CN103346718A - Control method of birotor permanent magnet wind power generation system under voltage imbalance - Google Patents

Abstract

The invention disclose a control method of a birotor permanent magnet wind power generation system under voltage imbalance, and relates to a control method of a variable speed constant frequency birotor permanent magnet wind power generation system under the condition that the network voltage is unbalanced. The method can achieve independent decoupling control over the average active power and the average reactive power of the output stator of a birotor motor, and can also achieves the following purposes respectively: firstly, active power output by a stator is constant, namely, the frequency-doubling grid frequency component of the active power of the stator is eliminated; secondly, a rotor current is balanced to enable the rotor current to contain no negative sequence component; thirdly, a stator current is balanced to enable a three-phase stator winding to emit heat in a balanced mode; fourthly, electromagnetic torque is made to be constant to relieve mechanical burden of a wind power system. Through coordination control over a grid side converter and a rotor side converter, overall operating performance of the birotor wind power generation system under the voltage imbalance can be improved.

Description

The control method of birotor permanent magnetic wind generator system under the Voltage unbalance

Technical field

The invention relates to the control method of a kind of variable speed constant frequency birotor permanent magnetic wind generator system under unbalanced source voltage, belong to technical field of wind power generation.

Background technology

Wind energy is to have one of regenerative resource the most widely on the earth, and it is directed to the sun to the radiation of the earth, is a kind of reformulations of solar energy, is can use it green energy resource without cease of inexhaustible usefulness for the mankind are a large amount of at present.The history of human use's wind energy is very long, and wind power energy is known by people always for thousands of years, but the electric power that utilizes the wind energy generation to be incorporated into the power networks but is the thing of nearest decades with the traditional power plant that replaces the burning petrochemical material.The oil crisis of the outburst seventies impels the western countries that lack petroleum resources to begin to introspect its energy policy, and has put into effect the policy of development alternative energy source in succession, and wherein most crucial content is exactly the regenerative resource that development comprises wind power generation.

Generator and control system thereof as the wind generator system core, be responsible for the conversion of whole wind electric system energy, its operation conditions and control technology have material impact for systematic function, modern wind generation technology great majority adopt the variable speed constant frequency generator technology, can require to regulate in real time the wind energy conversion system rotating speed according to maximal wind-energy capture, make it to run on the optimum speed that changes the wind speed correspondence, optimize the service conditions of wind energy conversion system, improve the generating efficiency of unit.The variable speed constant frequency generator technology is by introducing control with power electronic technology, vector conversion control technology and microcomputer information treatment technology, can realize and the flexibly connecting of electrical network that easier realization is incorporated into the power networks and stable operation.Two kinds of the most frequently used speed-variable frequency-constant wind-driven generators are that double-fed asynchronous generator and direct-drive permanent-magnetism synchronous generator exist some shortcomings separately at present,, gear box low as the double-fed generator power density wants periodic maintenance, electric network fault to pass through poor performance, direct-drive permanent-magnetism synchronous generator not only costliness but also heaviness, need to adopt total power pwm converter etc., a kind of is that the novel variable-speed constant-frequency wind power generation system of core is brought into schedule with the birotor permanent magnetic wind-driven generator, to satisfy modern large-scale wind electricity field for the demand of low-cost high-efficiency wind power generation system.

The system configuration of variable speed constant frequency birotor permanent magnetic wind generator system as shown in Figure 2, the birotor permanent magnetic wind-driven generator is core to decide frequently, this generator comprises Wound-rotor type internal rotor and permanent-magnetic outer rotor, cancel traditional mechanical step-up gear and the power inverter interface that is incorporated into the power networks, by wind energy conversion system by the direct drive motors internal rotor of rotating shaft, stator winding links to each other with electrical network, is connected to two part power inverters that are connected back-to-back between internal rotor winding and electrical network.System configuration has been simplified in above-mentioned measure, has reduced maintenance workload, improves system's operational reliability, has the characteristics of magneto simultaneously concurrently, has higher power density and efficient.

Along with the installed capacity of wind-powered electricity generation unit improves constantly, the various running statuses of wind-powered electricity generation unit have been subjected to common concern and broad research to the influence of the stability of electrical network and the influence of wind-driven generator self during Voltage unbalance, various countries Utilities Electric Co. has proposed some row requirements one after another to the wind-powered electricity generation unit, comprises LVRT, idle control, the control of meritorious control rate of change, FREQUENCY CONTROL etc.

