CN104883109A - Control method for restraining harmonic current of doubly-fed wind generator stator side - Google Patents

Abstract

The invention provides a control method for restraining harmonic current of a doubly-fed wind generator stator side. The method comprises the steps that a doubly-fed wind generator mathematical model under an nth-degree harmonic rotating coordinate system is established, and a voltage control compensation item under an nth-degree harmonic rotor dq coordinate system is obtained; the decision variable of the fifth-degree harmonic current control link and the decision variable of the seventh-degree harmonic current control link are introduced into vector control of a doubly-fed wind generator side converter, and reference instructions of the fifth-degree harmonic and the seventh-degree harmonic of a doubly-fed wind generator stator and the voltage component and the rotor modulation voltage under the dq coordinate system are obtained; PWM control signals of the doubly-fed wind generator side converter are generated through modulation. The control target of restraining the stator harmonic current is achieved, and the effect of the harmonic current on a wind generator is reduced.

Description

A kind of control method suppressing double-fed aerogenerator stator side harmonic current

Technical field

The present invention relates to a kind of control method, be specifically related to a kind of control method suppressing double-fed aerogenerator stator side harmonic current.

Background technology

Wind-powered electricity generation is as the huge regenerative resource of reserves, and in recent years, rapidly, installed capacity of wind-driven power has risen to the whole world first in the installed capacity of wind-driven power development of China.Because wind energy has certain randomness, wind energy turbine set is in process of construction, and will take into full account the actual conditions of wind energy turbine set access point when dropping into operation of power networks, namely need to consider wind power resources, load and electrical network on the whole, to meet the relation in a basic balance of the electric parameters of electrical network, the stable coordination realizing wind energy turbine set and electric power system runs.Wind farm grid-connected the stable operation of quality of power supply situation to wind energy turbine set has great importance; because the control system of wind power generation is design under the desirable condition of line voltage mostly; and the existence of mains by harmonics voltage will produce corresponding stator harmonic current in fan stator side; affect the control system of Wind turbines; Wind turbines is caused damage, its off-grid time serious, may be caused to shut down.

Harmonic wave except causing supplementary load loss, also can produce mechanical oscillation, noise and overvoltage and electric resonance on the impact of double feedback electric engine.The method of harmonic wave control conventional in electrical network mainly contains passive filtering and active power filtering, due to the harmonic treating apparatus adopted, needs initial outlay and the operation expense of increase equipment.

Summary of the invention

The present invention proposes a kind of control method suppressing double-fed aerogenerator stator side harmonic current, is obtained the pwm control signal of pusher side current transformer by space vector modulation, achieves the control objectives suppressing stator harmonic current; Efficiently solve the governing problem of doubly-fed generation machine stator harmonic current under mains by harmonics voltage, decrease the impact of harmonic current on wind-driven generator.

The object of the invention is to adopt following technical proposals to realize:

Suppress a control method for double-fed aerogenerator stator side harmonic current, described method comprises, and builds the double-fed wind power generator Mathematical Modeling under nth harmonic rotating coordinate system, obtains the voltage controling compensation item under nth harmonic rotor dq coordinate system; Respectively the decision variable of quintuple harmonics and the seventh harmonic Current Control link is introduced in the vector control of double-fed wind power generator pusher side current transformer, obtain the component of voltage under the reference instruction of double-fed wind power generator rotor electric current quintuple harmonics and the seventh harmonic component, dq coordinate system and rotor modulation voltage; The pwm control signal of double-fed wind power generator side converter is generated through ovennodulation.

Preferably, the double-fed wind power generator Mathematical Modeling expression formula under described structure nth harmonic rotating coordinate system is:

$\left\{\begin{array}{c}{\mathrm{\Ψ}}_{sdqn}^n=L_s{i}_{sdqn}^n+L_m{i}_{rdqn}^n\\ {\mathrm{\Ψ}}_{rdqn}^n=L_s{i}_{rdqn}^n+L_m{i}_{sdqn}^n\end{array}\right.$

