CN104113256A - Position estimation method for surface-mounted permanent magnet synchronous motor and system thereof - Google Patents

Abstract

The invention is suitable for the technical field of household electrical appliances, and provides a position estimation method for a surface-mounted permanent magnet synchronous motor. The method comprises the steps that a q-shaft current iq of the surface-mounted permanent magnet synchronous motor is acquired; and mechanical angular position theta of electrical equipment of the surface-mounted permanent magnet synchronous motor is estimated. The technical scheme has advantages of being low in position estimation deviation and low in calculation amount at low speed.

Description

The location estimation method of surface-mount type permanent magnet synchronous motor and system

Technical field

The invention belongs to field of household appliances, relate in particular to a kind of surface-mount type permanent magnet synchronous motor (English abbreviation: location estimation method SPMSM) and system.

Background technology

Along with the raising of people to energy attention degree, frequency control has been widely used in household electrical appliances, weaving, and the every field such as automobile, for the restriction of cost or operational environment, can adopt the speed regulating method of position-sensor-free in many occasions.Because permagnetic synchronous motor needs detection rotor position to complete commutation in running, this is the basis of permagnetic synchronous motor control, and the quality of location estimation directly affects final debug performance.

Traditional location-estimation algorithm depends on the electric parameter of motor more, as the magnetic linkage estimation technique, the model reference adaptive estimation technique or high frequency signal injection method etc.; Although it is insensitive that the location estimation based on EKF changes the electric parameter of motor, algorithm is realized complicated, and measures noise and also more difficult adjusting of plant noise.

Conventionally the general principle of the location-estimation algorithm of surface-mount type permanent magnet synchronous motor is as follows:

SPMSM at the voltage equation of the static α β of stator two-phase coordinate system is:

$\left[\begin{array}{c}{u}_{\mathrm{\α}}\\ u_{\mathrm{\β}}\end{array}\right]=\left[\begin{array}{cc}R+\mathrm{pL}& 0\\ 0& R+\mathrm{pL}\end{array}\right]\left[\begin{array}{c}{i}_{\mathrm{\α}}\\ i_{\mathrm{\β}}\end{array}\right]+\mathrm{\ω}{\mathrm{\Ψ}}_f\left[\begin{array}{c}-\sin \mathrm{\θ}\\ \cos \mathrm{\θ}\end{array}\right]$

（1）

The voltage equation that obtains two-phase rotation dq coordinate system after Coordinate Conversion is:

$\left[\begin{array}{c}{u}_d\\ u_q\end{array}\right]=\left[\begin{array}{cc}R+\mathrm{pL}& -\mathrm{\ωL}\\ \mathrm{\ωL}& R+\mathrm{pL}\end{array}\right]\left[\begin{array}{c}{i}_d\\ i_q\end{array}\right]+\mathrm{\ω}{\mathrm{\Ψ}}_f\left[\begin{array}{c}1\\ 0\end{array}\right]$

（2）

Wherein, u _α, u _β, u _d, u _qbe respectively stator voltage α β axle and dq axle component; i _α, i _β, i _d, i _qbe respectively stator current α β axle and dq axle component; R, L is respectively stator resistance and stator inductance; ω is rotor speed; θ is rotor-position; ψ _ffor rotor permanent magnet magnetic linkage; P is differential operator.

Suppose estimated position θ _eand the error theta between physical location θ _err=θ _e-θ, and establish based on estimated position θ _erotor two cordic phase rotators be d _eq _eso, can obtain rotor according to formula (1) and estimate two-phase rotation d _eq _ethe Mathematical Modeling of coordinate is:

$\left[\begin{array}{c}{u}_d^e\\ u_q^e\end{array}\right]=\left[\begin{array}{cc}R+\mathrm{pL}& -{\mathrm{\ω}}_{e}L\\ {\mathrm{\ω}}_{e}L& R+\mathrm{pL}\end{array}\right]\left[\begin{array}{c}{i}_d^e\\ i_d^e\end{array}\right]+\left[\begin{array}{c}{e}_d^e\\ e_q^e\end{array}\right]---\left(3\right)$

