Summary of the invention
The technical problem to be solved in the present invention just is: at the technical problem that prior art exists, provide a kind of control more easy, stable, can promote the control method of the line inductance electromotor of line inductance electromotor trailer system overall performance.
For solving the problems of the technologies described above, the solution that the present invention proposes is: a kind of control method of line inductance electromotor, it is characterized in that: according to input voltage or input voltage and the input current of inverter line inductance electromotor, obtain the actual magnetic linkage frequency and the magnetic linkage amplitude of the elementary magnetic linkage of line inductance electromotor, gather the real-time speed of line inductance electromotor then, obtain the frequency reference amount and the amplitude reference quantity of the elementary magnetic linkage of line inductance electromotor by real-time speed, the shape of elementary magnetic linkage under the while combining target state, determine that suitable primary voltage space vector makes actual magnetic linkage amplitude and magnetic linkage frequency be tending towards amplitude reference quantity and frequency reference amount respectively, the inverter between DC power supply and the line inductance electromotor be will the control signal corresponding send to, thereby the speed or the thrust of line inductance electromotor changed with the primary voltage space vector.
The present invention wherein a kind of step of scheme further is:
(1). gather the DC power supply magnitude of voltage of inverter input,, obtain the input voltage u of line inductance electromotor in conjunction with the control signal of last cycle microprocessor to inverter
a, u
b, u
c, obtain u through 3/2 conversion
S α, u
S β, 1. obtain accurate primary magnetic chain space vector by following formula
ψ iComponent ψ at rectangular coordinate system α, β axle
I α, ψ
I β, further can be regarded as in view of the above accurate elementary magnetic linkage actual magnitude ψ
iAnd accurate elementary magnetic linkage real space azimuth θ
ψ iOr 2. obtain accurate elementary magnetic linkage actual angular speed ω by following formula
ψ i
ψ
iα,β=∫u
sα,βdt.....................................................................①;
...............②
(2). gather the real-time motor velocity signal v of line inductance electromotor, can tentatively determine the basic reference quantity of slippage angular frequency, further optimize in conjunction with actual conditions on this basis and determine slip-frequency reference quantity ω by this rate signal v
Sl *, and can 3., 4. obtain accurate primary magnetic chain space azimuth reference quantity θ by following formula
ψ i *Or 4. obtain accurate primary magnetic chain space azimuth speed reference amount ω by following formula
ψ i *, wherein τ is an electric motor primary coil pole span;
...................③
...................④
(3). can directly obtain accurate primary magnetic chain space vector magnitude reference quantity ψ according to needed target propulsive force
i *, perhaps according to the rate signal v and the target setting rate signal reference value v that obtain
*Between error carry out PI and regulate and to obtain accurate primary magnetic chain space vector magnitude reference quantity ψ
i *
(4). in conjunction with the target shape of the elementary magnetic linkage of line inductance electromotor, determine that suitable primary voltage space vector makes accurate elementary magnetic linkage real space azimuth ω
ψ iBe tending towards accurate primary magnetic chain space azimuth reference quantity θ
ψ i *Perhaps make accurate elementary magnetic linkage actual angular speed ω
ψ iBe tending towards accurate primary magnetic chain space azimuth speed reference amount ω
ψ i *Accurate elementary magnetic linkage actual magnitude ψ
iBe tending towards accurate primary magnetic chain space vector magnitude reference quantity ψ
i *, also just obtain control signal corresponding and send inverter between DC power supply and the line inductance electromotor to, finish control to line inductance electromotor.
