CN103840480B - A kind of six cross streams motor harmonic current control strategies - Google Patents

Abstract

A kind of six cross streams motor harmonic current control strategies on conventional three phase alternating current motor control method basis, increase negative phase-sequence detect and closed loop control method with positive sequence 7 subharmonic current for 5 times.The phase-locked loop of the first stator not only exports magnetic linkage angle and the frequency of the first stator, also add negative phase-sequence 6 angles and positive sequence 6 angles output, and poor according to the designed phase of two stators, export the magnetic linkage angle of the second stator, the second stator negative phase-sequence 6 times and positive sequence 6 angles; Again according to the feature of two stator currents on synchronous rotating frame, decomposite negative phase-sequence 5 times and the positive sequence 7 subharmonic current component of stator current, then closed-loop control is carried out to negative phase-sequence 5 times and positive sequence 7 primary current, control result after coordinate transform, be added to the first-harmonic control voltage that fundamental current control exports on synchronous rotating frame, again through synchronously rotating reference frame inverse transformation and PWM module output pulse width ripple, control the current transformer power unit of corresponding power electronic device composition.

Description

A kind of six cross streams motor harmonic current control strategies

Technical field

The present invention relates to a kind of harmonic current control method of six cross streams motors.

Background technology

In recent years, day by day serious along with energy shortage and ecological deterioration problem, the utilization of regenerative resource especially wind energy more and more comes into one's own.In numerous wind power generation schemes, double-fed unit and total power unit are two kinds of common types.Total power Wind turbines adopts permanent magnetism or electric excitation synchronous alternator as electrical energy conversion device, flexibly connected by full power convertor between generator and electrical network, there is good grid adaptability, and the range of speeds is wider, be conducive to the wind energy utilizing little wind speed, be more and more subject to the favor of domestic and international blower fan manufacturer.

Wind turbines single-machine capacity is increasing, but the output voltage of current transformer and electric current are by the restriction of power electronic device manufacture level, can only adopt device series-parallel system, have high voltage and big current two developing direction.In early days in 1.5MW and following Wind turbines, widely use electric topology as shown in Figure 1, active power is outputted to DC bus after exporting the pusher side current transformer via diode uncontrollable rectifier+Boost circuit composition by generator, and the net side converter that DC bus energy forms through pwm converter is transported to electrical network.Six cross streams motors, compared with three phase alternating current motor, can suppress 6m ± 1 primary current harmonic wave to enter main flux, and DC voltage ripple can be brought up to 12 times from 6 times, are widely used in the converter diodes of pusher side shown in Fig. 1 uncontrollable rectifier occasion.

The development of blower fan technology, control to propose more and more higher demand to current transformer, pusher side current transformer gradually adopts based on the diode uncontrollable rectifier+boost circuit mode shown in the PWM convertor circuit alternate figures 1 of IGBT.Consider the continuity of its technical and property easy to maintenance, generator quite a few still adopt six cross streams motor modes.Like this, corresponding six cross streams motors, in electric topology shown in Fig. 2, pusher side current transformer comprises the six phase power cells be made up of power electronic device (being generally IGBT), adopt vector control strategy to generator torque and idlely carry out uneoupled control, wherein A1, B1, C1 are stator 1 three-phase, and A2, B2, C2 are stator 2 three-phase, advanced stator 2 electrical degree π/6 of stator 1.

For six cross streams motors, suppose that six phase winding inductance are identical, analyze the magnetic circuit of each harmonic circulation for A phase magnetic linkage.If A phase magnetic linkage is interlinked leakage is L _σ, alternate magnetic linkage is L _a, six phase current i _a1, i _b1, i _c1, i _a2, i _b2, i _c2amplitude is equal.Then A phase magnetic linkage expression formula is:

Bring six phase current expression formulas into flux linkage equations when n=6m ± 1(m be 1,2 ... positive integer) time, A phase magnetic linkage expression formula mutual inductance part is cancelled out each other, only relevant with A phase leakage inductance.This illustrates that 6m ± 1 time magnetic linkage does not enter main magnetic circuit, only relevant with this phase current and leakage inductance.

