CN104362930A - Stator counter electromotive force-based fast calculation method of synchronous motor rotating speeds - Google Patents

Abstract

The invention discloses a stator counter electromotive force-based fast calculation method of synchronous motor rotating speeds. The fast calculation method is characterized by comprising the following steps: sampling phase voltage and phase current of a stator by use of a hardware sampling circuit and calculating counter electromotive force of the stator by virtue of vector conversion and coordinate conversion; obtaining a stator flux linkage by use of an integral method with a saturated feedback link by adopting the counter electromotive force obtained in the first step, thereby obtaining a stator flux linkage angle; and calculating a power angle between a rotor and the stator, thereby obtaining a rotor flux linkage angle, calculating the angular velocity of the rotor by virtue of derivation on the rotor flux linkage angle, and further calculating the rotating speed of the rotor. The stator counter electromotive force-based fast calculation method of the synchronous motor rotating speeds is capable of quickly estimating the rotating speed and the position of the motor under the condition of reducing the dependency of a system on speed measuring hardware; as a result, the response speed of a generator side converter is increased, and the accuracy and the stability of a rotating speed estimation method of the synchronous motor and the angle conversion of the generator side converter or a full-power type converter can be improved.

Description

Based on the fast algorithm of the synchronous machine rotating speed of stator back electromotive force

Technical field

The invention belongs to motor control technology field, be specifically related to the fast algorithm of the synchronous machine rotating speed based on stator back electromotive force.

Background technology

Synchronous machine obtains applying more and more widely in the SERVO CONTROL such as Digit Control Machine Tool, industrial robot field.In control system for permanent-magnet synchronous motor, mechanical pick-up device is generally installed on armature spindle to judge initial position and the motor speed of rotor.But, mechanical pick-up device brings a lot of problem to control system for permanent-magnet synchronous motor, as rotor moment of inertia increases, mechanical dimension strengthens, accuracy of detection is easily affected by environment, how system cost raisings etc., therefore remove the mechanical pick-up device in control system for permanent-magnet synchronous motor, become a study hotspot problem of AC Drive.Meanwhile, in high-performance without in fast sensor sensing rotor Field Oriented Vector Control System, the requirement judged for motor speed is particularly strict, because major part all has inseparable associating with the position of motor speed and rotor about the control algolithm of synchronous machine.

Summary of the invention

For solving deficiency of the prior art, the invention provides the fast algorithm of the synchronous machine rotating speed based on stator back electromotive force, solve mechanical pick-up device device in motor speed measurement problems, improve ageing, the Stability and veracity of motor speed measurement.

In order to realize above-mentioned target, the present invention adopts following technical scheme: a kind of fast algorithm of the synchronous machine rotating speed based on stator back electromotive force, is characterized in that, comprise step:

Step 1, carries out the sampling of stator phase voltage, phase current by hardware sample circuit, calculated the back electromotive force of stator by vector and coordinate transform;

Step 2, by the back electromotive force of stator described in step 1, adopts the saturated feedback element integration method of band to obtain stator magnetic linkage, thus obtains stator magnetic linkage angle;

Step 3, by calculating the merit angle angle between rotor and stator, can obtain rotor flux angle, by obtaining the angular speed of rotor to the differentiate of rotor flux angle, thus calculating the rotating speed of rotor.

The fast algorithm of aforesaid a kind of synchronous machine rotating speed based on stator back electromotive force, is characterized in that, in described step 1, the back electromotive force calculation procedure of stator comprises:

1) by the sampling to stator voltage, the stator voltage u under three-phase static coordinate system is obtained _a, u _b, u _c, the component of voltage u of stator voltage α and β axle under two-phase rest frame is drawn by Clark conversion _α, u _β:

$\left\{\begin{array}{c}{u}_{\mathrm{\α}}=u_a\\ u_{\mathrm{\β}}=\frac{\sqrt{3}}{3}(u_b-u_c)\end{array}\right.---\left(3\right)$

In formula, u _a: stator a phase voltage under three-phase static coordinate system; u _b: stator b phase voltage under three-phase static coordinate system; u _c: stator c phase voltage under three-phase static coordinate system; u _α: stator α shaft voltage component under two-phase rest frame; u _β: stator β shaft voltage component under two-phase rest frame;