In the such scheme, the azimuth error ε that 5. the present invention further obtains by following formula by the numerical value that obtains in step (1), (2) and (3)
θOr 6. obtain angular speed error ε by following formula
ω, to azimuth error ε
θOr angular speed error ε
ωThe ring that stagnates is controlled, and makes azimuth error ε
θOr angular speed error ε
ωEqual or go to zero, promptly obtain the FREQUENCY CONTROL of magnetic linkage; Simultaneously the magnetic linkage amplitude is stagnated and encircle control, making the error between actual magnetic linkage amplitude and magnetic linkage amplitude reference quantity is zero, and this promptly obtains amplitude control of magnetic linkage, or utilizes θ
ψ i *And ψ
i *, in conjunction with the target shape of the elementary magnetic linkage of line inductance electromotor, utilize the method for space vector modulation, reach the FREQUENCY CONTROL and the amplitude control of magnetic linkage simultaneously.
.........⑤
............⑥
The step of the another kind of scheme of the present invention further is:
(1). gather the DC power supply magnitude of voltage of inverter input,, obtain the input voltage u of line inductance electromotor in conjunction with the control signal of last cycle microprocessor to inverter
a, u
b, u
c, obtain u through 3/2 conversion
S α, u
S β, can obtain input current value i equally
S α, i
S β, 7. obtain primary magnetic chain space vector by following formula
ψ sComponent ψ at rectangular coordinate system α, β axle
S α, ψ
S β, further can be regarded as in view of the above its elementary magnetic linkage actual magnitude ψ
sAnd elementary magnetic linkage real space azimuth θ
ψ sOr 8. obtain elementary magnetic linkage actual angular speed ω by following formula
ψ s
ψ
sα,β=∫(u
sα,β+i
sα,βR
s)dt.........................................................⑦
.....................⑧
(2). gather the real-time motor velocity signal v of line inductance electromotor, can tentatively determine the basic reference quantity of slippage angular frequency, further optimize in conjunction with actual conditions on this basis and determine slip-frequency reference quantity ω by this rate signal v
Sl *, and can 9., 10. obtain primary magnetic chain space azimuth reference quantity θ by following formula
ψ s *Or 10. obtain primary magnetic chain space azimuth speed reference amount ω by following formula
ψ s *, wherein τ is an electric motor primary coil pole span;
...................⑨
...................⑩
(3). can directly obtain primary magnetic chain space vector magnitude reference quantity ψ according to needed target propulsive force
s *, perhaps according to the rate signal v and the target setting rate signal reference value v that obtain
*Between error carry out PI and regulate and to obtain primary magnetic chain space vector magnitude reference quantity ψ
s *
(4). in conjunction with the shape of the elementary magnetic linkage of line inductance electromotor, determine that suitable primary voltage space vector makes elementary magnetic linkage real space azimuth θ
ψ sEqual or be tending towards primary magnetic chain space azimuth reference quantity θ
ψ s *Perhaps make elementary magnetic linkage actual angular speed ω
ψ sBe tending towards primary magnetic chain space azimuth speed reference amount ω
ψ s *, make elementary magnetic linkage actual magnitude ψ simultaneously
sBe tending towards primary magnetic chain space vector magnitude reference quantity ψ
s *, also promptly obtain control signal corresponding and send inverter between DC power supply and the line inductance electromotor to, finish control to line inductance electromotor.
In the such scheme, the present invention just further passes through following formula by the numerical value that obtains in step (1), (2) and (3)
The azimuth error ε that obtains
θOr pass through following formula
Obtain angular speed error ε
ω, to azimuth error ε
θOr angular speed error ε
ωThe ring that stagnates is controlled, and makes azimuth error ε
θOr angular speed error ε
ωEqual or go to zero, promptly obtain the FREQUENCY CONTROL of magnetic linkage; Simultaneously the magnetic linkage amplitude is also stagnated and encircle control, making the error between actual magnetic linkage amplitude and magnetic linkage amplitude reference quantity is zero, and this promptly obtains amplitude control of magnetic linkage, or utilizes θ
ψ i *And ψ
i *, in conjunction with the target shape of the elementary magnetic linkage of line inductance electromotor, utilize the method for space vector modulation, reach the FREQUENCY CONTROL and the amplitude control of magnetic linkage simultaneously.
