CN100570391C - The real-time detection of permanent-magnetism synchronous motor permanent magnetic field aberration and analytical approach and device thereof - Google Patents

Abstract

The real-time detection of permanent-magnetism synchronous motor permanent magnetic field aberration and analytical approach and device thereof belong to the electric machines control technology field.This detection and analytical approach are easily surveyed signal based on motor speed, voltage and electric current, rotor-position etc., the permanent magnetic field changing condition of real-time monitored permagnetic synchronous motor, calculating permanent-magnetism synchronous motor permanent magnetic magnetic field in real time is back emf coefficient at the permanent magnetism magnetic linkage that rotates under the dq coordinate system synchronously; Analyze the magnetic linkage component of permanent magnetic field in each phase winding-be corresponding back emf coefficient, can analyze and obtain the permanent magnetic field waveform and be reflected to harmonic components in the motor phase windings back emf coefficient.Based on above-mentioned detection and analytical approach, can predict and prevent the situation of permanent magnet of permanent magnet motor loss of excitation, realize the Optimal Control Strategy of permagnetic synchronous motor.The result that said method obtains can be used in online detection of motor loss of excitation and the motor high performance control.

Description

The real-time detection of permanent-magnetism synchronous motor permanent magnetic field aberration and analytical approach and device thereof

Technical field

The present invention relates to a kind of magnetic field detection and analytical approach of motor, belong to the motion servo technical field.

Background technology

Along with permanent magnetic material performance improve constantly and perfect, magneto research and development experience progressively ripe, permagnetic synchronous motor is to high-power, high-performance and microminiaturized development.Owing to adopt permanent magnet that air-gap flux is provided, that permagnetic synchronous motor all has is simple in structure, volume is little, in light weight, loss is little, the efficient advantages of higher.Obtained to use widely in fields such as PHEV, naval vessel propelling, high-performance servocontrol.

Compare with electro-magnetic motor, the inferior position of magneto maximum is permanent magnetic field fluctuation and loss of excitation problem at present: because the Nd-Fe-Bo permanent magnet material Curie temperature is on the low side, temperature stability is relatively poor, its irreversible loss and temperature coefficient are all higher, cause under the high temperature magnetic loss serious, and can not guarantee that demagnetizing curve is a straight line, electric current increases sharply under electric motor starting, brake or failure condition, the working point can be moved to the knee point of demagnetizing curve, causes irreversible loss of excitation.Magnetic field of permanent magnet fluctuation and loss of excitation can cause that the motor feels hot and the torque performance variation, and seriously motor may be scrapped under the situation, and this problem has greatly limited the range of application of magneto.

In the magneto actual motion, for different operating conditions and temperature variation, the variation maximum of permanent magnetism magnetic linkage amplitude can reach about 20%, and its torque that causes changes much larger than the saturated output torque that causes of ac-dc axis inductance and changes.According to the electromagnetic torque expression formula of permagnetic synchronous motor as can be known, if will obtain the higher torque control performance, need permanent magnet magnetic chain information accurately.

At permanent magnet loss of excitation problem, the method for the most normal employing at present is from the design of electrical motor angle, optimizes magnetic structure, reduces the loss of excitation risk.These class methods still belong to a kind of prevention scheme of static state, and basic point of departure improves the allowance of motor apart from loss of excitation point for taking into full account the motor operating mode, but the motor actual operating mode is often quite complicated, is difficult to take into full account, and the demagnetization phenomenon still is difficult to avoid sometimes.And to the operating loss of excitation of motor; just shut down detection after often will arriving the initiation obvious fault; common method is carried out Measurement and analysis for adopting teslameter, magnetic-flux meter, direct current magnetic characteristic tester or no load test method; the repairing means are for changing magnetic sheet or magnetizing again; so this detection method can only be called the off-line analysis method behind a kind of loss of excitation, the loss of excitation degree of energy initiating failure is often very serious.At the magnetic field of permanent magnet fluctuation problem, generally only consider the fluctuation of magnetic linkage amplitude in the control, seldom consider the variation of magnetic direction and the distortion of magnetic flux density waveforms.

Present existing Chinese invention patent (CN 1830135A) utilizes permagnetic synchronous motor to control used q shaft voltage controlled quentity controlled variable to come guestimate permagnetic synchronous motor degaussing amount, estimated accuracy is limited, and the sinusoidal waveform amplitude when only having considered the magnetic field of permanent magnet loss of excitation reduces, and does not consider problems such as magnetic field fluctuation and the distortion of waveform non-sinusoidal.

Summary of the invention

The object of the present invention is to provide a kind of method that can carry out online detection and analysis to permanent-magnetism synchronous motor permanent magnetic field aberration.That permagnetic synchronous motor all has is simple in structure, volume is little, in light weight, loss is little, the efficient advantages of higher.Obtained to use widely in fields such as PHEV, naval vessel propelling, high-performance servocontrol.But because magnetic field of permanent magnet fluctuation and loss of excitation can cause that the motor feels hot and the torque performance variation, seriously motor may be scrapped under the situation, and this problem has greatly limited the range of application of magneto.According to the electromagnetic torque expression formula of permagnetic synchronous motor as can be known, if will obtain the higher torque control performance, need permanent magnet magnetic chain information accurately.The invention provides a kind of method that can carry out online detection and analysis to permanent-magnetism synchronous motor permanent magnetic field aberration.

Technical scheme of the present invention is as follows:

A kind of permanent-magnetism synchronous motor permanent magnetic field aberration detects and analytical approach in real time, it is characterized in that this method comprises the steps:

1) permanent-magnetism synchronous motor permanent magnetic field aberration real-time detection method

A. obtain motor rotor position θ by position transducer, calculate motor speed ω by the revolution speed calculating module; Rotational speed omega is input in the motor control module;

B. with the stator voltage u of permagnetic synchronous motor under two phase coordinates _α, u _βThrough stator voltage u under the α dq coordinate system that β/the dq coordinate transform obtains _d, u _qWith the stator current i of permagnetic synchronous motor under ABC three phase coordinate systems _A, i _BAnd i _C, obtain dq coordinate system stator current i through abc/ α β, twice coordinate transform of α β/dq _d, i _q

C. with θ, ω, i _d, i _q, u _d, u _qAs the input signal of flux observer, obtain permanent magnetism magnetic linkage component ψ under the dq coordinate system _Fd, ψ _Fq, obtain back emf coefficient K under the dq coordinate system divided by the motor number of pole-pairs _Bd, K _Bq

D. select stator current i under the dq coordinate system _d, i _q, ψ _Fd, ψ _FqBe state variable, stator current is for measuring vector under the dq coordinate system, and stator voltage is an input vector under the dq coordinate system, makes up the system state equation and the output equation of observation permanent magnet magnetic linkage observation:

System state equation:

$\frac{d}{\mathrm{dt}}\left[\begin{array}{c}{i}_d\\ i_q\\ {\mathrm{\ψ}}_{\mathrm{fd}}\\ {\mathrm{\ψ}}_{\mathrm{fq}}\end{array}\right]=\left[\begin{array}{cccc}\frac{-R_s}{L_d}& \mathrm{\ω}\frac{L_q}{L_d}& 0& \frac{\mathrm{\ω}}{L_d}\\ -\mathrm{\ω}\frac{L_d}{L_q}& \frac{{-R}_s}{L_q}& -\frac{\mathrm{\ω}}{L_q}& 0\\ 0& 0& 0& 0\\ 0& 0& 0& 0\end{array}\right]\left[\begin{array}{c}{i}_d\\ i_q\\ {\mathrm{\ψ}}_{\mathrm{fd}}\\ {\mathrm{\ψ}}_{\mathrm{fq}}\end{array}\right]+\left[\begin{array}{cc}\frac{1}{L_d}& 0\\ 0& \frac{1}{L_q}\\ 0& 0\\ 0& 0\end{array}\right]\left[\begin{array}{c}{u}_d\\ u_q\end{array}\right]$

Measure equation:

$y=\begin{array}{c}\left[\begin{array}{cccc}1& 0& 0& 0\\ 0& 1& 0& 0\end{array}\right]\left[\begin{array}{c}{i}_d\\ i_q\\ {\mathrm{\ψ}}_{\mathrm{fd}}\\ {\mathrm{\ψ}}_{\mathrm{fq}}\end{array}\right]=\left[\begin{array}{c}{i}_d\\ i_q\end{array}\right]\end{array}$

Equation above utilizing makes up permanent magnet magnetic linkage observer, realizes permanent magnetism magnetic linkage ψ under the dq coordinate system _Fd, ψ _FqReal-time monitored;

2) permanent-magnetism synchronous motor permanent magnetic field aberration analytical approach

A. on the basis of the real-time detection method in step 1), arrive the transformation matrix of rotation dq coordinate system synchronously according to the ABC coordinate system transformation:

$C_{3s/2r}=\sqrt{\frac{2}{3}}\left[\begin{array}{ccc}{\cos \mathrm{\θ}}^{\′}& \cos ({\mathrm{\θ}}^{\′}-\frac{2\mathrm{\π}}{3})& \cos ({\mathrm{\θ}}^{\′}+\frac{4\mathrm{\π}}{3})\\ -\sin {\mathrm{\θ}}^{\′}& -\sin ({\mathrm{\θ}}^{\′}-\frac{2\mathrm{\π}}{3})& -\sin ({\mathrm{\θ}}^{\′}+\frac{4\mathrm{\π}}{3})\\ \frac{1}{\sqrt{2}}& \frac{1}{\sqrt{2}}& \frac{1}{\sqrt{2}}\end{array}\right]$

Wherein, θ and coordinate transform angle θ ' differ a fixed angle Δ θ, i.e. θ '=θ+Δ θ,

Obtain that the back emf coefficient transformation relation is under three-phase back emf coefficient and the dq coordinate system:

$\left[\begin{array}{c}{K}_{\mathrm{Ed}}\\ K_{\mathrm{Eq}}\end{array}\right]=C_{3s/2r}\left[\begin{array}{c}{K}_{\mathrm{EA}}\\ K_{\mathrm{EB}}\\ K_{\mathrm{EC}}\end{array}\right]$

Because synchronously rotation dq coordinate system is with the rotation of three-phase back emf coefficient fundamental frequency, the back emf coefficient first-harmonic transforms to dq coordinate system following time under the ABC coordinate system, obtains dq axle back emf coefficient and is:

$K_{\mathrm{Ed}}=\underset{i}{\mathrm{\Σ}}{K}_{{\mathrm{Ed}}_i},(i=6n,n=\mathrm{0,1,2,3}\·\·\·\·\·\·)$

$K_{\mathrm{Eq}}=\underset{i}{\mathrm{\Σ}}{K}_{{\mathrm{Eq}}_i},(i=6n,n=\mathrm{0,1,2,3}\·\·\·\·\·\·)$

Ignore under the higher hamonic wave situation, back emf coefficient is a direct current biasing waveform under the dq coordinate system, at 2 π 6 pulsation, this conclusion and detection method 1 is arranged in the cycle) in the result that obtains be consistent;

Three-phase back emf coefficient and d, the q axle back emf coefficient represented according to following formula concern that can carry out data analysis to the magnetic linkage waveform that flux observer obtains, obtaining its magnetic linkage in phase winding is back emf coefficient;

3), the permanent magnet of permanent magnet motor loss of excitation is predicted and is prevented based on above-mentioned detection and analytical approach:

A. judge at first whether back emf coefficient has fluctuation under the dq coordinate system,, the non-sinusoidal distortion does not take place if ripple disable explanation magnetic field of permanent magnet waveform has only amplitude and phase change; If amplitude reduces and surpass given restriction Δ ψ ₁Then provide loss of excitation amplitude overload alarm, wherein Δ ψ ₁Specifically determine by motor permanent magnetic material demagnetizing curve;

If b. back emf coefficient has fluctuation under the dq coordinate system, then by 2) in the permanent magnetic field aberration analytical approach mentioned carry out frequency analysis, if the pulsation of 6 subharmonic surpasses given restriction Δ ψ ₂Then provide permanent magnet magnetic field distortion overload alarm, wherein Δ ψ ₂Specifically determine by motor permanent magnetic material demagnetizing curve;

4) based on the permagnetic synchronous motor Optimal Control Strategy of the online testing result of permanent magnet magnetic linkage:

, a. back emf coefficient ripple disable under the dq coordinate system, magnetic linkage amplitude do not surpass given restriction Δ ψ as yet if reducing ₁, then carry out field orientation control again according to real-time detected magnetic field of permanent magnet amplitude and phase place;

If b. back emf coefficient has fluctuation under the dq coordinate system, by 2) in the permanent magnetic field aberration analytical approach mentioned carry out frequency analysis, if the pulsation of 6 subharmonic surpasses given restriction Δ ψ as yet in the analysis result ₂, then add the harmonic wave feedforward compensation, to suppress the torque pulsation that the harmonic wave back-emf causes at the given place of current of electric.

The present invention also provides a kind of device of implementing said method, it is characterized in that: this device by motor control module, SVPWM module, PWM inverter, contain that permanent magnetic field aberration detects in real time and permanent magnet magnetic linkage observer, position transducer, the magneto of distortion analysis software program constitute; Wherein, the output with motor control module inserts permanent magnet magnetic linkage observer and SVPWM module respectively, SVPWM module output access PWM inverter, control magneto; Position transducer is installed on the magneto, and outgoing position feeds back signal to motor control module; With the stator current i of permagnetic synchronous motor under ABC three phase coordinate systems _A, i _BAnd i _C, obtain dq coordinate system stator current i through abc/ α β, twice coordinate transform of α β/dq _d, i _qi _d, i _qInput to motor control module and permanent magnet magnetic linkage observer respectively, carry out the observation and the detection of magnetic linkage by permanent magnet magnetic linkage observer.

