to formula (3), calculate induced electromotive force and be:
e≈u-Ri-L(i)di/dt (6)
Suppose by the Laplace transform of current probe 13 detected current signals (i) and represent that by I (s) filtering portion 21 is with timeconstant
1Carry out filtering.Filtering portion 21 is calculated by i according to following formula
f(its Laplace transform is by I for the filtered circuit signal of expression
f(s) expression):
I
f(s)={1/(τ
1s+1)}I(s) (7)
Obtain by e according to following formula
f(its Laplace transform is by E for the filtering of expression and the electromotive force signal of amplification
f(s) expression):
E
f(s)=K
1{U(s)-R?I
f(s)-L{s/(τ
2s+1)}I
f(s)} (8)
Wherein U (s) is by the piezoelectric detector 14 detected Laplace transforms that apply voltage (u).
(has timeconstant by differential portion 22, filtering portion 23
2), brake coil resistance value 24, (have gain K by the coil inductance value 25 and the enlarging section 27 of adjustment of inductance portion 26 appointments
1), calculate above-mentioned formula (8).
Below, will the operation of adjustment of inductance portion 26 be described.Obtain inductance L=L (i) in advance, and the relation between brake coil current (i) and the inductance L is made table.Motion detector and motion indicator unit 16 call or choose inductance L based on the filtering signal of current probe 13 from this table, and change inductance L in electro-motive force estimation portion 18.
Then, when voltage variation detectors 15 detects the abnormal voltage variation, in motion detection algorithm A portion 19, use filtered electromotive force signal e
f(s) 28, with according to the threshold level that appointment in the portion 17 is set at threshold level, carry out armature movement and detect.
As the result that electro-motive force changes, A.1 the armature movement detection algorithm (represented by algorithm) under the situation of armature pull-up as shown in Figure 6, and (A.2 represented by algorithm) as shown in Figure 7 under the situation that armature discharges when having or not having armature control.
Below, the operation of this embodiment is described.
In Fig. 6, (A.1 represent), to by e by algorithm
fThe filtered electromotive force signal 28 of expression be provided with at threshold level that the threshold level of being represented by TH1 of appointment compares in the portion 17.If signal 28e
fAlways, mean that then electro-motive force does not increase, and impliedly represent not motion of armature less than threshold level TH1.Thus, the logical signal of being represented by SET1 that detects armature movement during pull-up is set as zero.
SET1=0 (9)
If by e
fThe signal 28 of expression becomes greater than threshold level TH1, and is becoming after a bit of time less than the threshold level TH2 that appointment in the portion 17 is set at threshold level, means that then the electro-motive force of estimation has increased.Next step is whether this electro-motive force increase of test is because the abnormal voltage variation of constant pressure source 11 causes.According to the operation of voltage variation detectors 15, if VD=0 then means the abnormal voltage variation has taken place, thereby signal SET1 is set as 0.
SET1=0 (10)
If VD=1 means that then electro-motive force changes owing to armature movement but not owing to the abnormal voltage variation causes.Thus, logical signal SET1 is set as 1.
SET1=1 (11)
In addition, if by e
fThe signal of representing 28 becomes greater than threshold level TH1, and is not reduced under the threshold level TH2, means that then the estimation electro-motive force increases because voltage increases owing to armature movement causes.Thus, logical signal SET1 is set as 0.
SET1=0 (12)
Armature movement when therefore, detecting drg release by logical signal SET1.If SET1=1, then armature moves, and if SET1=0, then armature as yet the motion.
Figure 7 illustrates under the situation that has or do not have control and detect in the armature movement of armature deenergized period.Below, the operation of this embodiment is described.In Fig. 7 (A.2 representing), to the electro-motive force e of estimation by algorithm
fThe threshold level of being represented by TH3 of appointment compares in the portion 17 with being provided with at threshold level.If by e
fThe signal 28 of expression then means not generate electro-motive force as yet always greater than threshold level TH3, and impliedly represents not motion of armature.Thus, the logical signal SET2 of the armature movement of expression deenergized period is set as zero.
