CN103208965B - Non-synchronous motor parameter offline identification method under inactive state - Google Patents

Abstract

The invention provides the non-synchronous motor parameter offline identification method under a kind of inactive state, the method comprises the following steps: first carry out identification by the stator resistance value of DC va method to motor; Then adopt single-phase rated frequency alternating voltage and single-phase low-frequency ac pressure as driving source respectively, single phase alternating current (A.C.) test is carried out to motor, detect the steady-state response electric current obtaining motor, and then calculate acquisition motor stator leakage inductance, rotor leakage inductance, rotor resistance and rotor mutual inductance value.This method calculates in strict accordance with the classical equivalent-circuit model of motor, accuracy is high, in addition, present method also contemplates the impact of electric machine controller output reference voltage and the inconsistent situation of virtual voltage and kelvin effect, and take corresponding indemnifying measure, further increase the accuracy of parameter identification.

Description

Non-synchronous motor parameter offline identification method under inactive state

Technical field

The present invention's design relates to a kind of parameter of electric machine identification technique, particularly relates to the non-synchronous motor parameter offline identification method under a kind of inactive state.

Background technology

In Induction Motor Vector Control System, particularly without PG(rotary encoder) in vector control or direct Torque Control, the parameter of electric machine occupies very important status.The accuracy of the parameter of electric machine directly has influence on the key links such as flux observation, speed estimate, controling parameters adjustment.The parameter of electric machine needed in vector control inquire about in motor nameplate less than, even if extrapolate the part parameter of electric machine according to the data of motor product handbook, usually also have relatively large deviation with real data.Therefore, parameter of electric machine identification is a very important problem in Motor Control Field always.

Parameter of electric machine identification comprises offline parameter identification and on-line parameter corrects two parts.Offline parameter identification referred to before motor runs, and applied a series of pumping signal to it, obtained the relevant parameter of motor by detecting motor response.What the parameter of electric machine self-setting function of general general purpose controller adopted is all traditional offline identification method, needs to carry out locked rotor test and blank experiment to motor.But for part specific work environments, heavy-duty motor, particularly high-voltage motor, above-mentioned two experiments are all difficult to carry out.This is because: first, heavy-duty motor moment is excessive, is manually difficult to pin its output revolving shaft, so locked rotor test is difficult to realize; Secondly, part motor fixedly mount with load before system debug, belongs to non-dismountable or is difficult to the state of dismounting, so no-load test is also difficult to carry out.

In the static parameter identification technique of motor, Chinese patent " non-synchronous motor parameter identification method based on adaptive equalization ", publication number is CN201110191565.9, disclose a kind of asynchronous machine parameter identification method under static state, the method adopts approximate formula to calculate rotor mutual inductance, and do not consider the impact of kelvin effect on rotor resistance identification precision, identification accuracy is not good enough.

Summary of the invention

The object of the invention is, for the poor practicability existed in existing non-synchronous motor parameter identification method, the inaccurate problem of accuracy of detection, to provide the off-line parameter identification method under a kind of motor inactive state.

To achieve these goals, the present invention adopts following technical scheme:

Non-synchronous motor parameter offline identification method under a kind of inactive state, the method realizes based on described asynchronous machine and the inverter that is connected with this asynchronous machine input, wherein, described asynchronous machine comprises rotor and the stator with polyphase windings, and the method comprises the following steps:

Step one, by following steps identification stator resistance:

S11, applies the first direct voltage excitation to any two phase windings of described stator;

S12, gathers first direct current of two phase windings when the first direct voltage excitation is issued to stable state in described step S11 by described inverter;

S13, applies the second direct voltage excitation to any two phase windings of described stator;

S14, gathers second direct current of two phase windings when the second direct voltage excitation is issued to stable state in described step S13 by described inverter;

S15, according to described first direct voltage and the second direct voltage and described first direct current and the second direct current accordingly, calculates and obtains described stator resistance;

Step 2, by following steps identification rotor resistance, stator leakage inductance and rotor leakage inductance:

S21, applies the first alternating voltage excitation of single-phase rated frequency to any two phase windings of described stator;

S22, obtains the first-phase electric current of two phase windings when the excitation of this first alternating voltage is issued to stable state in described step S21 and the first-phase parallactic angle between described first alternating voltage and described first-phase electric current;

S23, calculates according to the effective value of described first alternating voltage, the effective value of described first-phase electric current and described first-phase parallactic angle and obtains described rotor resistance, stator leakage inductance and rotor leakage inductance;

Step 3, revises the described rotor resistance calculated in described step 2, to suppress kelvin effect on the impact of described rotor resistance identification precision;

Step 4, calculates total reactance of the T-shaped equivalent electric circuit obtaining the every phase winding of described motor by following steps:

S41, applies the single-phase first low-frequency ac voltage excitation of frequency within the scope of 0.1 ~ 0.5Hz to any two phase windings of described stator;

S42, obtains the first low-frequency phase electric current of two phase windings when described first low-frequency ac voltage excitation is issued to stable state in described step S41 and the first low-frequency phase parallactic angle between described first low-frequency ac voltage and described first low-frequency phase electric current;

S43, according to the effective value of described first low-frequency ac voltage, the effective value of described first low-frequency phase electric current and described first low-frequency phase parallactic angle, calculate real part and the imaginary part of first total reactance of the T-shaped equivalent electric circuit of every phase winding under described first low-frequency ac voltage excitation obtaining described motor stator;

Step 5, by the mutual inductance of following steps identification rotor:

S51, adopt the second low-frequency ac voltage excitation of frequency within the scope of 0.1 ~ 0.5Hz to repeat described step 4, calculate the imaginary part of second total reactance of the T-shaped equivalent electric circuit of every phase winding under described second low-frequency ac voltage excitation obtaining described motor stator;

S52, adopt the three low-frequency ac voltage excitation of frequency within the scope of 0.1 ~ 0.5Hz to repeat described step 4, calculate the imaginary part of the 3rd total reactance of the T-shaped equivalent electric circuit of every phase winding under described 3rd low-frequency ac voltage excitation obtaining described motor stator;

S53, according to the imaginary part of described rotor mutual inductance and described first total reactance, second total reactance and the 3rd total reactance, calculates and obtains described rotor mutual inductance.

Non-synchronous motor parameter offline identification method under aforementioned a kind of inactive state, described step S15 comprises:

Set described first direct voltage and the second direct voltage is respectively U1, U2, described first direct current and the second direct current are respectively I accordingly in setting ₁, I ₂, calculate according to formula (1) and obtain described stator resistance R _s,

$R_s=\frac{U_2-U_1}{I_2-I_1}\×\frac{1}{2}---\left(1\right).$

Non-synchronous motor parameter offline identification method under aforementioned a kind of inactive state,

Described step S21 comprises: the described first alternating voltage excitation any two phase windings of described motor stator being applied to single-phase rated frequency, and this first alternating voltage is raised gradually until the phase current of described two phase windings reaches rated current;

Described step S22 comprises: the instantaneous value detecting the first-phase electric current of two phase windings when the excitation of this first alternating voltage is issued to stable state in described step S21, and calculates the effective value U of described first alternating voltage and described first-phase electric current _sn1and I _sn1, then adopt the phase place of phase-locked described first alternating voltage of a phase-locked loop and described first-phase electric current, and calculate the phase difference obtained between described first alternating voltage and described first-phase electric current

Described step S23 comprises: calculate obtain rotor resistance first identifier R according to formula (21), (22) _r1, stator leakage inductance L _{σ s}with rotor leakage inductance L _{σ r}:

In formula, f ₁represent the frequency of described first alternating voltage.

Further, described step 3 comprises the following steps:

S31, the second single-phase alternating voltage excitation is applied to any two phase windings of described motor stator, and this second alternating voltage is raised gradually until the phase current of described two phase windings reaches rated current, wherein, the frequency of described second alternating voltage, lower than described rated frequency, is 40 ~ 45Hz;

S32, detects the instantaneous value of the second-phase electric current of two phase windings when the excitation of this second alternating voltage is issued to stable state in described step S31, and calculates the effective value U of described second alternating voltage and described second-phase electric current _sn2and I _sn2, then adopt the phase place of phase-locked described second alternating voltage of described phase-locked loop and described second-phase electric current, and calculate the phase difference between described second alternating voltage and described second-phase electric current thus calculate acquisition rotor resistance second identifier

S33, according to formula (3), calculates the rotor resistance R obtaining and overcome kelvin effect impact _r:

$R_r=\frac{R_{r2}{f}_1-R_{r1}{f}_2}{f1-f2}---\left(3\right),$

In formula, f ₁for the frequency of described first alternating voltage, f ₂for the frequency of described second alternating voltage.

