CN101257272A - Method for deducing initial magnetic pole position of permanent magnet synchronous motor - Google Patents

Abstract

The invention discloses a deduction method for the initial magnetic pole position of a permanent magnet synchronous motor, in which, firstly, when the elevator band brake is not switching-on, approximate initial magnetic pole position is calculated by the salient pole saturation effect and formula(1); then a vector transformation control is used, supposing an orthogonal shaft (D, Q) when the rotor magnetic linkage and force moment current position are not accurately known, supposing the setting of the Q shaft is zero, and meanwhile a D shaft current vector Id' twice of the motor rating current, constructing a position ring, according to the motor rotary direction after switching-on the band brake, countermovement on the setting current vector Id' direction allows the motor to quickly balance and static; finally the current vector (2) at this time is directly to the load to once more balancing, and then using the triangular theorem to obtain a formula (3), thereby requesting an actual motor load T'and an accurate motor magnetic pole position beta. The invention possesses the advantages of not only being capable of obtaining load values at the motor shaft terminal, but also being capable of more accurately testing the initial magnetic pole position, thereby the startup will be more comfortable and smoothing.

Description

The deduction method of permanent magnet synchronous motor initial magnetic pole position

Technical field:

The present invention relates to a kind of deduction method of the permanent magnet synchronous motor initial magnetic pole position under rotor field-oriented control.

Background technology:

At present, the vector control that is used for the permanent magnet synchronous motor on the elevator be field orientation control general what adopt is that the rotor flux that the control method of ID=0 promptly will make the permanent magnet of rotor produce is accurately positioned in the D axle of vector control, thereby guarantee the comfortableness of permanent magnet synchronous motor start-up course and the stability of control procedure.But, because the initial position of rotor has randomness, if not carrying out position of magnetic pole detects, rotor flux just is difficult to be accurately positioned on the D axle when motor just starts, when the rotor flux deviations is big, just make the control failure of motor easily, so the detection of position of magnetic pole is the key that is used for the control of the permanent magnet synchronous motor of elevator.It is that the signal that Hall magnetic pole detecting element produces is measured position of magnetic pole that the detection of prior art permanent magnet synchronous motor initial magnetic pole position normally utilizes the UVW signal of encoder, but utilize the UVW signal to judge that can there be bigger error in initial magnetic pole position, influences the control of permanent magnet synchronous motor.And, in elevator control, in order to guarantee the comfortableness of start-up course, motor need obtain initial torque compensation accurately, prior art is to adopt weighing detection device to obtain this initial torque compensation accurately, but because the distortion of elevator cage bottom and the problems such as drift of analog signal, there is the big and high problem of maintenance cost of maintenance workload in actual elevator weighing apparatus.

At the problems referred to above, disclosing a kind of application number on the China national intellectual property board web is 200510024266.0 patents of invention that are called the deduction method of permanent magnet synchronous motor initial magnetic pole position, this patent adopts the control method of ID=0, earlier according to current controller integration output valve voltage difference delta U (Δ U=U _d+ I _q* L _q* ω) and the product signs Y (Y=Δ U* ω) of rotor speed ω infer whether this increase or reduce angle between the rotor flux of actual rotor flux and hypothesis, promptly when Y＜0, make the D axial advancement move angle delta θ; When Y＞0, make axially back move angle Δ θ of D, at last, whether determining near zero whether vector space coordinate D axle accurately has been positioned rotor flux promptly default on the magnetic field of rotor flux and has overlapped in the rotor flux of reality according to Δ U, thereby can draw the initial position angle of rotor magnetic pole.

Yet the applicant finds that the deduction method that foregoing invention adopts need know motor inductance accurately in advance, otherwise will declare the symbol of wrong Δ U, is easy to vibration when making the plus-minus angle; And when Δ U trend is zero, will near null value, vibrate, its sign change is more obvious, has bigger acceleration change when causing motor start-up, thereby makes angle obtain to be not easy convergence, can't guarantee the comfortableness of motor start-up; And, adopt this deduction method can not obtain the load size of motor shaft end.

