CN104980078A - Measurement method of motor rotational inertia, measurement device of motor rotational inertia and motor control system - Google Patents

Abstract

The present invention discloses a measurement method of a motor rotational inertia, a measurement device of the motor rotational inertia and a motor control system. When a motor is located in no-load or light load operation, the measurement method of the motor rotational inertia comprises the following steps of obtaining a preset straight axis reference current and a preset quadrature axis reference current within a preset time quantum, and controlling the rotating speed of the motor to accelerate with a preset angular acceleration; sampling a DC of the motor at a preset sampling point of the preset time quantum to obtain a sampling current, and calculating an electromagnetic torque of the motor according to the sampling current; calculating the rotational inertia of the motor according to the electromagnetic torque and the preset angular acceleration. The rotational inertia measurement method of the present invention can obtain the more accurate rotational inertia, is simple to operate and easy to realize, is low in measurement cost, and can be applied to the engineering practice.

Description

The method of measurement of the moment of inertia of motor and measurement mechanism and electric machine control system

Technical field

The present invention relates to technical field of motors, particularly the measurement mechanism of a kind of method of measurement of moment of inertia of motor, a kind of moment of inertia of motor and a kind of electric machine control system.

Background technology

Along with development and the maturation of vector frequency conversion control technology, increasing equipment configuration variable frequency drives carrys out the operation of drive motors.Such as, all variable frequency drives is equipped with at equipment such as domestic air conditioning, kitchen appliance, washing machine, refrigerator, elevators.But, there is stronger dependence to the parameter of motor when variable frequency drives adopts vector control technology to drive motor, if the parameter of motor is inaccurate, then can affect greatly the driveability of motor, energy-saving effect, starting characteristic etc.The producer of usual motor all can provide motor Common Parameters, such as, resistance, inductance are along with the curve, back EMF coefficient, magnetic pole logarithm etc. of curent change, but motor producer does not generally provide this parameter of moment of inertia or institute to there is comparatively big error to moment of inertia parameter.Therefore, moment of inertia parameter is measured accurately and effectively very necessary.

Correlation technique proposes a kind of method calculating moment of inertia, and the method, based on the equation of motion, is considered that motor is under no-load condition, rotor acceleration when measuring electric motor starting and stop, then obtained the moment of inertia of motor by computing.But the method needs to use the complicated testing tool such as photoelectric encoder, accurately time measuring instrument, measures cost high, and carries out start stop operation to motor, from not easy to operate engineering practice.

To sum up, there are the needs improved in the method for measuring rotary inertia in correlation technique.

Summary of the invention

Object of the present invention is intended to solve above-mentioned technological deficiency at least to a certain extent.

For this reason, first object of the present invention is the method for measurement of the moment of inertia proposing a kind of motor, can obtain moment of inertia more accurately, and simple to operate, measures cost low.

Second object of the present invention is the measurement mechanism of the moment of inertia proposing a kind of motor.3rd object of the present invention is to propose a kind of electric machine control system.

For achieving the above object, the method of measurement of the moment of inertia of the motor that first aspect present invention embodiment proposes, comprise the following steps: when described motor is in zero load or light running, obtain in preset time period and preset d-axis reference current and default quadrature axis reference current, and the rotating speed controlling described motor accelerates with preset angle acceleration; Sample to obtain sample rate current at the electric current of default sampled point to described motor of described preset time period, and calculate the electromagnetic torque of described motor according to described sample rate current; The moment of inertia of motor according to described electromagnetic torque and described preset angle acceleration calculation.

According to the method for measurement of the moment of inertia of the motor of embodiment of the present invention proposition, when motor is in zero load or light running, the rotating speed controlling motor in preset time period accelerates with preset angle acceleration, sample to obtain sample rate current at the electric current of default sampled point to motor of preset time period, and calculate the first electromagnetic torque of motor according to sample rate current, and then according to the moment of inertia of electromagnetic torque and preset angle acceleration calculation motor.Thus, moment of inertia more accurately can be obtained, and simple to operate, realize easily, measuring cost low, can engineering practice being applied to.