Technical characterictic of the present invention also is: said permanent magnetism flux observer is based on the method for Kalman filter.

The real-time detection of permanent-magnetism synchronous motor permanent magnetic field aberration provided by the invention and analytical approach and device thereof, can analyze the permanent magnetic field waveform and be reflected to harmonic components in the motor phase windings back emf coefficient, thereby the reliability of control device and torque control performance are improved.Use the inventive method can obtain permanent magnet magnetic chain information accurately, realize higher torque control performance.

Description of drawings

Fig. 1 comprises the control system for permanent-magnet synchronous motor block diagram of permanent magnetism magnetic linkage real-time detection function.

Fig. 2 permanent-magnetism synchronous motor permanent magnetic magnetic linkage changes synoptic diagram.

Fig. 3 is the real-time detection computations flow process of permanent magnetism magnetic linkage of example with the permanent magnet magnetic linkage observer based on Kalman filter.

Real-time detection waveform during Fig. 4 permanent magnetic field sinusoidal variations; (a) dq coordinate axis permanent magnetism magnetic linkage before the changes of magnetic field; (b) dq coordinate axis permanent magnetism magnetic linkage after the changes of magnetic field.

Real-time detection waveform during the distortion of Fig. 5 permanent magnetic field non-sinusoidal; (a) d axle permanent magnetism magnetic linkage (back emf coefficient) before and after the distortion; (b) q axle permanent magnetism magnetic linkage (back emf coefficient) before and after the distortion.

Fig. 6 is to the prediction and the prevention of permanent magnet of permanent magnet motor loss of excitation.

Embodiment

Below the specific embodiment of the present invention is further described.

Fig. 1 is the control system for permanent-magnet synchronous motor block diagram that comprises permanent magnetism magnetic linkage real-time detection method.With three phase electric machine commonly used is example, it by motor control module, SVPWM module, PWM inverter, contain that permanent magnetic field aberration detects in real time and permanent magnet magnetic linkage observer, position transducer, the magneto of distortion analysis software program constitute; Wherein, the output with motor control module inserts permanent magnet magnetic linkage observer and SVPWM module respectively, SVPWM module output access PWM inverter, control magneto; Position transducer is installed on the magneto, and outgoing position feeds back signal to motor control module; With the stator current i of permagnetic synchronous motor under ABC three phase coordinate systems _A, i _BAnd i _C, obtain dq coordinate system stator current i through abc/ α β, twice coordinate transform of α β/dq _d, i _qi _d, i _qInput to motor control module and permanent magnet magnetic linkage observer respectively, carry out the observation and the detection of magnetic linkage by permanent magnet magnetic linkage observer.Wherein dotted line is divided into the disclosed technology of the present invention with inside, and the motor control module outside the dotted line, SVPWM, PWM inverter, permagnetic synchronous motor, position transducer etc. partly are common scheme.It in the dotted line a complete permanent magnet magnetic linkage observation module.

1. permanent-magnetism synchronous motor permanent magnetic field aberration disclosed by the invention detects with the concrete implementation step of analytical approach as follows in real time:

1) permanent-magnetism synchronous motor permanent magnetic field aberration real-time detection method

As shown in Figure 1, at first obtain motor stator three-phase current stator current i by the current sensor senses on the motor power-supply wire _A, i _B, i _C, it is carried out the coordinate transform that three-phase/two-phase is abc/ α β, obtain the current component i under the two-phase rest frame _α, i _β:

$\left[\begin{array}{c}{i}_{\mathrm{\α}}\\ i_{\mathrm{\β}}\end{array}\right]=\sqrt{\frac{2}{3}}\left[\begin{array}{ccc}1& -\frac{1}{2}& -\frac{1}{2}\\ 0& \frac{\sqrt{3}}{2}& \frac{\sqrt{3}}{2}\end{array}\right]\left[\begin{array}{c}{i}_a\\ i_b\\ i_c\end{array}\right];$

Through static-rotation is α β/dq coordinate transform, obtains the current component i under the two synchronised rotation dq coordinate system _d, i _q:

$\left[\begin{array}{c}{i}_d\\ i_q\end{array}\right]=\left[\begin{array}{cc}\cos \mathrm{\θ}& \sin \mathrm{\θ}\\ -\sin \mathrm{\θ}& \cos \mathrm{\θ}\end{array}\right]\left[\begin{array}{c}{i}_{\mathrm{\α}}\\ i_{\mathrm{\β}}\end{array}\right]$

In the formula, θ is the electrical angle that permanent magnet machine rotor rotates through, and is obtained by the position transducer of motor side;

Voltage detection device detects permagnetic synchronous motor stator voltage u under α β two phase coordinate systems _α, u _β, pass through stator voltage u under the dq coordinate system that α β/dq coordinate transform obtains afterwards _d, u _q:

$\left[\begin{array}{c}{u}_d\\ u_q\end{array}\right]=\left[\begin{array}{cc}\cos \mathrm{\θ}& \sin \mathrm{\θ}\\ -\sin \mathrm{\θ}& \cos \mathrm{\θ}\end{array}\right]\left[\begin{array}{c}{u}_{\mathrm{\α}}\\ u_{\mathrm{\β}}\end{array}\right];$

Calculate motor rotor position θ according to position sensor output signal, the calculating of revolution speed calculating module is about to the θ differential and obtains rotational speed omega;

That utilizes that above-mentioned steps obtains is θ, ω, i _d, i _q, u _d, u _q, based on following system state equation and measurement equation, carry out the online calculating of permanent magnet magnetic linkage by flow process shown in the accompanying drawing 3, obtain permanent magnetism magnetic linkage component ψ under the dq coordinate system _Fd, ψ _FqDivided by the motor number of pole-pairs also is back emf coefficient K under the dq coordinate system _Ed, K _Eq

System state equation:

$\frac{d}{\mathrm{dt}}\left[\begin{array}{c}{i}_d\\ i_q\\ {\mathrm{\ψ}}_{\mathrm{fd}}\\ {\mathrm{\ψ}}_{\mathrm{fq}}\end{array}\right]=\left[\begin{array}{cccc}\frac{-R_s}{L_d}& \mathrm{\ω}\frac{L_q}{L_d}& 0& \frac{\mathrm{\ω}}{L_d}\\ -\mathrm{\ω}\frac{L_d}{L_q}& \frac{{-R}_s}{L_q}& -\frac{\mathrm{\ω}}{L_q}& 0\\ 0& 0& 0& 0\\ 0& 0& 0& 0\end{array}\right]\left[\begin{array}{c}{i}_d\\ i_q\\ {\mathrm{\ψ}}_{\mathrm{fd}}\\ {\mathrm{\ψ}}_{\mathrm{fq}}\end{array}\right]+\left[\begin{array}{cc}\frac{1}{L_d}& 0\\ 0& \frac{1}{L_q}\\ 0& 0\\ 0& 0\end{array}\right]\left[\begin{array}{c}{u}_d\\ u_q\end{array}\right]$