In like manner, by the sampling to stator current, obtain the stator current i under three-phase static coordinate system _a, i _b, i _c, obtain α and β axle stator current components i under two-phase rest frame respectively by Clark and Park conversion _αand i _β, and d axle and q axle stator current components i under two-phase rotating coordinate system _dand i _q, θ is the angle of stator current resultant vector and α axle, and formula is as follows:

$\left\{\begin{array}{c}{i}_{\mathrm{\α}}=i_a\\ i_{\mathrm{\β}}=\frac{\sqrt{3}}{3}(i_b-i_c)\end{array}\right.---\left(4\right)$

$\left\{\begin{array}{c}{i}_d=i_{\mathrm{\α}}\cos \mathrm{\θ}+i_{\mathrm{\β}}\sin \mathrm{\θ}\\ i_q=-i_{\mathrm{\α}}\sin \mathrm{\θ}+i_{\mathrm{\β}}\cos \mathrm{\θ}\end{array}\right.---\left(5\right)$

2) stator back electromotive force under two-phase rest frame is extrapolated by the stator voltage under two-phase rest frame and current component:

$\left\{\begin{array}{c}\mathrm{em}{f}_{\mathrm{\α}}=u_{\mathrm{\α}}-R_s{i}_{\mathrm{\α}}\\ \mathrm{em}{f}_{\mathrm{\β}}=u_{\mathrm{\β}}-R_s{i}_{\mathrm{\β}}\end{array}\right.---\left(6\right)$

In formula, emf _αfor stator α axle back electromotive force component under two-phase rest frame; emf _βfor stator β axle back electromotive force component under two-phase rest frame; R _sfor stator resistance actual value; i _αfor stator α shaft current component under two-phase rest frame; i _βfor stator β shaft current component under two-phase rest frame.

The fast algorithm of aforesaid a kind of synchronous machine rotating speed based on stator back electromotive force, is characterized in that: the transfer function formula with saturated feedback element integration method in described step 2 is:

$G\left(s\right)=G1\·X\left(s\right)=\frac{1}{s+{\mathrm{\ω}}_c}X\left(s\right)$

$Y\left(s\right)=G\left(s\right)+G2=\·Y\left(s\right)=G\left(s\right)+\frac{{\mathrm{\ω}}_c}{s+{\mathrm{\ω}}_c}Y\left(s\right)$

$\frac{Y\left(s\right)}{X\left(s\right)}=\frac{1}{s}---\left(2\right)$

$G1=\frac{1}{s+{\mathrm{\ω}}_c}$

$G2=\frac{{\mathrm{\ω}}_c}{s+{\mathrm{\ω}}_c}$

Wherein, G (s) is complex field lower integral system output variables, and G1 is the transfer function of integrating system of the present invention, and X (s) is whole system input variable under complex field, and s represents the unit function under complex field, ω _crepresent the angular frequency of low-pass filter function cut-off frequency, Y (s) is whole system output variable under complex field, and G2 is the transfer function of reponse system of the present invention.

The fast algorithm of aforesaid a kind of synchronous machine rotating speed based on stator back electromotive force, it is characterized in that: in described step 2, by the back electromotive force of stator described in step 1, adopt the saturated feedback element integration method of band to obtain stator magnetic linkage, thus obtain stator magnetic linkage angle, step comprises:

1) the stator magnetic linkage ψ under adopting the saturated feedback element integration method of band to obtain two-phase rest frame _α, ψ _βexpression formula in time domain is:

$\left\{\begin{array}{c}{\mathrm{\ψ}}_{\mathrm{\α}}=e^{-{\mathrm{\ω}}_{c}t}\·\mathrm{em}{f}_{\mathrm{\α}}+{\mathrm{\ψ}}_{\mathrm{\α}\_\mathrm{com}}\\ {\mathrm{\ψ}}_{\mathrm{\β}}=e^{-{\mathrm{\ω}}_{c}t}\·\mathrm{em}{f}_{\mathrm{\β}}+{\mathrm{\ψ}}_{\mathrm{\β}\_\mathrm{com}}\end{array}\right.---\left(7\right)$