SET2=0 (13)
If by e
fThe signal 28 of expression becomes less than threshold level TH3, and becoming after a bit of time greater than the threshold level of being represented by TH4 that appointment in the portion 17 is set at threshold level, means that then the electro-motive force of estimation reduces.Whether next step is that this electro-motive force of test reduces is because the abnormal voltage of constant pressure source 11 changes causes.According to the operation of voltage variation detectors 15, if VD=0 then means the abnormal voltage variation has taken place, thereby signal SET2 is set as 0.
SET2=0 (14)
If VD=1 means that then electro-motive force changes owing to armature movement but not owing to the abnormal voltage variation causes.Thus, logical signal SET2 is set as 1.
SET2=1 (15)
If by e
fThe signal 28 of expression becomes less than threshold level TH3, and does not increase to such an extent that surpass threshold level TH4, then mean the variation of electro-motive force of estimation because voltage descends owing to armature movement causes.Thus, logical signal SET2 is set as 0.
SET2=0 (16)
Armature movement when therefore, detecting brake application by logical signal SET2.If SET2=1, then armature moves, and if SET2=0, then armature as yet the motion.
As previously mentioned, during brake application, brake block is run into brake wheel and is produced undesirable noise, and this noise can utilize arrester control device to reduce.
In this case, it is also conceivable that and utilize voltage detection department 14 to measure the voltage that is applied on the brake coil 10, use the algorithm (shown in Figure 7) that presents.
Second embodiment
Armature movement based on transient electromagnetic power estimating and monitoring detects
Below, the example based on the armature movement detecting device of transient electromagnetic power estimating and monitoring according to second embodiment of the invention is described.
Fig. 8 is the exemplary view according to the basic operation of the armature movement detecting device of second embodiment of the invention.(a) among Fig. 8 shows the voltage that imposes on brake coil 10, and (b) among Fig. 8 shows the displacement of armature 12, and (c) among Fig. 8 shows the transient electromagnetic power variation of electromagnet.In Fig. 8, when releasing the brake, apply pick-up voltage to brake coil 10, so that be provided with the electromagnet adhesive armature 12 of brake coil 10 at time point T1.At F/s, the instantaneous power ((c) among Fig. 8) that is stored in the electromagnetic field increases, and when electromagnetic attraction overcomes spring 7, the armature setting in motion, and instantaneous power descends and increase once more after a bit of time.Armature movement finishes at time point T2.
When the brake application device, the voltage that is applied on the brake coil 10 becomes zero at time point T3 place from pick-up voltage, the result, and the drg electric current begins to reduce, and impliedly instantaneous power ((c) among Fig. 8) descends.When electromagnetic attraction became less than elastic force, armature 12 began to descend or move towards brake wheel, thereby instantaneous power increases shown in (c) among Fig. 8.At time point T4, armature 12 finishes its step-down operation, shown in (b) among Fig. 8.
Fig. 9 is the constructional drawing that the armature movement detecting device is shown.The present inventor is stored into the fact that the instantaneous power in the electromagnetic field changes when noticing the armature setting in motion.
When the armature pull-up, the portion of energy that is stored in the magnetic field is converted into kinetic energy, reduces to be stored into the instantaneous power in the electromagnetic field thus.
When discharging armature, the part kinetic energy of motion armature is converted into magnetic energy, increases the instantaneous power that is stored in the electromagnetic field thus.
When current probe 13 detects electric current, detect the instantaneous power in the electromagnetic field that is stored into brake coil 10 (electromagnet) that provides by driving circuit 9 by transient electromagnetic power estimating portion 29.Output signal and threshold level (being assigned to threshold level is provided with in the portion 17) by motion detection algorithm (being assigned in the motion detection algorithm B portion 30) comparison transient electromagnetic power estimating portion 29 detect armature movement.
Motion indicator portion 20 with visual means (for example, if armature movement or not motion connect or close LED) and/or, use the signal indication armature movement with electronics mode (sending digital signal) to monitor unit.
Below, the transient electromagnetic power estimating portion 29 (shown in Figure 10) according to second embodiment of the invention is described.
