CN104378035A - Mixed excitation synchronous motor field weakening control method for judging field weakening moment through voltage differences - Google Patents

Abstract

The invention discloses a mixed excitation synchronous motor field weakening control method for judging the field weakening moment through voltage differences. The operating area of a mixed excitation motor is judged through the difference between busbar voltage and counter potential; when the difference between the busbar voltage and the counter potential is greater than zero, the mixed excitation synchronous motor operates in a low speed area, the control strategy that id is equal to zero is adopted, and axis-d current, axis-q current and exciting current are allocated in a coordinating mode according to loads; when the difference between the busbar voltage and the counter potential is equal to zero, the motor operates in a high speed area, the axis-d current and the exciting current are adopted for field weakening jointly, in other words, when the mixed excitation motor enters the high speed area, the exciting current is adopted for field weakening firstly, and after the exciting current reaches the rated value, the axis-d current continues to be adopted for field weakening. By means of the mixed excitation synchronous motor field weakening control method for judging the field weakening moment on the basis of the difference between the busbar voltage and the counter potential, output voltage of an inverter is sufficiently utilized, and the operating efficiency of the mixed excitation motor is improved.

Description

Voltage difference judges the hybrid exciting synchronous motor field weakening control method in weak magnetic moment

Technical field

The invention belongs to electric drive technology field, relate to a kind of weak magnetic strategy, particularly relate to a kind of hybrid exciting synchronous motor control method.

Background technology

Hybrid exciting synchronous motor is a kind of wide range speed control motor grown up on the basis of permanent-magnet synchronous and electric excitation synchronous motor, and its main purpose is the problem being difficult to regulate to solve permagnetic synchronous motor air-gap field.Hybrid exciting synchronous motor has two kinds of excitation sources, and one is permanent magnet, and another kind is electric excitation, and the magnetic potential that permanent magnet produces is main magnetic potential, and the magnetic potential that excitation winding produces is auxiliary magnetic potential.This motor combines the advantage of permanent-magnet synchronous and electric excitation synchronous motor, and two kinds of excitation sources interact and produce main flux in motor gas-gap, when electric magnet exciting coil passes into the exciting current of forward, produces forward electromagnetic torque and increases motor torque; Otherwise, when electric magnet exciting coil passes into reverse exciting current, then produce opposing magnetic field and weaken the object that air-gap field reaches weak magnetic speed-up, thus widened the speed adjustable range of motor.

At present, for the mixed excitation electric machine weak magnetic moment judge field weakening control method and Research on Driving System also less, pertinent literature is not a lot, substantially can be classified as a class, namely judges the weak magnetic moment based on rotating speed.Judge that the field weakening control method in weak magnetic moment is fairly simple and it is the most extensive to use based on rotating speed, when the motor speed of service reaches base speed, motor enters weak magnetic field operation region, utilizes rotating speed to judge, controls simple and convenient; Shortcoming is that motor runs below nominal load and after entering high-speed cruising region, the output voltage of inverter is not fully used.

Summary of the invention

Technical problem: the deficiency that the present invention is directed to prior art, on the basis analyzing existing hybrid exciting synchronous motor field weakening control method, proposes the hybrid exciting synchronous motor field weakening control method that a kind of voltage difference judges the weak magnetic moment.

Technical scheme: voltage difference of the present invention judges the hybrid exciting synchronous motor field weakening control method in weak magnetic moment, comprises the following steps:

(1) phase current i is gathered from motor main circuit _a, i _bwith exciting current i _f, accurate initial position detection is carried out to motor, collection signal from motor encoder, sends into controller and process, draw rotating speed n and rotor position angle θ;

(2) the phase current i will gathered _a, i _bthrough signal condition and A/D conversion, then carry out park transforms, obtain the d shaft current i under two-phase rotating coordinate system _dwith q shaft current i _q;