For variable speed constant frequency birotor permanent magnetic wind generator system, under the unbalanced source voltage situation, no matter birotor generator pwm converter (comprising rotor-side converter and grid side converter) is that employing stator voltage vector oriented or employing are stator magnetic linkage oriented, all is that passing ratio integration (PI) adjuster is implemented control to dq axle current weight in just changeing with the leg speed rotating coordinate system.Because pi regulator can only be realized floating tracking control to DC component, when imbalance appears in electrical network, the birotor generator pwm converter removes the flip-flop that comprises positive sequence in just changeing with the leg speed rotating coordinate system, also show two powerful frequency multiplication mains frequency negative phase-sequence alternating components, cause single PI controller can't obtain accurate control effect.To make three-phase current unbalance cause the stator and rotor heating in winding; Unit is meritorious, reactive power fluctuation; Simultaneously also cause burden to dc-link capacitance.And the wind-powered electricity generation unit mostly is in power tip, and environment is abominable, needs the situation of wind-powered electricity generation unit under unbalanced source voltage also to possess the safe operation ability.Therefore under unbalanced source voltage, effective control of variable speed constant frequency birotor permanent magnetic wind generator system also is the problem that current urgent need will solve.

Summary of the invention

Technical problem: the control method that the object of the present invention is to provide variable speed constant frequency birotor permanent magnetic wind generator system under a kind of unbalanced source voltage situation.Under the unbalanced source voltage, under two (positive and negative) synchronous rotating frame there be the pwm converter rotor-side of variable speed constant frequency birotor permanent magnetic generator

Four amounts can be controlled, so decapacitation carries out to the double-rotor machine output stator is on average meritorious, idle that independent decoupling zero control is outer can also to realize following target respectively:

1. constant stator active power of output is namely eliminated two frequency multiplication mains frequency components of stator active power.

2. the balancing rotor electric current makes rotor current not contain negative sequence component.

3. the balance stator current makes the equilibrium of threephase stator winding generate heat.

4. constant electromagnetic torque is to alleviate the mechanical burden of wind power system axle system.

Same grid side converter also has under positive and negative synchronous rotating frame

Four amounts can be controlled, and under unbalanced source voltage, grid side converter can also be realized following control target respectively except the independent decoupling zero control that can realize DC bus-bar voltage, average reactive power:

1. constant birotor electricity generation system active power of output is namely eliminated two times in the total active power of whole wind electric system

Frequency component.

2. the total output current balance of whole wind electric system that comprises birotor generator stator and grid side converter.

3. constant DC bus-bar voltage, and alleviate DC link electric capacity burden and to the influence of rotor-side converter.

4. constant birotor electricity generation system is exported reactive power, namely eliminates two frequencys multiplication of the total reactive power of whole wind electric system

Component.

By the coordination control to grid side converter and rotor-side converter, can improve the overall operation performance of dual-rotor wind power generation system under the uneven electrical network.

Technical scheme: the control device of birotor permanent magnetic wind generator system comprises birotor permanent magnetic generator, rotor-side converter, dc capacitor, grid side converter, rotor-side controlling unit and net side controlling unit under a kind of Voltage unbalance of the present invention; Wherein, the rotor-side controlling unit comprises rotor-side control object module, stator magnetic linkage detection module, trapper 2 ω ₁Module, forward-order current control module, negative-sequence current control module, rotor-side positive sequence voltage control module, rotor-side negative sequence voltage control module, SVPWM signal generating module; Net side controlling unit comprises two coordinate software locks phase modules (DDSRF-PLL), trapper 2 ω ₁Module, net side control object module, forward-order current control module, negative-sequence current control module, net side positive sequence voltage control module, net side negative sequence voltage control module, SVPWM signal generating module.

This control method is based on the control system of being made up of birotor permanent magnetic generator, rotor-side converter, dc capacitor, grid side converter, rotor-side controlling unit and net side controlling unit: wherein, rotor-side convertor controls link adopts two coordinate software locks phase modules to obtain machine end stator voltage lock phase angle theta ₁, will lock phase angle theta ₁To machine end stator current I _SabcCarry out the Clark conversion, through just changeing synchronous coordinate Park conversion and counter-rotating synchronous coordinate Park conversion, the result after both conversion is through trapper 2 ω again ₁Module extractor end stator current forward rotates the DC component electric current synchronously

And reverse sync rotation DC component electric current

With machine end stator three-phase voltage U _SabcAnd machine end stator current I _SabcSampled value enters the stator magnetic linkage module and calculates, and the magnetic linkage result calculated is passed through forward and reverse sync coordinate PARK conversion equally, and the result with both enters trapper 2 ω at last ₁Module is extracted the magnetic linkage forward and is rotated the DC component magnetic linkage synchronously

And reverse sync rotation DC component magnetic linkage

Calculate rotor current instruction under the rotor current forward synchronously rotating reference frame according to rotor-side control target and rotor-side converter current command calculations module

With the rotor current instruction under the reverse sync rotational coordinates The phase angle theta that adopts two coordinate software locks phase modules to obtain ₁Deduct the inside lock θ that optical code disk obtains internal rotor _r, obtain rotor current conversion synchronous rotation transformation angle θ ₁-θ _r, to rotor current I _RabcCarry out forward and reverse sync rotational coordinates PARK conversion, the result after both conversion is through trapper 2 ω ₁Module is extracted the rotor current forward and is rotated the DC component electric current synchronously