Summary of the invention:

The technical problem to be solved in the present invention is, a kind of size that not only can obtain the motor shaft end load is provided, and can make the detection of initial magnetic pole position more accurate, thereby make the deduction method of more comfortable, the level and smooth permanent magnet synchronous motor initial magnetic pole position of startup.

Technical solution of the present invention is that a kind of deduction method with permanent magnet synchronous motor initial magnetic pole position of following three steps is provided: it at first adopts salient pole saturation effect and formula when the elevator band-type brake is not opened ${\mathrm{\&theta;}}_r\&ap;\frac{\mathrm{<figure-callout\; id="2"\; label="cos"\; filenames="A20071016477100121.png"\; state="\{\{state\}\}">cos</figure-callout>}\frac{2\mathrm{\&pi;}}{3}}{\mathrm{<figure-callout\; id="2"\; label="sin"\; filenames="A20071016477100121.png"\; state="\{\{state\}\}">sin</figure-callout>}\frac{2\mathrm{\&pi;}}{3}}\frac{(\mathrm{\&Delta;}{I}_c-\mathrm{\&Delta;}{I}_b)}{(\mathrm{\&Delta;}{I}_c+\mathrm{\&Delta;}{I}_b)}$ Try to achieve initial magnetic pole position roughly; Then in the permanent magnet synchronous motor system of field orientation, adopt transform vector control, when not knowing the position of rotor flux and torque current accurately, suppose (the D of a quadrature, Q) axle, what make the Q axle is given as zero, and the D shaft current vector I ' of a given twice rated current of while _d, making up a position ring, the rotation direction of motor after opening according to band-type brake oppositely moves given current phasor I ' _dDirection, finally make the quick balance of motor static; Utilize the constant characteristics of elevator traction machine motor load behind the band-type brake of opening at last, reduce given current phasor I ' _dExtremely

Times motor rated current makes the current phasor of this moment $I_d^{\&prime;\&prime;}=\frac{\sqrt{3}}{2}{I}_d^{\&prime;},$ Until load balance once more, utilize the triangle theorem to obtain formula then $\mathrm{\&beta;}=\mathrm{arctg}\frac{\sin \mathrm{\&gamma;}}{\sqrt{3}-\cos \mathrm{\&gamma;}}$ And T '=I " _dSin β obtains actual motor load T ' and accurate motor poles position β according to these two formula, stores the initial position of motor poles at last, as the startup operation of next time.

After adopting method of the present invention, we just can make the quick balance of motor not needing to know under the situation of accurate motor parameter such as stator coil inductance etc.; And we can also obtain the size and the accurate more motor initial magnetic pole position of motor shaft end load, thereby make motor carry more comfortable, level and smooth startup under the situation at band.

Description of drawings:

Fig. 1 is the direction of the rotor flux when being positive direction of the electric current on the phase winding and the direction schematic diagram of the magnetic linkage that electric current produces.

Fig. 2 is the direction of the electric current rotor flux in the other direction time the on the phase winding and the direction schematic diagram of the magnetic linkage that electric current produces.

Fig. 3 is the control circuit schematic diagram of each phase winding of motor.

Fig. 4 is the current feedback schematic diagram of each phase winding when U applies the forward voltage pulse mutually.

Fig. 5 is that the stator coil inductance value changes schematic diagram with electrical degree.

Fig. 6 is that current changing rate changes schematic diagram with electrical degree.

Fig. 7 is rotor schematic diagram to each phase winding current affects degree when the mechanical sector of difference.

Fig. 8 is a motor start-up axle head load schematic diagram.

Fig. 9 is band-type brake quick balance schematic diagram of motor when opening.

Figure 10 is a schematic diagram of measuring the load size.

Figure 11 is the operation principle flow diagram of the deduction method of permanent magnet synchronous motor initial magnetic pole position of the present invention.