The present invention further is controlled to be circle, hexagon, ten octagon magnetic linkages or other polygon with the magnetic linkage shape of the elementary magnetic linkage of line inductance electromotor, and this also is the target shape of elementary magnetic linkage.
Described slip shows as: when motor is in traction mode, slip s be on the occasion of, when normal force meets the requirements, s 〉=s
MaxAnd make | s-s
Max| as far as possible little, promptly line inductance electromotor operates near the maximum thrust point of mechanical property; When motor was in braking mode, slip s was a negative value, when normal force meets the requirements, and s≤s
MinAnd make | s-s
Min| as far as possible little, promptly line inductance electromotor operates near the maximum braking force point of mechanical property.
Compared with prior art, advantage of the present invention just is: relative Current Control, elementary magnetic linkage control will realize manyly easily, and the high-quality control that more is easy to get.This is because elementary magnetic linkage obtains easily accurately, and is the same with direct torque control, only needs current of electric measured value and magnetic linkage handled to get final product.Flux linkage vector change direction and big I are accurately predicted, and when especially the target magnetic linkage is hexagon or ten octagons when high speed, switching frequency are reduced greatly, reduce switching loss, and its harmonic wave still keep less relatively.These linear electric motors for middle high power capacity lead control and are even more important.This control method even need not carried out thrust and be calculated (this thrust also is difficult for accurately obtaining in real time in actual the use), and this control method combines the characteristic of linear electric motors, can make linear electric motors obtain higher efficient and higher hauling ability.Because itself and structural certain similitude of electric rotating machine direct torque control have kept direct torque control major part advantage.Good as robustness, control is simple to be realized easily, and contrast linear electric motors control method in the past has remarkable advantages.
Description of drawings
Fig. 1 is the flow process framework schematic diagram of control method of the present invention;
Fig. 2 is a structural framing schematic diagram of using control method of the present invention;
Fig. 3 is the schematic diagram of primary voltage vector and hexagon target magnetic linkage in the present embodiment;
Fig. 4 is the schematic diagram of primary voltage vector and ten octagon target magnetic linkages in the present embodiment;
Fig. 5 is the present invention program one a control flow schematic diagram;
Fig. 6 is the present invention program two a control flow schematic diagram.
Marginal data
1, velocity transducer 2, voltage and current sensor
3, microprocessor 4, inverter
5, line inductance electromotor 6, DC power supply
7, memory cell
Symbol description
The t time;
ω sl slippage angular frequency;
The v motor speed;
τ electric motor primary coil pole span;
L
mMotor excitation inductance (mutual inductance);
Sa, Sb, Sc: be respectively motor stator A, B, C go up gate signal such as thyristor or IGBT mutually, are 1, and brachium pontis conducting on the inverter is 0, following brachium pontis conducting;
ω
ψ sPrimary magnetic chain angular speed;
ω
r: motor secondary electric angle speed
ψ
I α, β: the α axle of accurate primary magnetic chain space vector or β axle value
ψ
S α, β: the α axle of primary magnetic chain space vector or β axle value;
u
S α, β: the α axle of primary voltage space vector or β axle value;
i
S α, β: the α axle of primary current space vector or β axle value;
i
a, i
b, i
c: be respectively electric motor primary (stator) A, B, C phase current;
R
s: electric motor primary resistance;
Is: primary current amplitude;
ω s primary current angular frequency;
u s The primary voltage space vector;
ψ s Primary magnetic chain space vector;
ψ r Secondary magnetic chain space vector;
ψ
sPrimary magnetic chain space vector magnitude;
ψ
i: accurate primary magnetic chain space vector magnitude;
ψ
rSecondary magnetic chain space vector magnitude;
Primary magnetic chain space azimuth;
Accurate primary magnetic chain space azimuth;
Secondary magnetic chain space azimuth;
θ: primary and secondary flux linkage space vector angle;
ε
θ: the error of elementary magnetic linkage (or accurate elementary magnetic linkage) space vector angle reference quantity and actual amount;
ε
ω: the error of elementary magnetic linkage (or accurate elementary magnetic linkage) space vector angular speed reference quantity and actual amount;
ε
ψ: the error of elementary magnetic linkage (or accurate elementary magnetic linkage) space vector amplitude reference quantity and actual amount;
M:L
sL
r-L
m 2;
L
s: primary inductance;
L
rSecondary inductance;
S: slip;
Smax: on the occasion of, electric current (or elementary magnetic linkage amplitude) a slip of maximum thrust point regularly;
Smin: be negative value, electric current (or elementary magnetic linkage amplitude) is the slip of minimum thrust point, the i.e. slip of maximum braking force point regularly;
SR: motor operation signal.SR=1, the motor operation.Otherwise motor stops;
*: the reference quantity of each value;
k: each is worth k step discrete magnitude;
Wherein, all secondary amounts all reduction to elementary.