(3) encoder is surveyed rotating speed n and given rotating speed n ^*after obtain rotating speed deviation delta n, described rotating speed deviation delta n input speed adjuster is obtained torque reference value after proportional integral computing by torque reference value busbar voltage U _dc, stator d shaft voltage u _d, stator q shaft voltage u _q, actual measurement rotating speed n and given rotating speed n ^*input current distributor, the weak magnetic moment is judged: when busbar voltage is greater than back-emf according to busbar voltage and back-emf difference, then hybrid exciting synchronous motor runs on low regime, enter step 4), when busbar voltage equals back-emf, hybrid exciting synchronous motor runs on high velocity, enters step 5);

(4) judge whether load torque meets T _l≤ T _n, wherein T _lfor load torque, T _nfor nominal torque;

Work as T _l≤ T _ntime, i _dref=0, i _fref=0, so following current sharing scheme can be obtained:

$\left\{\begin{array}{c}{i}_{\mathrm{dref}}=0\\ i_{\mathrm{qref}}=\frac{{2T}_{\mathrm{eref}}}{3{\mathrm{p\ψ}}_{\mathrm{pm}}}\\ i_{\mathrm{fref}}=0\end{array}\right.$

Work as T _l>T _ntime, i _dref=0, i _qref=i _qN, so following current sharing scheme can be obtained:

$\left\{\begin{array}{c}{i}_{\mathrm{dref}}=0\\ i_{\mathrm{fref}}=\frac{{2T}_{\mathrm{eref}}-3{\mathrm{p\ψ}}_{\mathrm{pm}}{i}_{\mathrm{qN}}}{3{\mathrm{pM}}_{\mathrm{sf}}{i}_{\mathrm{qN}}}\\ i_{\mathrm{qref}}=i_{\mathrm{qN}}\end{array}\right.$

Wherein, i _dreffor d shaft current reference value, i _qreffor q shaft current reference value, i _freffor excitation winding current reference value; ψ _pmfor permanent magnet flux linkage, p is motor number of pole-pairs; i _qNfor q shaft current rated value, M _sffor the mutual inductance between armature winding and excitation winding, T _ereffor electromagnetic torque reference value;

(5) the 1st stages adopt exciting current to carry out weak magnetic, can obtain following current sharing scheme:

$\left\{\begin{array}{c}{\mathrm{\ω}}_e=\frac{U_{\mathrm{dc}}/\sqrt{3}}{\sqrt{{\left(L_q{i}_{\mathrm{qref}}\right)}^2+{({\mathrm{\ψ}}_{\mathrm{pm}}+M_{\mathrm{sf}}{i}_{\mathrm{fref}})}^2}}\\ i_{\mathrm{dref}}=0\\ T_{\mathrm{eref}}=\frac{3}{2}{\mathrm{pi}}_{\mathrm{qref}}({\mathrm{\ψ}}_{\mathrm{pm}}+M_{\mathrm{sf}}{i}_{\mathrm{fref}})\end{array}\right.$

After exciting current reaches rated value, the 2nd stage continues to adopt d shaft current to carry out weak magnetic, can obtain following current sharing scheme:

$\left\{\begin{array}{c}{\mathrm{\ω}}_e=\frac{U_{\mathrm{dc}}/\sqrt{3}}{\sqrt{{\left(L_q{i}_{\mathrm{qref}}\right)}^2+{({\mathrm{\ψ}}_{\mathrm{pm}}+{L_d{i}_{\mathrm{dref}}+M}_{\mathrm{sf}}{i}_{\mathrm{fN}})}^2}}\\ i_{\mathrm{fref}}=i_{\mathrm{fN}}\\ T_{\mathrm{eref}}=\frac{3}{2}{\mathrm{pi}}_{\mathrm{qref}}[{\mathrm{\ψ}}_{\mathrm{pm}}+{(L_d-L_q)i_{\mathrm{dref}}+M}_{\mathrm{sf}}{i}_{\mathrm{fN}}]\end{array}\right.$

Wherein, ω _efor angular rate, U _dcfor the maximum voltage that inverter can provide, i _fNfor exciting current rated value, L _dstator winding d axle inductance, L _qfor stator winding q axle inductance;

