CN103607155B - Based on the permagnetic synchronous motor method for controlling position-less sensor of rotatory current vector - Google Patents

Abstract

The present invention relates to electric drive field, aim to provide a kind of permagnetic synchronous motor method for controlling position-less sensor based on rotatory current vector.The method comprises: the amplitude of setting rotatory current vector; The angular frequency of setting rotatory current vector; The position angle of setting permanent-magnetic synchronous motor rotor; Coordinate transform is carried out to the stator output current of three-phase permanent magnet synchronous motor; The PI computing of virtual d-q coordinate system; Coordinate inverse transformation, and realize whole driving through inverter; The merit angle observation of permagnetic synchronous motor; Permagnetic synchronous motor completes starting after above-mentioned seven steps.The present invention utilizes permagnetic synchronous motor when out-of-step free, and rotor speed can this inherent characteristic of given frequency of synchronized tracking stator rotating magnetic field.It is controlled by the running status of load torque angle observation permagnetic synchronous motor, ensure that the stability of a system.Cost of the present invention is low, control algolithm simple, and the full speed section that perfect can realize permagnetic synchronous motor position-sensor-free is run.

Description

Based on the permagnetic synchronous motor method for controlling position-less sensor of rotatory current vector

Technical field

The present invention relates to a kind of permagnetic synchronous motor Sensorless Control Technique, belong to electric drive field.

Background technology

Compared with induction machine, permagnetic synchronous motor has the advantages such as high torque (HT)/ratio of inertias, high power density, high efficiency.Permanent-magnetic synchronous motor rotor adopts permanent magnet, and without field circuit, rotor, without excitation loss and iron loss, simplifies the structure of rotor, reduces the moment of inertia of motor, and efficiency and the power factor of motor are higher.Along with improving constantly of rare earth permanent-magnetic material performance, the maturation of permagnetic synchronous motor control technology, permagnetic synchronous motor in Digit Control Machine Tool, robot, motor vehicle, the contour precision controlling field of Aero-Space, and has had in fields such as blower fan, pump class, compressors and has applied widely.

The control system of permagnetic synchronous motor needs the position transducer such as photoelectric encoder or resolver to obtain the real time information of rotor-position, realizes field orientation, and extra transducer and cable will improve the cost of system and reduce the reliability of system cloud gray model; When position transducer breaks down, system cannot normally work.The Fault Tolerance Control Technology of position-sensor-free will be considered in the occasion had higher requirements to reliability for some such as the fields such as Aero-Space, motor vehicle, nuclear power engineering; The more severe occasion of other environment is as larger in mechanical shock, too high or the limited occasion being not suitable for installation site transducer in locus of operating ambient temperature, and the application Sensorless Control Technique of some cost compare sensitivities has more advantage.

Method based on first-harmonic model: comprise direct computing method, back electromotive force method, third harmonic component voltage method, model reference adaptive method.These class methods are comparatively responsive to the Parameters variation of permanent magnet motor, poor robustness.In addition, when permanent magnet motor is static or low cruise time, because back electromotive force is too small or the noise of signal is smaller, useful signal is fallen into oblivion and maybe cannot detect and cause detecting or estimating unsuccessfully, speed when being therefore only applicable to permanent magnet motor middling speed or high-speed cruising and position estimation.

Estimation algorithm based on observer: the essence of observer is a kind of state reconstruction, its principle re-constructs a system, utilize the output signal (as stator current) that can directly measure in original system and input signal (drive singal and DC bus-bar voltage) as the input signal of reconfiguration system, and the error that the principle making its estimating signal be equivalent to the state equivalent of original system is under certain condition for both can level off to zero in dynamic change Asymptotic Stability.Usually, title estimating signal is reconstituted state or the estimated state of the state of original system, and claims this to be observer in order to realize the system of state reconstruction.Main employing has nonlinear observer, full-order state observer, reduced-order state observer, extended Kalman filter and sliding mode observer at present.