$\left\{\begin{array}{c}{\mathrm{\ψ}}_{\mathrm{\α}\_\mathrm{com}}={{\mathrm{\ω}}_{c}e}^{-{\mathrm{\ω}}_{c}t}\·{\mathrm{\ψ}}_{\mathrm{\α}}\\ {\mathrm{\ψ}}_{\mathrm{\β}\_\mathrm{com}}={{\mathrm{\ω}}_{c}e}^{-{\mathrm{\ω}}_{c}t}\·{\mathrm{\ψ}}_{\mathrm{\β}}\end{array}\right.---\left(8\right)$

2) simultaneously under cartesian coordinate system by the amplitude of stator magnetic linkage resultant vector | ψ _s| be limited in therefore, the angle θ of stator magnetic linkage _ssine and cosine formula is:

$\left\{\begin{array}{c}\cos {\mathrm{\θ}}_s=\frac{{\mathrm{\ψ}}_{\mathrm{\α}}}{\sqrt{{\mathrm{\ψ}}_{\mathrm{\α}}^2+{\mathrm{\ψ}}_{\mathrm{\β}}^2}}\\ \sin {\mathrm{\θ}}_s=\frac{{\mathrm{\ψ}}_{\mathrm{\β}}}{\sqrt{{\mathrm{\ψ}}_{\mathrm{\α}}^2+{\mathrm{\ψ}}_{\mathrm{\β}}^2}}\end{array}\right.---\left(9\right)$

In formula, ψ _α: stator α axle magnetic linkage component under two-phase rest frame; ψ _β: stator β axle magnetic linkage component under two-phase rest frame; ψ _{α _ com}: stator α axle flux compensation component under two-phase rest frame; ψ _{β _ com}: stator β axle flux compensation component under two-phase rest frame; θ _s: stator magnetic linkage angle; i _q: stator q shaft current component under two-phase rotating coordinate system; L _q: the direct-axis synchronous reactance value component of synchronous machine; ψ _fit is the rotor flux of motor.

The fast algorithm of aforesaid a kind of synchronous machine rotating speed based on stator back electromotive force, it is characterized in that: in described step 3, by calculating the merit angle angle between rotor and stator, rotor flux angle can be obtained, by obtaining the angular speed of rotor to the differentiate of rotor flux angle, thus calculate the rotating speed of rotor, step comprises:

1) angle of attack angle δ between stator and rotor is calculated:

$\left\{\begin{array}{c}\cos \mathrm{\δ}=\frac{{\mathrm{\ψ}}_f}{\sqrt{L_q^2{i}_q^2+{\mathrm{\ψ}}_f^2}}\\ \sin \mathrm{\δ}=\frac{L_{\mathrm{q\β}}{i}_q}{\sqrt{L_q^2{i}_q^2+{\mathrm{\ψ}}_f^2}}\end{array}\right.q---\left(10\right)$

ψ _fit is the rotor flux of motor; i _q: stator q shaft current component under two-phase rotating coordinate system; L _q: the synchronous machine direct-axis synchronous reactance value component that motor manufacturer provides;

2) the rotating speed computing formula of rotor is:

θ _r＝θ _s+δ

ω _r＝θ _r' (11)

$n_r=\frac{60f}{p}=\frac{60\·{\mathrm{\ω}}_r}{p\·2\mathrm{\π}}$

In formula, θ _rexpression is the rotor flux angle of motor; θ _r' represent the differentiate of rotor magnetic linkage angle; ω _rexpression is the rotor flux angular speed of motor; n _r: the rotating speed of motor; F: motor speed angular frequency; P: the number of pole-pairs of motor.

The beneficial effect that the present invention reaches: the present invention can be estimated to rotating speed and the position of motor fast in the dependent situation of minimizing system for the hardware that tests the speed, improve the response speed of pusher side current transformer, improve the Stability and veracity of the turn count method of synchronous machine and the angle conversion of total power type current transformer pusher side current transformer.

Accompanying drawing explanation

Fig. 1 is the stator magnetic linkage schematic diagram based on complex plane;

Fig. 2 is the fast algorithm transfer function figure of the synchronous machine rotating speed based on stator back electromotive force;

Fig. 3 is the fast algorithm flow chart of the synchronous machine rotating speed based on stator back electromotive force;

Fig. 4 is the vector diagram of a synchronous electric machine under two-phase rest frame;

Reference numeral implication: a, b, c: three-phase static coordinate system axle; α, β: two-phase rest frame axle; D, q: two-phase rotating coordinate system axle; θ _s: stator magnetic linkage angle; i _q: stator q shaft current component under two-phase rotating coordinate system; L _q: the direct-axis synchronous reactance value component of synchronous machine; ψ _fit is the rotor flux of motor; δ is the merit angle angle between stator magnetic linkage and rotor flux; θ _rrotor flux angle; u _sfor stator voltage time history synthesis vector.