Suppose the electric current that flows through coil 10 by (i) expression, and the instantaneous power that is stored in the electromagnetic field of brake coil 10 is represented by P, then is stored into instantaneous power P in the electromagnetic field and the relation between the electric current (i) and represents by following formula:
P=L(i)*i*(di/dt) (17)
Be stored into the instantaneous power in the electromagnetic field, proportional with the product of the first derivative of electric current and electric current.
Below, the instantaneous power detecting device according to second embodiment of the invention is described.Suppose by the Laplace transform of current probe 13 detected current signals (i) and represent that by I (s) filtering portion 31 is with timeconstant
1Carry out filtering.Filtering portion 31 is calculated by i according to following formula
f(its Laplace transform is by I for the filtered current signal of expression
f(s) expression):
I
f(s)={1/(τ
1s+1)}I(s) (18)
Obtain by P according to following formula
f(its Laplace transform is by P for the filtering of expression and the instantaneous power signal of amplification
f(s) expression):
P
f(s)=K
2*L*{I
f(s)}{s/(τ
2s+1)}I
f(s)={L/(τ
1s+1)^2}{s/(τ
2s+1)}I^2(s)
(19)
(has timeconstant by differential portion 32, filtering portion 33
2), (have gain K by the coil inductance value 34 and the enlarging section 36 of adjustment of inductance portion 35 appointments
2), calculate above-mentioned formula (19).
The operation of adjustment of inductance portion 35 is similar to the operation of adjustment of inductance portion 26.Obtain inductance L=L (i) in advance, and the relation between brake coil current (i) and the inductance L is made table.Motion detector and motion indicator unit 16 call or choose inductance L based on the filtering signal of current probe 13 from this table, and change inductance L in transient electromagnetic power estimating portion 29.Instantaneous power signal by 37 sign filtering and amplification.
As the result that the instantaneous power that is stored in the electromagnetic field changes, B.1 the armature movement detection algorithm (represented by algorithm) under the situation of armature pull-up as shown in Figure 11, and (B.2 represented by algorithm) as shown in figure 12 under the situation that armature discharges.And when carrying out brake application (armature release) under control, the armature movement detection algorithm shown in Figure 12 is expanded with the algorithm shown in Figure 13 (B.3 being represented by algorithm).
Below, the operation of this embodiment is described.In Figure 11 (B.1 representing), to by P by algorithm
fThe filtered instantaneous power signal 37 of expression be provided with at threshold level that the threshold level of being represented by TH1 of appointment compares in the portion 17.If signal 37P
fAlways, mean that then instantaneous power does not reduce, and impliedly represent not motion of armature greater than threshold level TH1.Thus, the logical signal of being represented by SET1 of the armature movement during the detection pull-up is set as zero.
SET1=0 (20)
If by P
fThe signal 37 of expression becomes less than threshold level TH1, and becoming after a bit of time greater than the threshold level TH2 that appointment in the portion 17 is set at threshold level, mean that then instantaneous power reduces because armature movement causes, and after armature stops, beginning again to increase.Obviously, instantaneous power changes and can be caused by the abnormal voltage variation of constant pressure source 11.Therefore, next step is test signal VD, and this signal VD detects abnormal voltage to be changed.According to the operation of voltage variation detectors 15, if VD=0 then means the abnormal voltage variation has taken place, thereby signal SET1 is set as 0.
If VD=1, then armature moves, thereby logical signal SET1 is set as 1.
SET1=1 (21)
If by P
fThe signal 37 of expression becomes less than threshold level TH1, and does not increase to such an extent that surpass threshold level TH2, means that then instantaneous power reduces owing to voltage decline but not owing to armature movement causes.Thus, logical signal SET1 is set as 0.
SET1=0 (22)
Armature movement when therefore, detecting drg release by logical signal SET1.If SET1=1, then armature moves, and if SET1=0, then armature as yet the motion.
The armature movement that figure 12 illustrates the armature deenergized period detects.
Below, the operation of this embodiment is described.In Figure 12 (B.2 representing), to the instantaneous power signal P of estimation by algorithm
fThe threshold level of being represented by TH3 of appointment compares in the portion 17 with being provided with at threshold level.If by P
fThe signal 37 of expression means then that always less than threshold level TH3 the instantaneous power that is stored in the electromagnetic field is reducing (changing into heat), and impliedly represents not motion of armature.Thus, the logical signal SET2 of the armature movement of expression deenergized period is set as zero.
