CN103269200A - High speed stabilizing drive control method of satellite-borne large inertia load mechanism - Google Patents

Abstract

A high speed stabilizing drive control method of a satellite-borne large inertia load mechanism includes the following steps: (1) powering direct currents on a motor and calculating the phase difference of the motor and a rotary transformer after the load mechanism is stabilized; (2) collecting the current rotating speed of the motor at the current speed ring sampling instant and calculating torque electric currents; (3) collecting the electric currents iA and the electric currents iB of the motor at the current speed ring sampling instant to obtain the harmonic frequency spectrum, the amplitude and the phase of the iA and the iB; (4) conducting harmonic compensation on the iA and the iB; (5) converting the A-phase winding currents and the B-phase winding currents of the motor after compensation under a rotor coordinate system; (6) calculating the two-shaft voltage of the rotor coordinate system; (7) determining the three-phase time value of a PWM waveform generator, wherein a SVPWM waveform generator generates voltage waves according to the three-phase time value, and the voltage waves are loaded on a motor winding to control the motor; (8) entering the next current ring sampling instant, and switching to the step (3) to execute repeatedly; (9) entering the next current ring sampling instant, and switching to the step (2) to execute repeatedly.

Description

The high speed stabilizing of a kind of spaceborne big inertia mechanism loading drives control method

Technical field

This method relates to the control driving method to big inertia rotating mechanism, and special requirement have high steady speed precision, belongs to antenna control technology field.

Background technology

Microwave radiometer sweep mechanism and scatterometer sweep mechanism are respectively applied to drive radiometer and scatterometer carries out conical scanning over the ground, and carries little detection head construction and internal electronic equipment, realizes earth observation.Scatterometer rotating part quality is 76.2kg, radiometer moment of inertia 7.8kgm ²(the rotating part quality is 61.3kg) is respectively with 95 °/s uniform rotation.

Sweep mechanism also claims mechanism loading to adopt identical direct drive mode, realizes the rigidity coupling of motor and load, to improve responding ability.Scanning servo mechanism structure schematic diagram as shown in Figure 1, sweep mechanism selects for use brushless D. C. torque motor to adopt outer-rotor structure, middle main shaft is the supporting construction of antenna and high frequency case, it is again the load spare of the whole rotating part of carrying, the top is conducting slip ring 1, the centre is resolver 3, and the bottom is the bearing 2 that motor (rotor 5 and electronics stator 6) has reached support and carrying effect.The sweep mechanism central shaft maintains static in the course of the work, motor-driven shell 4 rotates, shell drives antenna again and the high frequency case rotates (7 are high frequency case interface among the figure), resolver is used for detecting the position that sweep mechanism rotates, and conducting slip ring is used for the electrical signal transfer (8 are satellite cabin plate mounting interface) in the satellite cabin of scatterometer.In rotation process, bearings mechanism does relative motion, and contact component is slip ring and bearing.Conducting slip ring is electric swivel joint parts, slip ring continual running in 24 hours.

The sweep mechanism control circuit is revolved by DSP, FPGA, thick smart binary channels and becomes resolving circuit, high-precision hall current acquisition circuit, three-phase bridge drive circuit and form, as Fig. 2.

Because the permagnetic synchronous motor strong nonlinearity, its parameter changes can influence control precision and dynamic responding speed, just must seek suitable control mode, to realize the high precision closed loop control to torque and rotating speed.

The moment of inertia of load is more big, and the mechanical time constant of motor control system is just more big, and the response time of system and overshoot are difficult to be in harmonious proportion, and the control dynamic characteristic of motor when rotation speed change is difficult to guarantee; And exist disturbance factor in the inertia system, as the quantization error of the fluctuation of the cogging torque of motor, measuring transducer and inverter dead band etc., these non-linear factors can produce torque ripple in system, thereby cause the fluctuation of speed.

The load of so big inertia is rotated, the torque meeting produces very big inertia torque, the instantaneous energy storage of motor is very big, and the cymomotive force (CMF) of its rotating speed must produce considerable influence to whole star attitude, can cause thus other sensing with pointing accuracy requirement load instrument on the star is caused interference; If velocity perturbation is big, even can have influence on the whole star life-span.