Embodiment

Below in conjunction with accompanying drawing, the invention will be further described.Following examples only for technical scheme of the present invention is clearly described, and can not limit the scope of the invention with this.

The physical model of stator magnetic linkage is the integration of stator back electromotive force in time domain, as shown in Figure 1.Definition ψ is stator magnetic linkage resultant vector on a complex plane, at the uniform velocity rotates with the speed of motor angular frequency, and when stator magnetic linkage is in unsaturated situation, namely ψ is when circle inner region forms track, and stator magnetic linkage is stable circular trace; ψ is reached when stator magnetic linkage generation is saturated _sattime, the integrating system due to the saturated feedback element of whole band is approximately a pure integrator, and stator magnetic linkage can cause track to be the skew of diversity due to once saturated generation.Because in Mathematical Modeling, all there is integral constant in the integration of any function, then returns generate integral constant again when integral constant is integrated again, therefore this Mathematical Modeling more original ideal situation after N integration, can produce diversity and be biased.Therefore, adopt the saturated feedback element integration method of band, amplitude limit can be carried out to stator magnetic linkage, enable it in saturated, get back to undersaturated position, on the magnetic linkage circle making it be in rule.If represent the limiting figure of magnetic linkage with Δ, then the integrating system of the saturated feedback element of whole band can be described as:

$U\·\frac{1}{s+{\mathrm{\ω}}_c}+\mathrm{\Δ}\·\mathrm{\ψ}\·\frac{{\mathrm{\ω}}_c}{s+{\mathrm{\ω}}_c}=\mathrm{\ψ}$

$\left\{\begin{array}{c}\mathrm{\Δ}=1\⇒\mathrm{\ψ}=\frac{U}{s}\\ \mathrm{\Δ}\≠1\⇒\mathrm{\ψ}=\frac{U}{s+(1-\mathrm{\Δ}){\mathrm{\ω}}_c}\end{array}\right.---\left(1\right)$

In formula, U represents voltage resultant vector under complex plane; S represents the unit function under complex field, ω _crepresent the angular frequency of low-pass filter function cut-off frequency.

A kind of fast algorithm of the synchronous machine rotating speed based on stator back electromotive force in the present invention, comprises step:

Step 1, carries out the sampling of stator phase voltage, phase current by hardware sample circuit, calculated the back electromotive force of stator by vector and coordinate transform;

Step 2, by the back electromotive force of stator described in step 1, adopts the saturated feedback element integration method of band to obtain stator magnetic linkage, thus obtains stator magnetic linkage angle;

Step 3, by calculating the merit angle angle between rotor and stator, can obtain rotor flux angle, by obtaining the angular speed of rotor to the differentiate of rotor flux angle, thus calculating the rotating speed of rotor.

As shown in Figure 2, fast algorithm based on the synchronous machine rotating speed of stator back electromotive force adopts the saturated feedback element integration method of band, be with saturated feedback element integrating system wherein to comprise anomalous integral and feed back two subsystems, transfer function on its continuous domain represents with G1 and G2 respectively, and whole system transfer function formula under continuous domain is:

$G\left(s\right)=G1\·X\left(s\right)=\frac{1}{s+{\mathrm{\ω}}_c}X\left(s\right)$

$Y\left(s\right)=G\left(s\right)+G2=\·Y\left(s\right)=G\left(s\right)+\frac{{\mathrm{\ω}}_c}{s+{\mathrm{\ω}}_c}Y\left(s\right)$

$\frac{Y\left(s\right)}{X\left(s\right)}=\frac{1}{s}---\left(2\right)$

$G1=\frac{1}{s+{\mathrm{\ω}}_c}$

$G2=\frac{{\mathrm{\ω}}_c}{s+{\mathrm{\ω}}_c}$

Wherein, G (s) is complex field lower integral system output variables, and G1 is the transfer function of integrating system of the present invention, and X (s) is whole system input variable under complex field, and s represents the unit function under complex field, ω _crepresent the angular frequency of low-pass filter function cut-off frequency, Y (s) is whole system output variable under complex field, and G2 is the transfer function of reponse system of the present invention.