High Frequency Injection: the basic thought of this method utilizes inverter, permanent magnet motor is imposed to voltage (electric current) excitation of high frequency, low amplitude value, electric current (voltage) response signal is obtained at the leading-out terminal of motor, the signal obtained is processed, speed and the position of motor can be estimated.A basic premise condition of this method is that permanent magnet motor has the salient pole (rotor is salient pole type) in space or the salient pole (Ld ≠ Lq) of magnetic circuit, and therefore this method is also referred to as salient pole back tracking method.But along with the raising of rotating speed, the back electromotive force of motor also will increase, and this part can not be left in the basket, and cause estimation precision to reduce along with the raising of rotating speed, and this algorithm can only be applicable to built-in type permagnetic synchronous motor.

Existing single position Sensorless Control algorithm all has certain limitation, otherwise be applicable to permagnetic synchronous motor run high regime as back electromotive force detection method, model reference adaptive method, sliding mode observer method etc.; Or be applicable to low speed segment as High Frequency Injection etc.

In order to solve single permagnetic synchronous motor method for controlling position-less sensor high regime existing in full velocity shooting or the poor problem of low speed segment accuracy of observation, existing main method is merged the position sensorless control method being suitable for low speed segment and high regime, adopts fusion position-sensorless control method to solve; Now many methods adopt High Frequency Injection at low speed segment and adopt back electromotive force method or model reference adaptive method in high speed section; And what realize two kinds of algorithms at middle low speed segment takes over seamlessly control.This will increase the complexity of system greatly, and with running to debug, certain difficulty is brought for the adaptivity of system, need the relatively accurate parameter of electric machine, and High Frequency Injection to require motor to have certain saliency, will not be suitable for for non-salient pole permagnetic synchronous motor.

Summary of the invention

The technical problem to be solved in the present invention is, overcomes the defect of prior art, provides a kind of permagnetic synchronous motor method for controlling position-less sensor based on rotatory current vector.

For technical solution problem, the technical solution used in the present invention is:

A kind of permagnetic synchronous motor method for controlling position-less sensor based on rotatory current vector is provided, is realized the starting of permagnetic synchronous motor by following steps:

(1) amplitude of rotatory current vector is set;

Setting i _{q_ref}=1.2 × I _n; i _{d_ref}=0;

Each symbol: i in formula _{q_ref}for q shaft current set-point, unit is ampere; I _nfor load current value, unit is ampere; i _{d_ref}for d shaft current set-point, unit is ampere;

(2) angular frequency of rotatory current vector is set by any one mode following _e,

Step-like manner: ω _e=constant; The span of this constant is 0≤ω _e≤ ω _n; ω _nfor the rated frequency of motor

Ramp system: ω _e=k ₁× t; k ₁span be k ₁>0;

Acceleration mode: ω _e=k ₂× t ²; k ₂span be k ₂>0;

Above-mentioned various middle t is the Accelerating running time of rotatory current azimuth frequency, and unit is second;

(3) angular position theta of permanent-magnetic synchronous motor rotor is set _e, θ _e=∫ ω _edt;

(4) coordinate transform is carried out to the stator output current of three-phase permanent magnet synchronous motor;

The stator current of the three-phase permanent magnet synchronous motor obtained of sampling is carried out CLARK conversion, obtains the current value i under two-phase alpha-beta rest frame _α, i _β; Then carry out PARK conversion, being wherein used for the angle of phasing adopts the angular position theta obtained in step (3) _e; Set up virtual d-q coordinate system, finally obtain step (3) angular position theta _ethe value i of phasing is fastened at virtual coordinates _d, i _q;

(5) the PI computing of virtual d-q coordinate system;

Given value of current value under virtual d-q coordinate system and actual feedback are compared, and carries out PI computing; Export voltage given value Ud, Uq under virtual d-q coordinate system;

(6) coordinate inverse transformation, and realize whole driving through inverter;

Voltage given value Ud, Uq under virtual d-q coordinate system are carried out park inverse transformation, obtains the voltage given value u under two-phase alpha-beta rest frame _α, u _β, and six drive singal of driver are obtained through SVPWM modulation, realize voltage modulated;

(7) the merit angle observation of permagnetic synchronous motor;

