CN104167969A - Position sensor-free control method used for sea wave power generation system - Google Patents

Abstract

The invention discloses a position sensor-free control method used for sea wave power generation system. A double-pulse nonlinear voltage applying method, a sliding-mode observer, a neural network controller and a rotor position anti-interference observer are combined; the sliding-mode observer is adopted to obtain rotor position information, firstly the sliding-mode observer is adopted to estimate back electromotive force (EEMF) of a permanent magnet synchronous generator (PMSG), and then a sliding film plane is formed through an error between measured current and observed current to observe EEMF, thereby accurately obtaining the rotor position; at the same time, the neural network controller is adopted to replace a conventional switch function Z, equivalent EEMF is obtained, thereby obtaining a rotor position detection value, and to reduce an observation error, an error generated by a phase lag of a low pass filter is compensated; the rotor position anti-interference observer is designed; and in addition, the double-pulse voltage applying method is adopted to calculate an initial position angle of the rotor. The position sensor-free control method used for the sea wave power generation system in the invention can accurately and effectively detect the rotor position information of the PMSG of the sea wave power generation system in real time.

Description

A kind of position sensorless control method for sea wave power generation system

Technical field

The present invention relates to a kind of position sensorless control method for sea wave power generation system, is a kind of dipulse non-linear voltage to be applied to the position-sensor-free technology that method, sliding mode observer, nerve network controller and the anti-interference observer of rotor-position etc. combine.

Background technology

Traditional energy is increasingly exhausted, problem of environmental pollution worsens, and new energy development is extremely urgent.Along with the development of power consumption wireless sensor, utilize clean environment regenerative resource as solar energy, wind energy and wave-energy power generation are made into micro-power supply for sensor node provides electric energy, be day by day subject to all circles' extensive concern.Compare wind energy and heliotechnics, wave-energy power generation technology will fall behind the more than ten years.But wave energy has its unique advantage, and wave energy energy density is high, be 4～30 times of wind energy; Compare solar energy, wave energy is not subject to weather effect.Wave-energy power generation power supply is the power supply that utilizes wave power generation to be made into, for sensing node power supply in ocean has plurality of advantages.At present, in the sea wave power generation system of various structures, adopt scheme and the efficiency thereof of magneto alternator (PMSG) higher, have without advantages such as field circuits, have consequence.Particularly, in little sea wave power generation system, PMSG is because these advantages have obtained more application.Generally, PMSG adopts mechanical position sensor to come detection rotor position, as photoelectric encoder and resolver.But the existence of mechanical sensor has brought a lot of drawbacks: 1) Connection Element between motor and controller increases, hole interference performance variation, has reduced system reliability; 2) strengthen motor bulk and volume, reduced power density, increased hardware cost and the maintenance cost of system; 3) in high temperature and strong corrosive environment, will make sensor performance variation, even lose efficacy, cause motor driven systems normally to work.Some is all the main cause that causes sea wave power generation system unstable operation above.Necessity especially therefore employing position-sensor-free technology seems.

And be that control system can be estimated accurately to the real time position of rotor and speed without the core of transducer, commonly use and can be divided into 3 classes without the control method of transducer:

(1) the open loop computing method of employing motor ideal model, as direct computing method, back electromotive force integration method etc.; Computational methods based on open loop are simply direct, dynamic property is better; But calculate time rely on the parameter of electric machine, and motor runtime parameter always in change among, will certainly affect like this rotor-position estimate accuracy; And in the time that motor speed is very low, back electromotive force is very little, easy and various interference signals are entrained in together, and signal to noise ratio step-down makes back-emf be difficult to detect.Institute in this way and estimate without sensing station while not being suitable for the static or low speed of motor.

(2) the rotor-position identification scheme of injecting based on outside high-frequency signals, as rotation high frequency signal injection method, rotation high frequency signal injection method and rotation high frequency current injection.High Frequency Injection is by injecting high-frequency signal (voltage or current signal) to motor three phase windings, rely on rotor self salient pole or due to the saturated saliency causing, the magnetic field that high-frequency signal is produced is subject to the modulating action of rotor with salient pole, therefore will be with rotor position information in high-frequency signal, then high-frequency signal demodulation from stator current or voltage out just can be extracted to the positional information of rotor.This method relies on extrinsic motivated signal, and does not rely on rotating speed, but the estimation needed time of rotor-position is longer, and position quantity renewal frequency is not high, so High Frequency Injection has better estimation effect when static and low speed at motor.

