CN101727522A - Acquisition method of model parameters of electromechanical transient state simulation of motor based on factory data - Google Patents

Abstract

The invention relates to an acquisition method of model parameters of the electromechanical transient state simulation of a motor based on factory data, which estimates the motor single-cage model parameters suitable for the electromechanical transient state simulation of an electrical power system on the basis of the factory data (such as rated power, rated power factor, maximum torque multiple, rotor rotation speed, and the like) of an induction motor. The algorithm sufficiently considers the torque-slip physical principle characteristics of the motor, has good convergence and high robustness and provides convenience for the selection of the motor model parameters adopted in the simulation of the electrical power system.

Description

A kind of acquisition method of model parameters of electromechanical transient state simulation of motor based on factory data

Technical field

The invention belongs to field of power, proposed a kind of method based on motor appearance data computation motor simulation parameters.

Background technology

The model parameter that is adopted in the electric system simulation is the important determinative of emulation accuracy, and with respect to the genset and the power transmission network model of comparative maturity, load model is still fairly simple.Along with the increase of domestic and international electrical network complexity, the expansion of electrical network scale, the dynamic stability of electrical network and voltage stable problem are more outstanding, and load model can not be ignored the influence of system emulation result of calculation.

In power system load, to the system stability properties influence bigger be induction-motor load.The pure static load model that twice power outage that on August 10th, 1996 and on August 4th, 2000 occur in U.S. WSCC impels WECC will adopt before in 2002 replaces with the transition load model (Interim Load Model) that comprises 20% motor.In addition, the load side busbar voltage occurs after since nineteen ninety repeatedly break down in U.S. California southern areas and recover phenomenon slowly, similar accident betides Florida electric power and illumination company equally, but adopts various conventional load models even comprise that the transition load model also can't simulate the characteristic that busbar voltage is slowly recovered after these faults.Result of study shows that the dynamic perfromance of these system stability characteristics and motor has very big relation.According to statistics, surpassing 60% in power system load all is induction-motor load, and the dynamic load characteristic after system breaks down in the several seconds is mainly derived from the comprehensive response characteristic of induction-motor load.

The model parameter of determining induction motor load is that power system load modeling and stability simulation calculating are necessary.Usually the motor model parameter that is adopted is directly with reference to several canonical parameters of IEEE from recommendation in 1987.The typical model parameter of the induction motor that IEEE recommends, apart from modern existing more than 20 year history, the adaptability and the accuracy that these typical model parameters are applied to the simulation analysis of current electrical network can be restricted.

Adaptability based on the definite motor simulation parameters of test measured data is the strongest, but owing to kind, the quantity of induction-motor load in the electric system are very many, determines that based on the model parameter of actual measurement the application of method is restricted.

Therefore, how according to the factory data of motor, as rated power, rated power factor, maximum electromagnetic torque, starting moment, starting current, rotor speed etc., estimation is applicable to that the motor model parameter that the electric system simulation program is used is in research state always, and this problem is not well solved so far.

Summary of the invention

The present invention is based on the motor three exponent numbers model that PSD-BPA transient stability simulated program adopts, the motor factory data of giving chapter and verse estimation is applicable to the method for the motor model parameter of electric system electromechanical transient simulation.The basic data of the algorithm computation motor model parameter of carrying is the factory data of motor, and the algorithm convergence characteristic is good, robustness is stronger.According to factory data computation model parameter, for the selection of the motor model parameter that adopts in the electric system simulation provides convenience.

The present invention proposes a kind of acquisition method of model parameters of electromechanical transient state simulation of motor based on factory data, this method is based on the factory data of induction motor, estimation can be used for the motor model parameter of electric system electromechanical transient simulation program, and the factory data of described induction motor comprises rated power, rated power factor, maximum electromagnetic torque, starting moment, starting current and rotor speed.