In two-phase alpha-beta rest frame, the merit angle of permagnetic synchronous motor is observed, to the i obtained in step (4), (6) _α, i _β, u _α, u _βcalculate, obtain the rotation magnetic linkage ψ under two-phase alpha-beta static coordinate _α, ψ _βvalue; Adopt following formula to solve again and obtain merit angle θ _t:

${\mathrm{\θ}}_T=\mathrm{arc}\tan \left(\frac{{\mathrm{\ψ}}_{\mathrm{\α}}{i}_{\mathrm{\β}}-{\mathrm{\ψ}}_{\mathrm{\β}}{i}_{\mathrm{\α}}}{{\mathrm{\ψ}}_{\mathrm{\α}}{i}_{\mathrm{\α}}+{\mathrm{\ψ}}_{\mathrm{\β}}{i}_{\mathrm{\β}}-L_s(i_{\mathrm{\α}}^2+i_{\mathrm{\β}}^2)}\right)$

In this formula, L _sfor the self-induction of permagnetic synchronous motor, unit is H;

Permagnetic synchronous motor completes starting after above-mentioned seven steps.

In the present invention, be also included in permagnetic synchronous motor and complete and start and after entering steady operation, the carrying out at permagnetic synchronous motor merit angle controlled;

(1) merit angle value θ during permagnetic synchronous motor steady operation is set _{t_ref};

For surface-mount type permagnetic synchronous motor, best efficiency point is at θ _{t_max}=90;

For the permagnetic synchronous motor of built-in type, best efficiency point exists

${\mathrm{\θ}}_{T\_\max }=\arccos \left\{\frac{X-\sqrt{X^2+8}}{4}\right\}$

Wherein this angle value is generally between 90-120 degree;

In formula, wherein ψ _ffor permanent magnet flux linkage, unit is Wb; L _qfor q axle inductance, unit is H; L _dfor d axle inductance, unit is H; i _sfor rotatory current vector magnitude, unit is ampere.

(2) adjustment at permagnetic synchronous motor merit angle is cut during steady operation;

Be switched to the dynamic PI adjustment state at merit angle; By the described merit angle value θ detected _tas feedback quantity, with the merit angle set point θ of permagnetic synchronous motor during steady operation _{t_ref}compare, as q shaft current initial set value i after PI computing _{q_ref}offset i _{q_com}; After dynamic adjustments, stable operation is setting on merit angle by system.

(3) adjustment at permagnetic synchronous motor merit angle is cut out during steady operation

System stable operation in setting merit angle on after, using the mobility scale at merit angle, ring width h is set as basis for estimation; When merit angle pulsation absolute value is within ring width, then think system stability; PI controller exports a stable q shaft current offset i _{q_com}, its offset is added with initial set value as the new set-point of q shaft current; Namely

i _{q_ref_new}=i _{q_ref}+i _{q_com}

Be switched to merit angular motion state PI adjustment state, control system for permanent-magnet synchronous motor runs on the mode of its control of frequency;

(4) Dynamic Regulating Process during load torque sudden change

When in frequency, its controls load fluctuates in operation to permagnetic synchronous motor, merit angle regulates and system can be made again to stablize; But when permagnetic synchronous motor generation load torque compared with macromutation to such an extent as to the regulated value at merit angle exceeds the ring width that step (3) arranges time, in order to ensure the stability that permagnetic synchronous motor runs and reliability, system gets back to the Dynamic Regulating Process at merit angle by switching, repeat step (2) and (3);

The steady operation of described permagnetic synchronous motor refers to that the mobility scale at merit angle is less than the ring width of setting.

In the present invention, the border point of safes when best efficiency point due to three-phase permanent magnet synchronous motor control system is also its control operation of permagnetic synchronous motor simultaneously, in order to take into account efficiency and the stability of system, the stability margin retaining 5 degree determines merit angle θ _{t_ref}reference value.

