CN102779214A - Modeling method for double-fed wind driven generator system analysis - Google Patents

Abstract

A modeling method for double-fed wind driven generator system analysis includes the following steps: (1) building a physical model for a serially-connected double-fed wind driven generator system; and (2) building a mathematical model according to the physical model and performing solving, wherein the mathematical model includes a circuit system mathematical model and a mechanical mathematical model. According to the physical model, a stator of a first motor is connected with a frequency converter, a stator of a second motor is connected with a power grid, and a rotor of the first motor is in commutating connection with a rotor of the second motor, wherein a loop F is formed between the phase A and the phase C of the first motor and the phase A and the phase B of the second motor, and current is if. The modeling method can be used in system analysis, electromagnetic analysis, energy flow analysis and frequency variation analysis of the serially-connected generator system and force analysis of two serially-connected motors, and is a powerful tool for research of serially-connected double-fed wind driven generators.

Description

The modeling method that is used for the double-fed wind power generator systematic analysis

Technical field

The present invention relates to a kind of double-fed wind power generator system.Particularly relate to a kind of modeling method that is used for the double-fed wind power generator systematic analysis that can be used for analyzing the analysis of tandem generator system.

Background technology

In the current wind generator system, the induction motor generator is because cost is simple, and strong robustness has obtained using widely.And the double-feedback aerogenerator system because frequency converter is connected in rotor-side, compares with the electricity generation system that is connected in stator side, and inexpensive is so obtained using widely.The tandem doubly fed induction generator is with two coaxial being cascaded of Wound-rotor asynchronous machine; One of them stator winding is connected with electrical network, and another is connected with converter, because two rotors are to be rigidly connected; So compare with unit double-feedback aerogenerator system; Can remove slip ring and brush, based on this advantage, the tandem wind generator system also becomes one of hot research direction.

Summary of the invention

Technical matters to be solved by this invention is to provide a kind of change that can simulate complete wind generator system or system design in detail to obtain the modeling method that is used for the double-fed wind power generator systematic analysis of feasible scheme.

The technical scheme that the present invention adopted is: a kind of modeling method that is used for the double-fed wind power generator systematic analysis comprises the steps:

1) the series connection dual feedback wind power generation system is set up physical model;

2) set up mathematical model according to physical model, find the solution, said mathematical model comprises Circuits System mathematical model and mechanical mathematics model.

Described physical model is that the stator of first motor is connected with frequency converter; The rotor of second motor is connected with electrical network, and the rotor of first motor is connected with the rotor commutation of second motor, wherein; The A of the A of first motor, C and second motor, B form loop E between mutually, and electric current is ie; The A of the A of first motor, B and second motor, C form loop F between mutually, and electric current is if.

Described Circuits System mathematical model has F loop mathematical model and E loop mathematical model; Wherein, Described F loop is the circuit that forms between mutually at the C of the B of first motor 3 and second motor 4, described E loop be the B of the C of first motor 3 and second motor 4 mutually between the circuit of formation.

Described F loop mathematical model is:

$N_{1b}\frac{{\mathrm{d\φ}}_{1b}}{\mathrm{dt}}+R_{1b}{i}_b-N_{1a}\frac{{\mathrm{d\φ}}_{1a}}{\mathrm{dt}}+R_{1a}(i_b+i_c)+N_{2c}\frac{{\mathrm{d\φ}}_{2c}}{\mathrm{dt}}+R_{2c}{i}_b-N_{2a}\frac{{\mathrm{d\φ}}_{2a}}{\mathrm{dt}}+R_{2a}(i_b+i_c)=0$

Wherein: i _{B, c}: the exciting current of b, c loop, A;

φ: magnetic flux, wb;

T: time, s;

R: field resistance, Ω.