Embodiment:

Be further described below in conjunction with the deduction method of the drawings and specific embodiments permanent magnet synchronous motor initial magnetic pole position of the present invention:

As shown in figure 11, the present invention mainly comprises following three steps:

(1), in permanent magnet synchronous motor, rotor flux can influence the magnetic linkage that phase winding produces, as shown in Figure 1 because the influence of saturated saliency, i.e. the magnetic linkage Ψ that produces when forward current _A+Direction and rotor flux Ψ _MDirection when basic identical, rotor flux can increase the degree of saturation of stator core by influencing phase winding (being the stator coil magnetic linkage), thereby reduces the inductance value of phase winding; As shown in Figure 2, the Ψ that produces when reverse current _A-Direction and rotor flux Ψ _MDirection when opposite, rotor flux can be by influencing the degree of saturation that phase winding (being the stator coil magnetic linkage) reduces stator core, thereby increase the inductance value of phase winding.Owing to the inductance of phase winding is that variation along with the stator core degree of saturation changes, so we can utilize the relation of variation inductance and rotor-position to try to achieve roughly motor initial magnetic pole position.

According to the saturated principle of above-mentioned salient pole, when opening at the elevator band-type brake, we under the motor rotor fixation case, do not send the potential pulse U of a forward earlier to the U phase winding _DC, be about to the K among Fig. 3 _U, K _VAnd K _WOpen, with K _U', K _V' and K _W' closure, going up of U phase managed conducting at this moment, V phase and W following pipe conducting mutually, and as shown in Figure 4, we measure the electric current maximum amplitude I of each phase winding of record respectively _A ⁺, I _B ^-And I _C ^-We send the reverse voltage pulse U that width is identical to the U phase winding then _DC, be about to K among Fig. 3 _U, K _VAnd K _WClosure is with K _U', K _V' and K _W' open, this moment the U phase following pipe conducting, V mutually and W mutually go up the pipe conducting, same, we also measure the electric current maximum amplitude I that writes down each phase winding respectively _A ^-, I _B ⁺And I _C ⁺

Fig. 5 and Fig. 6 are the schematic diagrames that stator coil inductance and current changing rate change with electrical degree, change and show as similar sine as Fig. 5 and Fig. 6, and the width of above-mentioned potential pulse can be made suitable adjustment according to recording inductance, makes impulse current roughly remain on motor rated current about twice.Then, below can constructing, we ask the formula model of each phase winding electric current, wherein I ₀Represent the mean value of current changing rate, as shown in Figure 6, I ₀Be roughly 42.5; Δ I ₀Be to record impulse current, it is with the electrical degree sinusoidal variations; θ _rBe motor initial magnetic pole position roughly.

I _a＝I ₀+ΔI ₀COS(2θ _r) (1)

$I_b=I_0+\mathrm{\&Delta;}{I}_0\mathrm{COS}({2\mathrm{\&theta;}}_r+\frac{2\mathrm{\&pi;}}{3})---\left(2\right)$

$I_c=I_0+\mathrm{\&Delta;}{I}_0\mathrm{COS}({2\mathrm{\&theta;}}_r-\frac{2\mathrm{\&pi;}}{3})---\left(3\right)$

We are by the conversion of above-mentioned formula, and the electric current maximum amplitude I of each phase winding that writes down when band-type brake is not opened according to elevator _a ^-, I _a ⁺, I _b ⁺, I _b ^-, I _c ^-And I _c ⁺The above-mentioned formula of substitution can be derived and be obtained following formula:

$\mathrm{\&Delta;}{I}_a=I_a^{+}+I_a^{-}=I_a-I_0---\left(4\right)$

$\mathrm{\&Delta;}{I}_b=I_b^{+}+I_b^{-}=I_b-I_0---\left(5\right)$

$\mathrm{\&Delta;}{I}_c=I_c^{+}+I_c^{-}=I_c-I_0---\left(6\right)$

With above-mentioned formula (2) and (3) substitution (5) and (6) respectively, we obtain:

$\frac{\sin \left({2\mathrm{\&theta;}}_r\right)}{\cos \left({2\mathrm{\&theta;}}_r\right)}=\frac{\cos \left(\frac{2\mathrm{\&pi;}}{3}\right)}{\sin \left(\frac{2\mathrm{\&pi;}}{3}\right)}\frac{(\mathrm{\&Delta;}{I}_c-\mathrm{\&Delta;}{I}_b)}{(\mathrm{\&Delta;}{I}_c+\mathrm{\&Delta;}{I}_b)}---\left(7\right)$