Particularly, in one embodiment of the invention, can according to following formulae discovery the moment of inertia of motor:

$J=\frac{Y_1}{X_1}$

Wherein, J is the moment of inertia of described motor, X ₁for described preset angle acceleration, Y ₁for described pre-given electromagnetic torque.

Further, in one embodiment of the invention, described electromagnetic torque obtains according to following formulae discovery:

Y ₁＝1.5PI _sq1[Ke+(L _sd1-L _sq1)I _sd1]

Wherein, Y ₁for described pre-given electromagnetic torque, I _sq1for the quadrature axis current under two-phase rotating coordinate system, L _sd1for the d-axis inductance under two-phase rotating coordinate system, L _sq1for the quadrature axis inductance under two-phase rotating coordinate system, I _sd1for the direct-axis current under two-phase rotating coordinate system, Ke is the rotor flux of described motor, and P is the magnetic pole logarithm of described motor.

In addition, in one embodiment of the invention, Clark coordinate transform and Park coordinate transform are carried out to obtain described quadrature axis current I to described sample rate current _sq1with described direct-axis current.

For achieving the above object, second aspect present invention embodiment also proposed a kind of measurement mechanism of moment of inertia of motor, comprising: acquisition module, and described acquisition module is used for obtaining in preset time period presetting d-axis reference current and default quadrature axis reference current; Sampling module, described sampling module is used for sampling to obtain sample rate current at the electric current of default sampled point to described motor of described preset time period; Control module, when described motor is in zero load or light running, the rotating speed that described control module is used for controlling in described preset time period described motor accelerates with preset angle acceleration, calculate the electromagnetic torque of described motor according to described sample rate current, and according to described electromagnetic torque and described preset angle acceleration calculation the moment of inertia of motor.

According to the measurement mechanism of the moment of inertia of the motor of embodiment of the present invention proposition, when motor is in zero load or light running, the rotating speed controlling motor in preset time period by control module accelerates with preset angle acceleration, the electromagnetic torque of motor is calculated according to sample rate current, and according to the moment of inertia of electromagnetic torque and preset angle acceleration calculation motor.Thus, moment of inertia more accurately can be obtained, and simple to operate, realize easily, measuring cost low, can engineering practice being applied to.

Particularly, in one embodiment of the invention, the moment of inertia of described control module motor according to following formulae discovery:

$J=\frac{Y_1}{X_1}$

Wherein, J is the moment of inertia of described motor, X ₁for described preset angle acceleration, Y ₁for described pre-given electromagnetic torque.

Further, in one embodiment of the invention, described control module electromagnetic torque according to following formulae discovery:

Y ₁＝1.5PI _sq1[Ke+(L _sd1-L _sq1)I _sd1]

Wherein, Y ₁for described pre-given electromagnetic torque, I _sq1for the quadrature axis current under two-phase rotating coordinate system, L _sd1for the d-axis inductance under two-phase rotating coordinate system, L _sq1for the quadrature axis inductance under two-phase rotating coordinate system, I _sd1for the direct-axis current under two-phase rotating coordinate system, Ke is the rotor flux of described motor, and P is the magnetic pole logarithm of described motor.

In addition, in one embodiment of the invention, described control module carries out Clark coordinate transform and Park coordinate transform to obtain described quadrature axis current I to described sample rate current _sq1with described direct-axis current.

For achieving the above object, third aspect present invention embodiment proposes a kind of electric machine control system, comprises the measurement mechanism of the moment of inertia of described motor.

According to the electric machine control system that the embodiment of the present invention proposes, moment of inertia more accurately can be obtained, and simple to operate, realize easily, measuring cost low, can engineering practice being applied to.

The aspect that the present invention adds and advantage will part provide in the following description, and part will become obvious from the following description, or be recognized by practice of the present invention.