In step 1, carried out the sampling of stator phase voltage, phase current by hardware sample circuit, calculated the back electromotive force of stator by vector and coordinate transform, step comprises:

1) by the sampling to stator voltage, the stator voltage u under three-phase static coordinate system is obtained _a, u _b, u _c, the component of voltage u of stator voltage α and β axle under two-phase rest frame is drawn by Clark conversion _α, u _β:

$\left\{\begin{array}{c}{u}_{\mathrm{\α}}=u_a\\ u_{\mathrm{\β}}=\frac{\sqrt{3}}{3}(u_b-u_c)\end{array}\right.---\left(3\right)$

In formula, u _a: stator a phase voltage under three-phase static coordinate system; u _b: stator b phase voltage under three-phase static coordinate system; u _c: stator c phase voltage under three-phase static coordinate system; u _α: stator α shaft voltage component under two-phase rest frame; u _β: stator β shaft voltage component under two-phase rest frame;

In like manner, by the sampling to stator current, obtain the stator current i under three-phase static coordinate system _a, i _b, i _c, obtain α and β axle stator current components i under two-phase rest frame respectively by Clark and Park conversion _αand i _β, and d and q axle stator current components i under two-phase rotating coordinate system _dand i _q, θ is the angle of stator current resultant vector and α axle, and formula is as follows:

$\left\{\begin{array}{c}{i}_{\mathrm{\α}}=i_a\\ i_{\mathrm{\β}}=\frac{\sqrt{3}}{3}(i_b-i_c)\end{array}\right.---\left(4\right)$

$\left\{\begin{array}{c}{i}_{\mathrm{\α}}=i_a\cos \mathrm{\θ}+i_{\mathrm{\β}}\sin \mathrm{\θ}\\ i_q=-i_{\mathrm{\α}}\sin \mathrm{\θ}+i_{\mathrm{\β}}\cos \mathrm{\θ}\end{array}\right.---\left(5\right)$

2) stator back electromotive force under two-phase rest frame can be extrapolated by the stator voltage under two-phase rest frame and current component:

$\left\{\begin{array}{c}\mathrm{em}{f}_{\mathrm{\α}}=u_{\mathrm{\α}}-R_s{i}_{\mathrm{\α}}\\ \mathrm{em}{f}_{\mathrm{\β}}=u_{\mathrm{\β}}-R_s{i}_{\mathrm{\β}}\end{array}\right.---\left(6\right)$

In formula, emf _α: stator α axle back electromotive force component under two-phase rest frame; emf _β: stator β axle back electromotive force component under two-phase rest frame; R _s: stator resistance actual value; i _α: stator α shaft current component under two-phase rest frame; i _β: stator β shaft current component under two-phase rest frame.

In step 2, by the back electromotive force of stator described in step 1, adopt the saturated feedback element integration method of band to obtain stator magnetic linkage, thus obtain stator magnetic linkage angle, step comprises:

1) the stator magnetic linkage ψ under adopting the saturated feedback element integration method of above-mentioned band to obtain two-phase rest frame _α, ψ _βexpression formula in time domain is:

$\left\{\begin{array}{c}{\mathrm{\ψ}}_{\mathrm{\α}}=e^{-{\mathrm{\ω}}_{c}t}\·\mathrm{em}{f}_{\mathrm{\α}}+{\mathrm{\ψ}}_{\mathrm{\α}\_\mathrm{com}}\\ {\mathrm{\ψ}}_{\mathrm{\β}}=e^{-{\mathrm{\ω}}_{c}t}\·\mathrm{em}{f}_{\mathrm{\β}}+{\mathrm{\ψ}}_{\mathrm{\β}\_\mathrm{com}}\end{array}\right.---\left(7\right)$

$\left\{\begin{array}{c}{\mathrm{\ψ}}_{\mathrm{\α}\_\mathrm{com}}={{\mathrm{\ω}}_{c}e}^{-{\mathrm{\ω}}_{c}t}\·{\mathrm{\ψ}}_{\mathrm{\α}}\\ {\mathrm{\ψ}}_{\mathrm{\β}\_\mathrm{com}}={{\mathrm{\ω}}_{c}e}^{-{\mathrm{\ω}}_{c}t}\·{\mathrm{\ψ}}_{\mathrm{\β}}\end{array}\right.---\left(8\right)$