(6) d shaft current reference value i distributing switch produced _drefwith q shaft current i _qrefrespectively with the d shaft current i in described step (2) _dwith q shaft current i _qafter obtain d shaft current deviation delta i _dwith q shaft current deviation delta i _q, by d shaft current deviation delta i _dinput d shaft current adjuster carries out proportional integral computing, obtains d shaft voltage u _d, by q shaft current deviation delta i _qinput q shaft current adjuster carries out proportional integral computing, obtains q shaft voltage u _q, then to described d shaft voltage u _dwith q shaft voltage u _qafter jointly carrying out rotating orthogonal-static two phase inversion, obtain α shaft voltage u under static two phase coordinate systems _αwith β shaft voltage u _β, by described α shaft voltage u _αwith β shaft voltage u _βinput pulse width modulation module, computing exports 6 road pulse width modulating signals, drives main power inverter;

The exciting current i simultaneously will gathered in step (1) _f, with exciting current reference value i after signal condition and A/D are changed _frefsend into DC excitation pulse width modulation module together, computing exports 4 road pulse width modulating signals to drive exciting power converter;

The exciting current i simultaneously will gathered in step (1) _f, with exciting current reference value i after signal condition and A/D are changed _frefsend into DC excitation pulse width modulation module together, computing exports 4 road pulse width modulating signals to drive exciting power converter.

In a kind of preferred version of the inventive method, step 6) in Pulse width modulation module be space vector pulse width modulation module.

Beneficial effect: existing hybrid exciting synchronous motor weak magnetics detect is all judge that the field weakening control method in weak magnetic moment exists many shortcomings based on rotating speed, one of them is exactly that inverter output voltage is not utilized effectively, the present invention is by step 4) and step 5) method in weak magnetic moment is judged based on busbar voltage and back-emf, accurately can judge the weak magnetic moment, make hybrid exciting synchronous motor accurately can enter weak magnetic area, so the relatively existing field weakening control method of the present invention has the following advantages:

Relative to the method judging the weak magnetic moment based on rotating speed, the method makes inverter output voltage be fully used;

Relative to the method judging the weak magnetic moment based on rotating speed, the method increase the efficiency of hybrid exciting synchronous motor;

Relative to the method judging the weak magnetic moment based on rotating speed, the method increase the load capacity in high velocity of hybrid exciting synchronous motor;

Relative to power factor 1 and efficiency-optimized control, the method has widened the output-constant operation scope of hybrid exciting synchronous motor further.

Accompanying drawing explanation

Fig. 1 judges mixed excitation electric machine weak magnetic moment system block diagram based on voltage difference;

Fig. 2 is first stage hybrid exciting synchronous motor weak magnetic field operation trajectory diagram;

Fig. 3 is second stage hybrid exciting synchronous motor weak magnetic field operation trajectory diagram;

Fig. 4 is the logical procedure diagram of the inventive method;

Fig. 5 is the system block diagram of the inventive method;

Fig. 6 is the structured flowchart realizing the inventive method;

Fig. 7 is simulation result of the present invention.

Embodiment

Fig. 3 is the system block diagram realizing hybrid exciting synchronous motor power factor control method of the present invention, and this control system is made up of AC power, rectifier, bus capacitor, dsp controller, main power inverter, auxiliary power inverter, transducer, hybrid exciting synchronous motor, photoelectric encoder etc.

AC power is powered to whole system, and after rectifier rectification, filtering, voltage stabilizing, give main and auxiliary power inverter, and Hall voltage transducer gathers busbar voltage, sends into controller after conditioning.The output termination hybrid exciting synchronous motor of main and auxiliary power inverter, Hall current instrument transformer gathers phase current and exciting current, send into controller after conditioning, code device signal gathers rotating speed and rotor-position signal, sends into controller and calculate rotor position angle and rotating speed after process.Controller exports 10 road pwm signals and drives main, exciting power converter respectively.