Non-synchronous motor parameter offline identification method under aforementioned a kind of inactive state,

Described step S41 comprises: apply the described first low-frequency ac voltage excitation of frequency within the scope of 0.1 ~ 0.5Hz to any two phase windings of described motor stator, and this first low-frequency ac voltage is raised gradually until the phase current of described two phase windings reaches rated current;

Described step S42 comprises: the instantaneous value detecting the first low-frequency phase electric current of two phase windings when the excitation of this first low-frequency ac voltage is issued to stable state in described step S41, and calculates the effective value U of described first low-frequency ac voltage and described first low-frequency phase electric current _s0and I _s0, then adopt the phase place of phase-locked described first low-frequency ac voltage of a phase-locked loop and described first low-frequency phase electric current, and calculate the phase difference obtained between described first low-frequency ac voltage and described first low-frequency phase electric current

Described step S43 comprises: according to formula (41), (42), calculates the real part Re (Z of first total reactance of the T-shaped equivalent electric circuit of every phase winding under described first low-frequency ac voltage excitation obtaining described motor ₁) and imaginary part Im (Z ₁):

Non-synchronous motor parameter offline identification method under aforementioned a kind of inactive state,

Described step S53 comprises: calculate according to formula (7) and obtain described rotor mutual inductance L _ms:

$L_{\mathrm{ms}}=\frac{{\mathrm{\ω}}_1^3{Z}_2{Z}_3({\mathrm{\ω}}_2^2-{\mathrm{\ω}}_3^2)+{\mathrm{\ω}}_2^3{Z}_1{Z}_3({\mathrm{\ω}}_3^2-{\mathrm{\ω}}_1^2)+{\mathrm{\ω}}_3^3{Z}_1{Z}_2({\mathrm{\ω}}_1^2-{\mathrm{\ω}}_2^2)}{{\mathrm{\ω}}_1{\mathrm{\ω}}_2{\mathrm{\ω}}_3[{\mathrm{\ω}}_1{Z}_1({\mathrm{\ω}}_3^2-{\mathrm{\ω}}_2^2)+{\mathrm{\ω}}_2{Z}_2({\mathrm{\ω}}_1^2-{\mathrm{\ω}}_3^2)+{\mathrm{\ω}}_3{Z}_3({\mathrm{\ω}}_2^2-{\mathrm{\ω}}_1^2)]}-L_{\mathrm{\σs}}---\left(5\right),$

In formula, ω ₁, ω ₂and ω ₃be respectively the angular frequency of described first low-frequency ac voltage, the second low-frequency ac voltage and the 3rd low-frequency ac voltage, and ω ₁=2 π f _low1, ω ₂=2 π f _low2, ω ₃=2 π f _low3, wherein, f _low1, f _low2and f _low3be respectively the frequency of described first low-frequency ac voltage, the second low-frequency ac voltage and the 3rd low-frequency ac voltage; Z ₁, Z ₂and Z ₃be respectively the imaginary part of described first total reactance, second total reactance and the 3rd total reactance.

Described on end, the off-line parameter identification method under motor inactive state of the present invention rotates without the need to motor, so practical, is specially adapted to Industry Control occasion.In addition, the present invention calculates in strict accordance with the classical equivalent-circuit model of motor, accuracy is high, and invention also contemplates that the impact of electric machine controller output reference voltage and the inconsistent situation of virtual voltage and kelvin effect, and take indemnifying measure, further increase the accuracy of parameter identification.

Accompanying drawing explanation

Fig. 1 is the T-shaped equivalent circuit diagram of the single-phase winding of motor;

Fig. 2 is the two phase winding equivalent circuit diagrams of motor in continuous current excitation test;

Fig. 3 is the two phase winding equivalent circuit diagrams of motor in single phase alternating current (A.C.) excitation test;

Fig. 4 is the two phase winding equivalent circuit diagrams of motor in the ac-excited test of single-phase rated frequency;

Fig. 5 is inverter output reference voltage and virtual voltage comparison diagram;

Fig. 6 is the phase place broken away view of inverter output voltage.

Embodiment

Below based on the T-shaped equivalent electric circuit of the motor shown in Fig. 1 and composition graphs 2-6 is described in detail as follows to technical scheme of the present invention.

Off-line parameter identification method under motor inactive state of the present invention is mainly used in the inner parameter calculating motor, the method realizes based on motor and the inverter that is connected with this input end of motor, inverter is mainly used in output motor control signal, and detect the voltage and current response signal of motor stator winding, asynchronous machine comprises stators and rotators, and this stator is with winding.Specifically, method of the present invention mainly comprises calculating stator resistance, stator leakage inductance, rotor resistance, rotor leakage inductance and rotor mutual inductance, and wherein, the concrete steps of the method are as follows;

Step one: apply direct voltage excitation to any two phase windings of motor stator, shown in two phase winding equivalent circuit diagrams 2 under continuous current excitation, utilizes voltammetry to calculate motor stator resistance, specifically, comprises the following steps:

S11, applies the first direct voltage excitation U to any two phase windings of stator ₁;

S12, by the first direct current I of two phase windings in inverter acquisition step S11 when the first direct voltage excitation is issued to stable state ₁;