2) simultaneously under cartesian coordinate system by the amplitude of stator magnetic linkage resultant vector | ψ _s| be limited in therefore, the angle θ of stator magnetic linkage _ssine and cosine formula is:

$\left\{\begin{array}{c}\cos {\mathrm{\θ}}_s=\frac{{\mathrm{\ψ}}_{\mathrm{\α}}}{\sqrt{{\mathrm{\ψ}}_{\mathrm{\α}}^2+{\mathrm{\ψ}}_{\mathrm{\β}}^2}}\\ \sin {\mathrm{\θ}}_s=\frac{{\mathrm{\ψ}}_{\mathrm{\β}}}{\sqrt{{\mathrm{\ψ}}_{\mathrm{\α}}^2+{\mathrm{\ψ}}_{\mathrm{\β}}^2}}\end{array}\right.---\left(9\right)$

In formula, ψ _α: stator α axle magnetic linkage component under two-phase rest frame; ψ _β: stator β axle magnetic linkage component under two-phase rest frame; ψ _{α _ com}: stator α axle flux compensation component under two-phase rest frame; ψ _{β _ com}: stator β axle flux compensation component under two-phase rest frame; θ _s: stator magnetic linkage angle; i _q: stator q shaft current component under two-phase rotating coordinate system; L _q: the direct-axis synchronous reactance value component of synchronous machine; ψ _fit is the rotor flux of motor.

In step 3, by calculating the merit angle angle between rotor and stator, can obtain rotor flux angle, by obtaining the angular speed of rotor to the differentiate of rotor flux angle, thus calculate the rotating speed of rotor, step comprises:

1) the synchronous machine vector vectogram under two-phase rest frame as shown in Figure 4, the merit angle δ between stator magnetic linkage with rotor flux is only relevant with the parameter of electric machine with electric current, calculates the angle of attack angle δ between stator and rotor:

$\left\{\begin{array}{c}\cos \mathrm{\δ}=\frac{{\mathrm{\ψ}}_f}{\sqrt{L_q^2{i}_q^2+{\mathrm{\ψ}}_f^2}}\\ \sin \mathrm{\δ}=\frac{L_{\mathrm{q\β}}{i}_q}{\sqrt{L_q^2{i}_q^2+{\mathrm{\ψ}}_f^2}}\end{array}\right.q---\left(10\right)$

ψ _fit is the rotor flux of motor; i _q: stator q shaft current component under two-phase rotating coordinate system; L _q: the direct-axis synchronous reactance value component of the synchronous machine that motor manufacturer provides.

2) the rotating speed n of motor _rcomputing formula is:

θ _r＝θ _s+δ

ω _r＝θ _r'(11)

$n_r=\frac{60f}{p}=\frac{60\·{\mathrm{\ω}}_r}{p\·2\mathrm{\π}}$

θ _rexpression is the rotor flux angle of motor; θ _r' represent the differentiate of rotor magnetic linkage angle; ω _rexpression is the rotor flux angular speed of motor; n _r: the rotating speed of motor; F: motor speed angular frequency; P: the number of pole-pairs of motor.

Based on the fast algorithm of the synchronous machine rotating speed of stator back electromotive force, minimizing system, for the rotating speed and the position that are estimated to motor in the dependent situation of the hardware that tests the speed fast, improves the response speed of the vector control of pusher side current transformer in total power wind-force generating converter.

The above is only the preferred embodiment of the present invention; it should be pointed out that for those skilled in the art, under the prerequisite not departing from the technology of the present invention principle; can also make some improvement and distortion, these improve and distortion also should be considered as protection scope of the present invention.

Claims (5)

1., based on a fast algorithm for the synchronous machine rotating speed of stator back electromotive force, it is characterized in that, comprise step:

Step 1, carries out the sampling of stator phase voltage, phase current by hardware sample circuit, calculated the back electromotive force of stator by vector and coordinate transform;

Step 2, by the back electromotive force of stator described in step 1, adopts the saturated feedback element integration method of band to obtain stator magnetic linkage, thus obtains stator magnetic linkage angle;

Step 3, by calculating the merit angle angle between rotor and stator, can obtain rotor flux angle, by obtaining the angular speed of rotor to the differentiate of rotor flux angle, thus calculating the rotating speed of rotor.