Because six cross streams motor 6m ± 1 primary current harmonic waves do not enter main magnetic circuit, impedance loop is only stator leakage inductance, and impedance is relatively very little.For PWM convertor circuit, comprising all 2n+1(n is 1,2 ... positive integer) secondary voltage harmonic, harmonic number more low amplitude value is larger.When six cross streams motor 6m ± 1 subharmonic and PWM converter 2n+1 subharmonic overlap, because line impedance is little, little voltage harmonic will produce certain harmonic current, especially the impact that 5,7 subharmonic cause can not be ignored, if do not controlled these current harmonicss, the performance of current transformer and generator can be had a strong impact on.After harmonic number uprises 11,13 times, harmonic voltage diminishes, and line impedance becomes large with frequency, and impact can be ignored substantially.

Control strategy conventional at present six cross streams motors is considered as one, adopts complicated transformation matrix, six phase currents are transformed to dq, z ₁z ₂, o ₁o ₂plane controls respectively to electric current.Be difficult to six phases (differing from 30 degree also known as stator double winding) alternating current machine and double winding three-phase (stator double winding is without difference) AC Motor Control program to realize compatible like this, increase current transformer software development and maintenance workload.

Summary of the invention

The object of the invention is the shortcoming overcoming prior art, a kind of harmonic current control strategy being applied to six cross streams motors is provided.The present invention, on the basis of three phase alternating current motor conventional vector control strategy, adds 5 times, 7 subharmonic currents separation and Closed-loop Control Strategies.When PWM converter drags six cross streams motors, adopt the present invention can control effectively to harmonic current, the design of current transformer hardware filter can be simplified, reduce generator loss, improve generator and current transformer performance.Simultaneously by simple configuration the first stator with the second stator phase is poor, 5 times, 7 subharmonic current pi regulator parameters, a set of program can be made to possess the matching capacity of six cross streams motors and double winding three phase alternating current motor.

The present invention is based on following principle:

In six cross streams current of electric equations:

In formula: I _aBC1, I _aBC2be respectively the three-phase current of the first stator and the second stator.

Adopt the synchronous rotating angle matrix that vector control is conventional:

$C_{32}=\sqrt{\frac{2}{3}}\left[\begin{array}{ccc}\cos \left(\mathrm{\ωt}\right)& \cos (\mathrm{\ωt}-\frac{2}{3}\mathrm{\π})& \cos (\mathrm{\ωt}+\frac{2}{3}\mathrm{\π})\\ -\sin \left(\mathrm{\ωt}\right)& -\sin (\mathrm{\ωt}-\frac{2}{3}\mathrm{\π})& -\sin (\mathrm{\ωt}+\frac{2}{3}\mathrm{\π})\end{array}\right]$

Respectively by the first stator current I _aBC1with the second stator current I _aBC2transform to dq two-phase synchronous rotating frame from ABC three-phase static coordinate system, following rule can be found:

(1), when n=1(first-harmonic) time, I _dq1=I _dq2, namely the first stator is equal with the second stator current;

(2) when n=6m ± 1, I _dq1+ I _dq2=0, namely the first stator is equal with the second stator current amplitude, and symbol is contrary; Utilize this rule, can be isolated 6m ± 1 subharmonic current of six cross streams motors by simple algebraic operation, namely for the first stator, 6m ± 1 harmonic current is there is harmonic current, the basis that just can control at conventional three phase alternating current motor has been added auxiliary harmonic current control strategy, realize the object of control six cross streams motor.

The technical scheme that the harmonic current control strategy that the present invention is applied to six cross streams motors adopts is:

The present invention adds 5 times, 7 subharmonic current control strategies on original three phase alternating current motor conventional control policy grounds.

Three phase alternating current motor conventional control strategy is: gather stator three-phase voltage and obtain magnetic linkage angle and frequency through phase-locked loop, gather threephase stator electric current after synchronous rotating angle, obtain excitation current component and torque current component, adopt pi regulator to control excitation current component and torque current component respectively; Control result output pulse width ripple after synchronously rotating reference frame inverse transformation and PWM module modulation, control the current transformer power unit of power electronic device composition.