The technical literature relevant with the application is described as follows:

[1] Yuan Li, Yang Lei. the technical research of the big inertia high accuracy of satellite camera low speed sweep mechanism. the academic nd Annual Meeting .2006 of the 12 space, the whole nation and movable body control technology;

[2] Han Changpei. the electric current loop design of the big inertia high accuracy of low speed scanning control system. infrared .2005;

[3] Pang Wei. with the space driving mechanism kinetic characteristic analysis of big inertia load. the master thesis .2009 of Nanjing Aero-Space University;

Document [1] need for optical-mechanical scanner realization high accuracy scanning to have proposed scan mode, scanning mirror light-weight design, support technology and the type of drive Consideration of consideration;

Document [2] proposes to be suitable for the current loop control method of No. four meteorological satellite scanning radiometers of wind and cloud scanning control system, and has provided the theory diagram of electric current loop;

Document [3] is by analyzing the load characteristic of solar array drive in space environment, made up the driving mechanism stress model under the big inertia load effect, the load speed of emulation driving mechanism under various operating modes and loading moment curve, and the resonance frequency of system carried out emulation.

Summary of the invention

Technology of the present invention is dealt with problems and is: overcome the deficiencies in the prior art, provide the high speed stabilizing of a kind of spaceborne big inertia mechanism loading to drive control method, utilize this method proof load mechanism speed stabilizing to rotate, the undulate quantity that satisfies speed can not surpass the index request of 0.2/s.

Technical solution of the present invention is: the high speed stabilizing of spaceborne big inertia mechanism loading drives control method, and described mechanism loading comprises motor, resolver and high frequency case, and method step is as follows:

(1) motor is passed to direct current, treat that mechanism loading is stable after, calculate the phase difference of motor and resolver;

(2) at the current rotating speed of present speed ring sampling instant collection motor, rated speed and current rotating speed according to motor utilize self-adaptive PID calculating torque electric current;

(3) gather motor A, B phase winding current i in current electric current loop sampling instant _A, i _BAnd it is carried out discrete fourier DFS calculate, obtain i _A, i _BHarmonic spectrum, amplitude, phase place;

(4) according to result and angle, the rotor field θ of step (3) _RCalculate penalty coefficient, utilize penalty coefficient to motor A, B phase winding current i _A, i _BCarry out harmonic compensation;

(5) the motor A after step (4) compensation, B phase winding current conversion are arrived under the rotor coordinate system;

(6) torque current that utilizes step (2) to calculate calculates two shaft voltages of rotor coordinate system;

(7) two shaft voltages that utilize step (6) to calculate are determined the three-phase time value of PWM waveform generator; The SVPWM waveform generator produces voltage wave according to the three-phase time value, this voltage wave is carried in the control that realizes on the motor winding motor;

(8) enter next electric current loop sampling instant, change step (3) over to and repeat;

(9) enter next speed ring sampling instant, change step (2) over to and repeat; The described speed ring sampling time is greater than the electric current loop sampling time and be the integral multiple in electric current loop sampling time.

The phase difference calculating formula of described step (1) is as follows:

${\mathrm{\θ}}_0=(\frac{\mathrm{\θ}\×p}{360}-\mathrm{INT}[\frac{\mathrm{\θ}\×p}{360}\left]\right)\×360$

Wherein, p-resolver number of pole-pairs; INT-rounds; The mechanical angle of θ-resolver.

Penalty coefficient C in the described step (4) _FactorComputing formula is as follows:

In the formula, a ₃, a ₅, a ₇, a ₉Be the amplitude of step (3) calculating,

Be the phase place that step (3) is calculated, the mechanical angle of θ-resolver.

Principle of the present invention is:

(1) at first finish the initial alignment that rotates load, to obtain the phase relation of motor and resolver in the mechanism, this phase difference has determined the maximum output torque of system.

(2) owing to reasons such as motor cogging torque, inverter dead band, transducer quantization error, AB current acquisition gain inconsistencies, can produce the motor output torque harmonic component, this harmonic wave can cause torque ripple; According to the kinetics equation of motor, can cause the fluctuation of speed of load thus.

The intrinsic deviation (as not matching of direct current biasing, gain) of phase current sense channel can produce biased error.Because the magnetic field positioning control is based upon current feedback, so any current detecting mistake all can directly influence the performance of torque.

Therefore, need to detect the motor output torque harmonic component, and the each harmonic component is compensated.Because the electric current on the motor winding has directly reflected motor output torque, therefore, the electric machine phase current harmonic component has represented the harmonic component of output torque.The motor winding current is carried out DFS calculate, obtain each harmonic frequency, phase place and amplitude; According to position, electric current, rotor field angle calculation penalty coefficient, by this penalty coefficient the motor winding current is proofreaied and correct.