And reverse sync rotation DC component electric current

With the rotor current positive sequence instruction current of rotor current under the forward synchronous rotating frame

With the actual forward rotor current

Enter the forward-order current modulation module, result calculated enters rotor-side positive sequence voltage modulation module again and obtains rotor voltage under the forward synchronously rotating reference frame

And it is carried out anti-PARK conversion; With the rotor current negative phase-sequence instruction current of rotor current under the reverse sync rotating coordinate system

With the reverse rotor current of reality

Enter the negative-sequence current modulation module, result calculated enters rotor-side negative sequence voltage modulation module and obtains rotor voltage under the reverse sync rotational coordinates

And it is carried out anti-PARK conversion; Result with the anti-PARK conversion of two rotor voltages sends into the SVPWM signaling module through adder at last, drives the action of rotor-side converter switches, produces required rotor current.

Described grid side converter controlling unit adopts two coordinate software locks phase modules phase-locked to machine end stator voltage, obtains phase angle theta ₁And angular velocity omega ₁, will lock phase angle theta ₁To current on line side I _GabcCarry out the Clark conversion, just changeing synchronous coordinate Park conversion and counter-rotating synchronous coordinate Park conversion again, the result after both conversion is through trapper 2 ω ₁Module extractor end stator forward rotates the DC component electric current synchronously

And reverse sync rotation DC component electric current

In like manner with machine end stator three-phase voltage U _SabcCarry out the Clark conversion, just changeing synchronous coordinate Park conversion and counter-rotating synchronous coordinate Park conversion again, the result after both conversion is through trapper 2 ω ₁Module extractor end stator forward rotates DC component voltage synchronously

And reverse sync rotation DC component voltage

With direct voltage U _DcInstruct with direct voltage

Carry out PI and regulate, enter grid side converter current-order computing module with net side control target, ask for the current on line side that is rotated in the forward under the coordinate With the current on line side under the reverse rotation coordinate

With the instruction of current on line side under the forward synchronous rotating frame

With current on line side under the actual forward synchronously rotating reference frame

Enter the forward-order current modulation module, result calculated enters net side positive sequence voltage modulation module again and obtains grid side converter voltage under the forward synchronously rotating reference frame And it is carried out anti-PARK conversion; With the instruction of current on line side under the reverse sync rotating coordinate system With current on line side under the actual reverse sync rotating coordinate system Enter the negative-sequence current modulation module, result calculated enters net side negative sequence voltage modulation module again and obtains grid side converter voltage under the reverse sync rotational coordinates

And it is carried out anti-PARK conversion; At last the voltage of the anti-PARK conversion of two grid side converters is sent into the SVPWM signaling module through adder, drive the grid side converter switch motion, produce required current on line side.

Beneficial effect: the invention has the advantages that: under the unbalanced source voltage situation, dual-rotor wind power generation machine pwm converter (rotor-side and grid side converter) is carried out forward and reverse synchronous coordinate conversion, can carry out independent control to positive sequence, negative sequence component, according to controlling target, rotor-side converter and grid side converter are carried out Collaborative Control, will eliminate imbalance of three-phase voltage and cause influences such as the stator and rotor heating in winding is inhomogeneous and unit meritorious, idle frequency multiplication fluctuation; Also can eliminate dc-link capacitance frequency multiplication wave component according to the control target simultaneously, reduce under the Voltage unbalance it is caused burden.

The present invention can improve the overall operation ability of double-rotor pneumatic electric system under the unbalanced electric grid voltage by taking all factors into consideration the coordination control ability of grid side converter and rotor-side converter.

Description of drawings

Fig. 1 is the variable speed constant frequency dual-rotor wind power generation control method theory diagram of Voltage unbalance;

Fig. 2 is the variable speed constant frequency dual-rotor wind power generation system diagram that comprises the rotor-exciting converter;

Fig. 3 is the variable speed constant frequency dual-rotor wind power generation control method structure chart of Voltage unbalance;

Fig. 4 is two coordinate software locks phase module (DDSRF-PLL) theory diagrams.

Embodiment

Variable speed constant frequency birotor permanent magnetic wind generator system control method under the Voltage unbalance mainly comprises the control of grid side converter and the control of rotor-side converter, and wherein grid side converter control step is as follows:

1, birotor pwm converter rotor-side is installed current Hall transducer (I at the rotor winding terminal _Rabc), at the generator unit stator output voltage hall sensor (U is installed _Sabc) and stator current Hall element (I _Sabc), in pwm converter net side current on line side Hall element (I is installed _Gabc).