On the basis of three-phase ac synchronous motor conventional control strategy, the present invention is applied in the harmonic current control strategy of six cross streams motors, the phase-locked loop of the first stator not only exports magnetic linkage angle and the frequency of the first stator, increase negative phase-sequence 6 angles and positive sequence 6 angles output, and poor according to the designed phase of two stators, export the magnetic linkage angle of the second stator, the second stator negative phase-sequence 6 times and positive sequence 6 angles; Again according to the feature of two stator currents on synchronous rotating frame, decomposite negative phase-sequence 5 times and the positive sequence 7 subharmonic current component of stator current, then closed-loop control is carried out to negative phase-sequence 5 times and positive sequence 7 primary current, control result and to be added to after coordinate transform the first-harmonic control voltage that fundamental current control exports on synchronous rotating frame.

In the present invention, 5 times, 7 subharmonic current decomposition strategies adopt two stator current excitation components on synchronous rotating frame and torque component are done subtraction respectively, obtain and 5 times, positive-negative sequence 6 primary current component that 7 subharmonic currents are relevant, then 6 primary current components are transformed to negative phase-sequence 5 times respectively by coordinate transform and on positive sequence 7 coordinate systems.Fasten at negative phase-sequence 5 rotational coordinatess, negative phase-sequence 5 subharmonic current is DC component, and positive sequence 7 subharmonic current is 12 order harmonic components, adopts low pass filter (LPF) filtering 12 subharmonic to obtain negative phase-sequence 5 subharmonic current component; To leach method identical with negative phase-sequence 5 primary current, fastens obtain positive sequence 7 subharmonic current component at positive sequence 7 rotational coordinatess.

In the present invention, negative phase-sequence 5 times and positive sequence 7 subharmonic current carry out pi regulator control on respective rotating coordinate system, result of calculation changes to synchronous rotating frame coordinate system through coordinate contravariant, with first-harmonic export superpose after modulate through synchronously rotating reference frame inverse transformation and PWM module again, output pulse width ripple control power electronic device composition current transformer power unit.

In the present invention, after the first stator fundamental current and the second stator fundamental current do addition, adopt a set of pi regulator to carry out closed-loop control, under 50% power, only start 1 cover winding also can follow the tracks of master control very well and gain merit given; By two stator phase differences are set to 0, by 5 times, 7 subharmonic pi regulator optimum configurations are 0, algorithm automatically switches to stator double winding three phase alternating current motor and controls, and realizes the switching of two kinds of motor control strategy, reduces software version and maintenance workload.

In the present invention to the concrete steps of six cross streams current of electric control methods be:

(1) six-phase motor stator is divided into the first stator and the second stator, advanced second stator electrical degree π/6 of the first stator, gather the first stator three-phase voltage, obtain the magnetic linkage angle θ of the first stator through phase-locked loop _s1, negative phase-sequence 6 angle θ _-6s1with positive sequence 6 angle θ _{+ 6s1}, and according to phase difference π/6 of the second stator and the first stator, obtain the magnetic linkage angle θ of the second stator _s2, negative phase-sequence 6 angle θ _-6s2with positive sequence 6 angle θ _{+ 6s2}.Gather the electric current of the first stator and the second stator, utilize the magnetic linkage angle θ of the first stator _s1, the second stator magnetic connect angle θ _s2by current transformation on respective synchronous rotating frame, fundamental current is equal, negative phase-sequence 5 times and positive sequence 7 subharmonic current become negative phase-sequence 6 times and positive sequence 6 subharmonic current, and the first stator is contrary with the second stator positive-negative sequence 6 subharmonic current amplitude equal symbol, the electric current correspondence of the first stator and the second stator is added, and obtains the fundamental current feedback in conventional three phase electric machine control strategy, the electric current correspondence of the first stator and the second stator is subtracted each other, and obtains positive-negative sequence 6 primary current excitation component I _{m (± 6)}with positive-negative sequence 6 primary current torque component I _{t (± 6)}.Positive-negative sequence 6 primary current excitation component I _{m (± 6)}, positive-negative sequence 6 primary current torque component I _{t (± 6)}through θ _-6s1rotating coordinate transformation, to negative phase-sequence 5 rotating coordinate systems, obtains negative phase-sequence 5 subharmonic current excitation component and the torque component of DC form with low pass filter; Positive-negative sequence 6 primary current excitation component I _{m (± 6)}, positive-negative sequence 6 primary current torque component I _{t (± 6)}through θ _{+ 6s1}rotating coordinate transformation, to positive sequence 7 rotating coordinate systems, obtains positive sequence 7 subharmonic current excitation component and the torque component of DC form with low pass filter;