Accompanying drawing explanation

The present invention above-mentioned and/or additional aspect and advantage will become obvious and easy understand from the following description of the accompanying drawings of embodiments, wherein:

Fig. 1 is the flow chart of the method for measurement of the moment of inertia of motor according to the embodiment of the present invention;

Fig. 2 is the change curve schematic diagram of d-axis reference current in the method for measurement of the moment of inertia of motor according to an embodiment of the invention, quadrature axis reference current and angular speed;

Fig. 3 is phase current i in the method for measurement of the moment of inertia of motor according to an embodiment of the invention _saschematic diagram;

Fig. 4 is Clark coordinate transform schematic diagram of the prior art;

Fig. 5 is Park coordinate transform schematic diagram of the prior art;

Fig. 6 is the block diagram of the measurement mechanism of the moment of inertia of motor according to the embodiment of the present invention;

Fig. 7 is the block diagram of the electric machine control system according to the embodiment of the present invention; And

Fig. 8 is the schematic diagram of the electric machine control system according to the present invention's specific embodiment.

Reference numeral:

The measurement mechanism 702 of the moment of inertia of acquisition module 1, sampling module 2, control module 3, motor, electric machine control system 701, motor 10, current sample module 20, first coordinate transferring 30, current correction module 40, direct-axis voltage module 50, quadrature-axis voltage module 60, second coordinate transferring 70, SVPWM driver module 80, inverter 90 and DC power supply 100.

Embodiment

Be described below in detail embodiments of the invention, the example of described embodiment is shown in the drawings, and wherein same or similar label represents same or similar element or has element that is identical or similar functions from start to finish.Being exemplary below by the embodiment be described with reference to the drawings, only for explaining the present invention, and can not limitation of the present invention being interpreted as.

Disclosing hereafter provides many different embodiments or example is used for realizing different structure of the present invention.Of the present invention open in order to simplify, hereinafter the parts of specific examples and setting are described.Certainly, they are only example, and object does not lie in restriction the present invention.In addition, the present invention can in different example repeat reference numerals and/or letter.This repetition is to simplify and clearly object, itself does not indicate the relation between discussed various embodiment and/or setting.In addition, the various specific technique that the invention provides and the example of material, but those of ordinary skill in the art can recognize the property of can be applicable to of other techniques and/or the use of other materials.In addition, fisrt feature described below second feature it " on " structure can comprise the embodiment that the first and second features are formed as directly contact, also can comprise other feature and be formed in embodiment between the first and second features, such first and second features may not be direct contacts.

In describing the invention, it should be noted that, unless otherwise prescribed and limit, term " installation ", " being connected ", " connection " should be interpreted broadly, such as, can be mechanical connection or electrical connection, also can be the connection of two element internals, can be directly be connected, also indirectly can be connected by intermediary, for the ordinary skill in the art, the concrete meaning of above-mentioned term can be understood as the case may be.

With reference to description below and accompanying drawing, these and other aspects of embodiments of the invention will be known.Describe at these and in accompanying drawing, specifically disclose some particular implementation in embodiments of the invention, representing some modes of the principle implementing embodiments of the invention, but should be appreciated that the scope of embodiments of the invention is not limited.On the contrary, embodiments of the invention comprise fall into attached claims spirit and intension within the scope of all changes, amendment and equivalent.

The method of measurement of moment of inertia of motor, the measurement mechanism of the moment of inertia of motor and the electric machine control system that propose according to the embodiment of the present invention are described with reference to the accompanying drawings.

Fig. 1 is the flow chart of the method for measurement of the moment of inertia of motor according to the embodiment of the present invention.As shown in Figure 1, the method for measurement of the moment of inertia of this motor comprises the following steps:

S1: when motor is in zero load or light running, obtains and preset d-axis reference current and default quadrature axis reference current, and the rotating speed controlling motor accelerates with preset angle acceleration in preset time period.

Wherein, when motor is in zero load or underloading, coefficient of friction and load torque are very little, can ignore.

Specifically, as shown in Figure 2, at preset time period and t ₁~ t ₂in time period, make d-axis reference current equal default d-axis reference current quadrature axis reference current equal default quadrature axis reference current and according to default d-axis reference current with default quadrature axis reference current vector control is carried out to motor, also controls the rotational speed omega of rotor according to preset angle acceleration X ₁accelerate.