Wherein, be respectively stator and rotor voltage dq axle component and the stator and rotor magnetic linkage dq axle component of nth harmonic; with be respectively the stator and rotor electric current dq axle component of nth harmonic; R _sand R _rbe respectively the every equivalent resistance of stator and rotor; L _s, L _rand L _mbe respectively the every phase winding complete inductance of equivalent stator and rotor and mutual inductance, ω _sand ω _rbe respectively stator synchronous angular velocity and rotor velocity; N is 5 or 7, represents harmonic number;

By stator flux orientation method, obtain the voltage controling compensation item under nth harmonic rotor dq coordinate system, its expression formula is:

$\left\{\begin{array}{c}{\mathrm{\ΔU}}_{rdn}^n=-({\mathrm{n\ω}}_s-{\mathrm{\ω}}_r){\mathrm{\σL}}_r{i}_{rdqn}^n\\ {\mathrm{\ΔU}}_{rqn}^n=({\mathrm{n\ω}}_s-{\mathrm{\ω}}_r)({\mathrm{\σL}}_r{i}_{rdqn}^n+\frac{{\mathrm{\Ψ}}_{sdqn}^n{L}_m}{L_s})\end{array}\right.$

In formula, $\mathrm{\σ}=1-\frac{L_m^2}{L_r{L}_s}$ For equivalent leakage inductance coefficient.

Preferably, the reference instruction of described acquisition double-fed wind power generator rotor electric current quintuple harmonics and the seventh harmonic component comprises, respectively by double-fed aerogenerator stator side quintuple harmonics and the seventh harmonic current reference amount with corresponding feedback quantity difference be sent to pi controller, export the reference instruction of double-fed wind power generator rotor electric current quintuple harmonics and the seventh harmonic component with

Further, respectively by the reference instruction of described double-fed wind power generator rotor electric current quintuple harmonics and the seventh harmonic component with with corresponding feedback quantity difference be sent to pi controller, export the component of voltage under double-fed wind power generator rotor quintuple harmonics and the seventh harmonic dq coordinate system with

Further, by the component of voltage under described rotor quintuple harmonics and the seventh harmonic dq coordinate system with with the voltage controling compensation item under rotor quintuple harmonics and the seventh harmonic dq coordinate system with be added; Obtain the rotor modulation voltage under quintuple harmonics and the seventh harmonic dq coordinate system with

Further, described rotor modulation voltage with synchronous rotating frame is utilized to be inversely transformed into through five times and seven park respectively with by itself and rotor fundamental voltage reference quantity do and, obtain rotor modulation voltage $U_{rabc}^{*}=U_{rabc1}^{1*}+U_{rabc5}^{5*}+U_{rabc7}^{7*}.$

Further, by described rotor modulation voltage carry out space vector modulation SVM, generate the pwm control signal of double-fed wind power generator side converter to realize the control of double-fed aerogenerator stator side electric current.

Compared with prior art, the beneficial effect that the present invention reaches is:

1) the method is by setting up the double-fed wind power generator Mathematical Modeling under 5,7 subharmonic rotating coordinate systems, by traditional PI controller, achieves the effective control for specific mains by harmonics stator harmonic current; The modulation voltage of double-fed wind power generator side converter obtains pwm voltage through coordinate transform and space vector modulation, and generator is exported and the opposite polarity offset current of harmonic current.

2) compared with the mode of traditional increase hardware filtering equipment, harmonic current is transformed to the harmonics restraint control strategy under synchronous rotating frame, efficiently solve the governing problem of doubly-fed generation machine stator harmonic current under mains by harmonics voltage, reduce the impact of harmonic current on wind-driven generator, its method is simple to operate, with strong points, and saved Financial cost.

Accompanying drawing explanation

Fig. 1 is the control method flow chart of suppression double-fed aerogenerator stator side provided by the invention harmonic current;

Fig. 2 is suppression double-fed aerogenerator stator side provided by the invention harmonic current control structure schematic diagram;

Fig. 3 is that provided by the invention five, the seventh harmonic current component extracts schematic diagram;

Embodiment

Below in conjunction with accompanying drawing, the specific embodiment of the present invention is described in further detail.