SET2=0 (23)
If by P
fThe signal 37 of expression becomes greater than threshold level TH3, and becoming after a bit of time less than the threshold level of representing by TH4 that appointment in the portion 17 is set at threshold level, then mean the increase that is stored into the instantaneous power in the electromagnetic field owing to armature movement causes, and after armature stops, beginning to reduce.Not changing if abnormal voltage does not take place constant pressure source 11, then is this situation.Therefore, in next stage, test detects the signal VD that abnormal voltage changes.According to the operation of voltage variation detectors 15, if VD=0 then means the abnormal voltage variation has taken place, thereby signal SET2 is set as 0.
If VD=1 means that then instantaneous power changes because armature movement causes, thus, SET2 is set as 1 with logical signal.
SET2=1 (24)
If by P
fThe signal 37 of expression becomes greater than threshold level TH3, and is not reduced under the threshold level TH4, and the increase that then means instantaneous power is owing to the voltage increase but not owing to armature movement causes.Thus, logical signal SET2 is set as 0.
SET2=0 (25)
Armature movement when therefore, having detected brake application by logical signal SET2.If SET2=1, then armature moves, and if SET2=0, then armature as yet the motion.
Yet during brake application, brake block is run into brake wheel, and produces undesirable noise, and this noise can utilize arrester control device to reduce.
Therefore, if arrester control device is used for noise reduction, then the armature movement detection algorithm (shown in Figure 12) according to brake application of the present invention the time expands to the algorithm shown in Figure 13.Even this demand is in order to guarantee that also correct armature movement detects under inappropriate armature control (control system lost efficacy or worked improperly).
In Figure 13 (B.3 representing), after the armature control period finishes, detect by P by algorithm
fThe signal 37 of expression, and the value of storing the logical signal SET2 that returns by the algorithm shown in Figure 12.
If by P
fThe signal 37 of expression is negative, means that then the instantaneous power that is stored in the electromagnetic field is reducing.If detected logical signal SET2 equals 1 by the algorithm shown in Figure 12, mean that then armature moves.
SET2=1 (26)
In addition,, then mean armature motion as yet if equal 0 by the detected logical signal SET2 of the algorithm shown in Figure 12, and only the reducing because voltage descends causes of instantaneous power.Thus,
SET2=0 (27)
If by P
fThe signal 37 of expression is positive, means that then the instantaneous power that is stored in the electromagnetic field is increasing, and if signal 37 is zero, then mean not discharge armature as yet.Thus,
SET2=0 (28)
Armature movement when therefore, utilizing logical signal SET2 to detect brake application.If SET2=1, then armature moves, and if SET2=0, then armature as yet the motion.
The 3rd embodiment
Detect based on the armature movement that applies the monitoring of voltage or control signal
There is the situation of wishing in the armature pull-up and controlling armature current during keeping.Usually carry out armature current control according to the controlling schemes that presents among Figure 14, wherein, controller K (s) has following transfer function usually:
K(s)=Kp+Ki/s (29)
Wherein, Kp is proportional gain, and Ki is a storage gain.
The control signal of Uc (s) expression is provided by following formula:
Uc(s)={Kp+Ki/s}Err(s) (30)
Wherein, error signal is current reference i
*And measure poor between the current i:
Err(s)=I
*(s)-I(s) (31)
Power inverter can be regarded as the ideal power changer in operating frequency range, therefore, applies voltage u and control signal u
cProportional.Thus, detect, can use whole two signals for armature movement.
Below, the example of the armature movement detecting device of (armature current is controlled) during the armature pull-up based on applying the monitoring of voltage or control signal according to third embodiment of the invention is described.
At the armature deenergized period, application of aforementioned method (based on estimation of electro-motive force or instantaneous power and monitoring) without change.
