CN104022706A - Sensorless type magnetic field guiding control system, method and device of permanent magnet motor - Google Patents

Abstract

The invention provides a sensorless type magnetic field guiding control system, method and device of a permanent magnet motor. The sensorless type magnetic field guiding control system comprises a Clark conversion module, a Parker conversion module and an angle estimation module. The Clark conversion module produces orthogonal current signals according to a motor phase current. The Parker conversion module responds to the orthogonal current signals and angle signals to produce current signals. The angle estimation module responds to the current signals to produce angle signals. The angle signals are related to the reversing angle of the permanent magnet motor. The current signals are controlled to be close to zero. The angle signals related to angle displacement signals is configured to produce three-phase motor voltage.

Description

Permanent magnet motor without sensor type magnetic field alignment control system, method and apparatus

Technical field

The present invention relates to a kind of for permanent magnetism (PM) motor without sensor type magnetic field steering control (field oriented control, be called for short FOC) technology, and more particularly, relate to a kind of for permanent magnet motor without sensor type magnetic field alignment control system, method and apparatus.

Background technology

Brushless PM synchronous motor (PMSM) is a kind of without sensor type PM motor, and is a kind of motor by exchanging (AC) electricity input driving.If the enable position without sensor type permanent magnet motor can be detected, can have no so the ground of impact actuating motor.

PMSM comprises have stator winding wound stator (wound stator), p-m rotor (permanent magnet rotor) sub-assembly and the sensing apparatus of (stator winding), and described sensing apparatus is for the rotor-position of sensing PM rotor stack.Sensing apparatus comprises Hall element (hall sensor) conventionally, and Hall element is provided for exact sequence the signal that electronic type is switched described stator winding, and described signal is in order to keep the rotation of PM rotor stack.Yet set Hall element has increased the cost of PMSM in sensing apparatus, and may cause fault and reduce the reliability of PMSM.Therefore, need to be a kind of for carry out the mechanism of PM Motor Control in the situation that there is no transducer.

Summary of the invention

The invention provides a kind of for permanent magnet motor without sensor type magnetic field alignment control system, method and apparatus.Describedly without sensor type magnetic field alignment control system, comprise Clarke conversion (Clarke transform) module, Park Transformation (Park transform) module and angle estimation module.Described Clarke conversion module produces a plurality of quadrature current signals according to a plurality of motor phase currents (motor phase current).Described Park Transformation module responds is carried out generation current signal in described a plurality of quadrature current signals and angle signal.Described angle estimation module responds produces angle signal in described current signal.Described angle signal is relevant to the commutation angle (commutation angle) of described permanent magnet motor.Described current signal is controlled as and approaches zero.Be configured to produce threephase motor voltage with the described angle signal of angular displacement signal correction connection.

From another viewpoint, the present invention also provide a kind of for permanent magnet motor without sensor type magnetic field guiding control appliance.Described equipment comprises Clarke conversion module, Park Transformation module, angle estimation module and summation (sum) module.Described Clarke conversion module produces a plurality of quadrature current signals according to a plurality of motor phase currents.Described Park Transformation module responds is carried out generation current signal in described a plurality of quadrature current signals and the first angle signal.Described angle estimation module responds produces described the first angle signal in described current signal.Described summation module produces the second angle signal according to described the first angle signal and angular displacement signal.Described current signal is controlled as and approaches zero.Described the second angle signal is configured to produce threephase motor voltage (three phase motor voltage).

From another viewpoint, the present invention also provide a kind of for permanent magnet motor without sensor type magnetic field guiding control method.Said method comprising the steps of.According to a plurality of motor phase currents, produce a plurality of quadrature current signals.In response to described a plurality of quadrature current signals and angle signal, carry out generation current signal.In response to described current signal, produce described angle signal.Described angle signal is relevant to the commutation angle of described permanent magnet motor; Described current signal is controlled as and approaches zero; And described angle signal is configured to produce threephase motor voltage.

Comprise accompanying drawing so that a further understanding of the present invention to be provided, and accompanying drawing is incorporated in this specification and forms the part of this specification.Described graphic explanation one exemplary embodiment of the present invention, and together with the description in order to explain principle of the present invention.

