CN105720877A - Parameter online identification method based on three-phase alternating current motor equivalent circuit - Google Patents

Abstract

The invention discloses a parameter online identification method based on a three-phase alternating current motor equivalent circuit. The method comprises following steps of collecting the stator voltage and the stator current of a normally operating three-phase alternating current motor; through building an alpha beta coordinate system, converting the stator voltage and the stator current into a stator voltage vector U < s > ^caret and a stator current vector I < s > ^caret; building a d q rotation coordinate system; defining the obtained stator voltage vector U < s > ^caret on the d axis in the coordinate; obtaining the exciting current vector L mu, the equivalent leakage inductance L sigma and the power supply angle frequency omega e of the three-phase alternating current motor; solving the initial value of an equivalent rotor voltage vector U <psi r0 > ^caret and an equivalent rotor flux linkage psi < r0 > ^caret according to a formula; in the d q rotation coordinate system, according to change of the voltage vector U <psi r0 > ^caret along with a stator resistance Rs, moving the voltage vector along a straight line p1 parallel to the current vector; moving the initial value I < mu0 > ^caret of the current vector decomposed from the stator current vector I < s > ^caret along a straight line p2 vertical to the stator current vector; through a formula, calculating a rotor equivalent resistance Rrref; and through a formula, obtaining the motor stator resistance Rs.

Description

On-line parameter identification method based on three phase alternating current motor equivalent circuit

Technical field

The invention belongs to three phase alternating current motor control field, be specifically related to a kind of on-line parameter identification method based on three phase alternating current motor equivalent circuit, can be applicable to the fields such as electric locomotive, diesel locomotive, electric automobile.Relate to Patent classificating number G01 to measure；Test G01R measures electric variable；Measure magnetic variable G01R27/00 and measure other two-pole characteristics of resistance, reactance, impedance or the device G01R27/02 resistance of its derived property, reactance, impedance or its derivation, for instance the real-valued or complex value of time constant is measured.

Background technology

At present, rotor flux-orientation vector control has become control program commonly used in AC Motor Control field.The program, based on alternating current generator mathematical model, realizes the uneoupled control of alternating current generator excitation and torque by mathematic(al) manipulation, thus improving static and dynamic performance.But, the raising of performance is accurately to obtain premised on the parameter of electric machine, motor steady-state equivalent circuit is as shown in Figure 1, wherein especially rotor resistance Rrref can change along with the change of motor temperature, if the change of rotor resistance is not carried out certain correction or compensation by control process, control dynamic property and system effectiveness will be substantially reduced.Therefore, if the parameter of electric machine especially rotor resistance can be carried out on-line identification by control process, the overall performance of electric machine control system will be improved undoubtedly.

Rotor resistance on-line identification method substantially can be divided three classes: one is by injecting distinctive signal in motor, calculating the parameter of electric machine by detecting voltage or current-responsive, this method for just producing certain disturbance the motor of real-time stabilization operation；Two are based on motor equation, utilize Kalman filter or Long Beige wave filter to estimate parameter, and the method complicated calculations amount is big；Three methods being based on model reference adaptive, have same physical implication but the mathematical model of different expression way by setting up, utilize actuator that parameter is carried out identification, and the method is simple but needs to increase extra actuator, and all the other parameters of electric machine are known.

Summary of the invention

The present invention is directed to the proposition of problem above, and a kind of on-line parameter identification method based on three phase alternating current motor equivalent circuit developed, there are following steps:

Gather stator voltage and the stator current of properly functioning three phase alternating current motor, by setting up α β coordinate system, change into stator voltage vectorAnd stator current vector

Set up dq rotating coordinate system, the stator voltage vector that will obtainDefinition d axle in a coordinate system；Obtain the excitation current vector L of described three phase alternating current motor_μ, equivalence leakage inductance L_σWith power supply angular frequency_eAccording to formula:

${\hat{U}}_{\mathrm{\&Psi;}r0}={\hat{U}}_s-j*{\mathrm{\&omega;}}_e*L_{\mathrm{\&sigma;}}*{\hat{I}}_s$

$\begin{array}{cc}{\widehat{\mathrm{\&Psi;}}}_{r0}=\frac{{\hat{U}}_{\mathrm{\&Psi;}r0}}{j*{\mathrm{\&omega;}}_e}& {\hat{I}}_{\mathrm{\&mu;}0}=\frac{{\widehat{\mathrm{\&Psi;}}}_{r0}}{L_{\mathrm{\&mu;}}}\end{array}$

Try to achieve the initial value of equivalence rotor voltage vectorWith equivalence rotor flux