Described E loop mathematical model is:

$N_{1c}\frac{{\mathrm{d\φ}}_{1c}}{\mathrm{dt}}+R_{1c}{i}_c-N_{1a}\frac{{\mathrm{d\φ}}_{1a}}{\mathrm{dt}}+R_{1a}(i_b+i_c)+N_{2b}\frac{{\mathrm{d\φ}}_{2b}}{\mathrm{dt}}+R_{2b}{i}_c-N_{2a}\frac{{\mathrm{d\φ}}_{2a}}{\mathrm{dt}}+R_{2a}(i_b+i_c)=0$

Wherein: i _{B, c}: the exciting current of b, c loop, A;

φ: magnetic flux, wb;

T: time, s;

R: field resistance, Ω;

Described mechanical mathematics model is:

The mechanical system variable of series connection wind generator system is following:

Series connection wind generator system formula is described below:

The modeling method that is used for the double-fed wind power generator systematic analysis of the present invention, the change that can simulate complete wind generator system or system design in detail is to obtain feasible scheme.The dynamic magnetic resistance circuit modeling that utilizes is based on the notion of motor equivalent magnetic circuit; Based on the experience of motor internal Distribution of Magnetic Field, motor internal is subdivided into each magnetoresistive cell, uses the kirchhoff voltage in the similar circuit then; Current law; And Ohm law, set up the formula and the equation of magnetic resistance circuit, find the solution then.Because the characteristic of electric rotating machine; This method has been used dynamic air-gap reluctance modeling; In the angle of each motor rotation, air-gap reluctance is carried out finding the solution of magnetic circuit system of equations then by modeling again under this rotor angle; Carry out the system of equations of next time step (rotor angle) afterwards again and find the solution, and then the dynamic property that can carry out motor is resolved.Because the unsaturation characteristic of the iron core of motor, each magnetic resistance of motor all contains nonlinear field curve, and with the method for difference, calculates the magnetic induction density of magnetic resistance inside according to the magnetic field intensity of magnetic resistance.This method is because equation is simple relatively; And there are enough precision and details in the place of paying close attention to the motor research designer; So be applicable to the associative simulation of single motor and multi-machine system; And in system, under the situation of existing electron device modeling, can carry out the associative simulation of total system.This method can be taken all factors into consideration distortion, harmonic wave, the slot ripples influence to system performance, for research series connection double-feedback aerogenerator provides low-cost, high-precision analytical approach.Can be used for analyzing the systematic analysis of tandem generator system, emi analysis, energy Flow analysis, and change of frequency analysis, and the force analysis of two series electric motors.For research series connection double-feedback aerogenerator provides strong instrument.

Description of drawings

Fig. 1 is that the series connection dual feedback wind power generation system constitutes synoptic diagram;

Fig. 2 is a three-phase line synoptic diagram between first motor and second motor;

Fig. 3 is the threephase stator current waveform figure of first motor, wherein

(a) converter stator A phase current, (b) converter stator B phase current, (c) converter stator C phase current;

Fig. 4 is rotor A phase current waveform figure;

Fig. 5 is generating grid side stator current waveforms figure.

Among the figure

1: impeller 2: gear case

4: the second motors of 3: the first motors

5: transformer 6: frequency converter

Embodiment

Below in conjunction with embodiment and accompanying drawing the modeling method that is used for the double-fed wind power generator systematic analysis of the present invention is made detailed description.

As shown in Figure 1; The series connection dual feedback wind power generation system comprises: the impeller 1 that is connected in series, gear case 2, first motor 3, second motor 4 and transformer 5; First motor 3 is connected with 4 commutations of second motor, wherein in this system if the generating frequency is when being higher than 50Hz, the output of described first motor 3 also connects described progress of disease depressor 5 through frequency converter 6; The output of described second motor 4 connects described transformer 5; The output of described transformer 5 connects electrical network, and when being lower than 50Hz as if the generating frequency, electrical network is through transformer 5 and frequency converter 6 feedback current to the first motors 3; Export electrical network jointly to second motor 4, to guarantee the stability of the frequency that electrical network is exported.