S2: sample to obtain sample rate current at the electric current of default sampled point to motor of preset time period, and the electromagnetic torque calculating motor according to sample rate current.

That is, at t ₁~ t ₂the default sampled point A of time period is to the three-phase current i of motor _sa, i _sb, i _scsample.As shown in Figure 3, with phase current i _safor example, can at A point to phase current i _sasample, wherein, phase current i _saat t ₁~ t ₂the amplitude of time period is i _sa1.

In the present invention's specific embodiment, electromagnetic torque obtains according to following formulae discovery:

Y ₁＝1.5PI _sq1[Ke+(L _sd1-L _sq1)I _sd1]

Wherein, Y ₁for pre-given electromagnetic torque, L _sd1for the d-axis inductance under two-phase rotating coordinate system, L _sq1for the quadrature axis inductance under two-phase rotating coordinate system, L _sd1and L _sq1can be provided by producer, I _sq1for the quadrature axis current under two-phase rotating coordinate system, I _sd1for the direct-axis current under two-phase rotating coordinate system, Ke is the rotor flux of motor, and P is the magnetic pole logarithm of motor.

Specifically, Clark coordinate transform and Park coordinate transform are carried out to obtain quadrature axis current I to the first sample rate current _sq1with direct-axis current I _sd1;

Generally speaking, for the vector control of motor, the most important thing is coordinate transform, coordinate transform mainly comprises two parts:

One is, Clark coordinate transform, namely transforms to alpha-beta two-phase rest frame from a-b-c three-phase static coordinate system, also can be described as Clark direct transform.In addition, also a-b-c three-phase static coordinate system can be transformed to from alpha-beta two-phase rest frame, i.e. Clark inverse transformation.Particularly, Clark direct transform C _3s/2swith Clark inverse transformation C _2s/3stransformation matrix be respectively:

$C_{3s/2s}=\frac{2}{3}\left[\begin{array}{ccc}1& -1/2& -1/2\\ 0& \sqrt{3}/2& -\sqrt{3}/2\end{array}\right]C_{2s/3s}=\left[\begin{array}{cc}1& 0\\ -\frac{1}{2}& \frac{\sqrt{3}}{2}\\ -\frac{1}{2}& -\frac{\sqrt{3}}{2}\end{array}\right]---\left(1\right)$

Above-mentioned transformation matrix is applicable to Clark direct transform and the Clark inverse transformation of voltage, electric current and magnetic linkage isovector.

Be illustrated in figure 4 Clark coordinate transform schematic diagram, wherein, i _sa, i _sb, i _scbe respectively the current component of three-phase current at a axle of three-phase static coordinate system, b axle, c-axis, u _sa, u _sb, u _scbe respectively the component of voltage of three-phase voltage at a axle, b axle, c-axis, L _sa, L _sb, L _scbe respectively the inductive component on a axle, b axle, c-axis, the α axle of alpha-beta two-phase rest frame and α axle advanced β axle 90 ° mutually vertical with β axle, i _{s α}, i _{s β}be respectively the current component of three-phase current at α axle and β axle, u _{s α}, u _{s β}be respectively the component of voltage of three-phase voltage at α axle and β axle, L _{s α}, L _{s β}be respectively the inductive component on α axle and β axle, F is air gap rotating synthesizing magnetic potential, and it to rotate along the direction of the axial c-axis of the axial b of a with synchronous speed angular rate ω by Sine distribution in the inter-air space, and induces three-phase current i in stator armature winding _sa, i _sb, i _scwith three-phase voltage u _sa, u _sb, u _sc.