Wherein, the basic step of this method comprises:

(1), comes the rated slip S of calculating motor according to the synchronous rotational speed that factory data provided and the motor number of pole-pairs of motor _n:

$s_n=\frac{n-n_n}{n}---\left(1\right)$

Wherein $n=\frac{60f}{p}$ Be synchronous rotational speed, unit is r/min, and f is a system frequency, and p is a number of pole-pairs;

(2) according to the motor rated voltage U that factory data provided of motor _n, rated current I _nWith rated power factor cos θ _n, the active power P and the reactive power Q of calculating motor input:

P＝3U _nI _ncosθ _n

Q＝Ptanθ _n (2)

(3) rated slip and the active power of the motor that step (2) calculates and the maximum electromagnetic torque multiple κ of the motor that factory data provided of the motor that calculates according to step (1) _m, the electromagnetic power P of calculating motor _EmWith maximum electromagnetic power P _{Em_max}:

$P_{\mathrm{em}}=\frac{P_n}{1-s_n}$ (3)

P _{em_max}＝κ _mP _em

And make P _{Emt_max}=P _{Em_max}, when the electric parameter of motor is all represented with perunit value, P=T is arranged, i.e. electromagnetic power and electromagnetic torque numerically equal, so, all replace electromagnetic torque in the algorithm with electromagnetic power.

(4) according to the resistance value R of the stator copper loss calculating motor stator winding of motor _s:

$R_s=\frac{P-P_{\mathrm{em}}}{{{3I}_n}^2}---\left(4\right)$

(5) calculate equivalent impedance Z under the motor rated slip condition according to rated voltage, the absorbed power of the Static Equivalent circuit of motor and motor _Deq:

$Z_{\mathrm{deq}}=\frac{{{3U}_n}^2}{P-\mathrm{jQ}}$

R _deq＝real(Z _deq) (5)

X _deq＝imag(Z _deq)

(6), see formula (6), the stator X of calculating motor by the inverting of maximum electromagnetic power formula _sWith rotor reactance X _r, because the maximum electromagnetic power that calculates according to the maximum electromagnetic power formula of simplifying is bigger than the maximum electromagnetic power of reality, so need revise stator and rotor reactance by alternative manner:

$X=\sqrt{{(\frac{{{3\mathrm{<figure-callout\; id="2"\; label="U\; n"\; filenames="H2009102418656E00021.png"\; state="\{\{state\}\}">U</figure-callout>}}_n}^2}{2P_{\mathrm{emt}\_\max }}-R_s)}^2-{{\mathrm{<figure-callout\; id="2"\; label="R\; s"\; filenames="H2009102418656E00021.png"\; state="\{\{state\}\}">R</figure-callout>}}_s}^2}$

$X_s=\frac{X}{2}---\left(6\right)$

X _r＝X _s

(7) the equivalent impedance Z of motor under the stator resistance, rotor reactance and the rated slip that have calculated of basis _DeqThe rotor resistance R of calculating motor _rWith excitatory reactance X _m:

$R_r=\frac{(K_r+{K_x}^2/K_r-\sqrt{{(K_r+{K_x}^2/K_r)}^2-{{4X}_s}^2})s_n}{2}$ (7)

$X_m=\frac{K_r{X}_s+K_x\frac{R_r}{s_n}}{\frac{R_r}{s_n}-K_r}$

K wherein _r=R _Deq-R _s, K _x=X _Deq-X _s

(8) according to all motor parameters that calculate: stator winding resistance R _sWith reactance X _s, rotor winding resistance R _rWith reactance X _r, excitatory reactance X _mWith rated slip s _n, again according to the maximum electromagnetic power of maximum electromagnetic torque formula calculating motor:

$P_{\mathrm{emt}\_\max i}=\frac{{{3\mathrm{<figure-callout\; id="2"\; label="U\; n"\; filenames="H2009102418656E00021.png"\; state="\{\{state\}\}">U</figure-callout>}}_n}^2}{2(R_s+\sqrt{{{\mathrm{<figure-callout\; id="2"\; label="R\; s"\; filenames="H2009102418656E00021.png"\; state="\{\{state\}\}">R</figure-callout>}}_s}^2+X^2})}---\left(8\right)$

(9) according to the critical slippage of Dai Weinan principle of equivalence calculating motor and the maximum electromagnetic power of motor reality:

Dai Weinan equivalent impedance Z _DpFor:

$Z_{\mathrm{dp}}={\mathrm{jX}}_r+\frac{{\mathrm{jX}}_m(R_s+{\mathrm{jX}}_s)}{R_s+j(X_s+X_m)}$

R _dp＝real(Z _dp) (9)

X _dp＝imag(Z _dp)

The condition that produces maximum electromagnetic power is:

$R_{\mathrm{pm}}=\frac{R_r}{s_m}=\sqrt{{{\mathrm{<figure-callout\; id="2"\; label="R\; dp"\; filenames="H2009102418656E00021.png"\; state="\{\{state\}\}">R</figure-callout>}}_{\mathrm{dp}}}^2+{X_{\mathrm{dp}}}^2}---\left(10\right)$

S _mBe critical slippage, the open-circuit voltage of Dai Weinan equivalent circuit is:

${\stackrel{\&CenterDot;}{U}}_o=U_n\frac{j{X}_m}{R_s+j(X_s+X_m)}---\left(11\right)$

Therefore, can recomputate the actual maximum electromagnetic torque of new argument correspondence according to following formula:

$P_{\mathrm{em}\_\max i}=\frac{{{3U}_o}^2{R}_{\mathrm{pm}}}{{(R_{\mathrm{dp}}+R_{\mathrm{pm}})}^2+{X_{\mathrm{dp}}}^2}---\left(12\right)$

(10) relatively (8) and (9) step in difference between two maximum electromagnetic torques obtaining, if difference between the two is very little, then calculates and finish, finally obtain the model parameter of motor, go on foot and carry out iterative computation again otherwise return (5).

Wherein, the step of described calculating motor rotor resistance and excitatory reactance is as follows:

(1) by calculating the equivalent impedance Z of induction motor _Deq, with the Static Equivalent circuit opening relationships of motor, real part and the imaginary part by relation forms the system of equations that comprises two variablees respectively, rotor resistance and excitatory reactance that these two variablees are motor, as the formula (13):

$\left(\frac{R_{\mathrm{deq}}-R_s}{S_n}\right)R_r-(X_{\mathrm{dep}}-X_s-X_r)X_m$

$=(X_{\mathrm{deq}}-X_s)X_r$

(13)

$\left(\frac{X_{\mathrm{deq}}-X_s}{S_n}\right)R_r+(R_{\mathrm{dep}}-R_s-\frac{R_r}{S_n})X_m$

$=-(R_{\mathrm{deq}}-R_s)X_r$

(2) the arrangement abbreviation above-mentioned system of equations that comprises two variablees is determined relation between rotor resistance and the excitatory reactance by one of them, and will be tried to achieve one of them variable in another equation of its substitution: rotor resistance R _rOr excitatory reactance X _m

(3), can try to achieve the size of another variable according to the relation between variable of having tried to achieve and two variablees.

Wherein, electric system electromechanical transient simulation program can be the PSD-BPA transient stability program software that China Electric Power Research Institute publishes and distributes.

Motor model calculation method of parameters of the present invention, the verification method of its validity is as follows:

By using above-mentioned method to carry out check analysis to 15 actual motor, and wherein 2 motor have been carried out the emulation contrast and analyzed according to dynamic model experiment, the further validity of motor model parameter simulation actual motor in the electric system electromechanical transient simulation is analyzed of obtaining according to carrying algorithm of checking.

The invention has the beneficial effects as follows:

1. load model is to the stable operation characteristic important influence of Da Qu interconnected network, and induction-motor load to surpass 60% in power system load all be induction-motor load, dynamic load characteristic after system breaks down in the several seconds is mainly derived from the comprehensive response characteristic of induction-motor load, accurately determine the model parameter of all kinds of induction-motor loads, to mentioning the electric system simulation precision, guaranteeing that the normal security that moves of electrical network, reliability operation have great importance.