Embodiment
Below with reference to the drawings and specific embodiments the present invention is described in further details.
Referring to illustrated in figures 1 and 2, the control method of line inductance electromotor of the present invention, input voltage according to 4 pairs of line inductance electromotors 5 of inverter, obtain the actual magnetic linkage frequency and the magnetic linkage amplitude of the elementary magnetic linkage of line inductance electromotor, gather the real-time speed of line inductance electromotor 5 then, obtain the frequency reference amount and the amplitude reference quantity of the elementary magnetic linkage of line inductance electromotor by real-time speed, the shape of elementary magnetic linkage under the while combining target state, determine that suitable primary voltage space vector makes actual magnetic linkage amplitude and magnetic linkage frequency be tending towards amplitude reference quantity and frequency reference amount respectively, the inverter 4 between DC power supply and the line inductance electromotor 5 be will the control signal corresponding send to, thereby the speed or the thrust of line inductance electromotor 5 changed with the primary voltage space vector.Wherein, DC power supply 6 is sent into line inductance electromotor 5 by inverter 4, and the real-time speed of line inductance electromotor 5 is gathered by velocity transducer 1, is sent to then in the microprocessor 3, and voltage and current sensor 2 can be gathered real-time magnitude of voltage and current value.Can be stored in the memory cell 7 by the data that obtain after microprocessor 3 processing.
The target shape of the elementary magnetic linkage of line inductance electromotor can be circle, hexagon, ten octagon magnetic linkages or other changeable shapes.When being controlled to be hexagon and ten octagons, the switching frequency of inverter 4 is low, and the high-speed driving ability is strong, but the harmonic wave of electric current and magnetic linkage high slightly (referring to Fig. 4 and Fig. 5).When being controlled to be loop circle flux, the switching frequency height of inverter 4, the high-speed driving ability, but harmonic content is low, and the user can select as required flexibly.This control strategy also has strong robustness in addition, and control is simple and easy to realize, controls advantages such as effective.In fact, in view of the plurality of advantages of this control method, it also can be used for other motor, especially the control of the motor of parameter mutability such as solid rotor electromotor.Simultaneously, this control method can make machine operation at breakdown torque (thrust) state, to make full use of capacity motor.This can't accomplish in direct torque control etc.
In general, by one dimension, bidimensional or the 3 D electromagnetic field analysis of line inductance electromotor 5, or, can obtain the operating characteristic of line inductance electromotor 5 by test.According to its operating characteristic, can tentatively determine the operation strategy of line inductance electromotor 5 greater efficiency.Obtain the slip-frequency that changes with speed as last, i.e. ω
Sl=f (v).This slip-frequency by the specificity analysis of line inductance electromotor 5, has been taken all factors into consideration high efficiency and is suppressed the limit end effect, avoids these requirements of too high normal force, and has established certain corresponding relation of itself and speed in advance.We also can be named its best slippage working point such working point, and promptly certain motor speed have corresponding slip-frequency corresponding, thereby motor speed is certain, and its supply frequency is certain.Because the motor power frequency changes with rate smoothing and as can be known, perhaps this operation conditions of line inductance electromotor 5 we can be referred to as metastable state.