S13, applies the second direct voltage excitation U to any two phase windings of stator ₂;

S14, by the second direct current I of two phase windings in inverter acquisition step S13 when the second direct voltage excitation is issued to stable state ₂;

S15, schematic diagram according to Fig. 2, calculates by formula (1) and obtains stator resistance R _s:

$R_s=\frac{U_2-U_1}{I_2-I_1}\×\frac{1}{2}---\left(1\right),$

In formula (1), adopting voltage and current increment to calculate stator resistance, is in order to avoid the error between the output reference voltage and virtual voltage of inverter is on the impact of identification precision.Error between hypothetical reference voltage and virtual voltage is Δ U, then the actual DC voltage of twice DC experiment is U ₁+ Δ U and U ₂+ Δ U, according to formula (11), the error amount Δ U that can calculate reference voltage and virtual voltage is:

$\mathrm{\ΔU}=\frac{U_2{I}_1-U_1{I}_2}{I_2-I_1}---\left(11\right),$

Then can calculate motor stator resistance R according to the actual DC voltage and current on two phase windings _sfor:

$R_s=\frac{U_1+\mathrm{\ΔU}}{I_1}\×\frac{1}{2}=\frac{U_2-U_1}{I_2-I_1}\×\frac{1}{2}.$

Step 2: the alternating voltage excitation any two phase windings of motor stator being applied to single-phase rated frequency, calculate the rotor resistance of motor, stator leakage inductance and rotor leakage inductance, specifically, comprise the following steps:

S21, any two phase windings of motor stator are applied to the first alternating voltage excitation of single-phase rated frequency, and make this first alternating voltage raise until the phase current of motor stator reaches rated current gradually, this is because consider the magnetically saturated impact of air gap, its exciter response electric current can not higher than rated current, so driving voltage amplitude is less;

S22, the instantaneous value of the first-phase electric current of two phase windings in detecting step S21 when the excitation of this first alternating voltage is issued to stable state, and calculate the effective value U of the first alternating voltage and first-phase electric current _sn1and I _sn1, then adopt the phase place of phase-locked first alternating voltage of a phase-locked loop and first-phase electric current, and calculate the phase difference between acquisition first alternating voltage and first-phase electric current

S23, calculates obtain rotor resistance first identifier R according to formula (21), (22) _r1, stator leakage inductance L _{σ s}with rotor leakage inductance L _{σ r}:

In formula, f ₁represent the frequency of the first alternating voltage.

The principle of such calculating is: when leading to single-phase alternating current to asynchronous machine winding, the electromagnetic torque of rotation can not be produced, so motor can not rotate, its electromagnet phenomenon is similar to locked rotor test, and the two phase winding equivalent electric circuits of motor under single phase alternating current (A.C.) excitation as shown in Figure 3.When the single phase alternating current (A.C.) driving voltage applied is rated frequency, rotor mutual inductance L _msmuch larger than stator leakage inductance L _{σ s}with rotor leakage inductance L _{σ r}, and driving frequency is higher, so energized circuit induction reactance ω L now _msmuch larger than leakage inductance loop reactances therefore, in motor equivalent electric circuit, can think energized circuit open circuit, that is, in this step, the equivalent electric circuit of Fig. 3 can be reduced to the equivalent electric circuit shown in Fig. 4, the equivalent electric circuit according to Fig. 4, can obtain above-mentioned formula (21), (22).

Step 3: to motor stator any two phase windings apply frequencies slightly underfrequency (such as 40 ~ 45Hz) alternating voltage excitation, to revise the rotor resistance value calculated in step 2, thus suppress kelvin effect on the impact of rotor resistance identification precision, specifically, comprise the following steps:

S31, the second single-phase alternating voltage excitation is applied to any two phase windings of motor stator, and makes this second alternating voltage raise until the phase current of two phase windings reaches rated current gradually, wherein, the frequency underfrequency of the second alternating voltage is 40 ~ 45Hz;

S32, the instantaneous value of the second-phase electric current of two phase windings in detecting step S31 when the excitation of this second alternating voltage is issued to stable state, and calculate the effective value U of the second alternating voltage and second-phase electric current _sn2and I _sn2, then adopt the phase place of phase-locked second alternating voltage of phase-locked loop and second-phase electric current, and calculate the phase difference between the second alternating voltage and second-phase electric current thus calculate acquisition rotor resistance second identifier

S33, according to formula (3), calculates the rotor resistance R obtaining and overcome kelvin effect impact _r:

$R_r=\frac{R_{r2}{f}_1-R_{r1}{f}_2}{f1-f2}---\left(3\right),$

In formula, f ₁be the frequency of the first alternating voltage, f ₂it is the frequency of the second alternating voltage.