2. this method is applicable to the method for the motor list cage model parameter of electric system electromechanical transient simulation based on factory data (as rated power, rated power factor, torque capacity multiple, the rotor speed etc.) estimation of induction motor.This algorithm has taken into full account the torque-slippage Physical Mechanism characteristic of motor, and its convergence property is good, strong robustness.According to factory data computation model parameter, for the selection of the motor model parameter that adopts in the electric system simulation provides convenience.

Description of drawings

Fig. 1 is the dynamic simulation test system, is similarly the numerical simulation system;

Fig. 2 is the contrast of motor set end voltage curve, and wherein solid line "-" is the dynamic model experiment measured curve of motor, the numerical simulation curve that the motor model parameter that dotted line calculates for the motor model calculation method of parameters according to invention obtains;

Fig. 3 is the contrast of motor active power curve;

Fig. 4 is the contrast of motor reactive power curve.

Embodiment

To in the electric system Numerical Simulation Analysis, adopt induction motor model, must know the concrete parameter of motor stator and rotor.Usually these parameters must can obtain by test figure, and still, the big or small induction-motor load quantity in the system is a lot, if test one by one, workload is very big.

So, have the important engineering practical value according to the model parameter of the estimation of the factory data on motor products catalogue motor.The factory data of motor comprises motor model, rated power P _n(kW), rated voltage U _n(V), rated current I _n(A), rated speed n _n(r/min), rated efficiency η _n(%), rated power factor cos θ _n, torque capacity multiple κ _m(κ _m=T _m/ T _n, T _nBe nominal torque, T _mBe maximum or breakdown torque), stall or detent torque multiple κ _St(κ _St=T _St/ T _n, T _StBe to start or torque), stall or starting current multiple κ i _St(κ i _St=I _St/ I _n, I _StFor starting or locked rotor current) and moment of flywheel GD ²(kg m2).Motor rotor number of pole-pairs p can calculate according to synchronous rotational speed.

Comprising 5 different electric parameters in single cage motor equivalent circuit, is independent variables but 4 parameters are only arranged.Therefore, between these 5 parameters, should increase a restrictive condition.Generally, suppose stator winding reactance X _sEqual rotor winding reactance X _r

By the equivalent electrical circuit of induction motor as seen, the active power P that absorbs of motor ₁A part consumes on the resistance of stator winding, is called stator copper loss P _Cu1A part of consumption on iron core is called iron loss, because its shared ratio is very little, this paper ignores it; Remaining most of electric power passes to rotor by air-gap field, is called electromagnetic power P _Em

Electromagnetic power P _EmBe divided into 2 parts: a part consumes on the rotor winding resistance, is called rotor copper loss P _Cu2Remainder then is converted into mechanical output P _MecBe delivered on the armature spindle, this paper is integrated into mechanical output P with mechanical loss that causes because of bearing friction, fan resistance etc. on the armature spindle and the assorted consumption that is caused by higher hamonic wave _MecIn.So mechanical output P _MecBe approximately equal to the mechanical output of motor output.

The specified electromagnetic power P of motor _EmnOr nominal torque T _Emn, rotor rated slip s _nWith maximum electromagnetic power P _{Em_max}Or maximum electromagnetic torque T _{Em_max}It is the several most important parameter that to represent mechanical property in the motor.Based on this, according to the method for factory data estimation induction motor model parameter.

Equivalent impedance, electromagnetic power and maximum electromagnetic power and the stator resistance value of motor under rated slip, active power and reactive power, the rated slip condition of motor can be at first progressively tried to achieve according to the factory data of motor, the stator reactance and the rotor reactance of motor can be calculated then according to (1) formula.Suppose X _r=X _s, and the X that calculates according to this formula _sAnd X _rInevitable less than normal, because the maximum electromagnetic power that calculates according to the maximum electromagnetic power formula of simplifying is bigger than the maximum electromagnetic power of reality.So need be by alternative manner to X _sAnd X _rRevise.