Accompanying drawing explanation

Fig. 1 shows the block diagram without sensor type magnetic field alignment control system for the FOC of PM motor;

Fig. 2 shows the schematic diagram of the algorithm (algorithm) of sliding-modes observer (sliding mode observer);

Fig. 3 shows the block diagram of sliding-modes observer;

Fig. 4 shows the schematic diagram of the equivalent model of PMSM;

Fig. 5 shows the FOC for PM motor according to an embodiment of the invention without the block diagram of sensor type magnetic field alignment control system;

Fig. 6 shows the block diagram of angle estimation module according to an embodiment of the invention;

Fig. 7 shows the block diagram of proportional integral according to an embodiment of the invention (proportional integral is called for short PI) controller;

Fig. 8 shows the block diagram of angle estimation module according to another embodiment of the present invention;

Fig. 9 shows FOC according to another embodiment of the present invention without the block diagram of sensor type magnetic field alignment control system;

Figure 10 shows the waveform that the sine-wave producer in Fig. 9 according to another embodiment of the present invention produces;

Figure 11 shows the flow chart without sensor type magnetic field guiding control method for permanent magnet motor according to an embodiment of the invention.

Description of reference numerals:

10: permanent magnet synchronous motor;

12: emf source;

15: three-phase bridge driver (three-phase bridge driver);

20: Clarke conversion module;

25: Park Transformation module;

30: Clarke inverse transformation (inverse Clarke transformation) module/space vector modulation (space vector modulation is called for short SVM) module;

35: Parker inverse transform module;

40,45,150: pi controller;

50: sliding-modes observer;

60: current observer;

61: frequency mixer (mixer);

62: error signal;

63-67: step;

71,72,120: low pass filter;

80: arctangent computation piece (arctangent calculation block);

90: sine wave signal generator;

95: summation unit;

100: angle estimation module;

110: summation module;

151,152: piece;

AS: angular displacement signal;

Duty: task signal;

Es: back electromotive force;

Esf: parameter;

The component of a vector of E α, E β: Es;

Ia, ib, ic, Is: phase current;

I α, i β: two axle quadrature currents;

Id, Iq: current signal;

Ikt: threshold value;

Ise: estimated phase current;

I _dREF, I _qREF: parameter;

KI, KP: gain;

KI1, KP1: original setting;

L: winding inductance;

R: winding resistance;

S1110, S1120, S1130: step;

Vd, Vq: signal;

Vp1, Vp2, Vp3: threephase motor voltage signal;

Vs: input voltage;

V α, V β: voltage/pulse-width signal;

V _a, V _b, V _c: threephase motor voltage signal;

X (t), y (t): error signal;

Z: the output calibration factor (correction factor) voltage;

θ, θ _a: angle signal;

ω: rate signal.

Embodiment

Compare with old-fashioned motor, PM motor represents high efficiency, small size, fast dynamic response and low noise and other advantages conventionally.Because the speed of the rotor field of PM motor must equal the speed of stator field (stator magnetic field), so the one in the rotor flux in magnetic field steering control (rotor flux), stator magnetic linkage (stator flux) and air gap flux linkage (air-gap flux) is regarded as being used to the basis of the referential (frame) that creates another magnetic linkage, torque component and magnetic linkage component are carried out to decoupling (decouple) in the electric current of stator.Armature supply is responsible for producing torque (torque), and exciting current is responsible for producing magnetic linkage (flux).In general, rotor flux is regarded as the referential for stator magnetic linkage and air gap flux linkage.The FOC that in Fig. 1, exemplary illustrated is used for PM motor is without sensor type magnetic field alignment control system and equipment.Fig. 1 shows the block diagram without sensor type magnetic field alignment control system for the FOC of PM motor.Without sensor type magnetic field alignment control system, comprise permanent magnet synchronous motor (PMSM) 10, three-phase bridge driver (three-phase bridge driver) 15 and space vector modulation (space vector modulation is called for short SVM) module 30.Clarke conversion module 20 is configured to three axle two-dimensional coordinate systems (with reference to stator) to be transformed to two axial coordinate systems substantially.Clarke conversion is also called alpha-beta conversion (alpha-beta transformation) in electrical engineering.The phase current being presented by vector of motor 10 can be expressed as following formula (1) to (3).