In the present invention, adopt the permagnetic synchronous motor method for controlling position-less sensor of rotatory current vector mainly to comprise following components: (A) by rotatory current vector generation portion, the rotatory current vector that the angle being mainly used to produce constant amplitude changes according to certain rules; (B) observation algorithm at permagnetic synchronous motor load torque angle, this algorithm is used for observing the merit angle of permagnetic synchronous motor, for judging the running status of permagnetic synchronous motor; (C) control section at the merit angle of permagnetic synchronous motor; (D) switching controls of permagnetic synchronous motor merit angle control.

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

This control method utilizes permagnetic synchronous motor when out-of-step free, and rotor speed can this inherent characteristic of given frequency of synchronized tracking stator rotating magnetic field.By the running status of load torque angle observation permagnetic synchronous motor, and it is controlled, ensure that the stability of system.Cost of the present invention is low, control algolithm simple, and the full speed section that perfect can realize permagnetic synchronous motor position-sensor-free is run.

Accompanying drawing explanation

Fig. 1 three-phase permanent magnet synchronous motor vector correlation figure;

Fig. 2 is based on the system block diagram of the three-phase permanent magnet synchronous motor position-sensor-free of rotatory current vector;

Fig. 3 three-phase permanent magnet synchronous motor merit angle observation algorithm block diagram.

Embodiment

One, the rotatory current vector Mathematical Modeling of starting without position

Below in conjunction with accompanying drawing, technology of the present invention is described further, the torque equation from permagnetic synchronous motor:

$T_e=\frac{3}{2}{n}_p[{\mathrm{\ψ}}_f{i}_q+(L_d-L_q)i_d{i}_q]---\left(1\right)$

Suppose that adopted permagnetic synchronous motor is that Surface Mount shows permagnetic synchronous motor, namely

L _d=L _q, $K_T=\frac{3}{2}{n}_p{\mathrm{\ψ}}_f$

Then, the electromagnetic torque of permagnetic synchronous motor is

T _e=K _Ti _q=K _TI _ssin(θ _ed)(2)

The mechanical motion equation of motor is:

$T_e-T_L=J\frac{{\mathrm{d\ω}}_r}{\mathrm{dt}}---\left(3\right)$

Initial condition when permagnetic synchronous motor starts is:

T _e0=K _TI _ssin(θ ₀)=T _L0(4)

θ ₀=arcsin(T _L0/K _TI _s)(5)

θ _T=θ ₀+θ _ei(6)

${\mathrm{\θ}}_{\mathrm{ei}}={\∫}_0^t({\mathrm{\ω}}_e-{\mathrm{\ω}}_r)\mathrm{dt}---\left(7\right)$

Permagnetic synchronous motor completes the state of termination of acceleration:

T _eend=K _TI _ssin(θ _end)=T _Lend(8)

θ _end=arcsin(T _Lend/K _TI _s)(9)

Parameter wherein:

θ _tby rotatory current vector I _smerit angle is defined as with the angle of d axle;

θ ₀for the electromagnetic torque moment equal to initial load torque, rotatory current vector I _swith the angle of d axle

θ _endfor having accelerated the moment, electromagnetic torque moment equal to load torque, rotatory current vector I _swith the angle of d axle (if be constant load torque, θ _end=θ ₀)

θ _eifor rotor start rotate after, rotatory current vector I _swith the recruitment at d axle clamp angle

ω _rfor the spinner velocity of permagnetic synchronous motor

ω _efor the magnitude of angular velocity of rotatory current vector

The condition of employing rotatory current vector permagnetic synchronous motor normal starting is:

${\mathrm{\θ}}_{\mathrm{ei}}={\∫}_0^{t_{\mathrm{end}}}({\mathrm{\ω}}_e-{\mathrm{\ω}}_r)\mathrm{dt}=\mathrm{\π}-{\mathrm{\θ}}_0-{\mathrm{\θ}}_{\mathrm{end}}---\left(10\right)$

Now, rotor speed omega _r(tend)>=ω _e(tend), critical condition is wherein ω _r(tend)=ω _e(tend)

As long as namely meet the condition of above-mentioned equation, when not needing position detection, permagnetic synchronous motor just can complete starting.