In described dq rotating coordinate system, according to voltage vectorWith the change of stator resistance Rs, will move along the straight line p1 parallel with current phasor；Described stator current vectorThe current phasor initial value resolved intoTo move along the straight line p2 vertical with stator current vector；Meanwhile, set up with described stator current vectorMould is diameter, with its midpoint S round c being the center of circle₂；Try to achieve described straight line p2 and the intersection point of circle c2, according to vector correlation, try to achieve current phasor

By formula,

$R_{rref}={\mathrm{\&omega;}}_r*\frac{{\mathrm{\&Psi;}}_r}{I_{rref}}$

Calculate rotor equivalent resistance R_rref；

By formula,

$R_s*{\hat{I}}_s={\hat{U}}_{\mathrm{\&Psi;}r0}-{\hat{U}}_{\mathrm{\&Psi;}r}=\mathrm{\&Delta;}{\hat{U}}_{\mathrm{\&Psi;}r}$

$R_s=\frac{{\mathrm{\&Delta;U}}_{\mathrm{\&Psi;}r}}{I_s}$

Obtain motor stator resistance Rs.

As preferred embodiment, described stator voltage vectorCalculated by equation below:

${\hat{U}}_s=0+j*U_{smax}=U_{smax}*e^{j\mathrm{\&pi;}/2}$

J is U_smaxThe component in the imaginary axis in dq coordinate system；For voltage initial phase；

U_smaxObtain by giving a definition in described α β coordinate system:

$U_{smax}=\sqrt{u_{s\mathrm{\&alpha;}}^2+u_{s\mathrm{\&beta;}}^2}$

U_smaxFor the voltage magnitude collected；ω_eFor synchro angle frequency, u_saVoltage is at the component of coordinate axes α；U_sβFor the voltage component at coordinate axes β.

As preferred embodiment, based on the on-line parameter identification method of three phase alternating current motor equivalent circuit, it is further characterized in that described stator current vectorCalculated by equation below and obtain:

I_sdFor the stator current projection at d axle；I_sqFor the stator current projection at q axle；J is U_smaxThe component in the imaginary axis in dq coordinate system, represents the axial unit vector of q；

Pass through I_smaxGive a definition in described α β coordinate system and obtain

$I_{smax}=\sqrt{i_{s\mathrm{\&alpha;}}^2+i_{s\mathrm{\&beta;}}^2}$

Wherein, i_saElectric current is at the component of coordinate axes α, i_sβElectric current is at the component of coordinate axes β；I_smax

Current amplitude, ω_eFor synchro angle frequency,Initial phase for electric current；

Described I can be obtained by Coordinate Conversion by the angle theta of α β coordinate system and dq rotating coordinate system_sdAnd I_sq。

$\mathrm{\&theta;}=2\arctan \frac{u_{s\mathrm{\&beta;}}}{U_{smax}+u_{s\mathrm{\&alpha;}}}$

As preferred embodiment, the equation of described straight line p2 is:

Q=q₀+K_p2*(d1-d₀)(1)

Wherein,K_p2Slope for straight line P2；

Wherein d is excitation current vectorIn the projection of d axle, d0 is excitation current vectorInitial value in the projection of d axle；Q is excitation current vectorIn the projection of q axle, q0 is excitation current vectorInitial value in the projection of q axle；

Rotating coordinate system dq defines oneMould be diameter, with its midpoint S round c being the center of circle₂；

${(d2-d_S)}^2+{(q-q_S)}^2=d_S^2+q_S^2---\left(2\right)$

Wherein, d_sFor stator current vectorThe midpoint projection of d axle, q in described rotating coordinate system_sStator current vectorMidpoint projection of q axle in described rotating coordinate system；

Make excitation current vectorCoordinate be (d_A, q_A)；

Simultaneous formula (1) and (2) obtain, the equation group of the intersection point of straight line p2 and circle c2, solve and obtain:

$d_{A1,2}=\frac{-b\&PlusMinus;\sqrt{b^2-4*a*c}}{2*a}$

q_A1,2=q₀+K_p2*(d_A1,2-d₀)

Wherein,

$b=2*(q_0*K_{p2}-d_S-d_0*K_{p2}^2-q_S*K_{p2})$

$c=q_0^2+d_0^2*K_{p2}^2-2*d_0*q_0*K_{p2}-2*q_S*q_0+2*q_S*K_{p2}*d_0$

In conjunction with position relationship in a coordinate system.