2, for grid side converter, at first with set end voltage (U _Sabc) send into two coordinate software locks phase modules (DDSRF-PLL), obtain the phase angle theta of set end voltage positive sequence component ₁And angular velocity omega ₁, again with current on line side (I _Gabc) and set end voltage (U _Sabc) carry out Clark respectively and be transformed into two-phase static coordinate I _{G α β}And U _{G α β}, just changeing the synchronously rotating reference frame conversion

With the conversion of counter-rotating synchronously rotating reference frame Positive sequence component shows DC component, negative sequence component and then shows as DC component in reversing with the leg speed rotational coordinates in just changeing with the leg speed rotational coordinates, and positive sequence component performance in counter-rotating is just being changeed with the leg speed rotational coordinates with leg speed rotational coordinates and negative sequence component is the of ac of two frequency multiplication mains frequencies.So the result of rotating synchronously rotating reference frame conversion is passed through trapper 2 ω ₁Namely can be with two frequency multiplication component rejections wherein, to obtain corresponding positive and negative order DC component

Wherein the continuous domain expression formula of second order trapper is:

$F_{\mathrm{notch}}\left(s\right)=\frac{s^2{\mathrm{\ω}}_0^2}{s^2+{2\mathrm{\ξ\ω}}_{0}s+{\mathrm{\ω}}_0^2}---\left(1\right)$

In the formula, ω ₀=2 ω ₁=200 π rad/s are cut-off frequency; ξ is attenuation coefficient.The stability of considering filter effect and control system in the actual engineering is generally got ξ=0.707;

3, DC bus-bar voltage reference value and actual DC busbar voltage are sent into subtracter, and through pi regulator, send into grid side converter current-order computing module in the lump with net side control target, calculate net side positive sequence reference current

And net side reference current instruction

4, will calculate the instruction of net side positive sequence reference current

With actual net side forward-order current

After the forward-order current control module, enter net side positive sequence voltage control module again, simultaneously net side negative phase-sequence reference current is instructed

With actual net side negative-sequence current

Behind negative-sequence current control molding piece, enter net side negative sequence voltage control module again.The result of both positive and negative sequence voltage control modules is carried out anti-PARK conversion respectively

Send into the SVPWM signaling module after becoming α, β rest frame amount, make it drive the switch motion of net side pwm converter, produce required current on line side, finish the control target.

As follows for rotor-side convertor controls step:

1, earlier with set end voltage (U _Sabc) machine end stator current (I _Sabc) send into the stator magnetic linkage detection module after the sampling, utilize two phase-locked modules of synchronous coordinate decoupling zero software to obtain the phase angle theta of set end voltage ₁Again stator magnetic linkage is carried out positive and negative synchronously rotating reference frame conversion, the structure after the conversion is sent into trapper 2 ω in the lump ₁Namely can be with two frequency multiplication component rejections wherein, thus the corresponding positive and negative order DC component of magnetic linkage obtained

2, to stator current I _Sabc, rotor current I _RabcAnd set end voltage U _SabcThe processing procedure of similar stator magnetic linkage is asked its positive and negative order DC component respectively respectively

With

3, send into rotor-side converter current reference calculation module in the lump according to coordinating the proper negative sequence voltage of control rotor-side control target and machine, calculate the instruction of rotor positive-negative sequence current

4, the positive sequence reference current is instructed

With actual rotor side forward-order current

After the forward-order current control module, enter rotor-side positive sequence voltage control module again, simultaneously rotor-side negative phase-sequence reference current is instructed

With actual rotor side negative-sequence current

After the negative-sequence current control module, enter rotor-side negative sequence voltage control module again.The result of both positive and negative sequence voltage control modules is carried out anti-PARK conversion respectively

Send into the SVPWM signaling module after becoming α, β rest frame amount, make it drive the switch motion of rotor-side pwm converter, produce required rotor-side electric current, to finish the control target.

Specific as follows:

The control method of variable speed constant frequency birotor permanent magnetic wind-driven generator under the Voltage unbalance described in the invention comprises controlling unit and the grid side converter controlling unit of rotor-side converter.Wherein, rotor-side convertor controls link is to machine end electric current I _SabcCarry out the Clark conversion, through just changeing synchronous coordinate Park conversion and counter-rotating synchronous coordinate Park conversion, the result after both conversion is through trapper 2 ω again ₁The module extractor is rectified to synchronous rotation DC component electric current And reverse sync rotation DC component electric current

In like manner with machine end stator voltage U _SabcAlso obtain forward according to the same flow processing of machine end stator current and rotate DC component voltage synchronously

With reverse sync rotation DC component voltage

Enter rotor-side converter current computing module according to the control target of rotor-side and calculate current-order under the rotor current forward synchronously rotating reference frame

And the current-order under the reverse sync rotational coordinates

Simultaneously with machine end three-phase voltage U _SabcAnd machine end three-phase current I _SabcSampled value enters the stator magnetic linkage module and calculates, and the magnetic linkage result calculated is passed through the PARK conversion of forward synchronous coordinate and reverse sync coordinate PARK conversion equally, and the result with both enters trapper 2 ω at last ₁Module is extracted the magnetic linkage forward and is rotated the DC component magnetic linkage synchronously