$\stackrel{\→}{\mathrm{ia}}+\stackrel{\→}{\mathrm{ib}}+\stackrel{\→}{\mathrm{ic}}=0.........\left(1\right)$

$\stackrel{\→}{\mathrm{i\α}}=\stackrel{\→}{\mathrm{i\β}}.........\left(2\right)$

$\stackrel{\→}{\mathrm{i\β}}=(\stackrel{\→}{\mathrm{ia}}+2\×\stackrel{\→}{\mathrm{ib}})\÷\sqrt{3}.........\left(3\right)$

Wherein ia, ib and ic are the phase currents of the motor 10 that presented by vector.I α and i β are mapping phase current ia, the ib of motor and two axles (two-axis) quadrature current of ic.

Park Transformation module 25 is configured to i α, i β and angle signal θ to be transformed to another two axle system corresponding to rotor flux.This two axles rotary coordinate system is called as " d-q axle ".Park Transformation module 25 is according to two axle quadrature current i α and i β generation current signal Id and Iq.In electrical engineering, Park Transformation is also called directly-quadrature-zero (direct – quadrature – zero) (or dq0) conversion or zero-directly-quadrature (zero – direct – quadrature) (or 0dq) conversion.Parameter θ represents the rotor angle (rotor angle) of the phase current of motor 10.The current signal Id and the Iq that by Park Transformation module 25, are produced can be expressed as following formula (4) to (5).

$\mathrm{Id}=\stackrel{\→}{\mathrm{i\α}}\×\cos \mathrm{\θ}+\stackrel{\→}{\mathrm{i\β}}\×\sin \mathrm{\θ}.........\left(4\right)$

$\mathrm{Iq}=(-\stackrel{\→}{\mathrm{i\α}})\×\sin \mathrm{\θ}+\stackrel{\→}{\mathrm{i\β}}\×\cos \mathrm{\θ}.........\left(5\right)$

Parker inverse transform module 35 is fixedly alpha-beta (that is, voltage/pulse-width signal V α and V β) for two axle rotation d-q systems (that is, signal Vd and Vq) are transformed to two axles.Signal Vd and Vq are produced by controller 40 and 45.Voltage/pulse-width signal V α and V β can be expressed as following formula (6) to (7).

Vα＝Vd×cosθ+Vq×sinθ………(6)

Vβ＝Vd×sinθ+Vq×cosθ………(7)

Clarke inverse transform module 30 for will fix two axles be alpha-beta (stationary two-axis frame) (, voltage/pulse-width modulation V α and V β) be transformed to and fix three axles (stationary three-axis) (the three-phase referential of stator) (that is, threephase motor voltage signal Vp1, Vp2 and Vp3).Threephase motor voltage signal Vp1, the Vp2 and the Vp3 that by Clarke inverse transform module 30, are produced can be expressed as following formula (8) to (10).

Vp1＝Vβ………(8)

$\mathrm{Vp}2=(-\mathrm{V\β}+\sqrt{3}\×\mathrm{V\α})\÷2.........\left(9\right)$

$\mathrm{Vp}3=(-\mathrm{V\β}-\sqrt{3}\×\mathrm{V\α})\÷2.........\left(10\right)$

These threephase motor voltage signals (Vp1, Vp2, Vp3) are used to by space vector modulation (SVM) technology and produce pulse-width modulation (pulse width modulation) signal.

Controller 40 and 45 is the error signal in Closed control loop (closed control loop) to be made to proportional integral (PI) controller of response.Closed control loop is configured to adjust controlled quentity controlled variable and reaches desired system responses.Control speed, torque or magnetic linkage that parameter can mean measurable amount.Error signal is by by the parameter of wanting (that is, the I for controlling _qREFand I _dREF) deduct that the actual measured value of that parameter obtains.The needed direction of sign indication control inputs of error signal.

Sliding-modes observer (SMO) 50 is configured for use in the speed that produces angle signal θ and estimate motor.Fig. 2 shows the schematic diagram of the algorithm (algorithm) of sliding-modes observer (sliding mode observer).Input voltage Vs represents to be applied to the input voltage of the motor 10 in Fig. 1, and parameter I s represents the phase current of motor 10, and parameter I se represents the estimated phase current of motor 10.Current observer 60 receives input voltage Vs and output represents the estimated phase current Ise of estimated phase current, and by frequency mixer 61, estimated phase current Ise and phase current Is is combined to produce error signal 62.Error signal 62 is input in determining step.Determining step 63 determines whether error signal 62 is less than build in value Error-min.If error signal 62 is less than build in value Error-min, output calibration factor voltage Z is made as so to zero in step 64.If error signal 62 is not less than build in value Error-min, algorithm proceeds to determining step 65 and determines whether error signal 62 is greater than zero so.If error signal 62 is not more than zero, in step 66, output calibration factor voltage Z equals negative parameter-Kslide so.If error signal 62 is greater than zero, in step 67, output calibration factor voltage Z equals positive parameter+Kslide so.