Figure 15 is the exemplary view according to the basic operation of the armature movement detecting device of third embodiment of the invention.(a) among Figure 15 shows the brake coil 10 of current controlled system, (b) among Figure 15 shows the displacement of armature 12, and (c) among Figure 15 shows the voltage that imposes in check brake coil 10, wherein, when armature movement, represent this voltage with solid-line curve 1, and when armature does not move, represent this voltage with dashed curve 2.
The electric current that the induced electromotive force that control system detects and compensation generates because of armature movement causes falls.(a) among Figure 16 shows the voltage that imposes on brake coil 10, and it has the crest that causes because of control action that is generated by armature movement.
The simplest mode that is used for detecting armature movement is derivative that applies voltage u or the control signal u shown in (c) of monitoring Figure 16
cDerivative.
Below, illustrate according to third embodiment of the invention based on apply voltage or control signal the monitoring the armature movement detecting device, as shown in Figure 17.
Suppose that applying voltage by 38 pairs of piezoelectric detectors detects, perhaps directly use the control signal u that calculates according to formula (30)
c, filtering portion 39 is with timeconstant
1Carry out filtering.40 pairs of filtering signal differentiates of differentiate portion, the signal after the differentiate (has gain K by enlarging section 41
1) amplify.
By motion detection algorithm (being assigned in the motion detection algorithm C portion 43) to comparing with threshold level (being assigned to threshold level is provided with in the portion 17) by 42 filtering that indicate and amplifying signal, thereby the detection armature movement.
Motion indicator portion 20 is with visual means and/or with electronics mode signal indication armature movement.Below, the operation of this embodiment is described.In Figure 18 (C represents by algorithm), to applying voltage or control signal and being provided with at threshold level that the threshold level of being represented by TH1 of appointment compares in the portion 17 after filtering and the differentiate.If signal 42, means then that current controller increases as yet always less than threshold level TH1 and applies voltage or control signal, thus, do not detect electric current as yet and fall, this impliedly represents not motion of armature.Therefore, the logical signal of being represented by SET1 of the armature movement during the detection pull-up is set as zero.
SET1=0 (32)
If signal 42 becomes greater than threshold level TH1, and becoming after a bit of time, meaning that then current controller does not apply voltage or control signal because of detected electric current falls to increase as yet less than the threshold level TH2 that appointment in the portion 17 is set at threshold level.
Obviously, the abnormal voltage of constant pressure source 11 changes and can cause that electric current falls.Therefore, next step is test signal VD, and this signal VD detects abnormal voltage to be changed.According to the operation of voltage variation detectors 15, if VD=0 then means the abnormal voltage variation has taken place, thereby logical signal SET1 is set as 0.
If VD=1, then motion has taken place in armature, thereby logical signal SET1 is set as 1.
SET1=1 (33)
If signal 42 becomes greater than threshold level TH1, and be not reduced under the threshold level TH2, mean that then voltage increases not because armature movement causes.Thus, logical signal SET1 is set as 0.
SET1=0 (34)
Armature movement when therefore, detecting drg release by logical signal SET1.If SET1=1 then armature move, and if SET1=0, then armature motion as yet.
Notice that easily though previous algorithm is simple, it has some shortcoming.Noise can influence the derivative that applies voltage or control signal, and this can cause limited opereating specification, and perhaps in the worst case, operation leads to errors.
Therefore, also proposed another kind of method, it is based on electro-motive force estimation and monitoring.
During the armature pull-up, the electric current that the induced electromotive force that generates because of armature movement by controller compensation causes falls.
Therefore, control signal falls with electric current and increases (integral that can ignore controller, armature movement are far faster than the integral time constant) pro rata, and it can be regarded as with induced electromotive force (e.m.f.) proportional.
Induced electromotive force is similar to following (also referring to formula (6)):
e≈u-Ri-L(i)di/dt (35)
Be used for signal that armature movement detects and be electro-motive force or with its proportional any value.
If armature is motion not, then induced electromotive force is approximately zero.If armature moves, then detect electric current and fall, and electric current is fallen compensate by increasing control signal (thereby impliedly increase applies voltage) by current controller.In this case, induced electromotive force has be not equal to zero value (in this case on the occasion of) shown in (d) among Figure 16.
By with carry out the armature movement detection algorithm in the identical mode of mode described in the first embodiment of the invention.