And reverse sync rotation DC component magnetic linkage

The phase angle theta that two coordinate software locks phase modules (DDSRF-PLL) are obtained ₁Deduct optical code disk internal rotor is obtained inside lock θ _r, obtain rotor current conversion synchronous rotation transformation angle (θ ₁-θ _r), to rotor current I _RabcCarry out the PARK conversion of forward synchronously rotating reference frame and reverse sync rotational coordinates PARK conversion, the result after both conversion is through trapper 2 ω ₁Module is extracted the rotor current forward and is rotated the DC component electric current synchronously

And reverse sync rotation DC component electric current With the instruction current of rotor current under the forward synchronous rotating frame

With the actual forward rotor current

Enter the forward-order current modulation module, result calculated enters rotor-side positive sequence voltage modulation module again and obtains rotor voltage under the forward synchronously rotating reference frame

And it is carried out anti-PARK conversion.Simultaneously with the instruction current of rotor current under the reverse sync rotating coordinate system

With the reverse rotor current of reality Enter the negative-sequence current modulation module, result calculated enters rotor-side negative sequence voltage modulation module and obtains rotor voltage under the reverse sync rotational coordinates

And it is carried out anti-PARK conversion.Result with the anti-PARK conversion of two rotor voltages sends into the SVPWM signal generating module through adder at last, drives the action of rotor-side converter switches, produces required rotor current.

Net side pwm converter controlling unit is to current on line side I _GabcCarry out the Clark conversion, rotate and reverse synchronous coordinate Park again, the result after both conversion is through trapper 2 ω ₁The module extractor is rectified to synchronous rotation DC component electric current

And reverse sync rotation DC component electric current

In like manner with machine end stator three-phase voltage U _SabcCarry out the Clark conversion, rotate and reverse synchronous coordinate Park conversion again, the result after both conversion is through trapper 2 ω ₁The module extractor is rectified to synchronous rotation DC component voltage

And reverse sync rotation DC component voltage

Control target with direct voltage U according to the net side _DcInstruct with direct voltage

Carry out PI and regulate, enter grid side converter current reference computing module in the lump with net side control target again, calculate the current on line side that is rotated in the forward under the coordinate system

With the current on line side under the reverse rotation coordinate system

Then with current on line side I _GabcInstruction under the forward synchronous rotating frame

With current on line side under the actual forward synchronously rotating reference frame

Enter the forward-order current modulation module, result calculated enters net side positive sequence voltage modulation module again and obtains grid side converter voltage under the forward synchronously rotating reference frame

And it is carried out anti-PARK conversion.Same with the instruction of current on line side under the reverse sync rotating coordinate system

With current on line side under the actual reverse sync rotating coordinate system

Enter the negative-sequence current modulation module, result calculated enters the negative sequence voltage modulation module again and obtains grid side converter voltage under the reverse sync rotational coordinates And it is carried out anti-PARK conversion.At last the voltage of the anti-PARK conversion of two grid side converters is sent into the SVPWM signal generating module through adder, drive the grid side converter switch motion, produce required current on line side.

The control method of birotor permanent magnetic wind generator system is under the Voltage unbalance: the rotor-side converter is to rotor current I _Rabc, stator current I _Sabc, set end voltage U _SabcCarry out forward and reverse synchronously rotating reference frame conversion, extract the forward rotor current

The forward stator current

The forward stator voltage

With reverse rotor current

Reverse stator current Reverse stator voltage

Simultaneously machine end stator current and machine end stator voltage are sent into the stator magnetic linkage detection module and calculated magnetic linkage under the rotating synchronous rotating frame

With

Enter rotor-side converter current computing module according to the control target and calculate current-order under the rotor forward synchronously rotating reference frame

And current-order under the reverse sync rotational coordinates Rotating sub-instructions electric current is sent into subtracter with actual rotating electron current respectively, result after its work difference is entered reversal adjustment module and rotor-side generating positive and negative voltage modulation module respectively, result with positive-negative sequence voltage modulated module carries out anti-PARK conversion respectively again, result after the anti-PARK conversion sends into SVPWM signal modulation module through adder, drives the action of birotor generator rotor-side converter switches.The birotor generator grid side converter is to current on line side I _Gabc, set end voltage U _SabcCarry out forward and reverse synchronously rotating reference frame conversion, extract the forward current on line side

The forward stator voltage With reverse current on line side

Reverse stator voltage The virtual voltage of DC link and the reference voltage of setting are relatively entered the PI governing loop, send into grid side converter current-order computing module in the lump with net side control target instruction target word again, calculate the current on line side instruction that rotates and reverse under the synchronous coordinate system The current on line side instruction is sent into subtracter respectively with actual rotating current on line side, subtracter is made difference back result and is entered positive-negative sequence current modulation module and net side positive-negative sequence voltage modulated module more respectively, obtains the voltage instruction under the positive and negative synchronously rotating reference frame of grid side converter.Result to net side positive-negative sequence voltage modulated module implements anti-PARK conversion respectively, and the result of the anti-PARK conversion under its positive and negative synchronous rotating frame sent into the SVPWM signal generating module after adder, drive the switch motion of birotor generator grid side converter, produce required current on line side.