(2) on the first stator synchronous rotating frame, adopt pi regulator to control excitation component and the torque component of fundamental current respectively, export first-harmonic control voltage U _1cm, U _1ct; On respective rotating coordinate system, closed-loop control is carried out respectively to negative phase-sequence 5 times and positive sequence 7 subharmonic current.Negative phase-sequence 5 subharmonic current is fastened as DC form at negative phase-sequence 5 rotational coordinatess, adopts pi regulator to be 0 by its closed-loop control, and exports the negative phase-sequence 5 subharmonic bucking voltage of DC form; Positive sequence 7 subharmonic current is fastened as DC form at positive sequence 7 rotational coordinatess, adopts pi regulator to be 0 by its closed-loop control, and exports the positive sequence 7 subharmonic bucking voltage of DC form;

(3) the negative phase-sequence 5 subharmonic bucking voltage of DC form that exports of step (2) is through θ _-6s1, θ _-6s2the negative phase-sequence 5 subharmonic bucking voltage on synchronous rotating frame is obtained after conversion; The positive sequence 7 subharmonic bucking voltage of DC form is through θ _{+ 6s1}, θ _{+ 6s2}θ is obtained after coordinate transform _s1, θ _s2positive sequence 7 subharmonic bucking voltage on synchronous rotating frame; The first-harmonic control voltage U that negative phase-sequence 5 subharmonic bucking voltage on synchronous rotating frame and positive sequence 7 subharmonic bucking voltage and step (2) export _1cm, U _1ctafter superposition, through θ _s1, θ _s2synchronously rotating reference frame inverse transformation and PWM module output pulse width ripple, control the current transformer power unit of corresponding power electronic device composition.

As the phase difference of the first stator of the present invention, the second stator is set to 0, negative phase-sequence 5 times, positive sequence 7 subharmonic current pi regulator optimum configurations are 0, the six cross streams motor control strategy that stator double winding differs from 30 degree are downgraded to the double winding three phase alternating current motor control strategy of stator double winding without difference automatically, just can realize the switching of coupling two kinds of motor control strategy.

Accompanying drawing explanation

Fig. 1 pusher side adopts the converter topology of uncontrollable rectifier+Boost circuit scheme;

Fig. 2 pusher side adopts the converter topology of PWM unsteady flow scheme;

5 times, 7 subharmonic current decomposition strategies in Fig. 3 the present invention;

Six cross streams current of electric control programs in Fig. 4 the present invention.

Embodiment

The present invention is further illustrated below in conjunction with the drawings and specific embodiments.

Full power convertor is connected topology as shown in Figure 2 with six cross streams motors.Full power convertor is surveyed current transformer 20 primarily of grid side current transformer 10 and motor and is formed.Grid side current transformer and motor side current transformer power unit are IGBT structure, and wherein grid side electric current connects electrical network by series reactor, and motor side current transformer is connected with generator unit stator by du/dt reactor 30, S ₁₁, S ₁₂composition A1 phase power cell 40, S ₂₁, S ₂₂composition B1 phase power cell 50, S ₃₁, S ₃₂composition C1 phase power cell 60, S ₄₁, S ₄₂composition A2 phase power cell 70, S ₅₁, S ₅₂composition B2 phase power cell 80, S ₆₁, S ₆₂composition C2 phase power cell 90.Power cell A1, B1, C1 are a set of, form the first stator current transformer, and power cell A2, B2, C2 are a set of, form the second stator current transformer.Control object of the present invention is by S ₁₁~ S ₆₂40, the pusher side current transformer of 50,60,70,80,90 power electronic device compositions.

The step of the harmonic current control strategy of the present invention six cross streams motor as shown in Figure 3, Figure 4.