By 7. formula as can be known, voltage and the electric current in addition certain when line inductance electromotor 5 are known, and flux linkage vector can accurately be known, thereby easily realized accurate optimization control.And when realizing ten octagons or hexagon magnetic linkage control, the combination of its voltage vector is very simple, thereby reduces switching frequency, reduces switching loss, and is certain when direct voltage, can improve the high-speed driving ability of line inductance electromotor 5.As adopting the hexagon magnetic linkage control, its magnetic linkage shape is seen Fig. 3 dotted line, can realize with 7 voltage vector simple combination.
As direct torque control, only need handle and to realize this control method by the primary current signal that records.The control of elementary magnetic linkage is not subjected to the influence that each parameter of T type equivalent electric circuit of line inductance electromotor 5 changes and can accurately obtains, and has very strong robustness.In addition:
By following formula
As can be known, by control azimuth θ, size that can quick adjustment
line inductance electromotor 5 thrusts.This also is the most basic control principle of control method such as Direct Torque, vector control in the past.When the amplitude or the angular speed of elementary flux linkage space vector changes fast, because the slow effect of leakage field, the amplitude of secondary magnetic linkage or angular speed also only can smoothly change.Therefore, in a certain short time period, we can think that secondary magnetic linkage vector magnitude and angular speed are constant.If slip-frequency and speed are certain, also be that primary magnetic chain angular speed is certain.This moment, primary and secondary flux linkage vector angle θ can not change yet obviously.And secondary magnetic linkage amplitude can not directly be controlled, so we can be by the elementary magnetic linkage amplitude ψ of control
sControl thrust.This basic control principle just of the present invention.
In a short time, suppose secondary angular velocity omega
rWith secondary magnetic linkage azimuth speed omega
ψ rConstant, if elementary magnetic linkage azimuth speed omega
ψ s(t) change rapidly, at t
0To t
1Time period, we obtain:
ω
sl(t)=ω
ψs(t)-ω
r
Obviously, primary and secondary flux linkage vector angle θ (t) is the function of slip-frequency, changes slip-frequency and promptly changes primary and secondary flux linkage vector angle.We can think that traditional slip-frequency control, vector control, direct torque control belongs to a kind of control method together from this point, promptly keep the flux linkage vector amplitude constant relatively, mainly regulate torque by changing the flux linkage vector angle.And the present invention is another kind of control method, promptly keeps the flux linkage vector angle constant relatively, and is main by change magnetic linkage amplitude adjusting torque (thrust), and then governing speed.Certainly, for traditional control method, the magnetic linkage amplitude neither be definitely constant, as reducing the magnetic linkage amplitude at weak magnetic area.Overregulate thrust or the torque that the magnetic linkage amplitude is regulated motor but it is obstructed.From this point as can be seen, although direct torque control is the same with this method, also can realize the magnetic linkage control (this requires to decide on controlling object and control) of circle, hexagon, ten octagons or other shape to magnetic linkage, but the present invention and direct torque control there is bigger difference.
Wherein, slip shows as: when line inductance electromotor 5 is in traction mode, s be on the occasion of, when normal force meets the requirements, s 〉=s
MaxAnd make | s-s
Max| as far as possible little, promptly line inductance electromotor 5 operates near the maximum thrust point of mechanical property; When line inductance electromotor 5 was in braking mode, s was a negative value, when normal force meets the requirements, and s≤s
MinAnd make | s-s
Min| as far as possible little, promptly line inductance electromotor 5 operates near the maximum braking force point of mechanical property;
Specifically, this difference shows: when line inductance electromotor 5 operates in certain speed, the former slip-frequency does not change with load, and this moment, slip-frequency was constant or constant substantially, general s 〉=s
MaxAnd the working point is at s
MaxThe point near.And for direct torque control, its slip-frequency changes with the load size.Load is big more, and slip-frequency is big more.And general s≤s
MaxIn control procedure, the slip of slip-frequency is embodied in: as s 〉=s
MaxThe time, line inductance electromotor 5 is in low regime; When | s-s
Max| when big, line inductance electromotor 5 is in the high speed district; When | s-s
Max| near 0, line inductance electromotor 5 is in the high speed district, and promptly line inductance electromotor 5 operates near the maximum thrust point of mechanical property.