Z is output calibration factor voltage.Described algorithm focuses on and calculates the needed commutation angle of FOC scheme (commutation angle) signal θ.The position of the motor 10 in Fig. 1 and estimation are to calculate according to measured electric current and the voltage calculating.

Fig. 3 shows the block diagram of sliding-modes observer.Sliding-modes observer 50 comprises current observer 60, low pass filter (LPF) 71 and 72 and arctangent computation piece (arctangent calculation block) 80.Fig. 4 shows the schematic diagram of the equivalent model of PMSM.The equivalent model 500 of PMSM comprises motor input voltage Vs, winding resistance R, winding inductance L and emf source (EMF) Es12 that is applied to PMSM.Below describe and should combine with Fig. 3 and Fig. 4.Relation between Ise, L, R, t, Vs and Es can be expressed as formula (11).

$\frac{d\left(\mathrm{Ise}\right)}{\mathrm{dt}}=\frac{R}{L}\×\mathrm{Ise}+\frac{1}{L}\×(\mathrm{Vs}-\mathrm{Es}-Z).........\left(11\right)$

Wherein Ise is estimated phase current; Vs is the input voltage of PMSM; Es is back electromotive force; Z is output calibration factor voltage.

Should consider two kinds of motor conditions.Under the first condition, to two identical input voltage Vs of system feed-in, and under the second condition, measured electric current I s should mate with carrying out the estimated electric current I se of self model.Therefore, the back electromotive force Es of hypothetical model is identical with the back electromotive force Es of motor.When the value of error signal is less than Error-min, current observer 60 operates in the range of linearity.For in the extraneous error signal of linearity, the output of current observer 60 is (+Kslide)/(Kslide), and this depends on the sign of error signal.Current observer 60 is for the motor model of compensation image 4, and estimates back electromotive force Es by carrying out filtering via 71 couples of correction factor Z of low pass filter.Estimated back electromotive force Es is through being further configured to produce the value (via arctangent computation piece 80) of E α and E β (component of a vector of Es) by filter 72 for estimated angle signal θ.By LPF72, according to estimated back electromotive force Es, produce parameter Esf.Estimated angle signal θ can be expressed as formula (12).

$\mathrm{\θ}=\arctan \left(\frac{\mathrm{E\α}}{\mathrm{E\β}}\right).........\left(12\right)$

Because the sliding-modes observer (SMO) in Fig. 1 50 needs motor parameter and complicated calculating accurately to estimate commutation angle signal θ, so need at a high speed and expensive digital signal processor (DSP) carries out this computing.The invention provides a kind of permission is implemented FOC without sensor type magnetic field alignment control system and is realized high performance straightforward procedure by the microcontroller of lower cost.

Fig. 5 shows the FOC for PM motor according to an embodiment of the invention without the block diagram of sensor type magnetic field alignment control system.Without sensor type magnetic field alignment control system comprise permanent magnet synchronous motor (PMSM) 10, three-phase bridge driver 15, for Clarke inverse transform module/space vector modulation (SVM) module 30, Clarke conversion module 20, Park Transformation module 25, Parker inverse transform module 35, proportional integral (PI) controller 40 and angle estimation module 100.Park Transformation module 25 generation current signal Id and Iq.Angle estimation module 100 produces commutation angle signal θ according to current signal Id simply.Commutation angle signal θ is further coupled to Park Transformation module 25 and Parker inverse transform module 35 with for threephase motor voltage signal generation current signal Iq and Id, voltage/pulse-width signal V α and V β.The description of other piece can be with reference to the description of figure 1.

Fig. 6 shows the block diagram of angle estimation module according to an embodiment of the invention.Angle estimation module 100 comprises summation module 110, proportional integral (PI) controller 150 and LPF120.Summation module 110 is added to produce the input signal of PI controller 150 by current signal Id and zero-signal (zero signal) O.PI controller 150 is through being coupled with received current signal Id for producing rate signal ω.By controlling described current signal Id, be approximately equal to the zero rate signal ω that derives.Filter 120 is for producing commutation angle signal θ according to rate signal ω.