(3) closed loop algorithm based on state observer, as sliding mode observer method (SMO), model reference adaptive systems approach (MRAS), extended Kalman filter method (EKF) etc.The essence of observer is exactly system mode reconstruct, re-construct a system, utilize the output vector that directly can measure in original system and the input vector input signal as it, and making the output signal of reconfiguration system be equivalent under certain conditions the state of original system, this system re-constructing is just called observer.

Summary of the invention

Goal of the invention: in order to overcome the deficiencies in the prior art, the invention provides a kind of position sensorless control method for sea wave power generation system, dipulse non-linear voltage is applied to method, sliding mode observer, nerve network controller and the anti-interference observer of rotor-position etc. to combine, in effectively to sea wave power generation system PMSG rotor initial estimation, the postrun rotor position information of real-time detection sea wave power generation system PMSG that can be accurate and effective.

Technical scheme: for achieving the above object, the technical solution used in the present invention is:

For a position sensorless control method for sea wave power generation system, dipulse non-linear voltage is applied to method, sliding mode observer, nerve network controller and the anti-interference observer of rotor-position etc. and combine, specifically comprise the following steps:

(1) initial position of rotor detects and adopts dipulse voltage to apply method, according to cross, straight axle inductance difference principle, apply 2 direction differences, wide voltage vector that amplitude is identical to motor, current response detected twice, thereby solve and the differential inductance component of rotor-position constituting-functions relation, finally draw initial position angle of rotor according to described functional relation;

(2) after sea wave power generation system brings into operation, adopt back electromotive force to come detection rotor position, adopt sliding mode observer to obtain rotor position information: first to adopt synovial membrane observer to estimate equivalence expansion back electromotive force EEMF, by the error formation mould sliding surface detecting between electric current and observation electric current, equivalence expansion back electromotive force EEMF is observed subsequently, thereby obtain rotor-position detected value; In order to reduce position estimation error, the error that hysteresis produces to low pass filter phase place compensates;

(3) for weakening the chattering phenomenon of sliding mode observer, adopt nerve network controller to replace traditional switch function Z, obtain equivalence expansion back electromotive force EEMF; Nerve network controller reflects the effect that detects electric current, observation electric current and the control of difference between the two to equivalent back electromotive force EEMF simultaneously;

(4) while producing because of the not even running of wave the perturbing torque that is greater than threshold value when sea wave power generation system, start rotor-position disturbance opposing observer, what the synovial membrane observer that solves the interference under the not steady service conditions of wave and may cause detected becomes greatly gradually to position signal errors, the even state of the value of losing contact with reality.

Beneficial effect: the position sensorless control method for sea wave power generation system provided by the invention, dipulse non-linear voltage is applied to method, sliding mode observer, nerve network controller and the anti-interference observer of rotor-position etc. to combine, compared to prior art, there is following advantage: 1, initial position detects the mode that adopts dipulse linear voltage injection method, armature winding to sea wave power generation system PMGM applies space voltage vector, can detect very accurately the initial position of rotor of sea wave power generation system PMGM; 2, save hardware cost and maintenance adult, improved anti-interference and the robustness of system simultaneously; 3, in order to weaken the chattering phenomenon of sliding mode observer, adopt nerve network controller to replace traditional switch function Z, obtain equivalent EEMF; 4, effectively solve becoming gradually greatly to position signal errors of may causing in the erratic fluctuations of wave that observer detects, the even state of the value of losing contact with reality.

Brief description of the drawings

Fig. 1 is PMSG model;

Fig. 2 is space voltage vector distribution map;

Fig. 3 is the expansion back electromotive force detection method schematic diagram with sliding mode observer;

Fig. 4 is the anti-interference observer Observation principle of rotor-position figure;

Fig. 5 is neural net fundamental diagram;

Fig. 6 is current sensor modulate circuit schematic diagram.

Embodiment

Below in conjunction with accompanying drawing, the present invention is further described.