Measure equation: $y=\begin{array}{c}\left[\begin{array}{cccc}1& 0& 0& 0\\ 0& 1& 0& 0\end{array}\right]\left[\begin{array}{c}{i}_d\\ i_q\\ {\mathrm{\ψ}}_{\mathrm{fd}}\\ {\mathrm{\ψ}}_{\mathrm{fq}}\end{array}\right]=\left[\begin{array}{c}{i}_d\\ i_q\end{array}\right]\end{array}$

Permanent magnetism magnetic linkage component waveform is converted to permanent magnetism magnetic linkage and back emf coefficient under the motor phase windings ABC coordinate system under the dq coordinate system that step (1) is obtained, and carries out the each harmonic analysis.

Analytic process is as follows: the concrete calculating formula of permanent magnetism flux observer is based on that permagnetic synchronous motor magnetic field volatility model obtains in the accompanying drawing 1.Permagnetic synchronous motor magnetic field volatility model is the mathematical model under the dq coordinate system of considering motor-field fluctuation situation.When fluctuate in permagnetic synchronous motor magnetic field, actual permanent magnet magnetic linkage ψ _fThe position may be inconsistent with the front position of fluctuating, magnetic field, and promptly the dq coordinate axis position of using with working control is inconsistent, causes actual permanent magnetism magnetic linkage all to have component ψ at two axles of dq coordinate system _Fd, ψ _Fq, as shown in Figure 2.If permanent magnetic field waveform generation non-sinusoidal distortion still can be represented the relation of permanent magnet magnetic linkage and dq coordinate axis with accompanying drawing 2, at this moment, the component of the dq coordinate axis that the permanent magnetism magnetic linkage uses in control no longer is normal value, but the percent ripple that changes with rotor-position.Like this, voltage equation can be expressed as under the permagnetic synchronous motor dq coordinate system

$u_d=R_s{i}_d+\frac{{\mathrm{d\ψ}}_d}{\mathrm{dt}}-\mathrm{\ω}{\mathrm{\ψ}}_q---\left(1\right)$

$u_q=R_s{i}_q+\frac{{\mathrm{d\ψ}}_q}{\mathrm{dt}}+{\mathrm{\ω\ψ}}_d---\left(2\right)$

Wherein

ψ _d＝L _di _d+ψ _fd (3)

ψ _q＝L _qi _q+ψ _fq (4)

Permagnetic synchronous motor electromagnetic torque expression formula is:

T _e＝P _n[(L _d-L _q)i _di _q+ψ _fdi _q+ψ _fqi _d] (5)

Formula (3), (4) substitution formula (1), (2) are got

$u_d=R_s{i}_d+\frac{{\mathrm{d\ψ}}_d}{\mathrm{dt}}-{\mathrm{\ω\ψ}}_q=R_s{i}_d+L_d\frac{{\mathrm{di}}_d}{\mathrm{dt}}+\frac{{\mathrm{d\ψ}}_{\mathrm{fd}}}{\mathrm{dt}}-\mathrm{\ω}(L_q{i}_q+{\mathrm{\ψ}}_{\mathrm{fq}})---\left(6\right)$

$=R_s{i}_d+L_d\frac{{\mathrm{di}}_d}{\mathrm{dt}}+\frac{{\mathrm{d\ψ}}_{\mathrm{fd}}}{\mathrm{dt}}-{\mathrm{\ωL}}_q{i}_q-\mathrm{\ω}{\mathrm{\ψ}}_{\mathrm{fq}}$

$u_q=R_s{i}_q+\frac{{\mathrm{d\ψ}}_q}{\mathrm{dt}}+\mathrm{\ω}{\mathrm{\ψ}}_d=R_s{i}_q+L_q\frac{{\mathrm{di}}_q}{\mathrm{dt}}+\frac{{\mathrm{d\ψ}}_{\mathrm{fq}}}{\mathrm{dt}}+\mathrm{\ω}(L_d{i}_d+{\mathrm{\ψ}}_{\mathrm{fd}})---\left(7\right)$

$=R_s{i}_q+L_q\frac{{\mathrm{di}}_q}{\mathrm{dt}}+\frac{{\mathrm{d\ψ}}_{\mathrm{fq}}}{\mathrm{dt}}+\mathrm{\ω}{L}_d{i}_d+{\mathrm{\ω\ψ}}_{\mathrm{fd}}$

Obtain through arrangement

$\frac{{\mathrm{di}}_d}{\mathrm{dt}}=\frac{u_d}{L_d}-\frac{R_s}{L_d}\mathrm{id}-\frac{1}{L_d}\frac{{\mathrm{d\ψ}}_{\mathrm{fd}}}{\mathrm{dt}}+\mathrm{\ω}\frac{L_q}{L_d}{i}_q+\mathrm{\ω}\frac{{\mathrm{\ψ}}_{\mathrm{fq}}}{L_d}---\left(8\right)$

$\frac{{\mathrm{di}}_q}{\mathrm{dt}}=\frac{u_q}{L_q}-\frac{R_s}{L_q}{i}_q-\frac{1}{L_q}\frac{{\mathrm{d\ψ}}_{\mathrm{fq}}}{\mathrm{dt}}-\mathrm{\ω}\frac{L_d}{L_q}{i}_d-\mathrm{\ω}\frac{{\mathrm{\ψ}}_{\mathrm{fd}}}{L_q}---\left(9\right)$

Formula (8), (9) utilize formula (8), (9) just can make up the online observation that observer is realized the permanent magnet magnetic linkage for equation under the permagnetic synchronous motor dq coordinate system of considering magnetic field fluctuation situation.

In general, permanent magnetic field fluctuation change procedure will be much slower than the electromagnetic transition process of motor, therefore when finding the solution above-mentioned equation, can suppose the component ψ of permanent magnet magnetic linkage in the dq coordinate axis _Fd, ψ _FqDerivative is zero, promptly

$\frac{{\mathrm{d\ψ}}_{\mathrm{fd}}}{\mathrm{dt}}=0---\left(10\right)$

$\frac{{\mathrm{d\ψ}}_{\mathrm{fq}}}{\mathrm{dt}}=0---\left(11\right)$

Select stator current, ψ under the dq coordinate system _Fd, ψ _FqBe state variable, stator current is for measuring vector under the dq coordinate system, and stator voltage is an input vector under the dq coordinate system, is the system state equation and the output equation of the observation of fundamental construction observation permanent magnet magnetic linkage with formula (8), (9), (10), (11).

