The angular position detector of switched reluctance machines and detection method
Technical field
The invention belongs to the switched reluctance machines field of electrical category, particularly a kind of position detector and detection method of switched reluctance machines angle control.
Background technology
The switched reluctance motor drive system is the integrated Alternating Current Governor System of a kind of novel electromechanical, mainly is made up of switched reluctance motor, power inverter, controller and position detector four parts.Wherein, the purpose of position probing is to confirm the relative position of motor stator and rotor, as the foundation of power controlling converter main switching device break-make.At present, the switched reluctance machines drive system generally adopts photosensitive formula position detector, and it is by being fixed on the photoelectric sensor on the stator and forming with the inductor (being commonly called as blanking disc) of rotor coaxial rotation.Photoelectric sensor is U type structure normally, and its reflector is a light-emitting diode, and receiver is a phototriode, and they lay respectively at the both sides of U type groove, and forms an optical axis, and when object process U type groove and blocking-up optical axis, photoelectric sensor just produces switching signal.Inductor has tooth and teeth groove, and its tooth, teeth groove number equal the rotor number of poles.The tooth of inductor or teeth groove just make light-sensitive element conducting or shutoff through the U type groove of photoelectric sensor, produce the cyclic pulse signal that comprises rotor position information.Because the inductive disks that existing detector all adopts tooth and space width to equate, the high-low level width of the pulse signal that each photoelectric sensor produces equates.The be separated by N road P-pulse combination of certain angle, like four phase motor N=2, three phase electric machine N=3 produces the uniform position signalling state of 2N kind width in an energising cycle.This position detector can be confirmed the break-make moment of each phase winding, but can not be used for the angle control of switched reluctance machines.What simultaneously, the detected winding commutation of this detector constantly neither be best cut-offs constantly.
For three-phase 12/8 pole switching reluctance motor, be placed in three photoelectric sensors on the stator differ successively in the space 15 °+k * 45 ° mechanical angle (k=0,1,2 ...), wherein the optical axis of first photoelectric sensor overlaps with certain pole center mutually.Inductor is 8 teeth, 8 teeth groove structures, and tooth and teeth groove respectively account for 22.5 °.Locate the tooth center of inductor and rotor pole center-aligned for ease.Its position signalling is 60 ° of electrical degrees at a distance from 7.5 ° of mechanical angles whenever, and a saltus step takes place.In an energising cycle, position signalling has 6 kinds of states.The turn-on angle of each phase winding of position signalling control is the i.e. 30 ° of electrical degrees of 3.75 ° of mechanical angles thus, and closing the angle of rupture is the i.e. 150 ° of electrical degrees of 18.75 ° of mechanical angles.Because turn-on angle is bigger, the rise time of winding current is not enough, and it is short that causes motor produces the time of effective torque; It is big to produce the required current peak of certain torque; And between the afterflow period, produce bigger opposing torque, cause the motor operational efficiency not high, and can produce very big vibration.For solving the bigger problem of turn-on angle that above-mentioned position detector is confirmed, the people is arranged with mechanical angle of the whole rotation of photoelectric sensor, but this makes again the position signalling logic asymmetric in positive and negative direction, influences the forward and backward performance of motor.
Summary of the invention
The technical barrier that the present invention will solve is the deficiency that overcomes existing detection method; Existing position detector is difficult to detect the best commutation moment of winding and the technical barriers such as angle control that position signalling can not be used for switched reluctance machines; Adopt through changing the method for the required turn-on angle of the extremely wide acquisition control strategy of inductor, for switched reluctance machines provide a kind of simple in structure, realize convenient, strong and reliable angular position detector.