For a position sensorless control method for sea wave power generation system, dipulse non-linear voltage is applied to method, sliding mode observer, nerve network controller and the anti-interference observer of rotor-position etc. and combine, specifically comprise the following steps:

(1) initial position of rotor detects and adopts dipulse voltage to apply method, according to cross, straight axle inductance difference principle, apply 2 direction differences, wide voltage vector that amplitude is identical to motor, current response detected twice, thereby solve and the differential inductance component of rotor-position constituting-functions relation, finally draw initial position angle of rotor according to described functional relation;

(2) after sea wave power generation system brings into operation, adopt back electromotive force to come detection rotor position, adopt sliding mode observer to obtain rotor position information: first to adopt synovial membrane observer to estimate equivalence expansion back electromotive force EEMF, by the error formation mould sliding surface detecting between electric current and observation electric current, equivalence expansion back electromotive force EEMF is observed subsequently, thereby obtain rotor-position detected value; In order to reduce position estimation error, the error that hysteresis produces to low pass filter phase place compensates;

(3) for weakening the chattering phenomenon of sliding mode observer, adopt nerve network controller to replace traditional switch function Z, obtain equivalence expansion back electromotive force EEMF; Nerve network controller reflects the effect that detects electric current, observation electric current and the control of difference between the two to equivalent back electromotive force EEMF simultaneously;

(4) while producing because of the not even running of wave the perturbing torque that is greater than threshold value when sea wave power generation system, start rotor-position disturbance opposing observer, what the synovial membrane observer that solves the interference under the not steady service conditions of wave and may cause detected becomes greatly gradually to position signal errors, the even state of the value of losing contact with reality.

Illustrated with regard to contents such as design philosophys of the present invention below.

Be illustrated in figure 1 PMSG model, under the static two-phase α β of stator coordinate system, the Mathematical Modeling of PMSG can be expressed as:

$\left[\begin{array}{c}{\mathrm{\μ}}_{\mathrm{\α}}\\ {\mathrm{\μ}}_{\mathrm{\β}}\end{array}\right]=R\left[\begin{array}{c}{i}_{\mathrm{\α}}\\ i_{\mathrm{\β}}\end{array}\right]+\left[\begin{array}{cc}{L}_1+L_2\cos 2{\mathrm{\θ}}_r& 2\sin {\mathrm{\θ}}_r\\ L_2\sin 2{\mathrm{\θ}}_r& L_1-L_2\cos 2{\mathrm{\θ}}_r\end{array}\right].D\left[\begin{array}{c}{i}_{\mathrm{\α}}\\ i_{\mathrm{\β}}\end{array}\right]+w_r{\mathrm{\ψ}}_{\mathrm{PM}}\left[\begin{array}{c}-\cos {\mathrm{\θ}}_r\\ \sin {\mathrm{\θ}}_r\end{array}\right]---\left(1\right)$

Wherein,

$\left\{\begin{array}{c}{L}_1=(L_d+L_q)/2\\ L_2=(L_d-L_q)/2\end{array}\right.---\left(2\right)$

In formula, u and i are stator voltage and the stator current under α β coordinate system, and R is stator phase resistance; ψ _pMfor permanent magnetism magnetic linkage; θ _rfor rotor-position; w _rfor PMSG electric angle speed; L _d, L _qbe divided into d axle inductance and the q axle inductance of PMSG; D is differential operator.In the time that PMSG remains static, its back electromotive force is zero, therefore formula (1) can be abbreviated as:

$\left[\begin{array}{c}{\mathrm{\μ}}_{\mathrm{\α}}\\ {\mathrm{\μ}}_{\mathrm{\β}}\end{array}\right]=R\left[\begin{array}{c}{i}_{\mathrm{\α}}\\ i_{\mathrm{\β}}\end{array}\right]+\left[\begin{array}{cc}{L}_1+L_2\cos 2{\mathrm{\θ}}_r& 2\sin {\mathrm{\θ}}_r\\ L_2\sin 2{\mathrm{\θ}}_r& L_1-L_2\cos 2{\mathrm{\θ}}_r\end{array}\right].D\left[\begin{array}{c}{i}_{\mathrm{\α}}\\ i_{\mathrm{\β}}\end{array}\right]---\left(3\right)$