The principle of such correction is: when motor being carried out to the single-phase rated frequency ac test in step 2, motor slip frequency is very high, namely, power frequency now in rotor is much larger than power frequency during actual motion, therefore the kelvin effect of rotor windings will affect the certainty of measurement of rotor resistance, and the impact of kelvin effect on rotor resistance identification is linear, be R with the pass of rotor current frequency _rx=R _r+ af,

In formula, R _rxthe rotor resistance value of identification, R _rbe real rotor resistance value, af represents the linearity error relevant with frequency produced by kelvin effect, and a is error linear degree constant.

Therefore, in order to compensate this linearity error, overcome the impact of kelvin effect, this step adopts frequency to repeat above-mentioned steps two a little less than the second alternating voltage excitation of rated frequency (such as 40 ~ 45Hz), and calculates the rotor resistance second identifier R of acquisition motor under the alternating voltage excitation of this frequency _r2, set up linear equation in two unknowns group (31) thus:

$\left\{\begin{array}{c}{R}_{r1}=R_r+{\mathrm{af}}_1\\ R_{r2}=R_r+{\mathrm{af}}_2\end{array}\right.---\left(31\right)$

Solve above-mentioned equation group (31), above-mentioned formula (3) can be obtained.

Step 4: low-frequency ac voltage excitation is applied to any two phase windings of motor stator, calculates real part and the imaginary part of total reactance of the T-shaped equivalent electric circuit of the every phase winding of now motor, specifically, comprise the following steps:

Step S41, the first low-frequency ac voltage excitation of frequency within the scope of 0.1 ~ 0.5Hz is applied to any two phase windings of motor stator, and make this first low-frequency ac voltage raise until the phase current of motor stator reaches rated current gradually, every phase winding equivalent electric circuit in this step is identical with Fig. 1, this is because the first low-frequency ac voltage frequency applied is very low, energized circuit induction reactance ω L _mscan not much larger than leakage inductance loop reactances so energized circuit can not be ignored, and now all loads of every phase winding can be equivalent to a reactance, in order to distinguish with the reactance in later step, this reactance are set as first total reactance;

Step S42, the instantaneous value of the first low-frequency phase electric current of two phase windings in detecting step S41 when the excitation of this first low-frequency ac voltage is issued to stable state, and calculate the effective value U of the first low-frequency ac voltage and the first low-frequency phase electric current _s0and I _s0, then adopt the phase place of phase-locked first low-frequency ac voltage of a phase-locked loop and the first low-frequency phase electric current, and calculate the phase difference between acquisition first low-frequency ac voltage and the first low-frequency phase electric current

Step S43, according to Fig. 3, according to formula (41), (42), calculates the real part Re (Z of first total reactance of the T-shaped equivalent electric circuit of every phase winding under the first low-frequency ac voltage excitation obtaining motor ₁) and imaginary part Im (Z ₁):

Step 5: adopt the single-phase low-frequency ac pressure excitation repeated execution of steps four of other two different frequencies each once, calculate rotor mutual inductance, specifically, comprise the steps:

S51, adopts the second low-frequency ac voltage excitation repeated execution of steps four of frequency within the scope of 0.1 ~ 0.5Hz, calculates the real part Re (Z of second total reactance of the T-shaped equivalent electric circuit of every phase winding under the second low-frequency ac voltage excitation obtaining motor stator ₂) and imaginary part Im (Z ₂);

S52, adopts the three low-frequency ac voltage excitation repeated execution of steps four of frequency within the scope of 0.1 ~ 0.5Hz, calculates the real part Re (Z of the 3rd total reactance of the T-shaped equivalent electric circuit of every phase winding under the 3rd low-frequency ac voltage excitation obtaining motor stator ₃) and imaginary part Im (Z ₃);

S53, according to formula (5), calculates and obtains rotor mutual inductance L _ms:

$L_{\mathrm{ms}}=\frac{{\mathrm{\ω}}_1^3{Z}_2{Z}_3({\mathrm{\ω}}_2^2-{\mathrm{\ω}}_3^2)+{\mathrm{\ω}}_2^3{Z}_1{Z}_3({\mathrm{\ω}}_3^2-{\mathrm{\ω}}_1^2)+{\mathrm{\ω}}_3^3{Z}_1{Z}_2({\mathrm{\ω}}_1^2-{\mathrm{\ω}}_2^2)}{{\mathrm{\ω}}_1{\mathrm{\ω}}_2{\mathrm{\ω}}_3[{\mathrm{\ω}}_1{Z}_1({\mathrm{\ω}}_3^2-{\mathrm{\ω}}_2^2)+{\mathrm{\ω}}_2{Z}_2({\mathrm{\ω}}_1^2-{\mathrm{\ω}}_3^2)+{\mathrm{\ω}}_3{Z}_3({\mathrm{\ω}}_2^2-{\mathrm{\ω}}_1^2)]}-L_{\mathrm{\σs}}---\left(5\right),$