${\hat{I}}_{rref}={\hat{I}}_s-{\hat{I}}_{\mathrm{\&mu;}}$

$\begin{array}{cc}{\widehat{\mathrm{\&Psi;}}}_r=L_{\mathrm{\&mu;}}*{\hat{I}}_{\mathrm{\&mu;}}& {\hat{U}}_{\mathrm{\&Psi;}r}=j*{\mathrm{\&omega;}}_e*{\widehat{\mathrm{\&Psi;}}}_r\end{array}$

By adopting technique scheme, a kind of on-line parameter identification method based on three phase alternating current motor equivalent circuit disclosed by the invention, it is based entirely on motor equivalent circuit, clear physics conception, it is only necessary to obtain voltageElectric currentPower supply angular frequency_e, rotational speed omega_r, and in conjunction with the known total leakage inductance L of motor_σWith equivalence magnetizing inductance L_μ, just can solve fixed rotor resistance by simple computation.

Accompanying drawing explanation

Technical scheme for clearer explanation embodiments of the invention or prior art, introduce the accompanying drawing used required in embodiment or description of the prior art is done one simply below, apparently, accompanying drawing in the following describes is only some embodiments of the present invention, for those of ordinary skill in the art, under the premise not paying creative work, it is also possible to obtain other accompanying drawing according to these accompanying drawings.

Fig. 1 is the motor steady-state equivalent circuit that vector controlled is corresponding

Fig. 2 is R_sThe vectogram that when=0, equivalent circuit is corresponding

Fig. 3 is R_sStart from scratch change time vectogram corresponding to equivalent circuit

Detailed description of the invention

For making the purpose of embodiments of the invention, technical scheme and advantage clearly, below in conjunction with the accompanying drawing in the embodiment of the present invention, the technical scheme in the embodiment of the present invention is carried out clear complete description:

As Figure 1-3: assume that motor is properly functioning, input voltage first-harmonic, stator current and stator voltage can be defined as under α β coordinate system:

Wherein, U_smaxFor voltage magnitude, I_smaxCurrent amplitude, ω_eFor synchro angle frequency,For voltage (electric current) initial phase, u_saVoltage is at the component of coordinate axes α, u_sβFor the voltage component at coordinate axes β, i_saElectric current is at the component of coordinate axes α, i_sβElectric current is at the component of coordinate axes β.

Definition dq rotating coordinate system, this coordinate system is with ω_eSpeed rotates, and q axle is oriented in input voltage vectorPosition.

J is U_smaxThe component in the imaginary axis in dq coordinate system.

Angle theta between α β and dq coordinate system can be obtained by equation below,

$\mathrm{\&theta;}=2\arctan \frac{u_{s\mathrm{\&beta;}}}{U_{smax}+u_{s\mathrm{\&alpha;}}}---\left(3\right)$

Having had after θ can be in the hope of by coordinate transform

I_sdFor the stator current projection at d axle；I_sqFor the stator current projection at q axle, j is U_smaxThe component in the imaginary axis in dq coordinate system.

In conjunction with Fig. 2, it is assumed that R_s=0, it is known thatL_μ、L_σAnd ω_e, then have

${\hat{U}}_{\mathrm{\&Psi;}r0}={\hat{U}}_s-j*{\mathrm{\&omega;}}_e*L_{\mathrm{\&sigma;}}*{\hat{I}}_s---\left(5\right)$

$\begin{array}{cc}{\widehat{\mathrm{\&Psi;}}}_{r0}=\frac{{\hat{U}}_{\mathrm{\&Psi;}r0}}{j*{\mathrm{\&omega;}}_e}& {\hat{I}}_{\mathrm{\&mu;}0}=\frac{{\widehat{\mathrm{\&Psi;}}}_{r0}}{L_{\mathrm{\&mu;}}}\end{array}---\left(6\right)$

L_μFor equivalence magnetizing inductance；L_σFor equivalence leakage inductance,: for equivalence rotor voltage vector initial value,For equivalence rotor flux.

Along with R_sChange, its voltage drop will be taken into account,By along the straight line p parallel with current phasor₁It is mobile,Will along straight line p₂Move and finally drop on A point.The equation making the straight line P2 vertical with stator current vector is:

Q=q₀+K_p2*(d1-d₀)(7)

Wherein,

c₂Be withMould be diameter, with its midpoint S circle being the center of circle, make c₂Equation is

${(d2-d_S)}^2+{(q-q_S)}^2=d_S^2+q_S^2---\left(8\right)$

Wherein,

Wherein d is excitation current vectorIn the projection of d axle, d0 is excitation current vectorInitial value in the projection of d axle；Q is excitation current vectorIn the projection of q axle, q0 is excitation current vectorInitial value in the projection of q axle；

OrderCoordinate be (d_A, q_A),

Simultaneous formula (7) and (8) obtain, and the equation group of the intersection point of p2 and c2, about the equation group of known variables d and q, solves and obtains:

$\begin{array}{c}{d}_{A1,2}=\frac{-b\&PlusMinus;\sqrt{b^2-4*a*c}}{2*a}\\ q_{A1,2}=q_0+K_{p2}*(d_{A1,2}-d_0)\end{array}---\left(9\right)$

Kp2 is the slope of straight line P2.