$X=\sqrt{{(\frac{{{3\mathrm{<figure-callout\; id="2"\; label="U\; n"\; filenames="H2009102418656E00021.png"\; state="\{\{state\}\}">U</figure-callout>}}_n}^2}{2P_{\mathrm{emt}\_\max }}-R_s)}^2-{{\mathrm{<figure-callout\; id="2"\; label="R\; s"\; filenames="H2009102418656E00021.png"\; state="\{\{state\}\}">R</figure-callout>}}_s}^2}$

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

X _r＝X _s

Calculating motor is according to the motor stator resistance R of being tried to achieve _s, stator reactance X _s, rotor reactance X _rWith the equivalent impedance under the motor rated slip condition, the rotor resistance R of motor can be tried to achieve in convolution (2) and (3) _rWith excitatory reactance X _m

K _r＝R _deq-R _s

(2)

K _x＝X _deq-X _s

$R_r=\frac{(K_r+{K_x}^2/K_r-\sqrt{{(K_r+{K_x}^2/K_r)}^2-{{4X}_s}^2})s_{\mathrm{<figure-callout\; id="2"\; label="n"\; filenames="H2009102418656E00021.png"\; state="\{\{state\}\}">n</figure-callout>}}}{2}$

(3)

$X_m=\frac{K_r{X}_s+K_x\frac{R_r}{s_n}}{\frac{R_r}{s_n}-K_r}$

But according to the approximate maximum electromagnetic power of formula of reduction calculating motor as the formula (4).

$P_{\mathrm{emt}\_\max i}=\frac{{{3\mathrm{<figure-callout\; id="2"\; label="U\; n"\; filenames="H2009102418656E00021.png"\; state="\{\{state\}\}">U</figure-callout>}}_n}^2}{2(R_s+\sqrt{{R_s}^2+X^2})}---\left(4\right)$

But according to the accurate maximum electromagnetic power of Dai Weinan equivalent circuit calculating motor, suc as formula (5)～(6).Formula (5) is the Dai Weinan equivalent impedance, and formula (6) is for producing the condition of maximum electromagnetic power, S _mBe critical slippage, formula (7) is the open-circuit voltage of Dai Weinan equivalent circuit, and formula (8) is accurate maximum electromagnetic power.

$Z_{\mathrm{dp}}={\mathrm{jX}}_r+\frac{{\mathrm{jX}}_m(R_s+{\mathrm{jX}}_s)}{R_s+j(X_s+X_m)}$

R _dp＝real(Z _dq) (5)

X _dp＝imag(Z _dp)

$R_{\mathrm{pm}}=\frac{R_r}{s_m}=\sqrt{{{\mathrm{<figure-callout\; id="2"\; label="R\; dp"\; filenames="H2009102418656E00021.png"\; state="\{\{state\}\}">R</figure-callout>}}_{\mathrm{dp}}}^2+{X_{\mathrm{dp}}}^2}---\left(6\right)$

${\stackrel{\&CenterDot;}{U}}_o=U_n\frac{j{X}_m}{R_s+j(X_s+X_m)}---\left(7\right)$

$P_{\mathrm{em}\_\max i}=\frac{{{3U}_o}^2{R}_{\mathrm{pm}}}{{(R_{\mathrm{dp}}+R_{\mathrm{pm}})}^2+{X_{\mathrm{dp}}}^2}---\left(8\right)$

The three phase short circuit fault test is at first carried out in the electric system that adopts 4 machines as shown in Figure 1 to send out, fail, join in this system in the dynamic model experiment chamber, record motor M2 and the set end voltage of M4, the active power and the reactive power of absorption as shown in Figure 1; Adopt the motor M2 that calculates according to the present invention and the model parameter of M4 then, adopt identical fault to obtain the set end voltage of M2 and M4, the active power and the reactive power of absorption equally by simulation calculation; Contrast dynamic model measured result and simulation result at last, shown in Fig. 2～4, contrasted active power and the reactive power curve of motor set end voltage, absorption.

As can be seen from Figure 3 the active power that absorbs at the moment motor that short trouble takes place and short trouble disappears can be undergone mutation, and the amplitude of active power sudden change is bigger, and the duration is of short duration.The simulation result that adopts motor model to obtain differs bigger at this value and the measured result that suddenlys change moment, mainly contains the reason of two aspects by analysis: 1) measure the error that causes; 2) the electro-magnetic transient sudden change amount that exists in the real system.For the electric system electromechanical transient simulation, do not consider electromagnetic transient, the motor model of employing is three rank electromechanical transient models.This error can be ignored in the research of electric system electromechanical transient simulation.