As shown in Figure 1, a kind of control method suppressing double-fed wind power generator (DFIG) stator side harmonic current, for the independent uneoupled control of double-fed wind power generator pusher side current transformer and net side converter, described method comprises, build the double-fed wind power generator Mathematical Modeling under nth harmonic rotating coordinate system, obtain the voltage controling compensation item under nth harmonic rotor dq coordinate system; Double-fed wind power generator Mathematical Modeling expression formula under described structure nth harmonic rotating coordinate system is:

$\left\{\begin{array}{c}{\mathrm{\Ψ}}_{sdqn}^n=L_s{i}_{sdqn}^n+L_m{i}_{rdqn}^n\\ {\mathrm{\Ψ}}_{rdqn}^n=L_s{i}_{rdqn}^n+L_m{i}_{sdqn}^n\end{array}\right.$

Wherein, be respectively stator and rotor voltage dq axle component and the stator and rotor magnetic linkage dq axle component of nth harmonic; with be respectively the stator and rotor electric current dq axle component of nth harmonic; R _sand R _rbe respectively the every equivalent resistance of stator and rotor; L _s, L _rand L _mbe respectively the every phase winding complete inductance of equivalent stator and rotor and mutual inductance, ω _sand ω _rbe respectively stator synchronous angular velocity and rotor velocity; N is 5 or 7, represents harmonic number;

By stator flux orientation method, obtain the voltage controling compensation item under nth harmonic rotor dq coordinate system, its expression formula is:

$\left\{\begin{array}{c}{\mathrm{\ΔU}}_{rdn}^n=-({\mathrm{n\ω}}_s-{\mathrm{\ω}}_r){\mathrm{\σL}}_r{i}_{rdqn}^n\\ {\mathrm{\ΔU}}_{rqn}^n=({\mathrm{n\ω}}_s-{\mathrm{\ω}}_r)({\mathrm{\σL}}_r{i}_{rdqn}^n+\frac{{\mathrm{\Ψ}}_{sdqn}^n{L}_m}{L_s})\end{array}\right.$

In formula, $\mathrm{\σ}=1-\frac{L_m^2}{L_r{L}_s}$ For equivalent leakage inductance coefficient.

As shown in Figure 3, respectively the decision variable of quintuple harmonics and the seventh harmonic Current Control link is introduced in the vector control of double-fed wind power generator pusher side current transformer; In order to introduce the suppression link of quintuple harmonics and the seventh harmonic, rotating coordinate transformation is utilized quintuple harmonics under the abc system of axis and the seventh harmonic current component to be transformed to DC component under dq coordinate system, and respectively by 200Hz and 300Hz notch filter by fundamental current component filtering, extract feedback quantity

Obtain the component of voltage under the reference instruction of double-fed wind power generator rotor electric current quintuple harmonics and the seventh harmonic component, dq coordinate system and rotor modulation voltage; The pwm control signal of double-fed wind power generator side converter is generated through ovennodulation.

The reference instruction of described acquisition double-fed wind power generator rotor electric current quintuple harmonics and the seventh harmonic component comprises, as shown in Figure 2, respectively by double-fed aerogenerator stator side quintuple harmonics and the seventh harmonic current reference amount with corresponding feedback quantity difference be sent to pi controller (PI), export the reference instruction of double-fed wind power generator rotor electric current quintuple harmonics and the seventh harmonic component with

Respectively by the reference instruction of described double-fed wind power generator rotor electric current quintuple harmonics and the seventh harmonic component with with corresponding feedback quantity difference be sent to pi controller, export the component of voltage under double-fed wind power generator rotor quintuple harmonics and the seventh harmonic dq coordinate system with

By the component of voltage under described rotor quintuple harmonics and the seventh harmonic dq coordinate system with with the voltage controling compensation item under rotor quintuple harmonics and the seventh harmonic dq coordinate system with be added; Obtain the rotor modulation voltage under quintuple harmonics and the seventh harmonic dq coordinate system with

Described rotor modulation voltage with synchronous rotating frame is utilized to be inversely transformed into through five times and seven park respectively with by itself and rotor fundamental voltage reference quantity do and, obtain rotor modulation voltage $U_{rabc}^{*}=U_{rabc1}^{1*}+U_{rabc5}^{5*}+U_{rabc7}^{7*}.$

By described rotor modulation voltage carry out space vector modulation SVM, generate the pwm control signal of double-fed wind power generator side converter to realize the control of double-fed aerogenerator stator side electric current.