If PMSG stator is applied to direction difference 2 times, 2 voltage vectors that amplitude is identical (specifically apply rule and see any two different voltage vectors of Fig. 2, as V ₁or V ₂, detect 2 primary current responses by current sensor, solve subsequently inductance matrix equation and be:

$\left[\begin{array}{cc}{\mathrm{\μ}}_{\mathrm{\α}1}& {\mathrm{\μ}}_{\mathrm{\α}2}\\ {\mathrm{\μ}}_{\mathrm{\β}1}& {\mathrm{\μ}}_{\mathrm{\β}2}\end{array}\right]=R\left[\begin{array}{cc}{i}_{\mathrm{\α}1}& i_{\mathrm{\α}2}\\ i_{\mathrm{\β}1}& i_{\mathrm{\β}2}\end{array}\right]+\left[\begin{array}{cc}{L}_1+L_2\cos 2{\mathrm{\θ}}_r& 2\sin {\mathrm{\θ}}_r\\ L_2\sin 2{\mathrm{\θ}}_r& L_1-L_2\cos 2{\mathrm{\θ}}_r\end{array}\right]D\left[\begin{array}{cc}{i}_{\mathrm{\α}1}& i_{\mathrm{\α}2}\\ i_{\mathrm{\β}1}& i_{\mathrm{\β}2}\end{array}\right]---\left(4\right)$

$\begin{array}{c}\left[\begin{array}{cc}{L}_{11}& L_{12}\\ L_{21}& L_{22}\end{array}\right]=\left[\begin{array}{cc}{L}_1+L_2\cos 2{\mathrm{\θ}}_r& 2\sin {\mathrm{\θ}}_r\\ L_2\sin 2{\mathrm{\θ}}_r& L_1-L_2\cos 2{\mathrm{\θ}}_r\end{array}\right]\\ =\left[\begin{array}{cc}{\mathrm{\μ}}_{\mathrm{\α}1}-{\mathrm{Ri}}_{\mathrm{\α}1}& {\mathrm{\μ}}_{\mathrm{\α}1}-{\mathrm{Ri}}_{\mathrm{\α}2}\\ {\mathrm{\μ}}_{\mathrm{\β}1}-{\mathrm{Ri}}_{\mathrm{\β}1}& {\mathrm{\μ}}_{\mathrm{\β}2}-{\mathrm{Ri}}_{\mathrm{\β}2}\end{array}\right]\left[\begin{array}{cc}\frac{{\mathrm{di}}_{\mathrm{\α}1}}{\mathrm{dt}}& \frac{{\mathrm{di}}_{\mathrm{\α}2}}{\mathrm{dt}}\\ \frac{{\mathrm{di}}_{\mathrm{\β}1}}{\mathrm{dt}}& \frac{{\mathrm{di}}_{\mathrm{\β}2}}{\mathrm{dt}}\end{array}\right]\end{array}---\left(5\right)$

According to being (5), rotor-position can be obtained by following formula:

${\mathrm{\θ}}_r=\frac{1}{2}{\tan }^{-1}\frac{L_{12}+L_{21}}{L_{11}-L_{22}}---\left(6\right)$

Can draw PMSG initial position angle of rotor according to formula (6).

When motor is after running status, adopt synovial membrane observer to obtain PMSG rotor position information, as shown in Figure 3, in d-q rotating coordinate system, the voltage equation of PMSG is structured flowchart:

$\left[\begin{array}{c}{u}_d\\ u_q\end{array}\right]=\left[\begin{array}{cc}R+{\mathrm{DL}}_d& -w_r{L}_d\\ w_r{L}_d& R+{\mathrm{DL}}_q\end{array}\right]\left[\begin{array}{c}{i}_d\\ i_q\end{array}\right]+\left[\begin{array}{c}0\\ w_r{K}_E\end{array}\right]---\left(7\right)$

Wherein, [u _du _q] ^tfor voltage under rotating coordinate system; [i _di _q] ^tfor electric current under rotating coordinate system; R is stator resistance; D is differential operator; w _rfor rotor velocity (electrical degree); K _efor back electromotive-force constant; L _dfor d axle inductance; L _qfor q axle inductance.