The given way of rotatory current azimuth frequency wherein mainly contains following three kinds of modes:

The first: step-like manner ω _e=constant; (11)

The second: ramp system ω _e=k ₁gt; (12)

The third: acceleration mode ω _e=k ₂gt ²; (13)

Two, implementation step

The present invention starts by the following technical solutions for solving the full velocity shooting position-sensor-free of permagnetic synchronous motor, devise a kind of based on rotatory current vector without position start mode, its concrete implementation step is as follows:

Step 1: the amplitude of setting rotatory current vector;

As shown in Figure 2, set

i _{q_ref}=1.2×I _N

i _{d_ref}=0

Given value of current value is set as 1.2 times of rated current by this part, reason is that driver all can leave enough safe clearances for driven motor when nominal load works, and 1.2 times can ensure the safe and reliable work of driver while, ensure that electric motor starting can adapt to all kinds load of below nominal load, and ensure acceleration performance fast; In actual implementation procedure, parameter value 1.2 can regulate according to actual loading type cases and drive case.

Step 2: the angular frequency of setting rotatory current vector, the major way of its setting has following three kinds of modes;

The first: step-like manner ω _e=constant; (11)

The second: ramp system ω _e=k ₁gt; (12)

The third: acceleration mode ω _e=k ₂gt ²; (13)

Step 3: the position angle of setting permanent-magnetic synchronous motor rotor;

θ _e=∫ω _edt(14)

Step 4: coordinate transform is carried out to the stator output current of three-phase permanent magnet synchronous motor;

Stator current sampling being obtained three-phase permanent magnet synchronous motor carries out CLARK and converts the current value i obtained under two-phase alpha-beta rest frame _α, i _β; And carry out PARK conversion, being wherein used for the angle of phasing adopts in step 3 the electric angle angle value obtained, and sets up virtual d-q coordinate system, finally obtains in step 3 θ _evirtual coordinates fastens the value i of phasing _d, i _q.

Step 5: the PI computing of virtual d-q coordinate system;

Given value of current value under virtual d-q coordinate system and actual feedback to be compared and through PI computing; Export voltage given value Ud, Uq under virtual d-q coordinate system.

Step 6: coordinate inverse transformation, and realize whole driving through inverter;

Voltage given value Ud, Uq under virtual d-q coordinate system is carried out park inverse transformation and obtains voltage given value u under two-phase alpha-beta rest frame _α, u _β, and obtain driver 6 drive singal through SVPWM modulation, realize voltage modulated.

Step 7: the merit angle observation of permagnetic synchronous motor;

In two-phase rest frame, the merit angle of permagnetic synchronous motor is observed, as shown in Figure 3, by the u obtained in step 4 and step 6 _α, u _β, i _α, i _βcalculate, obtain the rotation magnetic linkage ψ under two-phase static coordinate _α, ψ _βvalue; Merit angle is solved in employing formula 15.

${\mathrm{\θ}}_T=\mathrm{arc}\tan \left(\frac{{\mathrm{\ψ}}_{\mathrm{\α}}{i}_{\mathrm{\β}}-{\mathrm{\ψ}}_{\mathrm{\β}}{i}_{\mathrm{\α}}}{{\mathrm{\ψ}}_{\mathrm{\α}}{i}_{\mathrm{\α}}+{\mathrm{\ψ}}_{\mathrm{\β}}{i}_{\mathrm{\β}}-L_s(i_{\mathrm{\α}}^2+i_{\mathrm{\β}}^2)}\right)---\left(15\right)$

Step 8: the control at permagnetic synchronous motor merit angle;

When permagnetic synchronous motor completes starting through above-mentioned seven steps, and after entering steady operation, during owing to starting, the starting current set point of the permagnetic synchronous motor of initial setting is larger; When permagnetic synchronous motor has started rear steady operation, merit angle is less, and the efficiency of system cloud gray model is lower, in order to optimizing operation efficiency carries out the control of merit angle, system is run on greater efficiency point.