Finally should be noted that: above embodiment is only in order to illustrate the technical scheme of the application but not the restriction to its protection range; although with reference to above-described embodiment to present application has been detailed description; those of ordinary skill in the field are to be understood that: those skilled in the art still can carry out all changes, amendment or equivalent replacement to the embodiment of application after reading the application; these change, amendment or equivalent to replace, and it is all within it applies for the right that awaits the reply.

Claims (7)

1. one kind is suppressed the control method of double-fed aerogenerator stator side harmonic current, it is characterized in that, described method comprises: build the double-fed wind power generator Mathematical Modeling under nth harmonic rotating coordinate system, obtains the voltage controling compensation item under nth harmonic rotor dq coordinate system; Respectively the decision variable of quintuple harmonics and the seventh harmonic Current Control link is introduced in the vector control of double-fed wind power generator pusher side current transformer, obtain the component of voltage under the reference instruction of double-fed wind power generator rotor electric current quintuple harmonics and the seventh harmonic component, dq coordinate system and rotor modulation voltage; The pwm control signal of double-fed wind power generator side converter is generated through ovennodulation.

2. the method for claim 1, is characterized in that, the double-fed wind power generator Mathematical Modeling expression formula under described structure nth harmonic rotating coordinate system is:

Wherein, be respectively stator and rotor voltage dq axle component and the stator and rotor magnetic linkage dq axle component of nth harmonic; with be respectively the stator and rotor electric current dq axle component of nth harmonic; R _sand R _rbe respectively the every equivalent resistance of stator and rotor; L _s, L _rand L _mbe respectively the every phase winding complete inductance of equivalent stator and rotor and mutual inductance, ω _sand ω _rbe respectively stator synchronous angular velocity and rotor velocity; N is 5 or 7, represents harmonic number;

By stator flux orientation method, obtain the voltage controling compensation item under nth harmonic rotor dq coordinate system, its expression formula is:

$\left\{\begin{array}{c}{\mathrm{\ΔU}}_{rdn}^n=-({\mathrm{n\ω}}_s-{\mathrm{\ω}}_r){\mathrm{\σL}}_r{i}_{sdqn}^n\\ {\mathrm{\ΔU}}_{rqn}^n=({\mathrm{n\ω}}_s-{\mathrm{\ω}}_r)({\mathrm{\σL}}_r{i}_{rdqn}^n+\frac{{\mathrm{\Ψ}}_{sdqn}^n{L}_m}{L_s})\end{array}\right.$

In formula, for equivalent leakage inductance coefficient.

3. the method for claim 1, is characterized in that, the reference instruction of described acquisition double-fed wind power generator rotor electric current quintuple harmonics and the seventh harmonic component comprises, respectively by double-fed aerogenerator stator side quintuple harmonics and the seventh harmonic current reference amount with corresponding feedback quantity difference be sent to pi controller, export the reference instruction of double-fed wind power generator rotor electric current quintuple harmonics and the seventh harmonic component with

4. method as claimed in claim 3, is characterized in that, respectively by the reference instruction of described double-fed wind power generator rotor electric current quintuple harmonics and the seventh harmonic component with with corresponding feedback quantity difference be sent to pi controller, export the component of voltage under double-fed wind power generator rotor quintuple harmonics and the seventh harmonic dq coordinate system with

5. method as claimed in claim 4, is characterized in that, by the component of voltage under described rotor quintuple harmonics and the seventh harmonic dq coordinate system with with the voltage controling compensation item under rotor quintuple harmonics and the seventh harmonic dq coordinate system with be added; Obtain the rotor modulation voltage under quintuple harmonics and the seventh harmonic dq coordinate system with

6. method as claimed in claim 5, is characterized in that, described rotor modulation voltage with synchronous rotating frame is utilized to be inversely transformed into through five times and seven park respectively with by itself and rotor fundamental voltage reference quantity do and, obtain rotor modulation voltage $U_{rabc}^{*}=U_{rabc1}^{1*}+U_{rabc5}^{5*}+U_{rabc7}^{7*}.$

7. method as claimed in claim 6, is characterized in that, by described rotor modulation voltage carry out space vector modulation SVM, generate the pwm control signal of double-fed wind power generator side converter to realize the control of double-fed aerogenerator stator side electric current.