(3) utilize the motor winding current after proofreading and correct to carry out the directed control strategy calculating of space magnetic field, namely along two components that in the rotor field-oriented synchronous coordinate system (dq coordinate system) stator current vector are decomposed into quadrature, one is torque current component (being q shaft current component); Another is excitation current component (being d shaft current component).By phase place and the amplitude size of control stator current space vector, just control phase place and the amplitude size of motor torque current component and excitation current component, realize the decoupling zero control to magnetic field and torque.If keep air gap magnetic linkage d axle component constant, torque just and the q shaft current be directly proportional, can realize direct control to motor torque by controlling the q shaft current like this.As Fig. 3.

The present invention compared with prior art beneficial effect is:

(1) the field orientation control strategy of magnetic field of the present invention harmonic compensation, utilize the Harmonics Calculation torque harmonic component of motor winding phase current, comprehensive compensation the harmonic component that is produced by non-linear factors such as motor cogging torque, inverter dead band, transducer quantization error, AB current acquisition gain inconsistencies, it is little to reduce the current harmonics component, improve the utilance of power supply, and can effectively reduce torque pulsation.

(2) the present invention proposes the algorithm of phase alignment between motor and the multipolar resolver, utilize this algorithm can obtain the installation zero-bit relation between the motor and multipolar resolver in the mechanism automatically.

(3) the present invention efficiently solves the problem that load such as microwave radiometer, microwave scatterometer are disturbed satellite platform attitude control generation owing to the fluctuation of rotating speed.

(4) the high speed stabilizing scanning of the spaceborne sweep mechanism of realization that provides of the present invention implementation, the design that can directly apply to satellite-borne microwave radiometer, microwave scatterometer, TMI, complete polarization microwave radiometer and high speed stabilizing antenna etc. realizes.

The application uses at satellite-borne microwave radiometer, the high speed stabilizing scanning of microwave scatterometer, on the basis that guarantees technical advance and Project Realization feasibility, drive aspects such as strategy design in conjunction with permagnetic synchronous motor design, control with the little characteristic of output torque ripple, make every effort to system export torque ripple be down to minimum, thereby realize the high speed stabilizing requirement of sweep mechanism.

Description of drawings

Fig. 1 is the sweep mechanism driver element;

Fig. 2 is the hardware platform theory diagram;

Fig. 3 is the directed control principle block diagram of magnetic field of the present invention harmonic compensation;

Fig. 4 is the inventive method flow chart;

Fig. 5 is motor winding current waveform of the present invention;

Fig. 6 is speed fluctuation test measurement result of the present invention.

Embodiment

For a better understanding of the present invention, at first the coordinate system that relates among the present invention is described.

Two-phase stator coordinate system (α β coordinate system):

The two-phase symmetric winding passes to the two-phase symmetrical current, also produces rotating magnetic field, and to a vector, custom is described with the two-phase rectangular coordinate system on the mathematics, so define two phase coordinate systems (α β coordinate system).

Motor two fixes winding α, β and spatially differs 90 degree, the alternating current i of biphase equilibrium _α, i _βDiffer 90 degree in phase place.

Threephase stator coordinate system (abc coordinate system):

The threephase stator winding of permagnetic synchronous motor is mutual deviation 120 degree spatially, are defined as a, b, c axle respectively along its axis, have then constituted an abc coordinate system.

Rotor coordinate system (dq coordinate system):

The rotor coordinate system is fixed on the rotor, and its d axle is positioned on the rotor axis, counterclockwise leading d axle 90 degree of q axle, and this coordinate system spatially rotates with rotor velocity with rotor.

High speed stabilizing described in the present invention drives control method and realizes finishing automatically mechanism's motor and revolve the calibration of covert position by design, realizes starting big inertia load with breakdown torque output; Simultaneously, by calculating the harmonic component of phase current, design magnetic field harmonic compensation algorithm is steadily exported to realize torque, reaches the purpose of high speed stabilizing.

As shown in Figure 4, performing step of the present invention is as follows:

(1) motor is passed to direct current, treat that mechanism loading is stable after, calculate the phase difference of motor and resolver.The phase difference calculating method is as follows:

${\mathrm{\θ}}_0=(\frac{\mathrm{\θ}\×p}{360}-\mathrm{INT}[\frac{\mathrm{\θ}\×p}{360}\left]\right)\×360---\left(1\right)$

P-resolver number of pole-pairs; INT-rounds; The mechanical angle of θ-resolver.