The 4th embodiment
Figure 19 shows the structure according to the whole brake system of the elevator of fourth embodiment of the invention.
In armature position estimation portion 51, carry out the armature position estimation, and by normal and the normal and unusual armature position of out-of-the way position indicator portion 52 indications.Other structure is identical with first embodiment.
Figure 20 shows when electromagnet energising and outage, applies the typical relation of voltage (u) and time (t) ((a) among Figure 20), armature displacement (x) and time (t) ((b) among Figure 20) and coil current (i) and time (t) ((c) among Figure 20).
When electric current is switched at first (the some A on the time point T1 on (a) figure among Figure 20 and (c) figure among Figure 20), the electric current gradual change increases, up to the intensity in the magnetic field that coil generates become be enough to the pull-up armature till.At this time point place, because armature movement, cause electric current (i) moment of flowing through coil to reduce (the some B on (c) figure among Figure 20).Finally, electric current reaches its steady-state value (the time point T2 on (a) figure among Figure 20, the some C on (c) figure among Figure 20) during the armature pull-up.After pull-up armature, apply voltage (between time point T2 and time point T3) during armature keeps and be reduced to lower level, so that reduce ohmic loss.
When electric current is cut off at first (the time point T3 on (a) figure among Figure 20, the some D on (c) figure among Figure 20), the electric current gradual change reduces, and till the power that generates up to the magnetic field of coil becomes less than spring force, thereby discharges armature.At this time point place, because armature movement, cause electric current (i) moment of flowing through coil to increase (the some E on (c) figure among Figure 20), finally reach its steady-state value (the time point T4 on (a) figure among Figure 20, the some F on (c) figure among Figure 20) at the armature deenergized period.
The inductance that Figure 21 shows under the situation of unsaturation electromagnetic actuators with respect to air gap changes.This means if estimate the inductance that coil or with it proportional any parameter, then can carry out the armature position estimation.
Figure 22 shows the basic thought of parameter in assessing, and wherein (u) is the incoming signal (being also referred to as ' injection signal ') that applies, and (i) is the output signal of measuring.
For the parameter of estimating system, incoming signal must be in citing document (Ljung, Astrom) middle " continuing excitation " condition of describing.For the situation of the electromagnetic actuators that uses in elevator brake, incoming signal can utilize hysteresis control loop shown in Figure 23 to generate.
Have different recurrence (online) parameter in assessing technology, it can and impliedly estimate at armature position and use at the inductance estimation.
A kind of in the known recurrence parameter in assessing method is recurrent least square method (RLS), and this described in [Ljung, Astrom].
This thought is to utilize method of least square to minimize square loss function of being represented by (V (θ)) (referring to formula (36)).
Wherein (θ) is parameter vector, (e) is output (y) of measuring and the output of estimating
Between poor.
{ Kailath, Astrom} are write as this parameter estimation algorithm by recursive form to utilize the matrix inversion lemma citing document.Although this method can provide good precision and fast speed convergence,, owing to its numerical complexity is unsuitable for many real-time technical applications.
{ the another kind of method of Astrom} is widely used in adaptive control, and is suitable for real-time realization more, although its precision is less than the precision of RLS to be known as the gradient method citing document.
This basic thought is to regulate parameter by the mode of minimum losses function (V (θ)).
For (V (θ)) diminished, reasonably be that the direction of pressing the negative gradient of (V (θ)) changes parameter, that is:
Wherein (γ) is positive constant.
Shown in algorithm can be write as different forms, and be known as gradient or projection algorithm citing document { Astrom}.In addition, also there is other alternative example, as:
With
They are called as sign symbolic algorithm (sign is known symbolic function).
The another kind of method that is used to estimate armature position is the switching frequency that estimation is in the electric current under the control that lags behind.{ Noh has described this method among the Mizuno}, and shows that inductance and switching frequency are inversely proportional at citing document.
Illustration in Figure 24, the high-pass filter (being used to remove the low frequency component of electric current) that utilizes the back to follow rectifier and low-pass filter (amplitude that is used for restituted signal) realize the inductance estimation, operate as a series of signal.