Step 1: the three-phase voltage gathering the first stator, calculates the magnetic linkage angle θ of the first stator by phase-locked loop _s1, deduct the magnetic linkage angle θ that π/6 obtain the second stator _s2, phase-locked loop calculates negative phase-sequence 6 angle θ of the first stator simultaneously _-6s1, positive sequence 6 angle θ _{+ 6s1}with negative phase-sequence 6 angle θ of the second stator _-6s2, positive sequence 6 angle θ _{+ 6s2}, as shown in Fig. 4 100;

Step 2: the three-phase current gathering the first stator, through θ _s1after synchronous rotating angle, obtain the excitation component I of the first stator current _m1ackwith torque component I _t1ack, as shown in 000-3 in Fig. 4; Gather the three-phase current of the second stator, through θ _s2the excitation component I of the second stator current is obtained after synchronous rotating angle _m2ackwith torque component I _t2ack, as shown in Fig. 4 200;

Step 3: the excitation component I of the first stator current _m1ack, torque component I _t1ackwith the excitation component I of the second stator current _m2ack, torque component I _t2ackenter fundamental current PI control module 400.Be added in fundamental current PI control module 400 and obtain fundamental current feedback, with exciting current I _mrefwith torque current I _trefthrough pi regulator relatively, realize the fundamental current closed-loop control in conventional control strategy.The first-harmonic control voltage U of the first stator and the second stator is obtained after the compensating fundamental wave voltage that fundamental current PI control module 400 exports adds electric voltage feed forward 410 _1cmand U _1ct;

Step 4: the excitation component I of the first stator current _m1ack, torque component I _t1ackwith the excitation component I of the second stator current _m2ack, torque component I _t2ackenter harmonic current decomposing module 300.Harmonic current decomposing module strategy as shown in Figure 3, in harmonic current decomposing module, the excitation component I of the first stator current _m1ackwith the excitation component I of the second stator current _m2acksubtract each other and be multiplied by 0.5 coefficient again, obtain θ _s16 subharmonic current excitation component I on synchronous rotating frame _{m (± 6)}, the torque component I of the first stator current _t1ackwith the torque component I of the second stator current _t2acksubtract each other and be multiplied by 0.5 coefficient again, obtain θ _s16 subharmonic current torque component I on synchronous rotating frame _{t (± 6)}, as shown in Fig. 3 001,002.6 subharmonic current excitation component I _{m (± 6)}with torque component I _{t (± 6)}through negative phase-sequence 6 angle θ _-6s1coordinate transform, as in Fig. 3 003, negative phase-sequence 5 subharmonic in stator current becomes direct current, and positive sequence 7 subharmonic becomes 12 subharmonic, negative phase-sequence 6 angle θ _-6s1the output of coordinate transformation module, through low pass filter LPF, as in Fig. 2 005,006, obtains the negative phase-sequence 5 subharmonic current excitation component I of DC form _-5mackwith torque component I _-5tack; 6 subharmonic current excitation component I _{m (± 6)}with torque component I _{t (± 6)}through positive sequence 6 angle θ _{+ 6s1}coordinate transform, as in Fig. 3 004, positive sequence 7 subharmonic in stator current becomes direct current, and negative phase-sequence 5 subharmonic becomes 12 subharmonic, positive sequence 6 angle θ _{+ 6s1}coordinate transformation module exports through low pass filter LPF, in Fig. 2 007,008, obtains the positive sequence 7 subharmonic current excitation component I of DC form _{+ 7mack}with torque component I _{+ 7tack}.

Step 5: carry out closed-loop control to negative phase-sequence 5 subharmonic current of DC form in-5 primary current PI control modules 401 ,-5 primary current PI control modules 401 output signal through θ _-6s1rotational coordinates inverse transformation, as in Fig. 4 602, obtains the first stator negative phase-sequence 5 subharmonic bucking voltage excitation component U _{1cm (-5)}with torque component U _{1ct (-5)},-5 primary current PI control modules 401 output signal through θ _-6s2rotational coordinates inverse transformation, as in Fig. 4 603, obtains the second stator negative phase-sequence 5 subharmonic bucking voltage excitation component U _{2cm (-5)}with torque component U _{2ct (-5)};