Accompanying drawing discloses the concrete structure of the embodiment of the invention without limitation, and the invention will be further described below in conjunction with accompanying drawing.

As seen from Figure 1, under the unbalanced source voltage, birotor permanent magnetic generator amature pwm converter control system comprises the positive negative control of rotor-side converter and the positive negative control of grid side converter.Wherein, the control of rotor-side converter comprises meritorious idle control, rotor-side converter current command calculations module, stator magnetic linkage detection module, trapper 2 ω according to coordinating the control target ₁Module, positive-negative sequence current control module, rotor-side positive-negative sequence voltage control module and SVPWM modulation signal produce link and constitute, and can drive the rotor-side converter by DSP microprocessor and related peripheral circuit output SVPWM modulation signal thereof; The control of grid side converter is similar to rotor-side, mainly comprises direct voltage control module, positive-negative sequence current control module, and net side positive-negative sequence voltage control module produces the SVPWM modulation signal with the DSP signal processor equally and drives the grid side converter switch motion.According to the coordination control of rotor-side converter and grid side converter, thereby can strengthen the overall operation ability of variable speed constant frequency birotor permanent magnetic wind-driven generator under unbalanced source voltage.

As seen from Figure 2, the variable speed constant frequency dual-rotor wind power generation system that comprises the rotor-exciting converter forms, its connected mode is that the rotor-side converter is connected with the internal rotor winding of birotor permanent magnetic generator, grid side converter is connected with electrical network, and rotor-side converter and grid side converter carry out decoupling zero by electric capacity.

As seen from Figure 3, variable speed constant frequency birotor permanent magnetic wind power generation control method comprises under the unbalanced source voltage: the control system of rotor-side converter and grid side converter.Wherein, the rotor-side convertor controls comprises meritorious idle control module, stator magnetic linkage detection module, trapper 2 ω ₁Module, forward-order current control module, negative-sequence current control module, rotor-side positive sequence voltage control module, rotor-side negative sequence voltage control module, SVPWM signaling module.Grid side converter control comprises direct voltage control module, trapper 2 ω ₁Module, forward-order current control module, negative-sequence current control module, net side positive sequence voltage control module, net side negative sequence voltage control module, SVPWM signaling module.

As seen from Figure 4, under unbalanced source voltage, need carry out the PARK conversion to stator voltage, stator current, rotor current etc., so need line voltage is carried out accurately phase-locked.Under unbalanced source voltage, use two coordinate software locks phase modules (DDSRF-PLL) phase-locked to machine end stator voltage, it mainly comprises positive sequence voltage decoupling zero conversion module, negative sequence voltage decoupling zero conversion module, single synchronous coordinate conversion software locks phase module (SSRF-PLL), set end voltage is carried out extracting after the positive-negative sequence decoupling zero conversion re-using that phase-locked angle that single synchronous coordinate software locks phase module extracts machine end stator positive sequence voltage under the unbalanced source voltage offers rotor-side and net side control system is used behind the positive sequence voltage.

The detailed principle of DDSRF-PLL is as follows: it comprises two rotating coordinate systems: the synchronous dq of forward ^{+ n}Coordinate system and reverse sync dq ^-mCoordinate system, respectively with ω and-rotation of the angular speed of ω.Under the unbalance voltage situation, there is negative sequence component U in set end voltage U ^-mWith positive sequence component U ^{+ n}, in rest frame α β, can be expressed as:

$U_{\left(\mathrm{\α\β}\right)}=\left[\begin{array}{c}{U}_{\left(\mathrm{\α}\right)}\\ U_{\left(\mathrm{\β}\right)}\end{array}\right]=U_{\left(\mathrm{\α\β}\right)}^{+n}+U_{\left(\mathrm{\α\β}\right)}^{-m}=U^{+n}\left[\begin{array}{c}\cos \left(\mathrm{\ωt}\right)\\ \sin \left(\mathrm{\ωt}\right)\end{array}\right]+U^{-m}\left[\begin{array}{c}\cos (-\mathrm{\ωt})\\ \sin (-\mathrm{\ωt})\end{array}\right]---\left(2\right)$

Wherein by the synchronous dq coordinate system of forward $\left[T_{\mathrm{dq}}^{+n}\right]=\left[\begin{array}{cc}\cos {\mathrm{\θ}}^{\′}& \sin {\mathrm{\θ}}^{\′}\\ -\sin {\mathrm{\θ}}^{\′}& \cos {\mathrm{\θ}}^{\′}\end{array}\right]$ After the conversion, can get dq ^{+ n}Positive sequence voltage vector in the coordinate system