(2) at big inertia load characteristic, in the sampling instant of present speed ring, according to rated speed and current rotating speed, utilize self-adaptive PID calculating torque electric current.

(3) gather motor A, B phase winding current i in current electric current loop sampling instant by Hall current sensor _A, i _BAnd it is carried out discrete fourier DFS calculate, obtain the amplitude a of harmonic spectrum _i, phase place

a _i-DFS amplitude;

-DFS phase place; f _i-DFS frequency; The M-hits; X[n]-sampled value of a n sampled point.

(4) according to the I that imports _A, I _B, the I of angle, rotor field θ _AAnd I _BCarry out harmonic compensation.Computing formula is as follows:

I _A*=C _factor×I _A (2)

I _B*=C _factor×I _B (3)

C _FactorBe penalty coefficient, I _A ^*And I _B ^*Be the result behind the harmonic compensation.

a ₃, a ₅, a ₇, a ₉Be the amplitude of DFS, Be the phase place of DFS, θ is the angle, rotor field.Because the non-linear and motor teeth groove harmonic torque of hardware mainly produces odd harmonic, so only partly compensate at odd harmonic in the above-mentioned coefficient.

(5) the phase winding current value I after will compensating _A ^*, I _B ^*Convert two-phase stator coordinate system I to _Alfa, I _Beta, be transformed into the i of rotor coordinate system dq axle again _d, i _qFinish the conversion that is tied to the dq axis coordinate system from the abc coordinate thus.

I _alfa=I _A

I _beta=(I _A+2*I _B)*0.577350269189625764509

I _d=I _alfa*cos(θ-θ ₀)+I _beta*sin(θ-θ ₀)

I _q=I _beta*cos(θ-θ ₀)-I _alfa*sin(θ-θ ₀)

(6) torque current that calculates according to step (2), proportion of utilization integration (PI) algorithm calculates the dq shaft voltage; Q shaft current pi regulator output q shaft voltage V _q, d shaft current pi regulator output d shaft voltage V _d

Q shaft voltage PI calculates:

e _qCurErr=I _qref-I _q

Δu=K _p[e _qCurErr-e _qLastErr]+K _ie _qCurErr

V _q=Δu+u _qLast

u _qLast=V _q

e _qLastErr=e _qCurErr

D shaft voltage PI calculates:

e _dCurErr=0-I _d

Δu=K _p[e _dCurErr-e _dLastErr]+K _ie _dCurErr

V _d=Δu+u _dLast

u _dLast=V _d

e _dLastErr=e _dCurErr

I _QrefBe torque current; I _qBe the q shaft current; I _dBe the d shaft current; V _qBe the q shaft voltage; V _dBe the d shaft voltage;

e _QCurErrBe q shaft current current time error amount; e _QLastErrBe a moment error amount on the q shaft current;

e _DCurErrBe d shaft current current time error amount; e _DLastErrBe a moment error amount on the d shaft current;

K _pBe proportionality coefficient; K _iBe integral coefficient.

(7) with the V of dq axle _dAnd V _qConvert the V of two-phase stator coordinate system to _AlfaAnd V _Beta(being V α, the V β among Fig. 3) finishes the conversion that the dq coordinate is tied to α β coordinate system.

V _alfa=[cos(θ-θ ₀)×V _d-sin(θ-θ ₀)×V _q]

V _beta=[sin(θ-θ ₀)×V _d+cos(θ-θ ₀)×V _q]

(8) judge V _AlfaAnd V _BetaThe sector at place

V _a=V _beta

V _b=0.5×(1.732051×V _alfa-V _beta)

V _c=0.5×(-1.732051×V _alfa-V _beta)

By V _a, V _b, V _cDefinite sector of tabling look-up.

If V _a0, a=1 then, otherwise a=0; If V _b0, b=1 then, otherwise b=0; If V _c0, c=1 then, otherwise c=0.If N=4c+2b+a, then it is as shown in the table for the corresponding relation of N and sector.