Step 6: carry out closed-loop control to positive sequence 7 subharmonic current of DC form in+7 primary current PI control modules 402 ,+7 primary current PI control modules 402 output signal through θ _{+ 6s1}rotational coordinates inverse transformation, as in Fig. 4 604, obtains the positive sequence 7 subharmonic bucking voltage excitation component U of the first stator _{1cm (+7)}with torque component U _{1ct (+7)},+7 primary current PI control modules 402 output signal through θ _{+ 6s2}rotational coordinates inverse transformation, as in Fig. 4 605, obtains the positive sequence 7 subharmonic bucking voltage excitation component U of the second stator _{2cm (+7)}with torque component U _{2ct (+7)};

Step 7: the negative phase-sequence 5 subharmonic bucking voltage excitation component U that step 5 exports _{1cm (-5)}, torque component U _{1ct (-5)}with the positive sequence 7 subharmonic bucking voltage excitation component component U that step 6 exports _{1cm (+7)}, torque component U _{1ct (+7)}do add operation, obtain the harmonic compensation voltage of the first stator, as the 502, first stator harmonic compensation voltage in Fig. 4 again with first-harmonic control voltage excitation component U _1cm, torque component U _1ctbe added, obtain the first stator and control full voltage, as in Fig. 4 500; The negative phase-sequence 5 subharmonic bucking voltage excitation component U that step 5 exports _{2cm (-5)}, torque component U _{2ct (-5)}with the positive sequence 7 subharmonic bucking voltage excitation component U that step 6 exports _{2cm (+7)}, torque component U _{2ct (+7)}do add operation and obtain stator 2 harmonic voltage compensate component, as in Fig. 4 503, stator 2 harmonic voltage compensate component again with first-harmonic control voltage excitation component U _2cm, torque component U _2ctaddition obtains the second stator and controls full voltage, as in Fig. 4 501;

Step 8: the first stator that step 7 exports controls full voltage through θ _s1α β control voltage U is obtained after rotational coordinates inverse transformation _{1c α}, U _{1c β}, as in Fig. 4 600; The second stator that step 7 exports controls full voltage through θ _s2α β control voltage U is obtained after rotational coordinates inverse transformation _{2c α}, U _{2c β}, as in Fig. 4 601;

Step 9: the first stator α β control voltage U that step 8 exports _{1c α}, U _{1c β}the power cell 40,50,60 that pulsewidth ripple removes to drive S11 ~ S32 composition is obtained through PWM module 700 modulation; The second stator α β control voltage U that step 8 exports _{2c α}, U _{2c β}the power cell 70,80,90 that pulsewidth ripple removes to drive S41 ~ S62 composition is obtained through PWM module 701 modulation.

Step 10: when control strategy coupling stator double winding of the present invention is without difference alternating current machine, first stator and the second stator phase difference are set to 0, and-5 primary current PI control modules 401 are set to 0 with parameter in+7 primary current PI control modules 402, control strategy is downgraded to the control strategy of double winding without difference alternating current machine automatically.

Claims (3)

1. six cross streams motor harmonic current control methods, is characterized in that described control method on conventional three phase alternating current motor control method basis, increases negative phase-sequence detect and closed loop control method with positive sequence 7 subharmonic current for 5 times; The phase-locked loop of the first stator not only exports magnetic linkage angle and the frequency of the first stator, also add negative phase-sequence 6 angles and positive sequence 6 angles output, and poor according to the designed phase of two stators, export the magnetic linkage angle of the second stator, the second stator negative phase-sequence 6 times and positive sequence 6 angles; Again according to the feature of two stator currents on synchronous rotating frame, decomposite negative phase-sequence 5 times and the positive sequence 7 subharmonic current component of stator current, then closed-loop control is carried out to negative phase-sequence 5 times and positive sequence 7 primary current, control result after coordinate transform, be added to the first-harmonic control voltage that fundamental current control exports on synchronous rotating frame, again through synchronously rotating reference frame inverse transformation and PWM module output pulse width ripple, control the current transformer power unit of corresponding power electronic device composition.