Wherein,

$b=2*(q_0*K_{p2}-d_S-d_0*K_{p2}^2-q_S*K_{p2})$

$c=q_0^2+d_0^2*K_{p2}^2-2*d_0*q_0*K_{p2}-2*q_S*q_0+2*q_S*K_{p2}*d_0$

In conjunction with Fig. 1 and Fig. 3, have

${\hat{I}}_{rref}={\hat{I}}_s-{\hat{I}}_{\mathrm{\&mu;}}---\left(10\right)$

$\begin{array}{cc}{\widehat{\mathrm{\&Psi;}}}_r=L_{\mathrm{\&mu;}}*{\hat{I}}_{\mathrm{\&mu;}}& {\hat{U}}_{\mathrm{\&Psi;}r}=j*{\mathrm{\&omega;}}_e*{\widehat{\mathrm{\&Psi;}}}_r\end{array}---\left(11\right)$

Known motor is powered angular frequency_eWith motor speed ω_r, then slippage angular frequency_sFor

ω_s=ω_e-ω_r(12)

Rotor equivalent resistance R_rrefJust can be obtained by following formula,

$R_{rref}={\mathrm{\&omega;}}_r*\frac{{\mathrm{\&Psi;}}_r}{I_{rref}}---\left(13\right)$

Motor stator resistance R_sThen can be calculated as follows,

$\begin{array}{c}{R}_s*{\hat{I}}_s={\hat{U}}_{\mathrm{\&Psi;}r0}-{\hat{U}}_{\mathrm{\&Psi;}r}=\mathrm{\&Delta;}{\hat{U}}_{\mathrm{\&Psi;}r}\\ R_s=\frac{{\mathrm{\&Delta;U}}_{\mathrm{\&Psi;}r}}{I_s}\end{array}---\left(14\right)$

Said method clear physics conception, it is only necessary to know voltageElectric currentPower supply angular frequency_e, rotational speed omega_r, and in conjunction with the known total leakage inductance L of motor_σWith equivalence magnetizing inductance L_μ, just can complete the evaluation work of fixed rotor resistance.

The above; it is only the present invention preferably detailed description of the invention; but protection scope of the present invention is not limited thereto; any those familiar with the art is in the technical scope that the invention discloses; it is equal to replacement according to technical scheme and inventive concept thereof or is changed, all should be encompassed within protection scope of the present invention.

Claims (4)

1. the on-line parameter identification method based on three phase alternating current motor equivalent circuit, it is characterised in that there are following steps:

Gather stator voltage and the stator current of properly functioning three phase alternating current motor, by setting up α β coordinate system, change into stator voltage vectorAnd stator current vector

Set up dq rotating coordinate system, the stator voltage vector that will obtainDefinition d axle in a coordinate system；Obtain the excitation current vector L of described three phase alternating current motor_μ, equivalence leakage inductance L_σWith power supply angular frequency_eAccording to formula:

${\hat{U}}_{\mathrm{\&Psi;}r0}={\hat{U}}_s-j*{\mathrm{\&omega;}}_e*L_{\mathrm{\&sigma;}}*{\hat{I}}_s$

$\begin{array}{cc}{\widehat{\mathrm{\&Psi;}}}_{r0}=\frac{{\hat{U}}_{\mathrm{\&Psi;}r0}}{j*{\mathrm{\&omega;}}_e}& {\hat{I}}_{\mathrm{\&mu;}0}=\frac{{\widehat{\mathrm{\&Psi;}}}_{r0}}{L_{\mathrm{\&mu;}}}\end{array}$

Try to achieve the initial value of equivalence rotor voltage vectorWith equivalence rotor flux

In described dq rotating coordinate system, according to voltage vectorWith the change of stator resistance Rs, will move along the straight line p1 parallel with current phasor；Described stator current vectorThe current phasor initial value resolved intoTo move along the straight line p2 vertical with stator current vector；Meanwhile, set up with described stator current vectorMould is diameter, with its midpoint S round c being the center of circle₂；Try to achieve described straight line p2 and the intersection point of circle c2, according to vector correlation, try to achieve current phasor

By formula,

$R_{rref}={\mathrm{\&omega;}}_r*\frac{{\mathrm{\&Psi;}}_r}{I_{rref}}$

Calculate rotor equivalent resistance R_rref；

By formula,

$R_s*{\hat{I}}_s={\hat{U}}_{\mathrm{\&Psi;}r0}-{\hat{U}}_{\mathrm{\&Psi;}r}=\mathrm{\&Delta;}{\hat{U}}_{\mathrm{\&Psi;}r}$

$R_s=\frac{{\mathrm{\&Delta;U}}_{\mathrm{\&Psi;}r}}{I_s}$

Obtain motor stator resistance Rs.