Hybrid exciting synchronous motor field weakening control method of the present invention, shown in Fig. 3, specifically comprises the following steps:

(1) three Hall current sensor gathers phase current i from motor main circuit respectively _a, i _bwith exciting current i _fthe signal collected is sent into controller after the signal conditions such as voltage follow, filtering, biased and overvoltage protection, carry out accurate initial position detection to motor, collection signal from motor encoder, process is sent into controller and is calculated rotating speed n and rotor position angle θ;

(2) the phase current i of controller will be sent into _a, i _bcarry out A/D conversion, to obtain the d shaft current i under two-phase rotating coordinate system through three phase coordinate systems to the park transforms of two-phase rotating coordinate system _dwith q shaft current i _q;

(3) encoder is surveyed rotating speed n and given rotating speed n ^*after obtain rotating speed deviation delta n, obtain torque reference value after rotating speed deviation delta n admission velocity adjuster by torque reference value busbar voltage U _dc, stator d shaft voltage u _d, stator q shaft voltage u _q, actual measurement rotating speed n and given rotating speed n ^*send into distributing switch, judge the weak magnetic moment according to voltage difference and carry out electric current distribution, even

$\left(1\right)---\mathrm{\Δu}=\frac{U_{\mathrm{dc}}}{\sqrt{3}}-\sqrt{u_d^2+u_q^2}$

As Δ u>0, then hybrid exciting synchronous motor runs on low regime, enters step 4), as Δ u=0, hybrid exciting synchronous motor runs on high velocity, enters step 5), as shown in Figure 1.

(4) low regime adopts i _d=0 strategy, specific as follows;

According to principle of vector control, in d-q coordinate system, draw the Mathematical Modeling of hybrid exciting synchronous motor.

Flux linkage equations:

$\left[\begin{array}{c}{\mathrm{\ψ}}_d\\ {\mathrm{\ψ}}_q\\ {\mathrm{\ψ}}_f\end{array}\right]=\left[\begin{array}{ccc}{L}_d& 0& M_{\mathrm{sf}}\\ 0& L_q& 0\\ 3/{2M}_{\mathrm{sf}}& 0& L_f\end{array}\right]\left[\begin{array}{c}{i}_d\\ i_q\\ i_f\end{array}\right]+\left[\begin{array}{c}{\mathrm{\ψ}}_m\\ 0\\ {\mathrm{\ψ}}_{\mathrm{mf}}\end{array}\right]---\left(2\right)$

Voltage equation:

$\left\{\begin{array}{c}{u}_d=R_s{i}_d+\frac{d{\mathrm{\ψ}}_d}{\mathrm{dt}}-{\mathrm{\ω}}_e{\mathrm{\ψ}}_q\\ u_q=R_s{i}_q+\frac{{\mathrm{d\ψ}}_q}{\mathrm{dt}}+{\mathrm{\ω}}_e{\mathrm{\ψ}}_d\\ u_f=R_f{i}_f+\frac{{\mathrm{d\ψ}}_f}{\mathrm{dt}}\end{array}\right.---\left(3\right)$

Torque equation:

$T_e=\frac{3}{2}{\mathrm{pi}}_q[{\mathrm{\ψ}}_{\mathrm{pm}}+i_d(L_d-L_q)+M_{\mathrm{sf}}{i}_f]---\left(4\right)$

Wherein, i _d, i _qbe respectively d axle and q shaft current, i _ffor excitation winding electric current; L _d, L _qbe respectively d axle and q axle inductance, M _sffor the mutual inductance between armature and excitation winding; ω _efor angular rate; ψ _mfor permanent magnet flux linkage, p is motor number of pole-pairs, u _d, u _qbe respectively the voltage of d axle and q axle, u _ffor excitation winding voltage; R _sfor armature winding resistance, R _ffor excitation winding resistance; ψ _d, ψ _q, ψ _fd axle, q axle and excitation winding magnetic linkage respectively; ψ _mfor permanent magnet flux linkage amplitude, ψ _mffor permanent magnet is through the magnetic linkage of excitation winding.