We suppose θ _rVery little, i.e. sin (2 θ _r)=θ _r, cos (2 θ _r)=1, behind the triangular transformation to formula (7), we obtain following formula:

${\mathrm{\&theta;}}_r\&ap;\frac{\mathrm{<figure-callout\; id="2"\; label="cos"\; filenames="A20071016477100121.png"\; state="\{\{state\}\}">cos</figure-callout>}\frac{2\mathrm{\&pi;}}{3}}{\sin \frac{2\mathrm{\&pi;}}{3}}\frac{(\mathrm{\&Delta;}{I}_c-\mathrm{\&Delta;}{I}_b)}{(\mathrm{\&Delta;}{I}_c+\mathrm{\&Delta;}{I}_b)}---\left(8\right)$

Because angle π=3.14, so the θ in the formula (8) _rCan be regarded as a angle with numeric representation,

What Fig. 7 represented is the influence degree schematic diagram that rotor is produced each phase winding electric current when the mechanical sector of difference, because Δ I _a, Δ I _bAnd Δ I _cThe both positive and negative situation is respectively arranged, so the number of sectors that shows among Fig. 7 is six, and shown sector width is positive and negative 30 degree, so we can be according to Δ I _a, Δ I _bAnd Δ I _cSymbol determine the roughly sector at electrical degree place, try to achieve roughly initial magnetic pole position according to formula (8) then.In other words, the θ that obtains according to formula (8) _rHaving two numerical value is electrical degree, and we can be according to Fig. 7 and Δ I _a, Δ I _bAnd Δ I _cSymbol determine i.e. roughly the initial magnetic pole position of one of them our required electrical degree.

(2), also there is approximately+/-12 deviation of degree in the initial magnetic pole position determined according to said method, so we obtain position of magnetic pole more accurately by following principle and step.

In rotor field-oriented vector control, rotor flux is to be oriented on the D axle of vector control, because the deviation of initial magnetic pole position, actual D axle and the D axial vector I that we send _dBetween have certain deviation, the angle of its deviation is θ. as shown in Figure 8, what we made the Q axle is given as zero, the D axle be given as that a direction is fixed and size is the D shaft current vector I ' of twice motor rated current _dThereby, produced the Q axle component I of a reality _q(T ').X shown in Fig. 8 is a motor reel.If actual Q axle component I _q(T ') is not enough to balance axle head load T, and we are after opening band-type brake so, and motor will rotate, because current phasor I ' _dDirection is fixing, and it can not change along with the electrical degree of feedback and change.Therefore, the feasible actual Q axle component I of the rotation of motor _q(T ') slowly strengthens, as Q axle component I _qWhen (T ') equaled axle head load T, motor had just been obtained balance.If actual Q axle component I _q(T ') greater than axle head load T, after opening band-type brake, the motor counter-rotation is because current phasor I ' _dDirection is fixing, and it can not change along with the electrical degree of feedback and change.Therefore, the feasible actual Q axle component I of the counter-rotation of motor _q(T ') slowly reduces, as Q axle component I _qWhen (T ') equaled axle head load T, motor had also just been obtained balance.But in actual application, because there is inertia in the motor load end when rotating, so motor might cross balance point stopping operating before, breaks through first or third quadrant, makes the Q axle component I of reality _q(T ') no longer by sinusoidal monotonic increase or successively decrease, thereby motor can't be averaged out.

For this reason, we can construct a position ring (angle position closed loop), and as shown in Figure 9, being input as of described position ring opened the angle θ that motor rotates behind the band-type brake ₁, position ring is output as the D shaft current vector I ' that we send _dReverse deflection angle theta ₂Be D shaft current vector I ' _dThe actual angle that moves, we introduce a load inertia coeffeicent K simultaneously _p, according to the feedback angle θ of motor rotation back encoder ₁Promptly open the angle that motor rotates behind the band-type brake, we are with θ ₁Multiply by K _pReverse afterwards fast moving D shaft current vector I ' _d, the output violent change that finally makes position ring is θ ₁+ θ ₂＜pi/2, θ ₁+ θ ₂The purpose of＜pi/2 be in order to ensure the current phasor that sends roughly within one, three quadrants, thereby make actual Q axle component T ' still keep monotonic increase roughly or successively decrease.Therefore, the feedback angle θ of encoder after we open according to band-type brake ₁Multiply by K _pCome the given D shaft current vector I ' of reverse fast moving _dAfter, the motor of this moment has turned over θ ₁Angle, our D shaft current vector I ' of sending so _dThe actual angle θ that moves ₂Should equal (K _p+ 1) θ ₁Behind the maximum angle of restriction vector move angle, select suitable K according to the inertia of load _pValue, thus motor is averaged out very fast, and can not produce excessive acceleration.