The corresponding relation of table 1N and sector

N	1	2	3	4	5	6
							The sector	1	5	0	3	2	4

(9) distribute V according to the sector _AlfaAnd V _BetaT action time of vector ₁And t ₂

X=V _beta

Y=0.5×(1.732051×V _alfa+V _beta)

Z=0.5×(-1.732051×V _alfa+V _beta)

Determined V by table 1 _AlfaAnd V _BetaThe sector, calculate t according to table 2 ₁And t ₂Time.t ₁And t ₂Represent V _AlfaAnd V _BetaThe time that acts on.For example: in the sector 0, V _AlfaT action time ₁Numerical value is-Z V _BetaThe time t that acts on ₁Numerical value is X.

Table 2t ₁And t ₂Time

The sector

0

1

2

3

4

5

t 1

－Z

Z

X

－X

－Y

Y

t 2

X

Y

－Y

Z

－Z

－X

(10) according to t ₁And t ₂The time value of calculating voltage space vector pulse duration modulation (SVPWM) waveform generator:

t _aon=(1.0-t ₁-t ₂)*0.5;

t _bon=t _aon+t ₁;

t _con=t _bon+t ₂;

With t _Aon, t _Bon, t _ConWrite the time register in the SVPWM waveform generator, produce the SVPWM voltage wave by inverter.

This SVPWM voltage wave is carried on the motor winding and forms sine-wave current, as Fig. 4.

(11) the electric current loop sampling time arrives, and returns the 3rd step, and repeating step 3～step 10 constitutes current closed-loop control successively.

(12) the speed ring sampling time arrives, and returns the 2nd step, according to current rotating speed, recomputates torque current, constitutes speed closed loop control.Fluctuation of speed measured value such as Fig. 5.

The speed ring sampling time requires the sampling time greater than electric current loop, and the speed ring sampling time is the integral multiple in electric current loop sampling time.

Utilize the present invention can guarantee that microwave radiometer sweep mechanism and scatterometer sweep mechanism rotate with high speed stabilizing, the undulate quantity that satisfies speed can not surpass the index request of 0.2/s.

The unspecified part of the present invention belongs to general knowledge as well known to those skilled in the art.

Claims (3)

1. the high speed stabilizing of spaceborne big inertia mechanism loading drives control method, and described mechanism loading comprises motor, resolver and high frequency case, it is characterized in that method step is as follows:

(1) motor is passed to direct current, treat that mechanism loading is stable after, calculate the phase difference of motor and resolver;

(2) at the current rotating speed of present speed ring sampling instant collection motor, rated speed and current rotating speed according to motor utilize self-adaptive PID calculating torque electric current;

(3) gather motor A, B phase winding current i in current electric current loop sampling instant _A, i _BAnd it is carried out discrete fourier DFS calculate, obtain i _A, i _BHarmonic spectrum, amplitude, phase place;

(4) according to result and angle, the rotor field θ of step (3) _RCalculate penalty coefficient, utilize penalty coefficient to motor A, B phase winding current i _A, i _BCarry out harmonic compensation;

(5) the motor A after step (4) compensation, B phase winding current conversion are arrived under the rotor coordinate system;

(6) torque current that utilizes step (2) to calculate calculates two shaft voltages of rotor coordinate system;

(7) two shaft voltages that utilize step (6) to calculate are determined the three-phase time value of PWM waveform generator; The SVPWM waveform generator produces voltage wave according to the three-phase time value, this voltage wave is carried in the control that realizes on the motor winding motor;

(8) enter next electric current loop sampling instant, change step (3) over to and repeat;

(9) enter next speed ring sampling instant, change step (2) over to and repeat; The described speed ring sampling time is greater than the electric current loop sampling time and be the integral multiple in electric current loop sampling time.

2. the high speed stabilizing of spaceborne big inertia mechanism loading according to claim 1 drives control method, and it is characterized in that: the phase difference calculating formula of described step (1) is as follows:

${\mathrm{\θ}}_0=(\frac{\mathrm{\θ}\×p}{360}-\mathrm{INT}[\frac{\mathrm{\θ}\×p}{360}\left]\right)\×360$

Wherein, p-resolver number of pole-pairs; INT-rounds; The mechanical angle of θ-resolver.

3. the high speed stabilizing of spaceborne big inertia mechanism loading according to claim 1 drives control method, it is characterized in that: the penalty coefficient C in the described step (4) _FactorComputing formula is as follows:

In the formula, a ₃, a ₅, a ₇, a ₉Be the amplitude of step (3) calculating,

Be the phase place that step (3) is calculated, the mechanical angle of θ-resolver.

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