Fig. 7 shows the block diagram of proportional integral according to an embodiment of the invention (proportional integral is called for short PI) controller.In piece 151, pass through by input signal (, error signal X (t)) be multiplied by the first gain (, gain KP) form the proportional (proportional term) of PI controller 150, and PI controller 150 is configured to produce the control response as the function of error magnitude.The integration item of PI controller 150 (integral term) is for eliminating little steady-state error.The continuous total amount of the integration item error signal of PI controller 150.In piece 152 by the steady-state error signal times of this accumulation with the second gain (that is, gain KI).Relation between error signal x (t), y (t), gain KP and KI can be expressed as formula (13):

y(t)＝K _P×x(t)-K _I∫x(t)dt………(13)

Fig. 8 shows the block diagram of angle estimation module according to another embodiment of the present invention.Angle estimation module 100 comprises proportional integral (PI) controller 150.PI controller 150 is configured to received current signal Id for producing rate signal ω.By controlling described Id signal approximation, equal zero to derive rate signal ω.Filter 120 is for producing commutation angle signal θ according to rate signal ω.Proportional integral (PI) controller 150 comprises two parameters controlling for PI, for example the first gain KP and the second gain KI.In order to ensure current signal Id, in the linear zone of loop, operate, piece 115 determines whether the value of current signal Id is greater than threshold value Ikt.If the value of current signal Id is less than threshold value Ikt, so the first gain KP and the second gain KI are made as to the original KP1 of setting and KI1.If the value of current signal Id is greater than threshold value Ikt, the first gain KP and the second gain KI will be made as respectively to KP2 and KI2 to obtain different loop response and operation so.

Fig. 9 shows FOC according to another embodiment of the present invention without the block diagram of sensor type magnetic field alignment control system.Described FOC comprises permanent magnet synchronous motor (PMSM) 10, three-phase bridge driver 15, Clarke conversion module 20, Park Transformation module 25, sine wave signal generator 90 and angle estimation module 100 without sensor type magnetic field alignment control system.Park Transformation module 25 is carried out generation current signal Id by receiving two axle quadrature current i α and i signal beta.Angle estimation module 100 produces angle signal θ according to current signal Id.Angle signal θ further feeds back to Park Transformation module 25.Sum unit 95 produces another angle signal θ according to angle signal θ and angular displacement signal AS _a.Angular displacement signal AS is used for adapting to various PM motor and/or for weak magnetic control system (weak magnet control).

Angle signal θ _aand task signal (duty signal) Duty is coupled to sine-wave producer 90 to produce pulse-width signal for threephase motor voltage signal (phase place A, phase place B and phase place C).Sine-wave producer 90 has two inputs, comprises value input and phase angle input.Task signal Duty is coupled in value input.Angle signal θ is coupled in phase angle input _a.

Figure 10 shows the waveform that the sine-wave producer in Fig. 9 according to another embodiment of the present invention produces.Threephase motor voltage signal V _a, V _band V _camplitude by task signal Duty, programmed.Threephase motor voltage signal V _a, V _band V _cangle by angle signal θ _adetermine.

Figure 11 shows the flow chart without sensor type magnetic field guiding control method for permanent magnet motor according to an embodiment of the invention.In the present embodiment, the described equipment that is applicable to Fig. 5 without sensor type magnetic field guiding control method.In step S1110, Clarke conversion module 20 produces a plurality of quadrature current signals (that is, two axle quadrature current i α and i signal betas) according to a plurality of motor phase currents (that is, phase current ia, ib and ic).In step S1120, Park Transformation module 25 is carried out generation current signal Id in response to described a plurality of quadrature current signals (that is, two axle quadrature current i α and i signal betas) and angle signal θ.In step S1130, angle estimation module 100 produces angle signal θ in response to current signal Id.Angle signal θ is relevant to the commutation angle of permanent magnet motor 10.Current signal Id is controlled as and approaches zero.The angle signal θ being associated with angular displacement signal AS is configured to produce threephase motor voltage (that is, phase place A, phase place B and phase place C).The technology combining with the detailed actuating of electronic building brick is described in the above embodiment of the present invention.