Therefore, from the contrast of Fig. 2～4 as can be seen, adopt the dynamic response characteristic of the simulation result of model parameter of the motor that the present invention calculates and actual motor very approaching, verified reliability of the present invention and validity.

Above by special embodiment content description the present invention, but those skilled in the art also can recognize the multiple possibility of modification and optional embodiment, for example, by combination and/or change the feature of single embodiment.Therefore, be understandable that these modification and optional embodiment will be considered as included among the present invention, only enclosed patent claims of scope of the present invention and coordinator restriction thereof.

Claims (5)

1. acquisition method of model parameters of electromechanical transient state simulation of motor based on factory data, this method is based on the factory data of induction motor, estimation can be used for the motor model parameter of electric system electromechanical transient simulation program, and the factory data of described induction motor comprises rated power, rated power factor, maximum electromagnetic torque, starting moment, starting current and rotor speed.

2. motor model calculation method of parameters as claimed in claim 1 is characterized in that the basic step of this method comprises:

(1), comes the rated slip S of calculating motor according to the synchronous rotational speed that factory data provided and the motor number of pole-pairs of motor _n:

$s_n=\frac{n-n_n}{n}---\left(1\right)$

Wherein $n=\frac{60f}{p}$ Be synchronous rotational speed, unit is r/min, and f is a system frequency, and p is a number of pole-pairs;

(2) according to the motor rated voltage U that factory data provided of motor _n, rated current I _nWith rated power factor cos θ _n, the active power P and the reactive power Q of calculating motor input:

P＝3U _nI _ncosθ _n

Q＝Ptanθ _n (2)

(3) rated slip and the active power of the motor that step (2) calculates and the maximum electromagnetic torque multiple κ of the motor that factory data provided of the motor that calculates according to step (1) _m, the electromagnetic power P of calculating motor _EmWith maximum electromagnetic power P _{Em_max}:

$P_{\mathrm{em}}=\frac{P_n}{1-s_n}$

P _{em_max}＝κ _mP _em (3)

And make P _{Emt_max}=P _{Em_max}, when the electric parameter of motor is all represented with perunit value, P=T is arranged, i.e. electromagnetic power and electromagnetic torque numerically equal, so, all replace electromagnetic torque in the algorithm with electromagnetic power.

(4) according to the resistance value R of the stator copper loss calculating motor stator winding of motor _s:

$R_s=\frac{P-P_{\mathrm{em}}}{3{I_n}^2}---\left(4\right)$

(5) calculate equivalent impedance Z under the motor rated slip condition according to rated voltage, the absorbed power of the Static Equivalent circuit of motor and motor _Deq:

$Z_{\mathrm{deq}}=\frac{3{U_n}^2}{P-\mathrm{jQ}}$

R _deq＝real(Z _deq) (5)

X _deq＝imag(Z _deq)

(6), see formula (6), the stator X of calculating motor by the inverting of maximum electromagnetic power formula _sWith rotor reactance X _r, because the maximum electromagnetic power that calculates according to the maximum electromagnetic power formula of simplifying is bigger than the maximum electromagnetic power of reality, so need revise stator and rotor reactance by alternative manner:

$X=\sqrt{{(\frac{3{U_n}^2}{2P_{\mathrm{emt}\_\max }}-R_s)}^2-{R_s}^2}$

$X_s=\frac{X}{2}---\left(6\right)$

X _r＝X _s

(7) the equivalent impedance Z of motor under the stator resistance, rotor reactance and the rated slip that have calculated of basis _DeqThe rotor resistance R of calculating motor _rWith excitatory reactance X _m:

$R_r=\frac{(K_r+{K_x}^2/K_r-\sqrt{{(K_r+{K_x}^2/K_r)}^2-4{X_s}^2})s_n}{2}---\left(7\right)$