2. the fast algorithm of a kind of synchronous machine rotating speed based on stator back electromotive force according to claim 1, is characterized in that, in described step 1, the back electromotive force calculation procedure of stator comprises:

1) by the sampling to stator voltage, the stator voltage u under three-phase static coordinate system is obtained _a, u _b, u _c, the component of voltage u of stator voltage α and β axle under two-phase rest frame is drawn by Clark conversion _α, u _β:

$\left\{\begin{array}{c}{u}_{\mathrm{\α}}=u_a\\ u_{\mathrm{\β}}=\frac{\sqrt{3}}{3}(u_b-u_c)\end{array}\right.---\left(3\right)$

In formula, u _a: stator a phase voltage under three-phase static coordinate system; u _b: stator b phase voltage under three-phase static coordinate system; u _c: stator c phase voltage under three-phase static coordinate system; u _α: stator α shaft voltage component under two-phase rest frame; u _β: stator β shaft voltage component under two-phase rest frame;

In like manner, by the sampling to stator current, obtain the stator current i under three-phase static coordinate system _a, i _b, i _c, obtain α and β axle stator current components i under two-phase rest frame respectively by Clark and Park conversion _αand i _β, and d axle and q axle stator current components i under two-phase rotating coordinate system _dand i _q, θ is the angle of stator current resultant vector and α axle, and formula is as follows:

$\left\{\begin{array}{c}{i}_{\mathrm{\α}}=i_a\\ i_{\mathrm{\β}}=\frac{\sqrt{3}}{3}(i_b-i_c)\end{array}\right.---\left(4\right)$

$\left\{\begin{array}{c}{i}_d=i_{\mathrm{\α}}\cos \mathrm{\θ}+i_{\mathrm{\β}}\sin \mathrm{\θ}\\ i_q=-i_{\mathrm{\α}}\sin \mathrm{\θ}+i_{\mathrm{\β}}\cos \mathrm{\θ}\end{array}\right.---\left(5\right)$

2) stator back electromotive force under two-phase rest frame is extrapolated by the stator voltage under two-phase rest frame and current component:

$\left\{\begin{array}{c}{\mathrm{emf}}_{\mathrm{\α}}=u_{\mathrm{\α}}-R_s{i}_{\mathrm{\α}}\\ {\mathrm{emf}}_{\mathrm{\β}}=u_{\mathrm{\β}}-R_s{i}_{\mathrm{\β}}\end{array}\right.---\left(6\right)$

In formula, emf _αfor stator α axle back electromotive force component under two-phase rest frame; emf _βfor stator β axle back electromotive force component under two-phase rest frame; R _sfor stator resistance actual value; i _αfor stator α shaft current component under two-phase rest frame; i _βfor stator β shaft current component under two-phase rest frame.

3. the fast algorithm of a kind of synchronous machine rotating speed based on stator back electromotive force according to claim 1, is characterized in that: the transfer function formula with saturated feedback element integration method in described step 2 is:

$G\left(s\right)=G1\·X\left(s\right)=\frac{1}{s+{\mathrm{\ω}}_c}X\left(s\right)$

$Y\left(s\right)=G\left(s\right)+G2\·Y\left(s\right)=G\left(s\right)+\frac{{\mathrm{\ω}}_c}{s+{\mathrm{\ω}}_c}Y\left(s\right)$

$\frac{Y\left(s\right)}{X\left(s\right)}=\frac{1}{s}---\left(2\right)$

$G1=\frac{1}{s+{\mathrm{\ω}}_c}$

$G2=\frac{{\mathrm{\ω}}_c}{s+{\mathrm{\ω}}_c}$

Wherein, G (s) is complex field lower integral system output variables, and G1 is the transfer function of integrating system of the present invention, and X (s) is whole system input variable under complex field, and s represents the unit function under complex field, ω _crepresent the angular frequency of low-pass filter function cut-off frequency, Y (s) is whole system output variable under complex field, and G2 is the transfer function of reponse system of the present invention.