Work as T _l≤ T _ntime, without the need to increasing magnetic control, so i _fref=0, in conjunction with i _dref=0 and formula (4) can obtain following electric current distribute:

$\left\{\begin{array}{c}{i}_{\mathrm{dref}}=0\\ i_{\mathrm{qref}}=\frac{{2T}_{\mathrm{eref}}}{3{\mathrm{p\ψ}}_{\mathrm{pm}}}\\ i_{\mathrm{fref}}=0\end{array}\right.---\left(5\right)$

Work as T _l>T _ntime, q shaft current reaches rated value, need carry out increasing magnetic control, therefore i _qref=0, in conjunction with i _dref=0 and formula (4) can obtain following electric current distribute:

$\left\{\begin{array}{c}{i}_{\mathrm{dref}}=0\\ i_{\mathrm{fref}}=\frac{{2T}_{\mathrm{eref}}-3{\mathrm{p\ψ}}_{\mathrm{pm}}{i}_{\mathrm{qN}}}{3{\mathrm{pM}}_{\mathrm{sf}}{i}_{\mathrm{qN}}}\\ i_{\mathrm{qref}}=i_{\mathrm{qN}}\end{array}\right.---\left(6\right)$

(5) after mixed excitation electric machine enters high velocity, have

$\left(7\right)---u_s^2=u_d^2+u_q^2\≤u_{s\max }^2={(U_{\mathrm{dc}}/\sqrt{3})}^2$

Thus can obtain

${\mathrm{\ω}}_e=\frac{U_{\mathrm{dc}}/\sqrt{3}}{\sqrt{{\left(L_q{i}_q\right)}^2+{({\mathrm{\ψ}}_{\mathrm{pm}}+L_d{i}_d+M_{\mathrm{sf}}{i}_f)}^2}}---\left(8\right)$

Wherein, ω _efor angular rate, U _dcfor the maximum voltage that inverter can provide;

Proposition utilizes d shaft current and exciting current to coordinate weak magnetic, specifically can be divided into 2 stages:

1st stage adopts exciting current to carry out weak magnetic, keeps d shaft current to continue to equal 0, namely has i _dref=0, convolution (4) and formula (8) can obtain following electric current and distribute:

$\left\{\begin{array}{c}{\mathrm{\ω}}_e=\frac{U_{\mathrm{dc}}/\sqrt{3}}{\sqrt{{\left(L_q{i}_{\mathrm{qref}}\right)}^2+{({\mathrm{\ψ}}_{\mathrm{pm}}+M_{\mathrm{sf}}{i}_{\mathrm{fref}})}^2}}\\ i_{\mathrm{dref}}=0\\ T_{\mathrm{eref}}=\frac{3}{2}{\mathrm{pi}}_{\mathrm{qref}}({\mathrm{\ψ}}_{\mathrm{pm}}+M_{\mathrm{sf}}{i}_{\mathrm{fref}})\end{array}\right.$

1st stage as shown in Figure 2, when the speed of service of hybrid exciting synchronous motor exceedes base speed ω ₁time, must weak magnetics detect be carried out.According to busbar voltage U _dcjudge the weak magnetic moment with the difference of back-emf, open weak magnetics detect algorithm, namely continue to keep d shaft current i _d=0, adopt exciting current i _fcarry out weak magnetic.Along with the increase of rotating speed, i _fto reach negative maximum, the operating point of HEAFFSM will move to C point from A point, and the center of circle of voltage limit circle is close to initial point, if can keep the center of circle will be intersected with current limitation circle I, and motor speed will reach infinitely great.