System state equation:

$\frac{d}{\mathrm{dt}}\left[\begin{array}{c}{i}_d\\ i_q\\ {\mathrm{\ψ}}_{\mathrm{fd}}\\ {\mathrm{\ψ}}_{\mathrm{fq}}\end{array}\right]=\left[\begin{array}{cccc}\frac{-R_s}{L_d}& \mathrm{\ω}\frac{L_q}{L_d}& 0& \frac{\mathrm{\ω}}{L_d}\\ -\mathrm{\ω}\frac{L_d}{L_q}& \frac{{-R}_s}{L_q}& -\frac{\mathrm{\ω}}{L_q}& 0\\ 0& 0& 0& 0\\ 0& 0& 0& 0\end{array}\right]\left[\begin{array}{c}{i}_d\\ i_q\\ {\mathrm{\ψ}}_{\mathrm{fd}}\\ {\mathrm{\ψ}}_{\mathrm{fq}}\end{array}\right]+\left[\begin{array}{cc}\frac{1}{L_d}& 0\\ 0& \frac{1}{L_q}\\ 0& 0\\ 0& 0\end{array}\right]\left[\begin{array}{c}{u}_d\\ u_q\end{array}\right]---\left(12\right)$

Measure equation:

$y=\begin{array}{c}\left[\begin{array}{cccc}1& 0& 0& 0\\ 0& 1& 0& 0\end{array}\right]\left[\begin{array}{c}{i}_d\\ i_q\\ {\mathrm{\ψ}}_{\mathrm{fd}}\\ {\mathrm{\ψ}}_{\mathrm{fq}}\end{array}\right]=\left[\begin{array}{c}{i}_d\\ i_q\end{array}\right]---\left(13\right)\end{array}$

Utilize formula (12), (13) can make up observers such as full order observer, Kalman filter and realize permanent magnetism magnetic linkage ψ under the dq coordinate system _Fd, ψ _FqReal-time monitored.

Be the performing step that example illustrates above-mentioned magnetic linkage real-time monitored algorithm with flux observer below, but this method is not limited to use Kalman filter based on Kalman filter.

Kalman filter is a kind of optimum linearity algorithm for estimating, it adopts state-space method designing filter in time domain, the multi-dimensional signal dynamics of any complexity is described with state equation, come down to the recursive algorithm that a cover is realized by digital machine, each recursion cycle comprised by the time of estimator upgrades and two processes of measurement renewal.

Utilize formula (12), (13) to make up Kalman filter observation permanent magnetism magnetic linkage.System state equation is expressed as:

Wherein, w is the system noise matrix, and A is a system matrix, and x is the system state vector, and B is an input matrix, and u is an input vector.

Measurement equation is:

Wherein, v is the measurement noise matrix, and H is system's output matrix.

Kalman filtering computation process comprises prediction steps and revises step:

1) forecast period

Predictor formula is:

xe(k|k-1)＝xe(k-1|k-1)+[A(k)xe(k-1|k-1)+Bu(k)]T _s (16)

The variance P of predicated error is:

P(k|k-1)＝P(k-1|k-1)+(A(k)P(k-1|k-1)+P(k-1|k-1)A ^T(k))T _s+Q _d (17)

2) the correction stage

Filter gain:

K(k)＝P(k|k-1)H ^T(HP(k|k-1)H ^T+R) ^-1 (18)

The filtering formula:

xe(k|k)＝xe(k|k-1)+K(k)(y(k)-Hxe(k|k-1)) (19)

The filtering variance:

P(k|k)＝P(k|k-1)-K(k)HP(k|k-1) (20)

Wherein, A (k), u (k), y (k) are system matrix, input vector and output vector after the discretize; Xe is the observed reading of virtual condition x, the modified value of the state estimation that xe (k-1|k-1) calculates for a preceding filtering, and xe (k|k-1) is current filter forecasting value, xe (k|k) current state wave-vector filtering modified value.T _sBe DSP interrupt cycle.K (k) is the Kalman filtering gain.Q _d, R is system noise and measurement noise covariance matrix, is taken as normal value diagonal matrix usually.P is a system state error variance battle array, the system state variance battle array that P (k-1|k-1) calculates for its filtering, and P (k|k-1) is current filter state variance battle array predicted value, P (k|k) is current filtering computing mode variance battle array.

Then adopt as shown in Figure 3 based on the permanent magnetism flux observer calculation procedure of Kalman filter.

Accompanying drawing 4 is dq coordinate axis permanent magnetism magnetic linkage (also corresponding back emf coefficient) situation of change during for the magneto magnetic field sinusoidal variations that adopts above-mentioned steps and observe, and accompanying drawing 5 is dq coordinate axis permanent magnetism magnetic linkage situation of change during for the magneto permanent magnetic field non-sinusoidal distortion adopting above-mentioned steps and observe.

(2) permanent-magnetism synchronous motor permanent magnetic field aberration analysis

Can further analyze the motor permanent magnetic field aberration after permanent magnetism magnetic linkage waveform is counter potential waveform under the dq coordinate system obtaining by above-mentioned detection method, obtaining its magnetic linkage in phase winding is back emf coefficient.The winding back emf coefficient of magneto is positive and negative half-wave symmetry for winding position, does not contain even harmonics.To every opposite potential COEFFICIENT K under the ABC coordinate system _ECarrying out harmonic wave decomposes and can get:

$K_{\mathrm{Ep}}=\underset{n=1}{\overset{\∞}{\mathrm{\Σ}}}{K}_{{\mathrm{Ep}}_n}=\underset{n=1}{\overset{\∞}{\mathrm{\Σ}}}{a}_n\cos \left(n(\mathrm{\θ}-\frac{2(p-1)}{3}\mathrm{\π})\right)+b_n\sin \left(n(\mathrm{\θ}-\frac{2(p-1)}{3}\mathrm{\π})\right),(n=\mathrm{1,3,5,7}\·\·\·\·\·\·;p=\mathrm{1,2,3})---\left(21\right)$

Wherein: n represents overtone order, the corresponding motor A of subscript p, B, C phase.

The ABC coordinate system transformation to the transformation matrix that rotates the d-q coordinate system synchronously is:

$C_{3s/2r}=\sqrt{\frac{2}{3}}\left[\begin{array}{ccc}{\cos \mathrm{\θ}}^{\′}& \cos ({\mathrm{\θ}}^{\′}-\frac{2\mathrm{\π}}{3})& \cos ({\mathrm{\θ}}^{\′}+\frac{4\mathrm{\π}}{3})\\ -\sin {\mathrm{\θ}}^{\′}& -\sin ({\mathrm{\θ}}^{\′}-\frac{2\mathrm{\π}}{3})& -\sin ({\mathrm{\θ}}^{\′}+\frac{4\mathrm{\π}}{3})\\ \frac{1}{\sqrt{2}}& \frac{1}{\sqrt{2}}& \frac{1}{\sqrt{2}}\end{array}\right]---\left(22\right)$

Wherein, θ and coordinate transform angle θ ' differ a fixed angle Δ θ, i.e. θ '=θ+Δ θ.