Two are, Park coordinate transform, namely transform to d-q two-phase rotating coordinate system from alpha-beta two-phase rest frame, also can be described as Park direct transform.In addition, also alpha-beta two-phase rest frame can be transformed to from d-q two-phase rotating coordinate system, i.e. Park inverse transformation.Particularly, Park direct transform C _2s/2rwith Park inverse transformation C _2r/2stransformation matrix be respectively:

$C_{2s/2r}=\left[\begin{array}{cc}\cos \mathrm{\θ}& \sin \mathrm{\θ}\\ -\sin \mathrm{\θ}& \cos \mathrm{\θ}\end{array}\right]C_{2r/2s}=\left[\begin{array}{cc}\cos \mathrm{\θ}& -\sin \mathrm{\θ}\\ \sin \mathrm{\θ}& \cos \mathrm{\θ}\end{array}\right]---\left(2\right)$

Wherein, θ is the angle of d axle and α axle.

Above-mentioned transformation matrix is applicable to Park direct transform and the Park inverse transformation of voltage, electric current and magnetic linkage isovector.

Be illustrated in figure 5 Park coordinate transform schematic diagram, wherein: the α axle of alpha-beta two-phase rest frame and α axle advanced β axle 90 ° mutually vertical with β axle, i _{s α}, i _{s β}be respectively the current component of three-phase current at α axle and β axle, u _{s α}, u _{s β}be respectively the component of voltage of three-phase voltage at α axle and β axle, L _{s α}, L _{s β}be respectively the inductive component on α axle and β axle, the d axle of d-q two-phase rotating coordinate system and q axle advanced d axle 90 ° mutually vertical with q axle, d-q two-phase rotating coordinate system is rotated counterclockwise to q direction along d with angular rate ω, i _sd, i _sqbe respectively the current component of three-phase current at d axle and q axle, u _sd, u _sqbe respectively the component of voltage of three-phase voltage at d axle and q axle, L _sd, L _sqbe respectively the inductive component on d axle and q axle.θ is the angle of d axle and α axle.

In addition, when using vector coordinate transform to carry out vector control to motor, need to do following hypothesis: the magnetic linkage in (1) air gap is by Sine distribution, and air gap is evenly distributed, air-gap reluctance is constant; (2) do not consider magnetic saturation phenomenon, namely armature winding equal and opposite in direction and and in winding the electric current that passes into have nothing to do; (3) eddy current and hysteresis effect is not considered; (4) what generator produced in armature winding is symmetrical three phase sine alternating current, and each equivalent resistance is identical; (5) rotor does not have damping winding, permanent magnet does not have damping action yet; (6) impact of the external conditions such as temperature on the parameter of electric machine is ignored.

Like this, under just can obtaining two-phase rotating coordinate system based on above-mentioned hypothesis, the following expression formula of motor relevant parameter can be obtained:

Electric moter voltage equation is:

$\left\{\begin{array}{c}{u}_{\mathrm{sd}}=R_s{I}_{\mathrm{sd}}+p{\mathrm{\ψ}}_d-{\mathrm{\ω}}_r{\mathrm{\ψ}}_q\\ u_{\mathrm{sq}}=R_s{I}_{\mathrm{sq}}+p{\mathrm{\ψ}}_q+{\mathrm{\ω}}_r{\mathrm{\ψ}}_d\end{array}\right.---\left(3\right)$

Wherein, R _sfor the stator resistance of motor, p is differential operator, ω _rfor the angular rate of rotor, ψ _dfor d-axis magnetic linkage, ψ _qfor quadrature axis magnetic linkage.

It should be noted that, in embodiments of the present invention, by controlling the angular rate ω of rotor _rwith preset angle acceleration X ₁accelerate, and then make the rotational speed omega of motor and the mechanical angle speed omega of rotor with preset angle acceleration X ₁accelerate.

Motor flux linkage equations is:

$\left\{\begin{array}{c}{\mathrm{\ψ}}_d=L_{\mathrm{sd}}{I}_{\mathrm{sd}}+{\mathrm{\ψ}}_f\\ {\mathrm{\ψ}}_q=L_{\mathrm{sq}}{I}_{\mathrm{sq}}\end{array}\right.---\left(4\right)$

Wherein, ψ _ffor the rotor flux of motor, the rotor flux of motor also can represent by Ke.

Motor electromagnetic torque equation is:

T _e＝1.5PI _sq*[ψ _f+(L _sd-L _sq)I _sd] （5）

Wherein, T _efor electromagnetic torque.