In formula, ω ₁, ω ₂and ω ₃be respectively the angular frequency of the first low-frequency ac voltage, the second low-frequency ac voltage and the 3rd low-frequency ac voltage, and ω ₁=2 π f _low1, ω ₂=2 π f _low2, ω ₃=2 π f _low3, wherein, f _low1, f _low2and f _low3be respectively the frequency of the first low-frequency ac voltage, the second low-frequency ac voltage and the 3rd low-frequency ac voltage; Z ₁, Z ₂and Z ₃be respectively the imaginary part Im (Z of first total reactance, second total reactance and the 3rd total reactance ₁), Im (Z ₂) and Im (Z ₂).

The principle of such calculating is as follows:

The T-shaped equivalent electric circuit of the every phase winding of motor according to Fig. 1, the real part Re (Z) of its total reactance and imaginary part Im (Z) is respectively shown in formula (51), (52):

$\mathrm{Re}\left(Z\right)=R_s+\frac{{\mathrm{\ω}}^2\mathrm{LT}(1-\mathrm{\ζ})}{1+{\mathrm{\ω}}^2{T}^2}---\left(51\right),$

$\mathrm{Im}\left(Z\right)=\mathrm{\ωL}\frac{1+\mathrm{\ζ}{\mathrm{\ω}}^2{T}^2}{1+{\mathrm{\ω}}^2{T}^2}---\left(52\right),$

In formula, L is full inductance L=L _ms+ L _{σ s}, T is rotor time constant ζ is leakage inductance coefficient ω is the angular rate ω=2 π f of driving voltage.

As can be seen from the above equation, mutual inductance L _msrelevant to L, T, ζ tri-variablees, try to achieve any one variable, mutual inductance L can have been tried to achieve _ms.

By calculating total reactance imaginary part Im (Z of the T-shaped equivalent electric circuit of the every phase winding of motor under acquisition three different frequencies ₁), Im (Z ₂) and Im (Z ₂), set up ternary linear function group (53) thus:

$\left\{\begin{array}{c}\mathrm{Im}\left(Z_1\right)={\mathrm{\ω}}_{1}L\frac{1+\mathrm{\ζ}{\mathrm{\ω}}_1^2{T}^2}{1+{\mathrm{\ω}}_1^2{T}^2}\\ \mathrm{Im}\left(Z_2\right)={\mathrm{\ω}}_{2}L\frac{1+\mathrm{\ζ}{\mathrm{\ω}}_2^2{T}^2}{1+{\mathrm{\ω}}_2^2{T}^2}\\ \mathrm{Im}\left(Z_3\right)={\mathrm{\ω}}_{3}L\frac{1+\mathrm{\ζ}{\mathrm{\ω}}_3^2{T}^2}{1+{\mathrm{\ω}}_3^2{T}^2}\end{array}\right.---\left(53\right),$

Solve above-mentioned equation group (53), obtain L, T and ζ tri-variate-values, rotor mutual inductance L can be obtained _msexpression formula as shown in Equation (5).

The reason using reactance imaginary part to carry out calculating in step 5 is mainly in order to avoid the error between the reference voltage and virtual voltage of inverter output is on the impact of identification precision.As shown in Figure 5, according to electric machine controller three-phase bridge operation principle, the error between reference voltage with virtual voltage and current polarity are contrary, so I _realfor timing, virtual voltage U _realbe less than reference voltage U _ref; I _realfor time negative, virtual voltage U _realbe greater than reference voltage U _ref.During counting circuit reactance, reactance real part Re (Z) equals the ratio of voltage and current in phase bit position, and imaginary part Im (Z) equals the ratio that voltage divides with electric current orthogonal part.

Alternating voltage in Fig. 5 is split into and the component U' of current in phase position and orthogonal component U'', specifically as shown in Figure 6.As can be seen from the curve chart of the component U' of the output voltage in Fig. 6 and current in phase position, one-period internal reference voltage U _1refeffective value be obviously greater than output voltage U _1realeffective value; And as can be seen from the curve chart of the output voltage component U'' orthogonal with electric current, one-period internal reference voltage U _2refwith the effective value U of virtual voltage _2realbe equal, again because in-phase component is relevant to the real part of total reactance, quadrature component is relevant to the imaginary part of total reactance, so the error between the reference voltage of control inverter output and virtual voltage only acts on reactance real part Re (Z).In addition, also containing stator resistance R in the expression formula of reactance real part _s, and resistance R _smeasure error also can affect the identification precision of mutual inductance.