Wherein, ω _efor rotor estimating speed, definition d _eq _eback electromotive force under coordinate is it is to convert d by the estimation difference on dq shaft voltage component between estimated voltage equation and real voltage equation via coordinate transform _eq _ecoordinate forms:

$\left[\begin{array}{c}{e}_d^e\\ e_q^e\end{array}\right]={\mathrm{\ω}}_e{\mathrm{\Ψ}}_f\left[\begin{array}{c}\sin {\mathrm{\θ}}_{\mathrm{err}}\\ \cos {\mathrm{\θ}}_{\mathrm{err}}\end{array}\right]---\left(4\right)$

In formula (3), comprise differential term, this will bring error to rotating speed and location estimation, even make control system portion stable.In actual applications, in the time of rotating speed and current stabilization, actual current always close to given electric current, can think that electric current time differential is now zero under the effect of current regulator.D proceeds from the reality _eq _ethe voltage model of coordinate system develops into:

$\left[\begin{array}{c}{u}_d^e\\ u_q^e\end{array}\right]=\left[\begin{array}{cc}R& -{\mathrm{\ω}}_{e}L\\ {\mathrm{\ω}}_{e}L& R\end{array}\right]\left[\begin{array}{c}{i}_d^e\\ i_d^e\end{array}\right]+{\mathrm{\ω}}_e{\mathrm{\Ψ}}_f\left[\begin{array}{c}\sin {\mathrm{\θ}}_{\mathrm{err}}\\ {\cos \mathrm{\θ}}_{\mathrm{err}}\end{array}\right]---\left(5\right)$

In the control system of position-sensor-free, dq shaft voltage equation cannot directly obtain, in order to calculate θ _errintroduce feedfoward control, definition feedfoward control set point is :

$\left[\begin{array}{c}{u}_{d\_\mathrm{ff}}^e\\ u_{q\_\mathrm{ff}}^e\end{array}\right]=\left[\begin{array}{cc}R& -{\mathrm{\ω}}_{e}L\\ {\mathrm{\ω}}_{e}L& R\end{array}\right]\left[\begin{array}{c}{i}_d^{*}\\ i_d^{*}\end{array}\right]+{\mathrm{\ω}}_e{\mathrm{\Ψ}}_f\left[\begin{array}{c}0\\ 1\end{array}\right]---\left(6\right)$

(6) formula is desirable voltage equation, and from formula (5) and formula (6), the voltage error between estimated value and reference value can be compensated by the pi regulator of electric current loop, definition error voltage direct axis component u _{d_err}with quadrature axis component u _{q_err}for:

$\left\{\begin{array}{c}{u}_{d\_\mathrm{err}}=R(i_d^e-i_d^{*})-{\mathrm{\ω}}_{e}L(i_q^e-i_q^{*})+{\mathrm{\ω}}_e{\mathrm{\Ψ}}_f\sin {\mathrm{\θ}}_{\mathrm{err}}\\ u_{q\_\mathrm{err}}=R(i_q^e-i_q^{*})+{\mathrm{\ω}}_{e}L(i_d^e-i_d^{*})+{\mathrm{\ω}}_e{\mathrm{\Ψ}}_f(\cos {\mathrm{\θ}}_{\mathrm{err}}-1)\end{array}\right.$

（7）

In the time that system works is stablized, i under the effect of current regulator and feedforward ^e≈ i ^*, and θ _errvery little, so simplifying, formula (7) obtains:

$\frac{u_{q\_\mathrm{err}}}{u_{d\_\mathrm{err}}}\≈\frac{\cos {\mathrm{\θ}}_{\mathrm{err}}-1}{\sin {\mathrm{\θ}}_{\mathrm{err}}}\≈-\frac{{\mathrm{\θ}}_{\mathrm{err}}}{2}---\left(8\right)$

Finally obtain:

${\mathrm{\θ}}_{\mathrm{err}}=-\frac{2u_{q\_\mathrm{err}}}{u_{d\_\mathrm{err}}}---\left(9\right)$

θ _errcan obtain through phase-locked loop speed and the position estimated again, the formula of phase-locked loop estimating speed is as follows:

ω _e=Kpθ _err+Ki∫θ _errdt (10)

Wherein Kp is proportionality coefficient, and Ki is integral coefficient.Again by ω _ecan obtain rotor-position estimated value:

θ _e=∫ω _edt (11)

The SPMSM position estimation method that prior art provides needs dependent resistor and inductance, so the deviation of its location estimation in the time of low speed is larger, the amount of calculation of above-mentioned calculating is also very large in addition.

Summary of the invention

The object of the embodiment of the present invention is to provide a kind of location estimation method of mounted permanent magnet synchronous motor, and the deviation that is intended to solve prior art location estimation in the time of low speed is larger, the problem that amount of calculation is large.

First aspect provides a kind of location estimation method of surface-mount type permanent magnet synchronous motor, and described method comprises:

Obtain the q shaft current i of surface-mount type permanent magnet synchronous motor _q;

Estimate the mechanical angle position θ of the electric equipment of surface-mount type permanent magnet synchronous motor;

ω=a/s

θ=ω/s

Wherein,

a=(K _ti _q-T _L)/J，，

ω mechanical angle speed, θ is mechanical angle position, T _lload torque, J is moment of inertia, and a is mechanical angle acceleration, and S is Laplace operator.

In conjunction with the technical scheme of first aspect, in the optional embodiment of the first of first aspect, when described surface-mount type permanent magnet synchronous motor underloading or while thering is inertia load,

a=K _ti _q/J。

Second aspect, provides a kind of position estimating system of surface-mount type permanent magnet synchronous motor, and described system comprises:

Acquiring unit, for obtaining the q shaft current i of surface-mount type permanent magnet synchronous motor _q;

Evaluation unit, for estimating the mechanical angle position θ of electric equipment of surface-mount type permanent magnet synchronous motor;

ω=a/s

θ=ω/s

Wherein,

a=(K _ti _q-T _L)/J

ω mechanical angle speed, θ is mechanical angle position, T _lload torque, J is moment of inertia, and a is mechanical angle acceleration, and S is Laplace operator.

In conjunction with the technical scheme of second aspect, in the optional technical scheme of the first of second aspect, when described surface-mount type permanent magnet synchronous motor underloading or while thering is inertia load,

a=K _ti _q/J。

Compared with prior art, beneficial effect is the embodiment of the present invention: it is little that technical scheme of the present invention has in the time of low speed location estimation deviation, the advantage that amount of calculation is little.

Brief description of the drawings

Fig. 1 is the flow chart of the location estimation method of a kind of surface-mount type permanent magnet synchronous motor of providing of the embodiment of the present invention;

Fig. 2 is the control block diagram of a kind of frequency conversion speed-adjusting system of providing of the embodiment of the present invention;

Fig. 3 is as resistance R=26 Ω, when inductance L=170mH, and the estimated position of two kinds of algorithm for estimating and the error curve diagram of physical location;

Fig. 4 is as resistance R=13 Ω, when inductance L=170mH, and the estimated position of two kinds of algorithm for estimating and the error curve diagram of physical location;

Fig. 5 is as resistance R=26 Ω, when inductance L=102mH, and the estimated position of two kinds of algorithm for estimating and the error curve diagram of physical location;

The structure chart of the position estimating system of a kind of surface-mount type permanent magnet synchronous motor that Fig. 6 provides for the specific embodiment of the invention.

Embodiment

In order to make object of the present invention, technical scheme and advantage clearer, below in conjunction with drawings and Examples, the present invention is further elaborated.Should be appreciated that specific embodiment described herein, only in order to explain the present invention, is not intended to limit the present invention.