Then the three-phase back emf coefficient to the dq coordinate system under the back emf coefficient transformation relation be:

$\left[\begin{array}{c}{K}_{\mathrm{Ed}}\\ K_{\mathrm{Eq}}\end{array}\right]=C_{3s/2r}\left[\begin{array}{c}{K}_{\mathrm{EA}}\\ K_{\mathrm{EB}}\\ K_{\mathrm{EC}}\end{array}\right]---\left(23\right)$

Because rotation dq coordinate system is with the rotation of three-phase back emf coefficient fundamental frequency synchronously, can be got by formula (20): the back emf coefficient first-harmonic transforms under the dq coordinate system under the ABC coordinate system, is DC quantity on d, q axle, i.e. the zero degree harmonic wave; Back emf coefficient 6n-1 (n=1,2,3 under the ABC coordinate system ...) the subharmonic sense of rotation is oppositely, transforming to the dq axle is the 6n subharmonic; Back emf coefficient 6n+1 (n=1,2,3 under the ABC coordinate system ...) the subharmonic sense of rotation is forward, transform to the dq axle and be similarly the 6n subharmonic; To transform to the dq coordinate axis be zero to all the other each time three-phase back emf coefficients of back emf coefficient under the ABC coordinate system.Be that example is analyzed the characteristics that it transforms to the dq coordinate system with first-harmonic and 5,7 subharmonic that account for principal ingredient in the back emf coefficient under the ABC coordinate system below.

The back emf coefficient first-harmonic transforms to dq coordinate system following time under the ABC coordinate system, and 0 subharmonic that obtains dq axle back emf coefficient is a DC component:

$K_{{\mathrm{Ed}}_0}=\sqrt{\frac{2}{3}}({\cos \mathrm{\θ}}^{\′}{K}_{{\mathrm{EA}}_1}+\cos ({\mathrm{\θ}}^{\′}-\frac{2\mathrm{\π}}{3})K_{{\mathrm{EB}}_1}+\cos ({\mathrm{\θ}}^{\′}-\frac{4\mathrm{\π}}{3})K_{{\mathrm{EC}}_1})---\left(24\right)$

$=\sqrt{\frac{3}{2}}{a}_1\cos \mathrm{\Δ\θ}-\sqrt{\frac{3}{2}}{b}_1\sin \mathrm{\Δ\θ}=\sqrt{\frac{3}{2}}(a_1\cos \mathrm{\Δ\θ}-b_1\sin \mathrm{\Δ\θ})$

$K_{{\mathrm{Eq}}_0}=-\sqrt{\frac{2}{3}}({\sin \mathrm{\θ}}^{\′}{K}_{{\mathrm{EA}}_1}+\sin ({\mathrm{\θ}}^{\′}-\frac{2\mathrm{\π}}{3})K_{{\mathrm{EB}}_1}+\sin ({\mathrm{\θ}}^{\′}-\frac{4\mathrm{\π}}{3})K_{{\mathrm{EC}}_1})---\left(25\right)$

$=-\sqrt{\frac{3}{2}}{a}_1\sin \mathrm{\Δ\θ}-\sqrt{\frac{3}{2}}{b}_1\cos \mathrm{\Δ\θ}=-\sqrt{\frac{3}{2}}(a_1\sin \mathrm{\Δ\θ}+b_1\cos \mathrm{\Δ\θ})$

Back emf coefficient 5 subharmonic sense of rotation are that oppositely 7 subharmonic sense of rotation are forward, transform under the dq coordinate system, are all 6 subharmonic under the ABC coordinate system.5 subharmonic transform to the dq coordinate system and obtain:

$K_{{\mathrm{Ed}}_6}^{\′}=\sqrt{\frac{2}{3}}({\cos \mathrm{\θ}}^{\′}{K}_{{\mathrm{EA}}_5}+\cos ({\mathrm{\θ}}^{\′}-\frac{2\mathrm{\π}}{3})K_{{\mathrm{EB}}_5}+\cos ({\mathrm{\θ}}^{\′}-\frac{4\mathrm{\π}}{3})K_{{\mathrm{EC}}_5})---\left(26\right)$

$=\sqrt{\frac{3}{2}}(a_5\cos (6\mathrm{\θ}+\mathrm{\Δ\θ})+b_5\sin (6\mathrm{\θ}+\mathrm{\Δ\θ}))$

$K_{{\mathrm{Eq}}_6}^{\′}=-\sqrt{\frac{2}{3}}({\sin \mathrm{\θ}}^{\′}{K}_{{\mathrm{EA}}_5}+\sin ({\mathrm{\θ}}^{\′}-\frac{2\mathrm{\π}}{3})K_{{\mathrm{EB}}_5}+\sin ({\mathrm{\θ}}^{\′}-\frac{4\mathrm{\π}}{3})K_{{\mathrm{EC}}_5})---\left(27\right)$

$=\sqrt{\frac{3}{2}}({-a}_5\sin (6\mathrm{\θ}+\mathrm{\Δ\θ})+b_5\cos (6\mathrm{\θ}+\mathrm{\Δ\θ}))$

7 subharmonic transform to the dq coordinate system and obtain:

$K_{{\mathrm{Ed}}_6}^{\′\′}=\sqrt{\frac{2}{3}}({\cos \mathrm{\θ}}^{\′}{K}_{{\mathrm{EA}}_7}+\cos ({\mathrm{\θ}}^{\′}-\frac{2\mathrm{\π}}{3})K_{{\mathrm{EB}}_7}+\cos ({\mathrm{\θ}}^{\′}-\frac{4\mathrm{\π}}{3})K_{{\mathrm{EC}}_7})---\left(28\right)$

$=\sqrt{\frac{3}{2}}(a_7\cos (6\mathrm{\θ}-\mathrm{\Δ\θ})+b_7\sin (6\mathrm{\θ}-\mathrm{\Δ\θ}))$

$K_{{\mathrm{Eq}}_6}^{\′\′}=-\sqrt{\frac{2}{3}}({\sin \mathrm{\θ}}^{\′}{K}_{{\mathrm{EA}}_7}+\sin ({\mathrm{\θ}}^{\′}-\frac{2\mathrm{\π}}{3})K_{{\mathrm{EB}}_7}+\sin ({\mathrm{\θ}}^{\′}-\frac{4\mathrm{\π}}{3})K_{{\mathrm{EC}}_7})---\left(29\right)$