The technical scheme that the present invention adopts is a kind of angular position detector of switched reluctance machines, it is characterized in that, angular position detector has N the static transducer and the inductor of a rotation; Transducer adopts photoelectric sensor or magneto-dependent sensor;
(1) when adopting photoelectric sensor, the structure of inductor 5 is the claw type structure, and promptly inductor 5 is the unequal claw type blanking discs of tooth and space width, and the polar arc angle β of its tooth confirms according to the desired turn-on angle of control strategy; Pcb board 6 supports 7 with insulation and is installed on the end cap 3 of motor through dog screw 4 successively; On the pcb board 6 the equidistance sequence interval be equipped with successively first, second ..., N transducer S1, S2 ..., SN, the axis of first sensor S1 aligns with a motor pole center mutually; First, second ..., N transducer S1, S2 ..., among the SN, the angle between adjacent two sensor axis equates; The number of teeth of inductor 5 equals the rotor number of poles, and inductor 5 is installed on the motor shaft 1 through flat key 2, guarantees the tooth center and the rotor pole center-aligned of inductor 5;
(2) when adopting magneto-dependent sensor; The structure of inductor is a disk-shaped structure; At this moment; Inductor is made up of round turntable 8 and the permanent magnetism magnetic pole 9 that sticks on the center of circle rotating disk 8, and the number of poles of permanent magnetism magnetic pole 9 equals the rotor number of poles of motor, and the polar arc angle β of permanent magnetism magnetic pole 9 confirms according to the desired turn-on angle of control strategy; Round turntable 8 is installed on the motor shaft 1 through flat key 2, the utmost point center-aligned of the center of permanent magnetism magnetic pole 9 and motor; Adopt N magneto-dependent sensor as first, second .... N transducer S1, S2 ... SN; First, second ... N transducer S1, S2 ... SN is directly installed on the end cap 3 of motor, a pole center of the center-aligned phase of first sensor S1; First, second ..., N transducer S1, S2 ..., among the SN, the angle between adjacent two sensor axis equates.
The angular position detector of described a kind of switched reluctance machines, the detection method characteristic that it adopts are that the method that obtains the desired turn-on angle of control strategy through the polar arc angle that changes inductor is carried out position probing; When the number of phases m of motor is even number, the transducer number of employing
When the number of phases m of motor is odd number, the transducer number N=m of employing; In angular position detector with
end cap 3 as stator, first, second ...,
N transducer S 1, S2 ... Among the SN, the angle between the adjacent device axis in space is equal,
Wherein, k=0,1,2, N
rBe the rotor number of poles;
The pole span angle τ of inductor does
When adopting photoelectric sensor, establish θ
FFor inductor teeth groove and tooth to 1/2 of the difference of central angle; When adopting magneto-dependent sensor, establish θ
FFor inductor interpolar and magnetic pole to 1/2 of the difference of central angle; Tooth or the magnetic pole of definition inductor right central angle be the polar arc angle β of inductor, the polar arc angle β of inductor is:
The natural turn-on angle θ of the switched reluctance machines that angular position detector obtains
On1For:
Wherein: N
S---be the stator poles of motor;
As the polar arc angle of inductor β during less than τ/2, its wide state angle θ the state that 2N kind width replaces appears, in the position signalling in energising cycle
HWith narrow state angle θ
LBe respectively:
Switched reluctance machines adopts following control strategy:
1) below rated speed, two states of every phase winding conducting, the conducting interval of every phase winding is to add between a wide state area between an adjacent back narrow state area, the natural turn-on angle of switched reluctance machines is θ
On1
During 2) below rated speed and near rated speed, state of a switched reluctance machines conducting, at this moment, the conducting interval that makes every phase winding only between wide state area, is equivalent to keep motor nature turn-on angle constant, turn-offs to have shifted to an earlier date θ constantly
L
3) more than rated speed, the natural turn-on angle of every phase winding is carried previous θ
L, at this moment, the conducting interval of every phase winding become adding between a wide state area between adjacent previous narrow state area, the turn-on angle of switched reluctance machines is θ
On2=θ
On1-θ
L
The present invention has following positive effect: 1) position detector can not only be confirmed the commutation moment of winding, can also be used for the angle control of switched reluctance machines, has further increased the flexibility of switched Reluctance Motor Control strategy.2) angular position detector can be confirmed the needed winding turn-on angle of commutation strategy, and forward and reverse complete symmetry.3) significantly improve the current waveform of switched reluctance machines, improve efficiency of motor, reduce vibration and noise.