$X_m=\frac{K_r{X}_s+K_x\frac{R_r}{s_n}}{\frac{R_r}{s_n}-K_r}$

K wherein _r=R _Deq-R _s, K _x=X _Deq-X _s

(8) according to all motor parameters that calculate: stator winding resistance R _sWith reactance X _s, rotor winding resistance R _rWith reactance X _r, excitatory reactance X _mWith rated slip s _n, again according to the maximum electromagnetic power of maximum electromagnetic torque formula calculating motor:

$P_{\mathrm{emt}\_\max i}=\frac{3{U_n}^2}{2(R_s+\sqrt{{R_s}^2+X^2})}---\left(8\right)$

(9) according to the critical slippage of Dai Weinan principle of equivalence calculating motor and the maximum electromagnetic power of motor reality: Dai Weinan equivalent impedance Z _DpFor:

$Z_{\mathrm{dp}}=j{X}_r+\frac{j{X}_m(R_s+j{X}_s)}{R_s+j(X_s+X_m)}$

R _dp＝real(Z _dp) (9)

X _dp＝imag(Z _dp)

The condition that produces maximum electromagnetic power is:

$R_{\mathrm{pm}}=\frac{R_r}{s_m}=\sqrt{{R_{\mathrm{dp}}}^2+{X_{\mathrm{dp}}}^2}---\left(10\right)$

s _mBe critical slippage, the open-circuit voltage of Dai Weinan equivalent circuit is:

${\stackrel{\&CenterDot;}{U}}_o=U_n\frac{j{X}_m}{R_s+j(X_s+X_m)}---\left(11\right)$

Therefore, can recomputate the actual maximum electromagnetic torque of new argument correspondence according to following formula:

$P_{\mathrm{em}\_\max i}=\frac{3{U_o}^2{R}_{\mathrm{pm}}}{{(R_{\mathrm{dp}}+R_{\mathrm{pm}})}^2+{X_{\mathrm{dp}}}^2}---\left(12\right)$

(10) relatively (8) and (9) step in difference between two maximum electromagnetic torques obtaining, if difference between the two is very little, then calculates and finish, finally obtain the model parameter of motor, go on foot and carry out iterative computation again otherwise return (5).

3. motor model calculation method of parameters as claimed in claim 2 is characterized in that the step of described calculating motor rotor resistance and excitatory reactance is as follows:

(1) by calculating the equivalent impedance Z of induction motor _Deq, with the Static Equivalent circuit opening relationships of motor, real part and the imaginary part by relation forms the system of equations that comprises two variablees respectively, rotor resistance and excitatory reactance that these two variablees are motor, as the formula (13):

$\left(\frac{R_{\mathrm{deq}}-R_s}{S_n}\right)R_r-(X_{\mathrm{deq}}-X_s-X_r)X_m$

$=(X_{\mathrm{deq}}-X_s)X_r$

$\left(\frac{X_{\mathrm{deq}}-X_s}{S_n}\right)R_r+(R_{\mathrm{deq}}-R_s-\frac{R_r}{S_n})X_m---\left(13\right)$

$=-(R_{\mathrm{deq}}-R_s)X_r$

(2) the arrangement abbreviation above-mentioned system of equations that comprises two variablees is determined relation between rotor resistance and the excitatory reactance by one of them, and will be tried to achieve one of them variable in another equation of its substitution: rotor resistance R _rOr excitatory reactance X _m

(3), can try to achieve the size of another variable according to the relation between variable of having tried to achieve and two variablees.

4. as the described motor model calculation method of parameters of claim 1-3, it is characterized in that electric system electromechanical transient simulation program can be a PSD-BPA transient stability program.

5. as the described motor model calculation method of parameters of claim 1-4, the verification method of its validity is as follows:

By using the described method of claim 1-4 to carry out check analysis to 15 actual motor, and wherein 2 motor have been carried out the emulation contrast and analyzed according to dynamic model experiment, the further validity of motor model parameter simulation actual motor in the electric system electromechanical transient simulation is analyzed of obtaining according to carrying algorithm of checking.

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