$U_{\mathrm{dq}}^{+n}=\left[\begin{array}{c}{U}_d^{+n}\\ U_q^{+n}\end{array}\right]=\left[T_{\mathrm{dq}}^{+n}\right]\left[\begin{array}{c}{U}_{\mathrm{\α}}\\ U_{\mathrm{\β}}\end{array}\right]=\left[\begin{array}{cc}\cos {\mathrm{\θ}}^{\′}& \sin {\mathrm{\θ}}^{\′}\\ -\sin {\mathrm{\θ}}^{\′}& \cos {\mathrm{\θ}}^{\′}\end{array}\right]\left[\begin{array}{c}\cos \left(\mathrm{\ωt}\right)\\ \sin \left(\mathrm{\ωt}\right)\end{array}\right]U^{+n}+\left[\begin{array}{cc}\cos {\mathrm{\θ}}^{\′}& \sin \mathrm{\θ}\′\\ -\sin {\mathrm{\θ}}^{\′}& \cos {\mathrm{\θ}}^{\′}\end{array}\right]\left[\begin{array}{c}\cos \left(\mathrm{\ωt}\right)\\ -\sin \left(\mathrm{\ωt}\right)\end{array}\right]U^{-m}$

$=\left[\begin{array}{c}\cos (\mathrm{\ωt}-{\mathrm{\θ}}^{\′})\\ \sin (\mathrm{\ωt}-{\mathrm{\θ}}^{\′})\end{array}\right]U^{+n}+\left[\begin{array}{c}\cos (-\mathrm{\ωt}-{\mathrm{\θ}}^{\′})\\ \sin (-\mathrm{\ωt}-{\mathrm{\θ}}^{\′})\end{array}\right]U^{-m}$ (3)

When ω t ≈ θ ', exist

By reverse sync dq coordinate system $\left[T_{\mathrm{dq}}^{-m}\right]=\left[\begin{array}{cc}\cos {\mathrm{\θ}}^{\′}& -\sin {\mathrm{\θ}}^{\′}\\ \sin {\mathrm{\θ}}^{\′}& \cos {\mathrm{\θ}}^{\′}\end{array}\right]$ After the conversion, can get dq ^-mNegative sequence voltage vector in the coordinate system

$U_{\mathrm{dq}}^{-m}=\left[\begin{array}{c}{U}_d^{-m}\\ U_q^{-m}\end{array}\right]=\left[T_{\mathrm{dq}}^{-m}\right]\left[\begin{array}{c}{U}_{\mathrm{\α}}\\ U_{\mathrm{\β}}\end{array}\right]=\left[\begin{array}{cc}\cos {\mathrm{\θ}}^{\′}& -\sin {\mathrm{\θ}}^{\′}\\ \sin {\mathrm{\θ}}^{\′}& \cos {\mathrm{\θ}}^{\′}\end{array}\right]\left[\begin{array}{c}\cos \left(\mathrm{\ωt}\right)\\ \sin \left(\mathrm{\ωt}\right)\end{array}\right]U^{+n}+\left[\begin{array}{cc}\cos {\mathrm{\θ}}^{\′}& -\sin {\mathrm{\θ}}^{\′}\\ \sin {\mathrm{\θ}}^{\′}& \cos {\mathrm{\θ}}^{\′}\end{array}\right]\left[\begin{array}{c}\cos \left(\mathrm{\ωt}\right)\\ -\sin \left(\mathrm{\ωt}\right)\end{array}\right]U^{-m}$

$=\left[\begin{array}{c}\cos (\mathrm{\ωt}+{\mathrm{\θ}}^{\′})\\ \sin (\mathrm{\ωt}+{\mathrm{\θ}}^{\′})\end{array}\right]U^{+n}+\left[\begin{array}{c}\cos (\mathrm{\ωt}-{\mathrm{\θ}}^{\′})\\ \sin (\mathrm{\ωt}-{\mathrm{\θ}}^{\′})\end{array}\right]U^{-m}$ (5)

When ω t ≈ θ ', exist

From formula (4) and formula (6) as can be seen, there are cross-linked two times of frequency components in positive-negative sequence dq component, in order to eliminate two times of frequency components, can carry out decoupling zero to it, decoupling principle is as follows: the DC component intersection of forward and reverse dq conversion module output is fed back to anyway to the dq conversion module, and carry out overlap-add procedure with input signal.Consider that there is the precision of harmonic effects genlock in line voltage, introduce low pass high resistant filtering LPF link

$\mathrm{LPF}\left(s\right)=\frac{{\mathrm{\ω}}_f}{s+{\mathrm{\ω}}_f}---\left(7\right)$

Wherein, ω _fBe low pass filter cutoff frequency.