Formula (7) is transformed under alpha-beta rest frame, obtains:

$\left[\begin{array}{c}{\mathrm{\μ}}_{\mathrm{\α}}\\ {\mathrm{\μ}}_{\mathrm{\β}}\end{array}\right]=\left[\begin{array}{cc}R+{\mathrm{DL}}_{\mathrm{\α}}& -w_r{L}_{\mathrm{\α\β}}\\ w_r{L}_{\mathrm{\α\β}}& R+D{L}_{\mathrm{\β}}\end{array}\right]\left[\begin{array}{c}{i}_{\mathrm{\α}}\\ i_{\mathrm{\β}}\end{array}\right]+w_r{K}_E\left[\begin{array}{c}-\sin {\mathrm{\θ}}_r\\ \cos {\mathrm{\θ}}_r\end{array}\right]---\left(8\right)$

[u _αu _β] ^tfor voltage under rotating coordinate system; [i _αi _β] ^tfor electric current under rotating coordinate system; L _α=L _o+ L ₁cos2 θ _r; L _{α β}=L ₁sin2 θ _r; L _β=L _o-L ₁cos2 θ _r; L _o=(L _d+ L _q)/2; L ₁=(L _d-L _q)/2; θ _rfor the PMSG position angle of sea wave power generation system in the time moving.

Formula includes θ in (8) _r, 2 θ _r, wherein 2 θ _rthe calculating of giving the later stage is brought to very large difficulty, therefore, can it be eliminated by suitable conversion, from formula (8), can find out: the asymmetric of inductance matrix is 2 θ _rthe main cause of appearance, thereby, the voltage equation of the PMSG under d-q axle (7) is rewritten as:

$\left[\begin{array}{c}{u}_d\\ u_q\end{array}\right]=\left[\begin{array}{cc}R+{\mathrm{DL}}_d& -w_r{L}_q\\ w_r{L}_q& R+{\mathrm{DL}}_d\end{array}\right]\left[\begin{array}{c}{i}_d\\ i_q\end{array}\right]+\left[\begin{array}{c}0\\ w_r{K}_E+(L_d-L_q)(w_r{i}_d-{\mathrm{di}}_q/\mathrm{dt})\end{array}\right]---\left(9\right)$

Formula (9) is transformed under alpha-beta rest frame:

$\begin{array}{c}\left[\begin{array}{c}{\mathrm{\μ}}_{\mathrm{\α}}\\ {\mathrm{\μ}}_{\mathrm{\β}}\end{array}\right]=\left[\begin{array}{cc}R+{\mathrm{DL}}_d& w_r(L_d-L_q)\\ -w_r(L_d-L_q)& R+{\mathrm{DL}}_d\end{array}\right]\left[\begin{array}{c}{i}_{\mathrm{\α}}\\ i_{\mathrm{\β}}\end{array}\right]\\ +\left[(w_r{K}_E+(L_d-L_q)(w_r{i}_d-\frac{{\mathrm{di}}_q}{\mathrm{dt}})\right]\begin{array}{c}\left[\begin{array}{c}-\sin {\mathrm{\θ}}_r\\ \cos {\mathrm{\θ}}_r\end{array}\right]\end{array}\end{array}---\left(10\right)$

For the ease of using synovial membrane observer to observe back electromotive force, voltage equation (7) is rewritten into the state equation form of electric current:

$\frac{d}{\mathrm{dt}}\left[\begin{array}{c}{i}_{\mathrm{\α}}\\ i_{\mathrm{\β}}\end{array}\right]=A\·\left[\begin{array}{c}{i}_{\mathrm{\α}}\\ i_{\mathrm{\β}}\end{array}\right]+\frac{1}{L_d}\left[\begin{array}{c}{\mathrm{\μ}}_{\mathrm{\α}}\\ {\mathrm{\μ}}_{\mathrm{\β}}\end{array}\right]+\frac{E}{L_d}\left[\begin{array}{c}\sin {\mathrm{\θ}}_m\\ -\cos {\mathrm{\θ}}_m\end{array}\right]---\left(11\right)$