(3), through after the above-mentioned steps, as shown in figure 10, after motor averages out because motor shaft end load T size after opening band-type brake is constant, the D shaft current vector I ' that we reduce to send _dTo the motor rated current

Doubly, i.e. Ci Shi D shaft current vector $I_d^{\&prime;\&prime;}=\frac{\sqrt{3}}{2}{I}_d^{\&prime;},$ Because D shaft current vector I " _dAngle not become be that D shaft current vector does not rotate, so Q axle component I _q(T ') will be not enough to balancing motor, and motor will rotate, and the rotation of motor will increase Q axle component I _q(T '), thus make motor balance again, because D shaft current vector is from I ' behind the rotation γ _dArrive I " _dThe position, the γ here=(K _p+ 1) θ ₁, therefore, according to the triangle theorem, we will obtain following formula:

I′ _d*cos(β+γ)＝I″ _dcosβ (9)

$\frac{\sqrt{3}}{2}=\frac{\cos (\mathrm{\&beta;}+\mathrm{\&gamma;})}{\cos \mathrm{\&beta;}}---\left(10\right)$

Formula (9) and formula (10) are behind triangular transformation, and we obtain following two formula

$\mathrm{\&beta;}=\mathrm{arctg}\frac{\sin \mathrm{\&gamma;}}{\sqrt{3}-\cos \mathrm{\&gamma;}}---\left(11\right)$

T′＝I″ _dsinβ (12)

Because γ and I in formula (11) and the formula (12) " _dAll be known, therefore, we can obtain actual D axle more accurately and the angle of deviation that we are present is that β is accurate motor initial magnetic pole position, and load is T ' on the present motor shaft, after the correction, the actual loading that records can be used as torque compensation and adds control, to obtain to start preferably comfortableness.

Claims (1)

1, a kind of deduction method of permanent magnet synchronous motor initial magnetic pole position, it comprises following three steps:

1. when not opening, adopts by the elevator band-type brake salient pole saturation effect and formula ${\mathrm{\&theta;}}_r\&ap;\frac{\cos \frac{2\mathrm{\&pi;}}{3}}{\sin \frac{2\mathrm{\&pi;}}{3}}\frac{(\mathrm{\&Delta;}{I}_c-\mathrm{\&Delta;}{I}_b)}{(\mathrm{\&Delta;}{I}_c+\mathrm{\&Delta;}{I}_b)}$ Try to achieve initial magnetic pole position roughly;

2., in the permanent magnet synchronous motor system of field orientation, the control of employing transform vector, when not knowing the position of rotor flux and torque current accurately, suppose (the D of a quadrature, Q) axle, what make the Q axle is given as zero, and the D shaft current vector I ' of a given twice motor rated current of while _d, making up a position ring, the rotation direction of motor after opening according to band-type brake oppositely moves given current phasor I ' _dDirection, finally make the quick balance of motor static;

3., utilize the constant characteristics of elevator traction machine motor load behind the band-type brake of opening, reduce given current phasor I ' _dExtremely

Times motor rated current makes the current phasor of this moment $I_d^{\&prime;\&prime;}=\frac{\sqrt{3}}{2}{I}_d^{\&prime;},$ Until load balance once more, utilize the triangle theorem to obtain formula then $\mathrm{\&beta;}=\mathrm{arctg}\frac{\sin \mathrm{\&gamma;}}{\sqrt{3}-\cos \mathrm{\&gamma;}}$ And T '=I " _dSin β obtains actual motor load T ' and accurate motor poles position β according to these two formula, stores the initial position of motor poles at last, as the startup operation of next time.

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