2. six cross streams motor harmonic current control methods according to claim 1, is characterized in that described control method comprises lower step:

(1) six-phase motor stator is divided into the first stator and the second stator, advanced second stator electrical degree π/6 of the first stator, gather the three-phase voltage of the first stator, obtain the magnetic linkage angle θ of the first stator through phase-locked loop _s1, negative phase-sequence 6 angle θ _-6s1with positive sequence 6 angle θ _{+ 6s1}, and according to phase difference π/6 of the second stator and the first stator, obtain the magnetic linkage angle θ of the second stator _s2, negative phase-sequence 6 angle θ _-6s2with positive sequence 6 angle θ _{+ 6s2}; Gather the electric current of the first stator and the second stator, utilize the magnetic linkage angle θ of the first stator _s1, the second stator magnetic linkage angle θ _s2by current transformation on respective synchronous rotating frame, fundamental current is equal, negative phase-sequence 5 times and positive sequence 7 subharmonic current become negative phase-sequence 6 times and positive sequence 6 subharmonic current, and the first stator is contrary with the second stator positive-negative sequence 6 subharmonic current amplitude equal symbol, the electric current correspondence of the first stator and the second stator is added, and obtains the fundamental current feedback in conventional three phase electric machine control strategy, the electric current correspondence of the first stator and the second stator is subtracted each other, and obtains positive-negative sequence 6 primary current excitation component I _{m (± 6)}with positive-negative sequence 6 primary current torque component I _{t (± 6)}; Positive-negative sequence 6 primary current excitation component I _{m (± 6)}, positive-negative sequence 6 primary current torque component I _{t (± 6)}through θ _-6s1rotating coordinate transformation, to negative phase-sequence 5 rotating coordinate systems, obtains negative phase-sequence 5 subharmonic current excitation component and the torque component of DC form with low pass filter; Positive-negative sequence 6 primary current excitation component I _{m (± 6)}, positive-negative sequence 6 primary current torque component I _{t (± 6)}through θ _{+ 6s1}rotating coordinate transformation, to positive sequence 7 rotating coordinate systems, obtains positive sequence 7 subharmonic current excitation component and the torque component of DC form with low pass filter;

(2) on the first stator synchronous rotating frame, adopt pi regulator to control excitation component and the torque component of fundamental current respectively, export first-harmonic control voltage U _1cm, U _1ct; On respective rotating coordinate system, closed-loop control is carried out respectively to negative phase-sequence 5 times and positive sequence 7 subharmonic current; Negative phase-sequence 5 subharmonic current is fastened as DC form at negative phase-sequence 5 rotational coordinatess, adopts pi regulator to be 0 by its closed-loop control, and exports the negative phase-sequence 5 subharmonic bucking voltage of DC form; Positive sequence 7 subharmonic current is fastened as DC form at positive sequence 7 rotational coordinatess, adopts pi regulator to be 0 by its closed-loop control, and exports the positive sequence 7 subharmonic bucking voltage of DC form;

(3) the negative phase-sequence 5 subharmonic bucking voltage of DC form that exports of described step (2) is through θ _-6s1, θ _-6s2the negative phase-sequence 5 subharmonic bucking voltage on synchronous rotating frame is obtained after conversion; The positive sequence 7 subharmonic bucking voltage of DC form is through θ _{+ 6s1}, θ _{+ 6s2}θ is obtained after coordinate transform _s1, θ _s2positive sequence 7 subharmonic bucking voltage on synchronous rotating frame; The first-harmonic control voltage U that negative phase-sequence 5 subharmonic bucking voltage on synchronous rotating frame and positive sequence 7 subharmonic bucking voltage and step (2) export _1cm, U _1ctafter superposition, through θ _s1, θ _s2synchronously rotating reference frame inverse transformation and PWM module output pulse width ripple, control the current transformer power unit of corresponding power electronic device composition.

3. six cross streams motor harmonic current control methods according to claim 1 and 2, it is characterized in that by the phase difference of the first stator and the second stator is set to 0, negative phase-sequence 5 times, positive sequence 7 subharmonic current pi regulator optimum configurations are 0, the six cross streams motor control strategy that stator double winding differs from 30 degree are downgraded to the double winding three phase alternating current motor control strategy of stator double winding without difference automatically, realize the switching of coupling two kinds of motor control strategy.