The specific embodiment of the invention provides a kind of location estimation method of surface-mount type permanent magnet synchronous motor, and the method is carried out by electric equipment, and this electric equipment is mainly, the electric equipment that comprises surface-mount type permanent magnet synchronous motor, the electric equipments such as such as air-conditioning, the method as shown in Figure 1, comprising:

101, obtain the q shaft current i of surface-mount type permanent magnet synchronous motor _q;

102, estimate the mechanical angle position θ of the electric equipment of surface-mount type permanent magnet synchronous motor;

ω=a/s （17）

θ=ω/s （18）

Wherein,

a=(K _ti _q-T _L)/J，，，，

ω mechanical angle speed, θ is mechanical angle position, T _lload torque, J is moment of inertia, and a is mechanical angle acceleration, and S is Laplace operator.

Technical scheme provided by the invention, in the time calculating, without knowing resistance and inductance, only needs to measure q shaft current i _q, and obtain load torque T _land moment of inertia J, and it calculates simple, only with carrying out simple computation and carry out quadratic integral to calculate the position that comprises surface-mount type permanent magnet synchronous motor, in addition, prove by experiment, the position that adopts said method to estimate has good low speed measurement characteristics.

Optionally, when surface-mount type permanent magnet synchronous motor underloading or while thering is inertia load,

a=K _ti _q/J （16）

Because in surface-mount type permanent magnet synchronous motor underloading or while thering is inertia load, T _e>>T _lso, now calculating the load torque that can ignore motor when a.

T _e=K _ti _q （14）

Introduce theoretical foundation of the present invention below

Have according to momental equation:

T _e-T _L=Ja （12）

In formula (12): T _efor electromagnetic torque, T _lfor load torque, J is moment of inertia, and a is mechanical angle acceleration;

Have according to electromagnetic torque equation again:

T _e=K _ti _q+(L _d-L _q)i _di _q （13）

In formula (13): K _tfor moment coefficient, i _qfor q shaft current, i _dfor d shaft current, L _dfor d axle inductance, L _qfor q axle inductance.

Because control object is surface-mount type permagnetic synchronous motor, i.e. L _d=L _q, therefore formula (13) becomes:

T _e=K _ti _q （14）

Be not difficult to draw by formula (12) and formula (14)

a=(K _ti _q-T _L)/J （15）

By formula (15), be not difficult to find out mechanical angle acceleration a only with moment coefficient K _{t, q}axle is measured current i _q, load torque T _land moment of inertia J is relevant, and with inductance L, resistance R and the independent of power voltage of motor.

Under underloading or inertia load condition, can think T _e>>T _l, formula (15) can be changed into:

a=K _ti _q/J （16）

Therefore,, under the condition of underloading or inertia load, mechanical angle acceleration a is well-determined.Mechanical angle speed can be tried to achieve by mechanical angle acceleration a integration, and mechanical angle position can be tried to achieve by mechanical angle acceleration quadratic integral.If mechanical angle speed is ω, mechanical angle position is θ, so have:

ω=a/s （17）

θ=ω/s （18）

In upper two formulas, S is Laplace operator.

The technique effect of technical scheme provided by the invention is described below by emulation experiment,

The present invention moves under the control block diagram of frequency conversion speed-adjusting system as shown in Figure 2, and the condition of its operation is:

Motor resistance R=26 Ω, motor inductance L=170mH, torque coefficient Kt=0.46789N.m/A, motor number of pole-pairs poles=4, moment of inertia 0.003kg.m ².

D shaft current ring PI parameter: Kp=300, Ki=0.3, sample rate is 15kHz;

Q shaft current ring PI parameter is identical with d axle.

Speed ring PI parameter: Kp=1, Ki=0.0005, sample rate 200Hz;

Input mechanical speed: 10Hz;

Load torque: 0.001N.m;

Supply voltage: 310V

As resistance R=26 Ω, when inductance L=170mH, the estimated position of two kinds of algorithm for estimating and the error curve of physical location are as shown in Figure 3; In Fig. 3, solid line is the error curve of estimated position of the present invention and physical location, dotted line is the estimated position of traditional algorithm and the error curve of physical location, Tu3Zhong abscissa unit counts, and ordinate unit is rad(radian), Fig. 4, Fig. 5 curve implication justice is identical with Fig. 3.