To sum up, in order to avoid the error between control inverter output reference voltage and virtual voltage is on the impact of rotor mutual inductance identification, adopts reactance imaginary part Im (Z) to calculate and obtain rotor mutual inductance L _ms.

Above-described, be only preferred embodiment of the present invention, and be not used to limit scope of the present invention, the above embodiment of the present invention can also make a variety of changes.Namely every claims according to the present patent application and description are done simple, equivalence change and modify, and all fall into the claims of patent of the present invention.

Claims (5)

1. the non-synchronous motor parameter offline identification method under an inactive state, the method realizes based on described asynchronous machine and the inverter that is connected with this asynchronous machine input, and wherein, described asynchronous machine comprises rotor and the stator with polyphase windings, it is characterized in that, the method comprises the following steps:

Step one, by following steps identification stator resistance:

S11, applies the first direct voltage excitation to any two phase windings of described stator;

S12, gathers first direct current of two phase windings when the first direct voltage excitation is issued to stable state in described step S11 by described inverter;

S13, applies the second direct voltage excitation to any two phase windings of described stator;

S14, gathers second direct current of two phase windings when the second direct voltage excitation is issued to stable state in described step S13 by described inverter;

S15, according to described first direct voltage and the second direct voltage and described first direct current and the second direct current accordingly, calculates and obtains described stator resistance;

Step 2, by following steps identification rotor resistance, stator leakage inductance and rotor leakage inductance:

S21, applies the first alternating voltage excitation of single-phase rated frequency to any two phase windings of described stator;

S22, obtains the first-phase electric current of two phase windings when the excitation of this first alternating voltage is issued to stable state in described step S21 and the first-phase parallactic angle between described first alternating voltage and described first-phase electric current;

S23, calculates according to the effective value of described first alternating voltage, the effective value of described first-phase electric current and described first-phase parallactic angle and obtains described rotor resistance, stator leakage inductance and rotor leakage inductance;

Step 3, is revised the described rotor resistance calculated in described step 2 by following steps, to suppress kelvin effect on the impact of described rotor resistance identification precision:

S31, the second single-phase alternating voltage excitation is applied to any two phase windings of described motor stator, and this second alternating voltage is raised gradually until the phase current of described two phase windings reaches rated current, wherein, the frequency of described second alternating voltage, lower than described rated frequency, is 40 ~ 45Hz;

S32, detects the instantaneous value of the second-phase electric current of two phase windings when the excitation of this second alternating voltage is issued to stable state in described step S31, and calculates the effective value U of described second alternating voltage and described second-phase electric current _sn2and I _sn2, then adopt the phase place of phase-locked described second alternating voltage of described phase-locked loop and described second-phase electric current, and calculate the phase difference between described second alternating voltage and described second-phase electric current thus calculate acquisition rotor resistance second identifier

S33, according to formula (3), calculates the rotor resistance R obtaining and overcome kelvin effect impact _r:

$R_r=\frac{R_{r2}{f}_1-R_{r1}{f}_2}{f1-f2}---\left(3\right),$

In formula, f ₁for the frequency of described first alternating voltage, f ₂for the frequency of described second alternating voltage;

Step 4, calculates total reactance of the T-shaped equivalent electric circuit obtaining the every phase winding of described motor by following steps:

S41, applies the single-phase first low-frequency ac voltage excitation of frequency within the scope of 0.1 ~ 0.5Hz to any two phase windings of described stator;

S42, obtains the first low-frequency phase electric current of two phase windings when described first low-frequency ac voltage excitation is issued to stable state in described step S41 and the first low-frequency phase parallactic angle between described first low-frequency ac voltage and described first low-frequency phase electric current;

S43, according to the effective value of described first low-frequency ac voltage, the effective value of described first low-frequency phase electric current and described first low-frequency phase parallactic angle, calculate real part and the imaginary part of first total reactance of the T-shaped equivalent electric circuit of every phase winding under described first low-frequency ac voltage excitation obtaining described motor stator;

Step 5, by the mutual inductance of following steps identification rotor:

S51, adopt the second low-frequency ac voltage excitation of frequency within the scope of 0.1 ~ 0.5Hz to repeat described step 4, calculate the imaginary part of second total reactance of the T-shaped equivalent electric circuit of every phase winding under described second low-frequency ac voltage excitation obtaining described motor stator;

S52, adopt the three low-frequency ac voltage excitation of frequency within the scope of 0.1 ~ 0.5Hz to repeat described step 4, calculate the imaginary part of the 3rd total reactance of the T-shaped equivalent electric circuit of every phase winding under described 3rd low-frequency ac voltage excitation obtaining described motor stator;

S53, according to the imaginary part of described rotor mutual inductance and described first total reactance, second total reactance and the 3rd total reactance, calculates and obtains described rotor mutual inductance.