Wherein, $A=\frac{1}{L_d}\left[\begin{array}{cc}-R& -{\mathrm{\ω}}_r(L_d-L_q)\\ {\mathrm{\ω}}_r(L_d-L_q)& -R\end{array}\right],$

$E=\left[\begin{array}{c}{E}_{\mathrm{\α}}\\ E_{\mathrm{\β}}\end{array}\right]=\left[(w_r{K}_E+(L_d-L_q)(w_r{i}_d-\frac{{\mathrm{di}}_q}{\mathrm{dt}})\right]\left[\begin{array}{c}-\sin {\mathrm{\θ}}_r\\ \cos {\mathrm{\θ}}_r\end{array}\right],$ And E is back electromotive force.

The synovial membrane observer being constructed as follows:

$\frac{d}{\mathrm{dt}}\left[\begin{array}{c}{\hat{i}}_{\mathrm{\α}}\\ {\hat{i}}_{\mathrm{\β}}\end{array}\right]=A\·\left[\begin{array}{c}{\hat{i}}_{\mathrm{\α}}\\ {\hat{i}}_{\mathrm{\β}}\end{array}\right]+\frac{1}{L_d}\left[\begin{array}{c}{\mathrm{\μ}}_{\mathrm{\α}}\\ {\mathrm{\μ}}_{\mathrm{\β}}\end{array}\right]+\frac{Z_{\mathrm{\α\β}}}{L_d}---\left(12\right)$

Wherein, for stator α and β shaft current measured value; In order to weaken the chattering phenomenon of sliding mode observer, adopt nerve network controller to replace traditional switch function Z _{α β}, concrete structure figure as shown in Figure 5.

Speed Controller of Networks will react measured current i _{α β}, observation electric current and difference ε between both differences _{α β}the effect of the control to expansion back electromotive force EEMF; Its output variable replace traditional switch function Z _{α β}.

Design of Neural Network Controller adopts 3 layer networks: input layer, hidden layer and output layer, as shown in Figure 5.Input layer has 3 input variables i _{α β}and ε _{α β}; Hidden layer has 6 neurons; Output layer is

Input layer: formed by 3 neurons

σ ₂＝i _αβ σ ₃＝ε _αβ

o _i(t)＝σ _i i＝1,2,3

$n_{2j}\left(t\right)=\underset{i=1}{\overset{6}{\mathrm{\Σ}}}{w}_{\mathrm{ji}}{o}_i\left(t\right)+{\mathrm{\θ}}_{2j},i=\mathrm{1,2,3}$

Hidden layer: formed by 6 neurons

o _2j(t)＝f ₁[n _2j(t)] j＝1,2,...,6

$n_3\left(t\right)=\underset{j=1}{\overset{6}{\mathrm{\Σ}}}{w}_{3j}{o}_{2j}\left(t\right)+{\mathrm{\θ}}_3,j=\mathrm{1,2},...,6$

Output layer: formed by 1 neuron

o ₃(t)＝f ₂[n ₃(t)]

Select different output functions can strengthen the mapping function of network, and improve network convergence speed.The output function of hidden layer is logsigmoid function, and the output function of output layer is trnsig moid function.

$f_1\left(x\right)=\log \mathrm{sig}\left(x\right)=\frac{1}{1+e^{-x}}$

$f_2\left(x\right)=\tan \mathrm{sig}\left(x\right)=\frac{1-e^{-2x}}{1+e^{-2x}}$

$Z_{\mathrm{\α\β}}=[\mathrm{ksgn}({\hat{i}}_{\mathrm{\α}}-i_{\mathrm{\α}}),-\mathrm{ksgn}({\hat{i}}_{\mathrm{\β}}-i_{\mathrm{\β}})],$ K is sliding formwork gain.