Merit angle value θ during 8.1 permagnetic synchronous motor steady operation _{t_ref}setting;

For surface-mount type permagnetic synchronous motor best efficiency point at θ _{t_ref}=90, and for the permagnetic synchronous motor of built-in type, best efficiency point exists

${\mathrm{\θ}}_{T\_\mathrm{ref}}=\arccos \left\{\frac{X-\sqrt{X^2+8}}{4}\right\}---\left(16\right)$

Wherein this angle value general is between 90-120 degree.

Border point of safes when best efficiency point due to three-phase permanent magnet synchronous motor control system is also its control operation of permagnetic synchronous motor simultaneously, in order to take into account efficiency and the stability of system, can stay the stability margin of about 5 degree to determine the reference value at merit angle.

The adjustment at permagnetic synchronous motor merit angle is cut during 8.2 steady operation

Close a switch S1, and the dynamic PI being switched to merit angle regulates; The merit angle set point of merit angle value detected in step 7 as permagnetic synchronous motor when feedback quantity and steady operation is compared, as q shaft current initial set value i after PI computing _{q_ref}offset i _{q_com}, after dynamic adjustments, stable operation is setting on merit angle by system.

The adjustment at permagnetic synchronous motor merit angle is cut out during 8.3 steady operation

When completing steps 8.2, system stable operation is on the merit angle of setting; Using the mobility scale at merit angle as basis for estimation, can ring width h be set, when merit angle pulsation absolute value is within ring width, then thinks system stability; PI controller can export a stable q shaft current offset i _{q_com}, its offset is added with initial set value as the new set-point of q shaft current;

i _{q_ref_new}=i _{q_ref}+i _{q_com}(17)

And cut-off switch S1, cut out merit angular motion state PI and regulate, control system for permanent-magnet synchronous motor runs on the mode of its control of frequency.

Dynamic Regulating Process during 8.4 load torque sudden change

When in its control of frequency runs, little fluctuation occurs permagnetic synchronous motor in load, the adjustment of merit angle among a small circle just can make system again stablize; But when the comparatively macromutation of permagnetic synchronous motor generation load torque, when the regulated value at merit angle exceeds the ring width of step 8.3 setting, in order to ensure the stability that permagnetic synchronous motor runs and reliability, system gets back to the Dynamic Regulating Process at merit angle by switching, repeat step 8.2 and 8.3.

Claims (2)

1. based on the permagnetic synchronous motor method for controlling position-less sensor of rotatory current vector, it is characterized in that, realized the starting of permagnetic synchronous motor by following steps:

(1) amplitude of rotatory current vector is set;

Setting i _{q_ref}=1.2 × I _n; i _{d_ref}=0;

Each symbol: i in formula _{q_ref}for q shaft current set-point, I _nfor load current value, i _{d_ref}for d shaft current set-point, unit is ampere;

(2) angular frequency of rotatory current vector is set by any one mode following _e,

Step-like manner: ω _e=constant; The span of this constant is 0≤ω _e≤ ω _n; ω _nfor the rated frequency of motor;

Ramp system: ω _e=k ₁× t; k ₁span be k ₁>0;

Acceleration mode: ω _e=k ₂× t ²; k ₂span be k ₂>0;

Above-mentioned various middle t is the Accelerating running time of rotatory current azimuth frequency, and unit is second;

(3) angular position theta of permanent-magnetic synchronous motor rotor is set _e, θ _e=∫ ω _edt;

(4) coordinate transform is carried out to the stator output current of three-phase permanent magnet synchronous motor;

The stator current of the three-phase permanent magnet synchronous motor obtained of sampling is carried out CLARK conversion, obtains the current value i under two-phase alpha-beta rest frame _α, i _β; Then carry out PARK conversion, being wherein used for the angle of phasing adopts the angular position theta obtained in step (3) _e; Set up virtual d-q coordinate system, finally obtain step (3) angular position theta _ethe value i of phasing is fastened at virtual coordinates _d, i _q;

(5) the PI computing of virtual d-q coordinate system;

Given value of current value under virtual d-q coordinate system and actual feedback are compared, and carries out PI computing; Export the voltage given value U under virtual d-q coordinate system _d, U _q;