2. the on-line parameter identification method based on three phase alternating current motor equivalent circuit according to claim 1, is further characterized in that described stator voltage vectorCalculated by equation below:

${\hat{U}}_s=0+j*U_{smax}=U_{smax}*e^{j\mathrm{\&pi;}/2}$

J is U_smaxThe component in the imaginary axis in dq coordinate system；For voltage initial phase；

U_smaxObtain by giving a definition in described α β coordinate system:

$U_{s\max }=\sqrt{u_{\mathrm{s\&alpha;}}^2+u_{\mathrm{s\&beta;}}^2}$

U_smaxFor the voltage magnitude collected；ω_eFor synchro angle frequency, u_saVoltage is at the component of coordinate axes α；U_sβFor the voltage component at coordinate axes β.

3. the on-line parameter identification method based on three phase alternating current motor equivalent circuit according to claim 1, is further characterized in that described stator current vectorCalculated by equation below and obtain:

I_sdFor the stator current projection at d axle；I_sqFor the stator current projection at q axle；J is U_smaxThe component in the imaginary axis in dq coordinate system, represents the axial unit vector of q；

Pass through I_smaxGive a definition in described α β coordinate system and obtain

$I_{s\max }=\sqrt{i_{s\mathrm{\&alpha;}}^2+i_{s\mathrm{\&beta;}}^2}$

Wherein, i_saElectric current is at the component of coordinate axes α, i_sβElectric current is at the component of coordinate axes β；I_smax

Current amplitude, ω_eFor synchro angle frequency,Initial phase for electric current；

Described I can be obtained by Coordinate Conversion by the angle theta of α β coordinate system and dq rotating coordinate system_sdAnd I_sq。

$\mathrm{\&theta;}=2arctan\frac{u_{s\mathrm{\&beta;}}}{U_{smax}+u_{s\mathrm{\&alpha;}}}$

4. the on-line parameter identification method based on three phase alternating current motor equivalent circuit according to claim 1, is further characterized in that the equation of described straight line p2 is:

Q=q₀+K_p2*(d1-d₀)(1)

Wherein,K_p2Slope for straight line P2；

Wherein d is excitation current vectorIn the projection of d axle, d0 is excitation current vectorInitial value in the projection of d axle；Q is excitation current vectorIn the projection of q axle, q0 is excitation current vectorInitial value in the projection of q axle；

Rotating coordinate system dq defines oneMould be diameter, with its midpoint S round c being the center of circle₂；

${(d2-d_S)}^2+{(q-q_S)}^2=d_S^2+q_S^2---\left(2\right)$

Wherein, d_sFor stator current vectorThe midpoint projection of d axle, q in described rotating coordinate system_sStator current vectorMidpoint projection of q axle in described rotating coordinate system；

Make excitation current vectorCoordinate be (d_A, q_A)；

Simultaneous formula (1) and (2) obtain, the equation group of the intersection point of straight line p2 and circle c2, solve and obtain:

$d_{A1,2}=\frac{-b\&PlusMinus;\sqrt{b^2-4*a*c}}{2*a}$

q_A1,2=q₀+K_p2*(d_A1,2-d₀)

Wherein,

$b=2*(q_0*K_{p2}-d_S-d_0*K_{p2}^2-q_S*K_{p2})$

$c=q_0^2+d_0^2*K_{p2}^2-2*d_0*q_0*K_{p2}-2*q_S*q_0+2*q_S*K_{p2}*d_0$

In conjunction with position relationship in a coordinate system.

${\hat{I}}_{rref}={\hat{I}}_s-{\hat{I}}_{\mathrm{\&mu;}}$

$\begin{array}{cc}{\widehat{\mathrm{\&Psi;}}}_r=L_{\mathrm{\&mu;}}*{\hat{I}}_{\mathrm{\&mu;}}& {\hat{U}}_{\mathrm{\&Psi;}r}=j*{\mathrm{\&omega;}}_e*{\widehat{\mathrm{\&Psi;}}}_r\end{array}$