Output signal to two-way dq conversion is carried out filtering, obtains positive-negative sequence dq component.Forward q axle component is adopted the phase-locked principle of PLL of similar single dq conversion to be implemented under line voltage symmetry, the asymmetric and voltage distortion situation positive sequence voltage phase place to be carried out accurately phase-locked.

Claims (2)

1. the control method of birotor permanent magnetic wind generator system under the Voltage unbalance, it is characterized in that this control method is based on the control system of being made up of birotor permanent magnetic generator, rotor-side converter, dc capacitor, grid side converter, rotor-side controlling unit and net side controlling unit: wherein, rotor-side convertor controls link adopts two coordinate software locks phase modules to obtain machine end stator voltage lock phase angle theta ₁, will lock phase angle theta ₁To machine end stator current I _SabcCarry out the Clark conversion, through just changeing synchronous coordinate Park conversion and counter-rotating synchronous coordinate Park conversion, the result after both conversion is through trapper 2 ω again ₁Module extractor end stator current forward rotates the DC component electric current synchronously

And reverse sync rotation DC component electric current

With machine end stator three-phase voltage U _SabcAnd machine end stator current I _SabcSampled value enters the stator magnetic linkage module and calculates, and the magnetic linkage result calculated is passed through forward and reverse sync coordinate PARK conversion equally, and the result with both enters trapper 2 ω at last ₁Module is extracted the magnetic linkage forward and is rotated the DC component magnetic linkage synchronously And reverse sync rotation DC component magnetic linkage

Calculate rotor current instruction under the rotor current forward synchronously rotating reference frame according to rotor-side control target and rotor-side converter current command calculations module

With the rotor current instruction under the reverse sync rotational coordinates

The phase angle theta that adopts two coordinate software locks phase modules to obtain ₁Deduct the inside lock θ that optical code disk obtains internal rotor _r, obtain rotor current conversion synchronous rotation transformation angle θ ₁-θ _r, to rotor current I _RabcCarry out forward and reverse sync rotational coordinates PARK conversion, the result after both conversion is through trapper 2 ω ₁Module is extracted the rotor current forward and is rotated the DC component electric current synchronously

And reverse sync rotation DC component electric current

With the rotor current positive sequence instruction current of rotor current under the forward synchronous rotating frame

With the actual forward rotor current

Enter the forward-order current modulation module, result calculated enters rotor-side positive sequence voltage modulation module again and obtains rotor voltage under the forward synchronously rotating reference frame

And it is carried out anti-PARK conversion; With the rotor current negative phase-sequence instruction current of rotor current under the reverse sync rotating coordinate system

With the reverse rotor current of reality

Enter the negative-sequence current modulation module, result calculated enters rotor-side negative sequence voltage modulation module and obtains rotor voltage under the reverse sync rotational coordinates

And it is carried out anti-PARK conversion; Result with the anti-PARK conversion of two rotor voltages sends into the SVPWM signaling module through adder at last, drives the action of rotor-side converter switches, produces required rotor current.

2. the control method of variable speed constant frequency birotor permanent magnetic wind generator system under the Voltage unbalance according to claim 1 is characterized in that described grid side converter controlling unit adopts two coordinate software locks phase modules phase-locked to machine end stator voltage, obtains phase angle theta ₁And angular velocity omega ₁, will lock phase angle theta ₁To current on line side I _GabcCarry out the Clark conversion, just changeing synchronous coordinate Park conversion and counter-rotating synchronous coordinate Park conversion again, the result after both conversion is through trapper 2 ω ₁Module extractor end stator forward rotates the DC component electric current synchronously And reverse sync rotation DC component electric current

In like manner with machine end stator three-phase voltage U _SabcCarry out the Clark conversion, just changeing synchronous coordinate Park conversion and counter-rotating synchronous coordinate Park conversion again, the result after both conversion is through trapper 2 ω ₁Module extractor end stator forward rotates DC component voltage synchronously And reverse sync rotation DC component voltage

With direct voltage U _DcInstruct with direct voltage

Carry out PI and regulate, enter grid side converter current-order computing module with net side control target, ask for the current on line side that is rotated in the forward under the coordinate

With the current on line side under the reverse rotation coordinate

With the instruction of current on line side under the forward synchronous rotating frame

With current on line side under the actual forward synchronously rotating reference frame

Enter the forward-order current modulation module, result calculated enters net side positive sequence voltage modulation module again and obtains grid side converter voltage under the forward synchronously rotating reference frame

And it is carried out anti-PARK conversion; With the instruction of current on line side under the reverse sync rotating coordinate system

With current on line side under the actual reverse sync rotating coordinate system

Enter the negative-sequence current modulation module, result calculated enters net side negative sequence voltage modulation module again and obtains grid side converter voltage under the reverse sync rotational coordinates And it is carried out anti-PARK conversion; At last the voltage of the anti-PARK conversion of two grid side converters is sent into the SVPWM signaling module through adder, drive the grid side converter switch motion, produce required current on line side.

Images