$=\sqrt{\frac{3}{2}}(a_7\sin (6\mathrm{\θ}-\mathrm{\Δ\θ})-b_7\cos (6\mathrm{\θ}-\mathrm{\Δ\θ}))$

Back emf coefficient 6 subharmonic are the acting in conjunction of opposite potential coefficient 5 subharmonic and 7 subharmonic under the dq coordinate system:

$K_{{\mathrm{Ed}}_6}=K_{{\mathrm{Ed}}_6}^{\′}+K_{{\mathrm{Ed}}_6}^{\′\′}$

$=\sqrt{\frac{3}{2}}(a_5\cos (6\mathrm{\θ}+\mathrm{\Δ\θ})+b_5\sin (6\mathrm{\θ}+\mathrm{\Δ\θ}))+\sqrt{\frac{3}{2}}(a_7\cos (6\mathrm{\θ}-\mathrm{\Δ\θ})+b_7\sin (6\mathrm{\θ}-\mathrm{\Δ\θ}))---\left(30\right)$

$K_{{\mathrm{Eq}}_6}=K_{{\mathrm{Eq}}_6}^{\′}+K_{{\mathrm{Eq}}_6}^{\′\′}$

$=\sqrt{\frac{3}{2}}({-a}_5\sin (6\mathrm{\θ}+\mathrm{\Δ\θ})+b_5\cos (6\mathrm{\θ}+\mathrm{\Δ\θ}))+\sqrt{\frac{3}{2}}(a_7\sin (6\mathrm{\θ}-\mathrm{\Δ\θ})-b_7\cos (6\mathrm{\θ}-\mathrm{\Δ\θ}))---\left(31\right)$

According to above analysis, d-q axle back emf coefficient can be expressed as:

$K_{\mathrm{Ed}}=\underset{i}{\mathrm{\Σ}}{K}_{{\mathrm{Ed}}_i},(i=6n,n=\mathrm{0,1,2,3}\·\·\·\·\·\·)---\left(32\right)$

$K_{\mathrm{Eq}}=\underset{i}{\mathrm{\Σ}}{K}_{{\mathrm{Eq}}_i},(i=6n,n=\mathrm{0,1,2,3}\·\·\·\·\·\·)---\left(33\right)$

Back emf coefficient comprises 6n (n=0,1,2,3 under the dq coordinate system ...) subharmonic.Because the higher hamonic wave amplitude is very little, to ignore under the higher hamonic wave situation, back emf coefficient is to have certain direct current biasing, at 2 π the waveform of 6 pulsation was arranged in the cycle under the dq coordinate system, this conclusion is consistent with the result that detection method obtains, and sees accompanying drawing 5.Three-phase back emf coefficient and d, q axle back emf coefficient according to formula (24)-(33) expression concern, can carry out data analysis to the magnetic linkage waveform (as accompanying drawing 5) that flux observer obtains.

(3) based on above-mentioned detection and analytical approach to the prediction and the prevention of permanent magnet of permanent magnet motor loss of excitation, carry out following processing as shown in Figure 6:

1) judges at first whether back emf coefficient has fluctuation under the dq coordinate system, have only amplitude and phase change, the non-sinusoidal distortion does not take place as ripple disable explanation magnetic field of permanent magnet waveform.If surpassing certain limitation then provide the loss of excitation amplitude, amplitude minimizing this moment reduces overload alarm.

2) if back emf coefficient is that fluctuation is arranged under the dq coordinate system, then carry out frequency analysis, if the pulsation of 6 subharmonic surpasses certain limitation then provides permanent magnet magnetic field distortion overload alarm by the harmonic components analytical approach.

(4) based on the permagnetic synchronous motor Optimal Control Strategy of the online testing result of permanent magnet magnetic linkage, carry out following processing:

Judge whether back emf coefficient has fluctuation under the dq coordinate system, have only amplitude and phase change, the non-sinusoidal distortion does not take place as ripple disable explanation magnetic field of permanent magnet waveform.This moment, the reduction of loss of excitation amplitude was not transfinited as yet, then carried out field orientation control again according to real-time detected magnetic field of permanent magnet amplitude and phase place, can reduce exciting current, reduced the wastage, and improved the efficient and the performance of magneto control; If back emf coefficient is that fluctuation is arranged under the dq coordinate system, then carry out frequency analysis by the harmonic components analytical approach, if the pulsation of 6 subharmonic does not surpass restriction as yet, then add the harmonic wave feedforward compensation, to suppress the torque pulsation that the harmonic wave back-emf causes at the given place of current of electric.

Claims (3)

1. a permanent-magnetism synchronous motor permanent magnetic field aberration detects and analytical approach in real time, it is characterized in that this method comprises the steps:

1) permanent-magnetism synchronous motor permanent magnetic field aberration real-time detection method

A. obtain motor rotor position θ by position transducer, calculate motor speed ω by the revolution speed calculating module; Rotational speed omega is input in the motor control module;

B. with the stator voltage u of permagnetic synchronous motor under two phase coordinates _α, u _βThrough stator voltage u under the α dq coordinate system that β/the dq coordinate transform obtains _d, u _qWith the stator current i of permagnetic synchronous motor under ABC three phase coordinate systems _A, i _BAnd i _C, obtain dq coordinate system stator current i through abc/ α β, twice coordinate transform of α β/dq _d, i _q

C. with θ, ω, i _d, i _q, u _d, u _qAs the input signal of permanent magnet magnetic linkage observer, obtain permanent magnetism magnetic linkage component ψ under the dq coordinate system _Fd, ψ _Fq, obtain back emf coefficient K under the dq coordinate system divided by the motor number of pole-pairs _Ed, K _Eq

D. select stator current i under the dq coordinate system _d, i _q, ψ _Fd, ψ _FqBe state variable, stator current is for measuring vector under the dq coordinate system, and stator voltage is an input vector under the dq coordinate system, makes up the system state equation and the output equation of observation permanent magnet magnetic linkage observation:

System state equation:

$\frac{d}{\mathrm{dt}}\left[\begin{array}{c}{i}_d\\ i_q\\ {\mathrm{\ψ}}_{\mathrm{fd}}\\ {\mathrm{\ψ}}_{\mathrm{fq}}\end{array}\right]=\left[\begin{array}{cccc}\frac{-R_s}{L_d}& \mathrm{\ω}\frac{L_q}{L_d}& 0& \frac{\mathrm{\ω}}{L_d}\\ -\mathrm{\ω}\frac{L_d}{L_q}& \frac{-R_s}{L_q}& -\frac{\mathrm{\ω}}{L_q}& 0\\ 0& 0& 0& 0\\ 0& 0& 0& 0\end{array}\right]\left[\begin{array}{c}{i}_d\\ i_q\\ {\mathrm{\ψ}}_{\mathrm{fd}}\\ {\mathrm{\ψ}}_{\mathrm{fq}}\end{array}\right]+\left[\begin{array}{cc}\frac{1}{L_d}& 0\\ 0& \frac{1}{L_q}\\ 0& 0\\ 0& 0\end{array}\right]\left[\begin{array}{c}{u}_d\\ u_q\end{array}\right]$