This method has following major defect:
● precision is limited;
● when magnetic core is saturated, use limited.
Armature position estimation---gradient method based on the coil parameter estimation
In the fourth embodiment of the present invention, utilize gradient method that an example based on the armature position estimating apparatus that is applied to elevator brake of coil parameter estimation is described.
Owing to the characteristic that is applied to the magnet stopper in the elevator causes:
● in the pull-up time, the electromagnetic actuators height is saturated;
● after a bit of time, the pull-up electric current is decreased to the holding current level.
Therefore, consider following parameter in assessing method.At first, during the armature pull-up, the resistance of estimation coil then, is in hysteresis at electric current and controls following time, during armature keeps and after armature discharges, uses the resistance value of estimating to estimate inductance or its inverse of coil.
Carry out this parameter in assessing method by two steps: at first, estimation resistance, then, estimation can be applied to the inductance of any electromagnetic actuators.Unique shortcoming is to have introduced little delay in parameter in assessing.
Below, utilize gradient method that the model structure of considering during parameter in assessing is described.
Under static state, that is, armature is motion not, and at the current value (like this, can consider magnetic saturation) of appointment, the model structure below considering:
u=R+Ldi/dt (41)
Wherein, be to apply voltage (u), (i) be electric current, (R) be coil resistance, and (L) be coil inductance.
During the armature pull-up after electric current reaches stable state, recursively estimate the resistance of coil according to following formula.
R
k=R
k-1+γ
R(u
k-R
k-1i
k-1) (42)
Wherein, subscript (k) refers to (t
k) and (γ
R) value when being positive constant.
Electric current be decreased to keep level after, armature current enters the hysteresis control that presents among (b) in Figure 25, and this hysteresis control loop provides so-called " injection signal ", it is used to estimate the inverse (G=1/L) of inductance (L) or inductance.
According to the inverse of following formula estimation inductance, it is derived according to gradient method.
And, can prove the form of above-mentioned formula below after approximate, can being write as:
Wherein (R) is the estimation resistance in the pull-up period, and subscript (k) refers to (t
k) and (γ
G) and (γ
L) value when being positive constant.
According to the structural change example of electromagnetic actuators, magnetic saturation level and signal to noise ratio, can use one or other estimation method.
Formula (8) and (9) can provide the precise parameters estimation, and this parameter in assessing is relevant with armature position, constitute the core of armature position estimation method thus.
Concern and concern x=f (p) between x=f (L), x=f (G) or estimation parameter (p) generally speaking and the armature position (x), may be approximately linear function, perhaps, can in memory device, store nonlinear function (f) as tracing table for high precision more.
Figure 26 shows the armature position estimation based on gradient method.Recurrence parameter in assessing portion 55 provides the parameter recurrence estimation (by two steps) of coil, and wherein, input value is:
● (u
k) be to utilize the voltage that applies that piezoelectric detector portion 14 measures, or the reference voltage that provides of driving circuit portion 9;
● (i
k) be the filtered circuit that low-pass filter (LPF) portion 53 provides, the input of this low-pass filter (LPF) portion 53 is provided by current probe portion 13;
● (di
k/ dt) be the electric current derivative that differentiate device (DER) portion 54 provides, the input of this differentiate device (DER) portion is provided by current probe portion 13.
Utilize Laplace transform table to reach, low-pass filter can be implemented as:
Wherein, k
1And τ
1It is positive constant.
The differentiate device can be implemented as:
Wherein, k
2And τ
2It is positive constant.
The output of recurrence parameter in assessing portion 55 has been carried out LPF by LPF portion 56, and this LPF portion 56 is provided for the input of trend estimator portion 57.
For relatively large air gap and unsaturation or slight saturable core, this algorithm can be used for armature position estimation at any electromagnetic actuators.
And, improve the precision of estimating parameter by so-called " trend estimator " portion 57.
For the armature position of appointment, under the situation of magnet stopper, the invariant parameter when inductance of estimation or its inverse are, but in fact, can observe near the little fluctuation aviation value, this fluctuation is owing to sensor noise, estimation error etc. causes.The estimation precision of invariant parameter in order to improve after the estimation parameter reaches its aviation value, is used so-called " trend estimator ".