(6) coordinate inverse transformation, and realize whole driving through inverter;

By the voltage given value U under virtual d-q coordinate system _d, U _qcarry out park inverse transformation, obtain the voltage given value u under two-phase alpha-beta rest frame _α, u _β, and six drive singal of driver are obtained through SVPWM modulation, realize voltage modulated;

(7) the merit angle observation of permagnetic synchronous motor;

In two-phase alpha-beta rest frame, the merit angle of permagnetic synchronous motor is observed, to the i obtained in step (4), (6) _α, i _β, u _α, u _βcalculate, obtain the rotation magnetic linkage ψ under two-phase alpha-beta static coordinate _α, ψ _βvalue; Adopt following formula to solve again and obtain merit angle θ _t:

${\mathrm{\θ}}_T=arctan\left(\frac{{\mathrm{\ψ}}_{\mathrm{\α}}{i}_{\mathrm{\β}}-{\mathrm{\ψ}}_{\mathrm{\β}}{i}_{\mathrm{\α}}}{{\mathrm{\ψ}}_{\mathrm{\α}}{i}_{\mathrm{\α}}+{\mathrm{\ψ}}_{\mathrm{\β}}{i}_{\mathrm{\β}}-L_s(i_{\mathrm{\α}}^2+i_{\mathrm{\β}}^2)}\right)$

In this formula, L _sfor the self-induction of permagnetic synchronous motor, unit is H;

Permagnetic synchronous motor completes starting after above-mentioned seven steps;

Complete at permagnetic synchronous motor and start and after entering steady operation, the carrying out at permagnetic synchronous motor merit angle controlled;

(A) merit angle value θ during permagnetic synchronous motor steady operation is set _{t_ref};

For surface-mount type permagnetic synchronous motor, best efficiency point is at θ _{t_max}=90;

For the permagnetic synchronous motor of built-in type, best efficiency point exists

${\mathrm{\θ}}_{T\_max}=arccos\left\{\frac{X-\sqrt{X^2+8}}{4}\right\}$

Wherein this angle value is between 90-120 degree;

In formula, ψ _ffor permanent magnet flux linkage, unit is Wb; L _qfor q axle inductance, unit is H; L _dfor d axle inductance, unit is H; i _sfor rotatory current vector magnitude, unit is ampere;

(B) adjustment at permagnetic synchronous motor merit angle is cut during steady operation;

Be switched to the dynamic PI adjustment state at merit angle; By the merit angle value θ calculated in step (7) _tas feedback quantity, with the merit angle set point θ of permagnetic synchronous motor during steady operation _{t_ref}compare, as q shaft current initial set value i after PI computing _{q_ref}offset i _{q_com}; After dynamic adjustments, stable operation is setting on merit angle by system;

(C) adjustment at permagnetic synchronous motor merit angle is cut out during steady operation

System stable operation in setting merit angle on after, using the mobility scale at merit angle, ring width h is set as basis for estimation; When merit angle pulsation absolute value is within ring width, then think system stability; PI controller exports a stable q shaft current offset i _{q_com}, its offset is added with initial set value as the new set-point of q shaft current; Namely

i _{q_ref_new}＝i _{q_ref}+i _{q_com}

Be switched to merit angular motion state PI adjustment state, control system for permanent-magnet synchronous motor runs on the mode of its control of frequency;

(D) Dynamic Regulating Process during load torque sudden change

When in frequency, its controls load fluctuates in operation to permagnetic synchronous motor, merit angle regulates and system can be made again to stablize; But when permagnetic synchronous motor generation load torque compared with macromutation to such an extent as to the regulated value at merit angle exceeds the ring width that step (C) arranges time, in order to ensure the stability that permagnetic synchronous motor runs and reliability, system gets back to the dynamic PI adjustment process at merit angle by switching, repeat step (B) and (C);

The steady operation of described permagnetic synchronous motor refers to that the mobility scale at merit angle is less than the ring width of setting.

2. method according to claim 1, is characterized in that, determines merit angle θ _{t_ref}reference value time, retain the stability margin of 5 degree.