After exciting current reaches rated value, namely there is i _fref=-i _fN, the 2nd stage continues to adopt d shaft current to carry out weak magnetic, and convolution (4) and formula (8) can obtain following electric current and distribute:

$\left\{\begin{array}{c}{\mathrm{\ω}}_e=\frac{U_{\mathrm{dc}}/\sqrt{3}}{\sqrt{{\left(L_q{i}_{\mathrm{qref}}\right)}^2+{({\mathrm{\ψ}}_{\mathrm{pm}}+{L_d{i}_{\mathrm{dref}}+M}_{\mathrm{sf}}{i}_{\mathrm{fN}})}^2}}\\ i_{\mathrm{fref}}=i_{\mathrm{fN}}\\ T_{\mathrm{eref}}=\frac{3}{2}{\mathrm{pi}}_{\mathrm{qref}}[{\mathrm{\ψ}}_{\mathrm{pm}}+{(L_d-L_q)i_{\mathrm{dref}}+M}_{\mathrm{sf}}{i}_{\mathrm{fN}}]\end{array}\right.$

2nd stage as shown in Figure 3.When the rotating speed of hybrid exciting synchronous motor is more than ω ₃time, i _freach negative maximum.If continue to improve rotating speed, then need to adopt d shaft current i _dcarry out weak magnetic, the operating point of hybrid exciting synchronous motor will move to D point from C point, and the operation motor of hybrid exciting synchronous motor is on current limitation circle II.

(6) d shaft current reference value i distributing switch produced _drefwith q shaft current i _qrefrespectively with the d shaft current i in step (2) _dwith q shaft current i _qobtain d shaft current deviation delta i more afterwards _dwith q shaft current deviation delta i _q, by Δ i _dwith Δ i _qsend into d shaft current adjuster and q shaft current adjuster respectively, obtain d shaft voltage u _dwith q shaft voltage u _q, after carrying out rotating orthogonal-static two phase inversion, obtain the voltage signal u under static two phase coordinate systems _αwith u _β, export 6 road pulse width modulating signals after sending into space vector pulse width modulation module, drive main power inverter; The exciting current i simultaneously will gathered in step (1) _f, with exciting current reference value i after signal condition and A/D are changed _frefsend into DC excitation pulse width modulation module together, computing exports 4 road pulse width modulating signals to drive exciting power converter.

Claims (2)

1. a hybrid exciting synchronous motor power factor control method, is characterized in that, the method comprises the following steps:

(1) phase current i is gathered from motor main circuit _a, i _bwith exciting current i _f, accurate initial position detection is carried out to motor, collection signal from motor encoder, sends into controller and process, draw rotating speed n and rotor position angle θ;

(2) the phase current i will gathered _a, i _bthrough signal condition and A/D conversion, then carry out park transforms, obtain the d shaft current i under two-phase rotating coordinate system _dwith q shaft current i _q;

(3) encoder is surveyed rotating speed n and obtain rotating speed deviation delta n with after given rotating speed n*, described rotating speed deviation delta n input speed adjuster is obtained torque reference value after proportional integral computing by torque reference value busbar voltage U _dc, stator d shaft voltage u _d, stator q shaft voltage u _q, actual measurement rotating speed n and given rotating speed n ^*input current distributor, the weak magnetic moment is judged according to busbar voltage and back-emf difference, when busbar voltage is greater than back-emf, then hybrid exciting synchronous motor runs on low regime, enter step 4), when busbar voltage equals back-emf, hybrid exciting synchronous motor runs on high velocity, enters step 5);

(4) judge whether load torque meets T _l≤ T _n, wherein T _lfor load torque, T _nfor nominal torque;

Work as T _l≤ T _ntime, i _dref=0, i _fref=0, so following current sharing scheme can be obtained:

$\left\{\begin{array}{c}{i}_{\mathrm{dref}}=0\\ i_{\mathrm{qref}}=\frac{{2T}_{\mathrm{eref}}}{3{\mathrm{p\ψ}}_{\mathrm{pm}}}\\ i_{\mathrm{fref}}=0\end{array}\right.$

Work as T _l> T _ntime, i _dref=0, i _qref=i _qN, so following current sharing scheme can be obtained:

$\left\{\begin{array}{c}{i}_{\mathrm{dref}}=0\\ i_{\mathrm{fref}}=\frac{{2T}_{\mathrm{eref}}-3p{\mathrm{\ψ}}_{\mathrm{pm}}{i}_{\mathrm{qN}}}{3{\mathrm{pM}}_{\mathrm{sf}}{i}_{\mathrm{qN}}}\\ i_{\mathrm{qref}}=i_{\mathrm{qN}}\end{array}\right.$

Wherein, i _dreffor d shaft current reference value, i _qreffor q shaft current reference value, i _freffor excitation winding current reference value; ψ _pmfor permanent magnet flux linkage, p is motor number of pole-pairs; i _qNfor q shaft current rated value, M _sffor the mutual inductance between armature winding and excitation winding, T _ereffor electromagnetic torque reference value;

(5) the 1st stages adopt exciting current to carry out weak magnetic, can obtain following current sharing scheme:

$\left\{\begin{array}{c}{\mathrm{\ω}}_e=\frac{U_{\mathrm{dc}}/\sqrt{3}}{\sqrt{{\left(L_q{i}_{\mathrm{qref}}\right)}^2+{({\mathrm{\ψ}}_{\mathrm{pm}}+M_{\mathrm{sf}}{i}_{\mathrm{fref}})}^2}}\\ i_{\mathrm{dref}}=0\\ T_{\mathrm{eref}}=\frac{3}{2}{\mathrm{pi}}_{\mathrm{qref}}({\mathrm{\ψ}}_{\mathrm{pm}}+M_{\mathrm{sf}}{i}_{\mathrm{fref}})\end{array}\right.$

After exciting current reaches rated value, the 2nd stage continues to adopt d shaft current to carry out weak magnetic, can obtain following current sharing scheme:

$\left\{\begin{array}{c}{\mathrm{\ω}}_e=\frac{U_{\mathrm{dc}}/\sqrt{3}}{\sqrt{{\left(L_q{i}_{\mathrm{qref}}\right)}^2+{({\mathrm{\ψ}}_{\mathrm{pm}}+L_d{i}_{\mathrm{dref}}+M_{\mathrm{sf}}{i}_{\mathrm{fN}})}^2}}\\ i_{\mathrm{fref}}=i_{\mathrm{fN}}\\ T_{\mathrm{eref}}=\frac{3}{2}{\mathrm{pi}}_{\mathrm{qref}}({\mathrm{\ψ}}_{\mathrm{pm}}+(L_d-L_q)i_{\mathrm{dref}}+M_{\mathrm{sf}}{i}_{\mathrm{fN}})\end{array}\right.$

Wherein, ω _efor angular rate, U _dcfor the maximum voltage that inverter can provide, i _fNfor exciting current rated value, L _dfor stator winding d axle inductance, L _qfor stator winding q axle inductance;

(6) d shaft current reference value i distributing switch produced _drefwith q shaft current i _qrefrespectively with the d shaft current i in described step (2) _dwith q shaft current i _qafter obtain d shaft current deviation delta i _dwith q shaft current deviation delta i _q, by d shaft current deviation delta i _dinput d shaft current adjuster carries out proportional integral computing, obtains d shaft voltage u _d, by q shaft current deviation delta i _qinput q shaft current adjuster carries out proportional integral computing, obtains q shaft voltage u _q, then to described d shaft voltage u _dwith q shaft voltage u _qafter jointly carrying out rotating orthogonal-static two phase inversion, obtain α shaft voltage u under static two phase coordinate systems _αwith β shaft voltage u _β, by described α shaft voltage u _αwith β shaft voltage u _βinput pulse width modulation module, computing exports 6 road pulse width modulating signals, drives main power inverter;

The exciting current i simultaneously will gathered in step (1) _f, with exciting current reference value i after signal condition and A/D are changed _frefsend into DC excitation pulse width modulation module together, computing exports 4 road pulse width modulating signals to drive exciting power converter.

2. according to claim 1ly judge weak magnetic moment hybrid exciting synchronous motor field weakening control method based on voltage difference, it is characterized in that, described step 6) in Pulse width modulation module be space vector pulse width modulation module.