For the aforementioned method that is only decided slip-frequency by speed, obviously its slip-frequency is constant under the certain speed.But, make s when operation because the air gap of line inductance electromotor 5 etc. change up and down around set point
MaxAlso have a little variation.This makes according to the air-gap setting value predetermined working point best operating point not necessarily when actual motion, can in the slip-frequency computing unit, add an on-line optimization program for this reason, line inductance electromotor 5 the aforementioned slip-frequency of only obtaining by speed changed according to air gap carries out on-line fine, even also can be operated near the best slip-frequency point when the air gap value changes.At this moment slip-frequency changes.Because the air gap changing value is less when normal operation, its slip-frequency changes still less relatively.And slip-frequency does not change with the load size, and the adjusting of thrust still mainly realizes by the adjusting of magnetic linkage amplitude.
Referring to illustrated in figures 1 and 2, the present invention program one step is:
(1). gather the DC power supply magnitude of voltage of inverter 4 inputs,, obtain the input voltage u of line inductance electromotor 5 in conjunction with the control signal of last cycle microprocessor to inverter 4
a, u
b, u
c, obtain u through 3/2 conversion
S α, u
S β, 1. obtain accurate primary magnetic chain space vector by following formula
ψ iComponent ψ at rectangular coordinate system α, β axle
I α, ψ
I β, further can be regarded as in view of the above accurate elementary magnetic linkage actual magnitude ψ
iAnd accurate elementary magnetic linkage real space azimuth θ
ψ iOr 2. obtain accurate elementary magnetic linkage actual angular speed ω by following formula
ψ i
ψ
iα,β=∫u
sα,βdt.....................................................................①;
........................②
(2). gather the real-time motor velocity signal v of line inductance electromotor 5, can tentatively determine the basic reference quantity of slippage angular frequency, further optimize in conjunction with actual conditions on this basis and determine slip-frequency reference quantity ω by this rate signal v
Sl *, and can 3. obtain accurate primary magnetic chain space azimuth reference quantity θ by following formula
ψ i *Or 4. obtain accurate primary magnetic chain space azimuth speed reference amount ω by following formula
ψ i *
...............................③
...............................④
(3). can directly obtain accurate primary magnetic chain space vector magnitude reference quantity ψ according to needed target propulsive force
i *, perhaps according to the rate signal v and the target setting rate signal reference value v that obtain
*Between error carry out PI and regulate and to obtain accurate primary magnetic chain space vector magnitude reference quantity ψ
i *
(4). in conjunction with the target shape of the elementary magnetic linkage of line inductance electromotor, determine that suitable primary voltage space vector makes accurate elementary magnetic linkage real space azimuth θ
ψ iBe tending towards accurate primary magnetic chain space azimuth reference quantity θ
ψ i *Perhaps make accurate elementary magnetic linkage actual angular speed ω
ψ iBe tending towards accurate primary magnetic chain space azimuth speed reference amount ω
ψ i *Accurate elementary magnetic linkage actual magnitude ψ
iBe tending towards accurate primary magnetic chain space vector magnitude reference quantity ψ
i *, also just obtain control signal corresponding and send inverter 4 between DC power supply and the line inductance electromotor 5 to, finish control to line inductance electromotor 5.