As seen from the figure, the error curve of algorithm of the present invention presents increase tendency, this is because this algorithm has been ignored load torque (because fans load meets underloading condition), and traditional algorithm rise site error is larger at the beginning, when this is very low because of speed, back-emf is not also well set up, obviously, algorithm of the present invention has better low speed measurement characteristics.

When resistance R=13 Ω (reducing 50%), when inductance L=170mH, the estimated position of two kinds of algorithm for estimating and the error curve of physical location are shown in Fig. 4;

As seen from Figure 4, the reducing of resistance produced great impact to the estimated accuracy of traditional location algorithm for estimating, and this closed-loop characteristic that affects the direct reduction system of meeting, even causes system normally to work, and algorithm of the present invention is had no effect.

As resistance R=26 Ω, inductance L=102mH(reduces 40%) time, the error curve of two kinds of algorithm for estimating estimated positions and physical location is shown in Fig. 5.Obviously, there is larger evaluated error at low speed segment in traditional algorithm, and algorithm of the present invention is by good low speed measurement characteristics.

The specific embodiment of the invention provides a kind of position estimating system of surface-mount type permanent magnet synchronous motor, and said system can be arranged in the microprocessor of electric equipment, and this system as shown in Figure 6, comprising:

Acquiring unit 601, for obtaining the q shaft current i of surface-mount type permanent magnet synchronous motor _q;

Evaluation unit 602, for estimating the mechanical angle position θ of electric equipment of surface-mount type permanent magnet synchronous motor;

ω=a/s

θ=ω/s

Wherein,

a=(K _ti _q-T _L)/J

ω mechanical angle speed, θ is mechanical angle position, T _lload torque, J is moment of inertia, and a is mechanical angle acceleration, and S is Laplace operator.

Optionally, when described surface-mount type permanent magnet synchronous motor underloading or while thering is inertia load,

a=K _ti _q/J。

It is little that system provided by the invention has in the time of low speed location estimation deviation, the advantage that amount of calculation is little.

The foregoing is only preferred embodiment of the present invention, not in order to limit the present invention, all any amendments of doing within the spirit and principles in the present invention, be equal to and replace and improvement etc., within all should being included in protection scope of the present invention.

Claims (4)

1. a location estimation method for surface-mount type permanent magnet synchronous motor, is characterized in that, described method comprises:

Obtain the q shaft current i of surface-mount type permanent magnet synchronous motor _q;

Estimate the mechanical angle position θ of the electric equipment of surface-mount type permanent magnet synchronous motor;

ω=a/s

θ=ω/s

Wherein,

a=(K _ti _q-T _L)/J

ω mechanical angle speed, θ is mechanical angle position, T _lload torque, J is moment of inertia, and a is mechanical angle acceleration, and S is Laplace operator.

2. method according to claim 1, is characterized in that, when described surface-mount type permanent magnet synchronous motor underloading or while thering is inertia load,

a=K _ti _q/J。

3. a position estimating system for surface-mount type permanent magnet synchronous motor, is characterized in that, described system comprises:

Acquiring unit, for obtaining the q shaft current i of surface-mount type permanent magnet synchronous motor _q;

Evaluation unit, for estimating the mechanical angle position θ of electric equipment of surface-mount type permanent magnet synchronous motor;

ω=a/s

θ=ω/s

Wherein,

a=(K _ti _q-T _L)/J

ω mechanical angle speed, θ is mechanical angle position, T _lload torque, J is moment of inertia, and a is mechanical angle acceleration, and S is Laplace operator.

4. system according to claim 3, is characterized in that, when described surface-mount type permanent magnet synchronous motor underloading or while thering is inertia load,

a=K _ti _q/J。