The modeling method that is used for the double-fed wind power generator systematic analysis of the present invention is to set up to series connection dual feedback wind power generation system as shown in Figure 1, comprises the steps:

1) the series connection dual feedback wind power generation system is set up physical model;

As shown in Figure 2; Described physical model is that the stator of first motor is connected with frequency converter; The rotor of second motor is connected with electrical network, and the rotor of first motor is connected with the rotor commutation of second motor, wherein; The A of the A of first motor, C and second motor, B form loop E between mutually, and electric current is ie; The A of the A of first motor, B and second motor, C form loop F between mutually, and electric current is if.

2) set up mathematical model according to physical model, find the solution, said mathematical model is to set up according to three-phase line synoptic diagram between first motor 3 as shown in Figure 2 and second motor 4.Specifically comprise Circuits System mathematical model and mechanical mathematics model.Described Circuits System mathematical model has F loop mathematical model and E loop mathematical model; Wherein, Described F loop is the circuit that forms between mutually at the C of the B of first motor and second motor, described E loop be the B of the C of first motor and second motor mutually between the circuit of formation.

Described F loop mathematical model is:

$N_{1b}\frac{{\mathrm{d\φ}}_{1b}}{\mathrm{dt}}+R_{1b}{i}_b-N_{1a}\frac{{\mathrm{d\φ}}_{1a}}{\mathrm{dt}}+R_{1a}(i_b+i_c)+N_{2c}\frac{{\mathrm{d\φ}}_{2c}}{\mathrm{dt}}+R_{2c}{i}_b-N_{2a}\frac{{\mathrm{d\φ}}_{2a}}{\mathrm{dt}}+R_{2a}(i_b+i_c)=0.$

Described E loop mathematical model is:

$N_{1c}\frac{{\mathrm{d\φ}}_{1c}}{\mathrm{dt}}+R_{1c}{i}_c-N_{1a}\frac{{\mathrm{d\φ}}_{1a}}{\mathrm{dt}}+R_{1a}(i_b+i_c)+N_{2b}\frac{{\mathrm{d\φ}}_{2b}}{\mathrm{dt}}+R_{2b}{i}_c-N_{2a}\frac{{\mathrm{d\φ}}_{2a}}{\mathrm{dt}}+R_{2a}(i_b+i_c)=0---\left(2\right).$

i _{B, c}: the exciting current of b, c loop, A;

φ: magnetic flux, wb;

T: time, s;

R: field resistance, Ω;

Subscript the 1, the 2nd in the formula, respectively corresponding first motor 3 and second motor 4.The B of first motor 3, C phase place are two separate variablees.

Described mechanical mathematics model is:

The mechanical system variable of series connection wind generator system is following:

Series connection wind generator system formula is described below:

According to above variable and formula, utilize formula 3-4 that the electric current of said system and power etc. are calculated again.

The Kirchhoff's current law (KCL) of magnetic circuit

$\underset{k}{\mathrm{\Σ}}{\mathrm{\φ}}_k=0$

φ wherein _k=∫ ∫ Bnda

B is a magnetic flux density;

The Kirchhoff's second law of magnetic circuit

$\underset{k}{\mathrm{\Σ}}{F}_k=F_c$

Wherein, $F_k=\underset{a_k}{\overset{b_k}{\∫}}\stackrel{\→}{H}\·d\stackrel{\→}{l}$

${\mathrm{<figure-callout\; id="0"\; label="F"\; filenames="HDA00001842540300022.png"\; state="\{\{state\}\}">F</figure-callout>}}_0=\&Integral;\&Integral;\stackrel{\&RightArrow;}{J}\&CenterDot;\stackrel{\&RightArrow;}{n}\mathrm{da}$

For explaining beneficial effect of the present invention, utilize said method to calculate below, and provide the simulation result of series connection dual feedback wind power generation system.

1) simulated conditions:

(1) series electric motor is two identical induction motors, and concrete parameter is seen table 1.