2. the non-synchronous motor parameter offline identification method under inactive state according to claim 1, is characterized in that:

Described step S15 comprises: set described first direct voltage and the second direct voltage is respectively U1, U2, and described first direct current and the second direct current are respectively I accordingly in setting ₁, I ₂, calculate according to formula (1) and obtain described stator resistance R _s,

$R_s=\frac{U_2-U_1}{I_2-I_1}\×\frac{1}{2}---\left(1\right).$

3. the non-synchronous motor parameter offline identification method under inactive state according to claim 2, is characterized in that:

Described step S21 comprises: the described first alternating voltage excitation any two phase windings of described motor stator being applied to single-phase rated frequency, and this first alternating voltage is raised gradually until the phase current of described two phase windings reaches rated current;

Described step S22 comprises: the instantaneous value detecting the first-phase electric current of two phase windings when the excitation of this first alternating voltage is issued to stable state in described step S21, and calculates the effective value U of described first alternating voltage and described first-phase electric current _sn1and I _sn1, then adopt the phase place of phase-locked described first alternating voltage of a phase-locked loop and described first-phase electric current, and calculate the phase difference obtained between described first alternating voltage and described first-phase electric current

Described step S23 comprises: calculate obtain rotor resistance first identifier R according to formula (21), (22) _r1, stator leakage inductance L _{σ s}with rotor leakage inductance L _{σ r}:

In formula, f ₁represent the frequency of described first alternating voltage.

4. the non-synchronous motor parameter offline identification method under inactive state according to claim 1, is characterized in that:

Described step S41 comprises: apply the described first low-frequency ac voltage excitation of frequency within the scope of 0.1 ~ 0.5Hz to any two phase windings of described motor stator, and this first low-frequency ac voltage is raised gradually until the phase current of described two phase windings reaches rated current;

Described step S42 comprises: the instantaneous value detecting the first low-frequency phase electric current of two phase windings when the excitation of this first low-frequency ac voltage is issued to stable state in described step S41, and calculates the effective value U of described first low-frequency ac voltage and described first low-frequency phase electric current _s0and I _s0, then adopt the phase place of phase-locked described first low-frequency ac voltage of a phase-locked loop and described first low-frequency phase electric current, and calculate the phase difference obtained between described first low-frequency ac voltage and described first low-frequency phase electric current

Described step S43 comprises: according to formula (41), (42), calculates the real part Re (Z of first total reactance of the T-shaped equivalent electric circuit of every phase winding under described first low-frequency ac voltage excitation obtaining described motor ₁) and imaginary part Im (Z ₁):

5. the non-synchronous motor parameter offline identification method under inactive state according to claim 4, is characterized in that:

Described step S53 comprises: calculate according to formula (5) and obtain described rotor mutual inductance L _ms:

$L_{\mathrm{ms}}=\frac{{\mathrm{\ω}}_1^3{Z}_2{Z}_3({\mathrm{\ω}}_2^2-{\mathrm{\ω}}_3^2)+{\mathrm{\ω}}_2^3{Z}_1{Z}_3({\mathrm{\ω}}_3^2-{\mathrm{\ω}}_1^2)+{\mathrm{\ω}}_3^3{Z}_1{Z}_2({\mathrm{\ω}}_1^2-{\mathrm{\ω}}_2^2)}{{\mathrm{\ω}}_1{\mathrm{\ω}}_2{\mathrm{\ω}}_3[{\mathrm{\ω}}_1{Z}_1({\mathrm{\ω}}_3^2-{\mathrm{\ω}}_2^2)+{\mathrm{\ω}}_2{Z}_2({\mathrm{\ω}}_1^2-{\mathrm{\ω}}_3^2)+{\mathrm{\ω}}_3{Z}_3({\mathrm{\ω}}_2^2-{\mathrm{\ω}}_1^2)]}-L_{\mathrm{\σs}}---\left(5\right),$

In formula, ω ₁, ω ₂and ω ₃be respectively the angular frequency of described first low-frequency ac voltage, the second low-frequency ac voltage and the 3rd low-frequency ac voltage, and ω ₁=2 π f _low1, ω ₂=2 π f _low2, ω ₃=2 π f _low3, wherein, f _low1, f _low2and f _low3be respectively the frequency of described first low-frequency ac voltage, the second low-frequency ac voltage and the 3rd low-frequency ac voltage; Z ₁, Z ₂and Z ₃be respectively the imaginary part of described first total reactance, second total reactance and the 3rd total reactance.