If be estimation parameter (under (L) or situation (G)) (p), then parameter model can be write as:
P=mt+n (47)
In above-mentioned formula, (t) be the time, be parameter (m) and (n).In ideal conditions, parameter (m) equals zero, thereby parameter (n) equals to estimate parameter.
Figure 28 shows the principle of trend estimator.The parameter of trend estimator (m) and (n) recursively estimate according to gradient method, this gradient method provides:
m
k=m
k-1+γ
mt
k(p
k-m
k-1t
k-n
k-1) (48)
n
k=n
k-1+γ
n(p
k-m
k-1t
k-n
k-1) (49)
(γ wherein
m) and (γ
n) be positive constant.
Figure 29 shows the recurrence trend estimator portion 57 according to formula (48) and (49).
Utilize this method, the estimation parameter becomes (n) parameter of trend estimator.And estimation parameter (m) is used to the transient state of monitoring estimation parameter (p).(ε<m<ε), then estimated value (n) can be regarded as effectively (for the armature position of appointment) in the clear and definite restricted portion if estimation parameter (m) is in the final time section by (Vt) expression.In ideal conditions, the invariant parameter time (m) equals zero.
Figure 30 shows normal and out-of-the way position indicator portion 52, wherein, adopts pseudo-programming language to describe relevant algorithm.
In Figure 30, (i) be the electric current of measuring, and (i
HTH) and (i
RTH) be respectively current threshold and the armature release current threshold afterwards during armature keeps.In addition, the parameter of (n) representing the estimation of trend estimator.Parameter (p
Hmin) and (p
Hmax) be limited to the normal parameter scope during armature keeps, and (p
Rmin) and (p
Rmax) being limited to armature release normal parameter scope afterwards, these parameters are all limited by user's priori.
Figure 31 shows an example, at the estimation inductivity of different armature positions.
The 5th embodiment
Utilization is based on the armature position estimation of the switching frequency estimation of benchmark model
The another kind of method that is used to estimate armature position is the switching frequency that estimation is in the electric current under the control that lags behind.Figure 24 illustrates the principle of this method.
Below, in the fifth embodiment of the present invention, as shown in figure 27,, utilize the armature position estimation of estimating based on the switching frequency of this benchmark model to describe to when handling the output of benchmark model concurrently with real system output.
In Figure 27, the demodulated error signal between the switching frequency of actual signal and the switching frequency of benchmark model provides the parameter that depends on armature position, and this parameter that depends on armature position is used to the armature position estimation." trend estimator " portion 57 of utilization realizes that by similar mode precision improves, and should " trend estimator " portion 57 provide the input at notch indicator portion 52.
This has expanded the saturated usually and air gap of magnetic core wherein usually less than the application of the elevator brake system of 1mm.
Utilize Laplace transform table to reach, the benchmark model among Figure 27 be expressed as:
Wherein, L
nAnd R
nBe that armature keeps and the armature deenergized period, with the corresponding nominal parameter of normal manipulation mode.
In addition, in Figure 27, can be by realizing low-pass filter (LPF) and high-pass filter (HPF) with formula (45) and the similar mode of formula (46).Frame among Figure 27 (ABS) means the absolute value of the number of winning the confidence.
In Figure 27, error signal 66 is calculated as poor between signal 64 and the signal 65.Signal 64 is to carry out high pass (high pass portion 58) at the electric current to measurement to obtain afterwards, and the electric current of this measurement is provided by current probe portion 13, is then provided after rectification by rectification part 59.Signal 65 is to obtain after the output of adopting benchmark model (portion 24), the input of this benchmark model is provided by driving circuit 9 or piezoelectric detector 14, the output of this benchmark model is carried out high pass by high pass portion 61, then carries out rectification by rectification part 62.
In Figure 27, utilize low-pass filter portion 63 demodulated error signal 66, the output of low-pass filter portion 63 is relevant with armature position, and this provides the input at trend estimator portion 57.
Carry out the armature position estimation and the position is indicated by the mode identical with the mode described in the fourth embodiment of the invention.