Table 1 unit parameter

The number of phases	3
		Connect	Triangle
Number of poles	4
		Power	15kW
Voltage	415V
		Frequency	50Hz
Electric current	27.08A
		Rotating speed	1454rpm
Torque	99.5Nm
		Efficient	0.891

(2) stator winding parameter is seen shown in the table 2:

Table 2 stator winding parameter

Every groove conductor	22
		Every groove number of plies	2
Structure	Three layers coaxial
		Coil pitch
	9 grooves

(3) be the example analysis with synchronous rotational speed 750rpm.

(4) under synchronous rotational speed, there is voltage to be added on the transducer side stator, so that the magnetic field of B motor can keep is stable.

(5) suppose that electric power flows into mechanical system for negative, flow into electric system for just.

2) analog result:

(1) gain-frequency relationship

DRM under synchronous rotational speed (dynamic magnetic resistance net) current analog waveform is seen shown in Fig. 3-5

Shown in Figure 3 is the threephase stator electric current of first motor, B, C and DC current.The A phase current is 0.

Wherein, Fig. 3 (a) is converter stator A phase current (place of d shown in Fig. 1)

Fig. 3 (b) converter stator B phase current (place of d shown in Fig. 1)

Fig. 3 (c) converter stator C phase current (place of d shown in Fig. 1)

Fig. 4 rotor A phase current (b shown in Fig. 1, c place), the phase current of rotor A shown in Fig. 4 frequency is 25Hz.

Fig. 5 grid side stator current waveforms (Fig. 1 plant shown in a place) of generating electricity, second motor shown in Figure 5 is under synchronous rotational speed, and frequency is 50Hz.

(2) power circuit between system terminal.

The DRM simulation result of power circuit is described below between the system terminal:

When rotating speed was 750rpm, power frequency was 25Hz, underfrequency 50Hz; So the first motor output power is negative value, the second motor output power be on the occasion of, reach after the stable state; Mechanical output is 4.09kW, produces electric energy 3.12kW, and converter power is 0.414kW; Well calculates, and overall power loss is 1.384kW.Emulation draws the total copper loss mistake of system and sees shown in the table 3:

The total copper loss of table 3 system is lost

Claims (6)

1. a modeling method that is used for the double-fed wind power generator systematic analysis is characterized in that, comprises the steps:

1) the series connection dual feedback wind power generation system is set up physical model;

2) set up mathematical model according to physical model, find the solution, said mathematical model comprises Circuits System mathematical model and mechanical mathematics model.

2. the modeling method that is used for the double-fed wind power generator systematic analysis according to claim 1; It is characterized in that described physical model is that the stator of first motor is connected with frequency converter, the rotor of second motor is connected with electrical network; The rotor of first motor is connected with the rotor commutation of second motor; Wherein, the A of the A of first motor, C and second motor, B form loop E between mutually, and electric current is ie; The A of the A of first motor, B and second motor, C form loop F between mutually, and electric current is if.

3. the modeling method that is used for the double-fed wind power generator systematic analysis according to claim 1; It is characterized in that; Described Circuits System mathematical model has F loop mathematical model and E loop mathematical model; Wherein, described F loop is the circuit that forms between mutually at the C of the B of first motor 3 and second motor 4, described E loop be the B of the C of first motor 3 and second motor 4 mutually between the circuit of formation.

4. the modeling method that is used for the double-fed wind power generator systematic analysis according to claim 3 is characterized in that, described F loop mathematical model is:

Wherein: i _{B, c}: the exciting current of b, c loop, A;

φ: magnetic flux, wb;

T: time, s;

R: field resistance, Ω.

5. the modeling method that is used for the double-fed wind power generator systematic analysis according to claim 3 is characterized in that, described E loop mathematical model is:

Wherein: i _{B, c}: the exciting current of b, c loop, A;

φ: magnetic flux, wb;

T: time, s;

R: field resistance, Ω.

6. the modeling method that is used for the double-fed wind power generator systematic analysis according to claim 1 is characterized in that, described mechanical mathematics model is:

The mechanical system variable of series connection wind generator system is following:

Series connection wind generator system formula is described below:

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