Formula (12) deducts formula (11), and the state equation that obtains electric current observation error is:

In the time of completely following condition, sliding mode observer enters sliding formwork state:

$[i_{\mathrm{\&alpha;}}-{\hat{i}}_{\mathrm{\&alpha;}},i_{\mathrm{\&beta;}}-{\hat{i}}_{\mathrm{\&beta;}}]\frac{d}{t}\left[\begin{array}{c}{i}_{\mathrm{\&alpha;}}-{\hat{i}}_{\mathrm{\&alpha;}}\\ i_{\mathrm{\&beta;}}-{\hat{i}}_{\mathrm{\&beta;}}\end{array}\right]<0---\left(14\right)$

If k is enough large in sliding formwork gain, inequality (18) is set up, and system enters synovial membrane state, has

$\frac{d}{t}\left[\begin{array}{c}{i}_{\mathrm{\&alpha;}}-{\hat{i}}_{\mathrm{\&alpha;}}\\ i_{\mathrm{\&beta;}}-{\hat{i}}_{\mathrm{\&beta;}}\end{array}\right]=\left[\begin{array}{c}{i}_{\mathrm{\&alpha;}}-{\hat{i}}_{\mathrm{\&alpha;}}\\ i_{\mathrm{\&beta;}}-{\hat{i}}_{\mathrm{\&beta;}}\end{array}\right]=0---\left(15\right)$

Above formula (15) is updated to formula (13):

Z＝E (16)

Wherein in Z, include discontinuous high-frequency signal, therefore, for removing discontinuous high-frequency signal, obtain controlled quentity controlled variable of equal value after being passed into low pass filter, that is:

$\left[\begin{array}{c}{Z}_{\mathrm{\&alpha;}}\\ Z_{\mathrm{\&beta;}}\end{array}\right]=\left[\begin{array}{c}{E}_{\mathrm{\&alpha;}}\\ E_{\mathrm{\&beta;}}\end{array}\right]=\left[(w_r{K}_E+(L_d-L_q)(w_r{i}_d-\frac{{\mathrm{di}}_q}{\mathrm{dt}})\right]\left[\begin{array}{c}-\sin {\mathrm{\&theta;}}_r\\ \cos {\mathrm{\&theta;}}_r\end{array}\right]---\left(17\right)$

By formula (17), can obtain the rotor position angle θ of PMSG in the time of high-speed cruising _r

${\mathrm{\&theta;}}_r=\arctan (-\frac{E_{\mathrm{\&alpha;}}}{E_{\mathrm{\&beta;}}})---\left(18\right)$

In order to reduce observation error, the error that hysteresis produces to low pass filter phase place compensates, and offset is:

${\widehat{\mathrm{\&theta;}}}_{\mathrm{re}}=\arctan \left(\frac{w_r}{w_{\mathrm{cutoff}}}\right)---\left(19\right)$

Wherein, w _cutoff=1/ τ ₀the cut-off frequency of low pass filter, τ ₀it is the time constant of low pass filter.

In order to prevent that sea wave power generation system is when the high-speed cruising, due to wind speed resistance make rotor-position measured value restrain situation, in order to solve this problem, patent of the present invention adds the anti-interference observer of rotor-position, its concrete operation principle is as follows:

Detect θ _hrfor T ₁the position angle that moment is detected, for T ₂detected position angle of moment, and T ₂-T ₁=20ms, establishes position error signal and using ξ as input, and add matrix feedforward input, according to the mechanical movement model of PMSG, can construct PMSG rotor-position observer equivalent structure figure.Position error signal is observed by linear feedback structural regime, thereby realizes the observation to rotor-position.The second-order differential item of electromagnetic torque for single order differential, for second-order differential) regard the equivalence input of observer as, thus can take into account lower different load disturbance situation of the rate that changes of different wind speed, make observer have enough holes to disturb ability.

The machine performance equation of PMSG rotor-position observer can be expressed as:

$\stackrel{\&CenterDot;}{X}=\mathrm{AX}+\mathrm{Bu}---\left(20\right)$

y＝CX (21)

In formula: $\stackrel{\&CenterDot;}{X}={\left[\begin{array}{cccc}{\stackrel{\&CenterDot;}{T}}_e& T_e& w_r& {\mathrm{\&theta;}}_r\end{array}\right]}^T;$ $u={\stackrel{\&CenterDot;\&CenterDot;}{T}}_e;$ y＝θ _r； $A=\left[\begin{array}{cccc}0& 0& 0& 0\\ 1& 0& 0& 0\\ 0& \frac{1}{J}& 0& 0\\ 0& 0& P_n& 0\end{array}\right];$ $B=\left[\begin{array}{c}1\\ 0\\ 0\\ 0\end{array}\right];$ $C=\left[\begin{array}{c}0\\ 0\\ 0\\ 1\end{array}\right];$ P _nnumber of pole-pairs; J is moment of inertia.