4. the fast algorithm of a kind of synchronous machine rotating speed based on stator back electromotive force according to claim 1, it is characterized in that: in described step 2, by the back electromotive force of stator described in step 1, the saturated feedback element integration method of band is adopted to obtain stator magnetic linkage, thus obtain stator magnetic linkage angle, step comprises:

1) the stator magnetic linkage ψ under adopting the saturated feedback element integration method of band to obtain two-phase rest frame _α, ψ _βexpression formula in time domain is:

$\left\{\begin{array}{c}{\mathrm{\ψ}}_{\mathrm{\α}}=e^{-{\mathrm{\ω}}_{c}t}\·{\mathrm{emf}}_{\mathrm{\α}}+{\mathrm{\ψ}}_{\mathrm{\α}\_\mathrm{com}}\\ {\mathrm{\ψ}}_{\mathrm{\β}}=e^{-{\mathrm{\ω}}_{c}t}\·{\mathrm{emf}}_{\mathrm{\β}}+{\mathrm{\ψ}}_{\mathrm{\β}\_\mathrm{com}}\end{array}\right.---\left(7\right)$

$\left\{\begin{array}{c}{\mathrm{\ψ}}_{\mathrm{\α}\_\mathrm{com}}={\mathrm{\ω}}_c{e}^{-{\mathrm{\ω}}_{c}t}\·{\mathrm{\ψ}}_{\mathrm{\α}}\\ {\mathrm{\ψ}}_{\mathrm{\β}\_\mathrm{com}}={\mathrm{\ω}}_c{e}^{-{\mathrm{\ω}}_{c}t}\·{\mathrm{\ψ}}_{\mathrm{\β}}\end{array}\right.---\left(8\right)$

2) simultaneously under cartesian coordinate system by the amplitude of stator magnetic linkage resultant vector | ψ _s| be limited in therefore, the angle θ of stator magnetic linkage _ssine and cosine formula is:

$\left\{\begin{array}{c}\cos {\mathrm{\θ}}_s=\frac{{\mathrm{\ψ}}_{\mathrm{\α}}}{\sqrt{{\mathrm{\ψ}}_{\mathrm{\α}}^2+{\mathrm{\ψ}}_{\mathrm{\β}}^2}}\\ \sin {\mathrm{\θ}}_s=\frac{{\mathrm{\ψ}}_{\mathrm{\β}}}{\sqrt{{\mathrm{\ψ}}_{\mathrm{\α}}^2+{\mathrm{\ψ}}_{\mathrm{\β}}^2}}\end{array}\right.---\left(9\right)$

In formula, ψ _α: stator α axle magnetic linkage component under two-phase rest frame; ψ _β: stator β axle magnetic linkage component under two-phase rest frame; ψ _{α _ com}: stator α axle flux compensation component under two-phase rest frame; ψ _{β _ com}: stator β axle flux compensation component under two-phase rest frame; θ _s: stator magnetic linkage angle; i _q: stator q shaft current component under two-phase rotating coordinate system; L _q: the direct-axis synchronous reactance value component of synchronous machine; ψ _fit is the rotor flux of motor.

5. the fast algorithm of a kind of synchronous machine rotating speed based on stator back electromotive force according to claim 1, it is characterized in that: in described step 3, by calculating the merit angle angle between rotor and stator, rotor flux angle can be obtained, by obtaining the angular speed of rotor to the differentiate of rotor flux angle, thus calculate the rotating speed of rotor, step comprises:

1) angle of attack angle δ between stator and rotor is calculated:

$\left\{\begin{array}{c}\cos \mathrm{\δ}=\frac{{\mathrm{\ψ}}_f}{\sqrt{L_q^2{i}_q^2+{\mathrm{\ψ}}_f^2}}\\ \sin \mathrm{\δ}=\frac{L_q{i}_q}{\sqrt{L_q^2{i}_q^2+{\mathrm{\ψ}}_f^2}}\end{array}\right.---\left(10\right)$

ψ _fit is the rotor flux of motor; i _q: stator q shaft current component under two-phase rotating coordinate system; L _q: synchronous machine direct-axis synchronous reactance value component;

2) the rotating speed computing formula of rotor is:

θ _r＝θ _s+δ

ω _r＝θ _r' (11)

$n_r=\frac{60f}{p}=\frac{60\·{\mathrm{\ω}}_r}{p\·2\mathrm{\π}}$

In formula, θ _rexpression is the rotor flux angle of motor; θ _r' represent the differentiate of rotor magnetic linkage angle; ω _rexpression is the rotor flux angular speed of motor; n _r: the rotating speed of motor; F: motor speed angular frequency; P: the number of pole-pairs of motor.