In step (4), the azimuth error ε that 5. obtains by following formula by the numerical value that obtains in step (1), (2) and (3)
θOr 6. obtain angular speed error ε by following formula
ω, to azimuth error ε
θOr angular speed error ε
ωThe ring that stagnates is controlled, and makes azimuth error ε
θOr angular speed error ε
ωEqual or go to zero, promptly obtain the FREQUENCY CONTROL of magnetic linkage; Simultaneously the magnetic linkage amplitude is also stagnated and encircle control, making the error between actual magnetic linkage amplitude and magnetic linkage amplitude reference quantity is zero, and this promptly obtains amplitude control of magnetic linkage, or utilizes θ
ψ i *And ψ
i *, in conjunction with the target shape of the elementary magnetic linkage of line inductance electromotor, utilize the method for space vector modulation, reach the FREQUENCY CONTROL and the amplitude control of magnetic linkage simultaneously.
.......⑤
........⑥
Referring to shown in Figure 3, when inverter place 4 during in Current Control, promptly during the Control current sinusoidal variations, this moment elementary magnetic linkage actual be loop circle flux, this will utilize limited several voltage vectors, for two-level inverter, voltage vector is
u 0 -u 7 Seven voltage vectors, obtain by combination, thereby switching frequency is higher, and has limited the high-speed driving ability of motor.
In general, especially for train, its direct voltage is not a steady state value, but fluctuation within the specific limits.At this moment just be necessary the input direct voltage of inverter 4 is measured, to obtain to control preferably effect.Simultaneously, for elementary stator magnetic linkage accurately being controlled the needs of protecting with elementary stator over-current, also need measure to its electric current.
The present invention program two step is:
(1). gather the DC power supply magnitude of voltage of inverter 4 inputs,, obtain the input voltage u of line inductance electromotor 5 in conjunction with the control signal of last cycle microprocessor to inverter 4
a, u
b, u
c, obtain u through 3/2 conversion
S α, u
S β, obtain input current value i after same collection converts
S α, i
S β, 7. obtain primary magnetic chain space vector by following formula
ψ sComponent ψ at rectangular coordinate system α, β axle
S α, ψ
S β, further can be regarded as in view of the above its elementary magnetic linkage actual magnitude ψ
sAnd elementary magnetic linkage real space azimuth θ
ψ sOr 8. obtain elementary magnetic linkage actual angular speed ω by following formula
ψ s
ψ
sα,β=∫(u
sα,β+i
sα,βR
s)dt.........................................................⑦
....................⑧
(2). gather the real-time motor velocity signal v of line inductance electromotor 5, can tentatively determine the basic reference quantity of slippage angular frequency, further optimize in conjunction with actual conditions on this basis and determine slip-frequency reference quantity ω by this rate signal v
Sl *, and can 9. obtain primary magnetic chain space azimuth reference quantity θ by following formula
ψ s *Or 10. obtain primary magnetic chain space azimuth speed reference amount ω by following formula
ψ s *
...........................⑨
...........................⑩
(3). can directly obtain primary magnetic chain space vector magnitude reference quantity ψ according to needed target propulsive force
s *, perhaps according to the rate signal v and the target setting rate signal reference value v that obtain
*Between error carry out PI and regulate and to obtain primary magnetic chain space vector magnitude reference quantity ψ
s *
(4). in conjunction with the shape of the elementary magnetic linkage of line inductance electromotor, determine that suitable primary voltage space vector makes elementary magnetic linkage actual magnitude ψ
sEqual primary magnetic chain space vector magnitude reference quantity ψ
s *, make elementary magnetic linkage real space azimuth θ simultaneously
ψ sEqual or be tending towards primary magnetic chain space azimuth reference quantity θ
ψ s *Perhaps make elementary magnetic linkage actual angular speed ω
ψ sEqual or be tending towards primary magnetic chain space azimuth speed reference amount ω
ψ s, also promptly obtain control signal corresponding and send inverter 4 between DC power supply and the line inductance electromotor 5 to, finish control to line inductance electromotor 5.