The state equation of rotor-position observer can be expressed as:

$\stackrel{\&CenterDot;}{\hat{X}}=\left[\begin{array}{cccc}0& 0& 0& 0\\ 1& 0& 0& 0\\ 0& \frac{1}{\hat{J}}& 0& 0\\ 0& 0& P_n& 0\end{array}\right]\hat{X}+\left[\begin{array}{c}1\\ 0\\ 0\\ 0\end{array}\right]u+\left[\begin{array}{c}{l}_1\\ l_2\\ \frac{l_3}{\hat{J}}\\ \frac{l_4}{\hat{J}}\end{array}\right](y-\hat{y})---\left(22\right)$

In defined formula (22) $\left[\begin{array}{cccc}{l}_1& l_2& \frac{l_3}{\hat{J}}& \frac{l_4}{\hat{J}}\end{array}\right]$ For feedback matrix.

According to the structure of the position detection device shown in Fig. 4, can set up the biography letter relational expression of position detection error and perturbing torque:

${\mathrm{\&Delta;\&theta;}}_e\left(s\right)=\frac{-\frac{\hat{J}}{J}{s}^2}{\hat{J}{s}^4+l_4{s}^3+l_3{s}^2+l_{2}s+l_1}{T}_d\left(s\right)---\left(23\right)$

T in formula _d(s) perturbing torque for causing because wave is unstable.

From formula (23), while producing very large perturbing torque because of sea wave power generation system because of the not even running of wave, start rotor-position disturbance opposing observer, solve becoming gradually greatly to position signal errors of may causing in the erratic fluctuations of wave that observer detects, the even state of the value of losing contact with reality.

Due in this experimentation, higher to the requirement of current sample, therefore designed a kind of current sampling signal modulate circuit as Fig. 6, LSTR15-NP the 10th pin is reference voltage input, and default value is 2.5V, and the 9th pin is voltage signal output end.Amplifier LM358 has the effect of following and driving to voltage signal, the voltage-stabiliser tube in parallel with output ensured that output voltage can not exceed the scope that board receives.

The above is only the preferred embodiment of the present invention; be noted that for those skilled in the art; under the premise without departing from the principles of the invention, can also make some improvements and modifications, these improvements and modifications also should be considered as protection scope of the present invention.

Claims (1)

1. for a position sensorless control method for sea wave power generation system, it is characterized in that: dipulse non-linear voltage is applied to the anti-interference observer of method, sliding mode observer, nerve network controller and rotor-position and combine, specifically comprise the following steps:

(1) initial position of rotor detects and adopts dipulse voltage to apply method, according to cross, straight axle inductance difference principle, apply 2 direction differences, wide voltage vector that amplitude is identical to motor, current response detected twice, thereby solve and the differential inductance component of rotor-position constituting-functions relation, finally draw initial position angle of rotor according to described functional relation;

(2) after sea wave power generation system brings into operation, adopt back electromotive force to come detection rotor position, adopt sliding mode observer to obtain rotor position information: first to adopt synovial membrane observer to estimate equivalence expansion back electromotive force EEMF, by the error formation mould sliding surface detecting between electric current and observation electric current, equivalence expansion back electromotive force EEMF is observed subsequently, thereby obtain rotor-position detected value; In order to reduce position estimation error, the error that hysteresis produces to low pass filter phase place compensates;

(3) for weakening the chattering phenomenon of sliding mode observer, adopt nerve network controller to replace traditional switch function Z, obtain equivalence expansion back electromotive force EEMF; Nerve network controller reflects the effect that detects the control to equivalence expansion back electromotive force EEMF of electric current, observation electric current and difference between the two simultaneously;

(4) while producing because of the not even running of wave the perturbing torque that is greater than threshold value when sea wave power generation system, start rotor-position disturbance opposing observer, what the synovial membrane observer that solves the interference under the not steady service conditions of wave and may cause detected becomes greatly gradually to position signal errors, the even state of the value of losing contact with reality.