Finally it should be noted that: each embodiment, only in order to technical scheme of the present invention to be described, is not intended to limit above; Although the present invention is had been described in detail with reference to aforementioned each embodiment, those of ordinary skill in the art is to be understood that: its technical scheme that still can record aforementioned each embodiment is modified, or some or all of technical characterictic is wherein equal to replacement; And these modifications or replacement do not make the essence of appropriate technical solution depart from the scope of various embodiments of the present invention technical scheme.

Claims (12)

1. For permanent magnet motor without a sensor type magnetic field alignment control system, it is characterized in that, comprising:

   Clarke conversion module, produces a plurality of quadrature current signals according to a plurality of motor phase currents;

   Park Transformation module, carrys out generation current signal in response to described a plurality of quadrature current signals and angle signal; And

   Angle estimation module, produces described angle signal in response to described current signal;

   Wherein said angle signal is relevant to the commutation angle of described permanent magnet motor; Described current signal is controlled as and approaches zero; Be configured to produce threephase motor voltage with the described angle signal of angular displacement signal correction connection.
2. 2. according to claim 1ly without sensor type magnetic field alignment control system, it is characterized in that, also comprise:

   Space vector modulation module, for producing described threephase motor voltage in response to described angle signal.
3. 3. according to claim 1ly without sensor type magnetic field alignment control system, it is characterized in that, described angle estimation module comprises:

   Pi controller, for generation of rate signal; And

   Filter, produces described angle signal according to described rate signal,

   Wherein said rate signal produces by described current signal being controlled for approaching zero.
4. 4. according to claim 3ly without sensor type magnetic field alignment control system, it is characterized in that, described pi controller comprises:

   The first gain parameter; And

   The second gain parameter,

   Wherein said the first gain parameter and the second gain parameter can be programmed in response to described current signal.
5. For permanent magnet motor without a sensor type magnetic field guiding control appliance, it is characterized in that, comprising:

   Clarke conversion module, produces a plurality of quadrature current signals according to a plurality of motor phase currents;

   Park Transformation module, carrys out generation current signal in response to described a plurality of quadrature current signals and the first angle signal;

   Angle estimation module, produces described the first angle signal in response to described current signal; And

   Summation module, produces the second angle signal according to described the first angle signal and angular displacement signal,

   Wherein said current signal is controlled as and approaches zero; Described the second angle signal is configured to produce threephase motor voltage.
6. 6. according to claim 5ly without sensor type magnetic field guiding control appliance, it is characterized in that, also comprise:

   Sine-wave producer, for producing described threephase motor voltage in response to described the second angle signal.
7. 7. according to claim 5ly without sensor type magnetic field guiding control appliance, it is characterized in that, described angle estimation module comprises:

   Pi controller, for generation of rate signal; And

   Filter, produces described angle signal according to described rate signal,

   Wherein said rate signal produces by described current signal being controlled for approaching zero; Described pi controller comprises the first gain parameter and the second gain parameter; Described the first gain parameter and the second gain parameter can be programmed in response to described current signal.
8. For permanent magnet motor without a sensor type magnetic field guiding control method, it is characterized in that, comprising:

   According to a plurality of motor phase currents, produce a plurality of quadrature current signals;

   In response to described a plurality of quadrature current signals and angle signal, carry out generation current signal;

   In response to described current signal, produce described angle signal;

   Wherein said angle signal is relevant to the commutation angle of described permanent magnet motor; Described current signal is controlled as and approaches zero; Described angle signal is configured to produce threephase motor voltage.
9. 9. according to claim 8ly without sensor type magnetic field guiding control method, it is characterized in that, also comprise:

   In response to described angle signal and error magnitude signal, produce described threephase motor voltage.
10. 10. according to claim 8ly without sensor type magnetic field guiding control method, it is characterized in that, the step of the described angle signal of described generation comprises the following steps:

    Passing ratio integral controller produces rate signal; And

    By filtering, according to described rate signal, produce described angle signal,

    Wherein said rate signal produces by described current signal being controlled for approaching zero.
11. 11. according to claim 8ly is characterized in that without sensor type magnetic field guiding control method, and described threephase motor voltage is produced by sine-wave producer.
12. 12. according to claim 10ly is characterized in that without sensor type magnetic field guiding control method, and described pi controller comprises the first gain parameter and the second gain parameter; Described the first gain parameter and described the second gain parameter are programmed in response to described current signal.