Wherein, R _sBe the stator resistance of permagnetic synchronous motor, L _dBe the d-axis main inductance of permagnetic synchronous motor, L _qBe the friendship axle main inductance of permagnetic synchronous motor,

Measure equation:

$y=\left[\begin{array}{cccc}1& 0& 0& 0\\ 0& 1& 0& 0\end{array}\right]\left[\begin{array}{c}{i}_d\\ i_q\\ {\mathrm{\ψ}}_{\mathrm{fd}}\\ {\mathrm{\ψ}}_{\mathrm{fq}}\end{array}\right]=\left[\begin{array}{c}{i}_d\\ i_q\end{array}\right]$

Equation above utilizing makes up permanent magnet magnetic linkage observer, realizes permanent magnetism magnetic linkage ψ under the dq coordinate system _Fd, ψ _FqReal-time monitored;

2) permanent-magnetism synchronous motor permanent magnetic field aberration analytical approach

A. on the basis of the real-time detection method in step 1), arrive the transformation matrix of rotation dq coordinate system synchronously according to the ABC coordinate system transformation:

$C_{3s/2r}=\sqrt{\frac{2}{3}}\left[\begin{array}{ccc}\cos {\mathrm{\θ}}^{\′}& \cos ({\mathrm{\θ}}^{\′}-\frac{2\mathrm{\π}}{3})& \cos ({\mathrm{\θ}}^{\′}+\frac{4\mathrm{\π}}{3})\\ -\sin {\mathrm{\θ}}^{\′}& -\sin ({\mathrm{\θ}}^{\′}-\frac{2\mathrm{\π}}{3})& -\sin ({\mathrm{\θ}}^{\′}+\frac{4\mathrm{\π}}{3})\\ \frac{1}{\sqrt{2}}& \frac{1}{\sqrt{2}}& \frac{1}{\sqrt{2}}\end{array}\right]$

Wherein, θ and coordinate transform angle θ ' differ a fixed angle Δ θ, i.e. θ '=θ+Δ θ,

Obtain that the back emf coefficient transformation relation is under three-phase back emf coefficient and the dq coordinate system:

$\left[\begin{array}{c}{K}_{\mathrm{Ed}}\\ K_{\mathrm{Eq}}\end{array}\right]=C_{3s/2r}\left[\begin{array}{c}{K}_{\mathrm{EA}}\\ K_{\mathrm{EB}}\\ K_{\mathrm{EC}}\end{array}\right]$

B. because synchronously rotation dq coordinate system is with the rotation of three-phase back emf coefficient fundamental frequency, and the back emf coefficient first-harmonic transforms to dq coordinate system following time under the ABC coordinate system, obtains dq axle back emf coefficient and be:

$K_{\mathrm{Ed}}=\underset{i}{\mathrm{\Σ}}{K}_{E{d}_i},$ (i＝6n，n＝0，1，2，3……)

$K_{\mathrm{Eq}}=\underset{i}{\mathrm{\Σ}}{K}_{E{q}_i},$ (i＝6n，n＝0，1，2，3……)

Ignore under the higher hamonic wave situation, back emf coefficient is a direct current biasing waveform under the dq coordinate system, at 2 π 6 pulsation, this conclusion and detection method 1 is arranged in the cycle) in the result that obtains be consistent;

Three-phase back emf coefficient and d, the q axle back emf coefficient represented according to following formula concern that can carry out data analysis to the magnetic linkage waveform that permanent magnet magnetic linkage observer obtains, obtaining its magnetic linkage in phase winding is back emf coefficient;

3), the permanent magnet of permanent magnet motor loss of excitation is predicted and is prevented based on above-mentioned detection and analytical approach:

A. judge at first whether back emf coefficient has fluctuation under the dq coordinate system,, the non-sinusoidal distortion does not take place if ripple disable explanation magnetic field of permanent magnet waveform has only amplitude and phase change; If amplitude reduces and surpass given restriction Δ ψ ₁, then provide loss of excitation amplitude overload alarm, wherein Δ ψ ₁Specifically determine by motor permanent magnetic material demagnetizing curve;

If b. back emf coefficient has fluctuation under the dq coordinate system, then set by step 2) the permanent magnetic field aberration analytical approach of mentioning in is carried out frequency analysis, if the pulsation of 6 subharmonic surpasses given restriction Δ ψ ₂, then provide permanent magnet magnetic field distortion overload alarm, wherein Δ ψ ₂Specifically determine by motor permanent magnetic material demagnetizing curve;

4) based on the permagnetic synchronous motor Optimal Control Strategy of the online testing result of permanent magnet magnetic linkage:

, a. back emf coefficient ripple disable under the dq coordinate system, magnetic linkage amplitude do not surpass given restriction Δ ψ as yet if reducing ₁, then carry out field orientation control again according to real-time detected magnetic field of permanent magnet amplitude and phase place;

If b. back emf coefficient has fluctuation under the dq coordinate system, set by step 2) the permanent magnetic field aberration analytical approach of mentioning in is carried out frequency analysis, if the pulsation of 6 subharmonic surpasses given restriction Δ ψ as yet in the analysis result ₂, then add the harmonic wave feedforward compensation, to suppress the torque pulsation that the harmonic wave back-emf causes at the given place of current of electric.

2. detect in real time and analytical approach according to the described permanent-magnetism synchronous motor permanent magnetic field aberration of claim 1, it is characterized in that: said permanent magnetism flux observer is based on the method for Kalman filter.

3. the permanent-magnetism synchronous motor permanent magnetic field aberration of implementing method according to claim 1 detects the device with analytical approach in real time, it is characterized in that: by motor control module, SVPWM module, PWM inverter, contain that permanent magnetic field aberration detects in real time and permanent magnet magnetic linkage observer, position transducer, the magneto of distortion analysis software program constitute; Wherein, the output with motor control module inserts permanent magnet magnetic linkage observer and SVPWM module respectively, SVPWM module output access PWM inverter, control magneto; Position transducer is installed on the magneto, and outgoing position feeds back signal to motor control module; With the stator current i of permagnetic synchronous motor under ABC three phase coordinate systems _A, i _BAnd i _C, obtain dq coordinate system stator current i through abc/ α β, twice coordinate transform of α β/dq _d, i _qi _d, i _qInput to motor control module and permanent magnet magnetic linkage observer respectively, carry out the observation and the detection of magnetic linkage by permanent magnet magnetic linkage observer.