In step (4), pass through following formula by the numerical value that obtains in step (1), (2) and (3)
The azimuth error ε that obtains
θOr obtain angular speed error ε by following formula 12
ω, to azimuth error ε
θOr angular speed error ε
ωThe ring that stagnates is controlled, and makes azimuth error ε
θOr angular speed error ε
ωEqual or go to zero, promptly obtain the FREQUENCY CONTROL of magnetic linkage; Simultaneously the magnetic linkage amplitude is also stagnated and encircle control, making the error between actual magnetic linkage amplitude and magnetic linkage amplitude reference quantity is zero, and this promptly obtains amplitude control of magnetic linkage, or utilizes θ
ψ i *And ψ
i *, in conjunction with the target shape of the elementary magnetic linkage of line inductance electromotor, utilize the method for space vector modulation, reach the FREQUENCY CONTROL and the amplitude control of magnetic linkage simultaneously.
Wherein can tentatively determine the basic reference quantity of slippage angular frequency by motor velocity signal v, the basic reference quantity of this slippage angular frequency, be to draw by specificity analysis to line inductance electromotor 5, take all factors into consideration high efficiency and suppress the limit end effect, avoid these requirements of too high normal force, and established certain corresponding relation of itself and speed in advance.The slip of this moment shows as: s 〉=s
Max, in low regime, | s-s
Max| bigger, and in the high speed district, | s-s
Max| near 0.Promptly in the high speed district, line inductance electromotor 5 operates near the maximum thrust point of mechanical property.And 4. can obtain the basic reference quantity of magnetic linkage angular frequency by formula.Because the air gap of linear electric motors etc. change up and down around set point, make s when operation
MaxAlso have a little variation.Need the further on-line optimization of the basic reference quantity of aforementioned gained angular frequency for this reason, the aforementioned slip-frequency of only obtaining by speed is changed according to air gap carry out on-line fine, even change in the air gap value, motor also can be operated near the best slip-frequency point when high speed is moved.Under certain speed, the reference quantity of elementary magnetic linkage frequency constant relatively (but not being definitely constant) mainly is the thrust control that obtains motor by the adjusting of magnetic linkage amplitude reference quantity size.
Referring to shown in Figure 5, the concrete control flow of corresponding scheme one is:
1, control system starts, and microprocessor 3 powers on to move and carries out initialization.The attached value of K is 1;
2, read the SR value;
3, SR is not 1, then finishes operation, and motor stops.SR is 1, then reads inverter 4 switching signal S
a k, S
b k, S
c k, read the DC input voitage U of inverter 4
Dc kAnd motor speed v
k
4, according to S
a k, S
b k, S
c k, U
Dc kPress following formula and obtain u
S α k, u
S β k,
5,1. obtain flux linkage vector amplitude ψ by following formula
i kAnd azimuth
6, given magnetic linkage amplitude reference quantity or speed is carried out PI control obtain the amplitude reference quantity
7, by speed v
kCalculate the slip-frequency reference value
Go forward side by side calculate magnetic linkage angular frequency reference value
With flux linkage space azimuth reference value
8, calculate flux linkage vector angle error and amplitude error ε
θ kAnd ε
ψ k,, select suitable stator (elementary) voltage vector again in conjunction with selected magnetic linkage shape
u s K+1Azimuth sum of errors amplitude error is controlled, thereby made ε
θ kAnd ε
ψ kDeng doing or be tending towards 0;
9, determined
u s K+1, also just determined S
a K+1, S
b K+1, S
c K+1, output S
a K+1, S
b K+1, S
c K+1Signal is controlled inverter 4;
10, k=k+1 changeed for 2 steps, and circulation is carried out.
Referring to shown in Figure 6, the flow process of the concrete control flow such scheme one of corresponding scheme two is basic identical, but in scheme two control flows the 5th the step change into: 2. obtain flux linkage vector amplitude ψ by formula
s kAnd azimuth θ
ψ s k, and the elementary accurate magnetic linkage ψ of other step
iCorrespondingly change elementary magnetic linkage ψ into
s, can finish the control of scheme two.