Description of drawings
Fig. 1 is the photosensitive formula angular position detector structure chart of switched reluctance machines, and Fig. 2 is that the K of Fig. 1 is to view.Wherein, 1 is motor shaft, and 2 is flat key, and 3 is end cap, and 4 is dog screw; 5 is inductor, and 6 is pcb board, and 7 support for insulation, S1, S2 ... SN is the first, the second; N transducer, α are the angle between adjacent two sensors axis, and β is the polar arc angle of inductor, and τ is the pole span angle of inductor.
Fig. 3 is the Mageneto-sensitive type angular position detector structure chart of switched reluctance machines, Fig. 4 be the A-A of Fig. 3 to view, Fig. 5 is that the B-B of Fig. 3 is to view.Wherein, 1 is motor shaft, and 2 is flat key, and 3 is end cap; 8 is round turntable, and 9 is permanent magnetism magnetic pole, S1, S2 ... SN is first, second ... The N transducer; α is the angle between adjacent two sensors axis, and β is the polar arc angle of inductor magnetic pole, and τ is the pole span angle of inductor.
Fig. 6 is the comparison of wave shape figure of phase current under specified running status.Wherein: the X coordinate is a position angle, and unit is an electrical degree, and the Y coordinate is an electric current, and unit is A, and curve 1 is for adopting the winding rated current of conventional detector; Curve 2 is for adopting the winding rated current of detector of the present invention.
Embodiment
Specify practical implementation of the present invention below in conjunction with accompanying drawing and technical scheme.
Embodiment 1: Fig. 1, shown in Figure 2 be a kind of photo-electric angle position detector of three-phase 12/8 pole switching reluctance motor; Its
inductor 5 is the claw type blanking disc of 8 teeth, 8 teeth groove structures, and the pole span angle τ of
inductor 5 is
keep the tooth center and the rotor pole center-aligned of inductor.Present embodiment adopts three photoelectric sensors as first, second, third transducer S1, S2, S3; First, second, third transducer S1, S2, S3 are installed on the pcb board 6, and pcb board 6 is fixed on the
end cap 3 of motor through
dog screw 4 with insulation support 7 successively.First, second, third transducer S1, S2, S3 at the mechanical angle α that the space is separated by successively are:
utmost point center in the motor three-phase of aliging successively, the center of first, second, third transducer S1, S2, S3.In the present embodiment: θ
F=2.75 °, induction
The polar arc angle β of device is:
The nature turn-on angle is:
The wide state width θ of position signalling
HWith narrow state width θ
LBe respectively:
When employing shifted to an earlier date the conducting strategy, its turn-on angle was: θ
On2=θ
On1-θ
L=1 °-2 °=-1 °
Embodiment 2, Fig. 3, Fig. 4 and shown in Figure 5 be a kind of Mageneto-sensitive type angular position detector of three-phase 12/8 pole switching reluctance motor; Its inductor is made up of
round turntable 8 and permanent magnetism
magnetic pole 9, and the pole span angle τ of inductor is:
pole center and the rotor pole center-aligned of maintenance inductor.Present embodiment adopts three magneto-dependent sensors as first, second, third transducer S1, S2, S3; First, second, third transducer S1, S2, S3 are directly installed on the
end cap 3 of motor.First, second, third transducer S1, S2, S3 at the mechanical angle α that the space is separated by successively are:
utmost point center in the three-phase of aliging respectively successively, the center of first, second, third transducer S1, S2, S3.
In the present embodiment: θ
F=2.75 °, the polar arc angle β of inductor magnetic pole is:
The nature turn-on angle is:
The wide state width θ of position signalling
HWith narrow state width θ
LBe respectively:
When employing shifted to an earlier date the conducting strategy, its turn-on angle was: θ
On2=θ
On1-θ
L=1 °-2 °=-1 °
As shown in Figure 6, the three-phase 12/8 pole switching reluctance motor of a 7.5kW, commutation under the natural turn-on angle of position detector, when adopting existing position detector, current peak reaches 46A under the specified running status; And when adopting the angular position detector of instance of the present invention, the phase current peak value has only 33A under specified running status.
Adopt angular position sensor of the present invention to make the control of switched reluctance machines more flexible, and can greatly improve motor properties.Angular position detection method of the present invention is applicable to two phases, three-phase, four phase or five mutually isostructural inside and outside rotor switched reluctance motors.