Like this, at default sampled point A, obtain sample rate current i _sa1, i _sb1, i _sc1after, first according to formula (1) and (2), Clark coordinate transform and Park coordinate transform are carried out to sample rate current, obtain quadrature axis current I _sq1with direct-axis current I _sd1, and calculate electromagnetic torque Y according to formula (5) ₁, i.e. electromagnetic torque Y ₁=1.5PI _sq1[Ke+ (L _sd-L _sq) I _sd1], wherein, Ke=ψ _f.

S3: according to the moment of inertia of electromagnetic torque and preset angle acceleration calculation motor.

In the present invention's specific embodiment, can according to the moment of inertia of following formulae discovery motor:

$J=\frac{Y_1}{X_1}$

Wherein, J is the moment of inertia of motor, X ₁for preset angle acceleration, Y ₁for pre-given electromagnetic torque.

Specifically, the popular motion equation of motor:

$T_e-T_L=\frac{\mathrm{Jd\ω}}{\mathrm{Pt}}+\mathrm{b\ω}---\left(6\right)$

Wherein, T _efor electromagnetic torque, T _lfor load torque, J be moment of inertia, ω is the rotating speed of motor, namely the mechanical angle speed of rotor, b are coefficient of friction, P magnetic pole logarithm.

Like this, when motor is in zero load or underloading, supposes that coefficient of friction and load torque are very little, can ignore, this pattern (6) can abbreviation be just:

$T_e=\frac{\mathrm{Jd\ω}}{\mathrm{Pdt}}---\left(7\right)$

Suppose, electromagnetic torque Y, moment of inertia J, angular acceleration X following variables replace:

$Y=T_e,A=J,X=\frac{\mathrm{d\ω}}{\mathrm{Pdt}}---\left(8\right)$

Further, suppose that the rotor mechanical angular acceleration X of motor can tracking fixed valure, i.e. preset angle acceleration faster.Like this, formula (8) is brought into formula (7) known:

Y＝AX (9)

Above formula (10) is linear equation with one unknown, as long as know that the value of a group (X, Y) just can ask for the size of moment of inertia A.

Like this, when motor is in zero load or underloading, suppose that coefficient of friction and load torque are very little, can ignore, the popular motion equation of motor can abbreviation be just formula (6), thus, as long as once simply test on the inverter of motor self outfit, i.e. given preset angle acceleration X ₁, and record electromagnetic torque Y ₁, bring (9) formula afterwards into and just can calculate moment of inertia:

$J=A=\frac{Y_1}{X_1}$

Thus, according to given preset angle acceleration X ₁, and calculate electromagnetic torque Y by step S1 and step S2 ₁, afterwards, by X ₁, Y ₁bring formula (10) into and just can calculate moment of inertia J.

In addition, as shown in Figure 2, the rotating speed of motor is being controlled with preset angle acceleration X ₁initial preset time period i.e. 0 ~ t before accelerating ₁in time period, first the rotor of motor is positioned, namely say, obtain initial d-axis reference current and initial quadrature axis reference current, wherein, initial d-axis reference current initial quadrature axis reference current linear increase, now the rotational speed omega of rotor is zero, and rotor is fixed on specifies initial position θ ^*=θ ₀, can position rotor.It should be noted that, can not be too little, at least want to overcome the moment of resistance that motor load and friction cause.

Further, after acquisition moment of inertia J, such as, more than t ₂time, motor carries out position-sensor-free estimation by phase-locked loop, controls the motor incision speed closed loop stage, and the moment of inertia of motor calculates and terminates.

To sum up, according to the method for measurement of the moment of inertia of the motor of embodiment of the present invention proposition, when motor is in zero load or light running, the rotating speed controlling motor in preset time period accelerates with preset angle acceleration, sample to obtain sample rate current at the electric current of default sampled point to motor of preset time period, and calculate the first electromagnetic torque of motor according to sample rate current, and then according to the moment of inertia of electromagnetic torque and preset angle acceleration calculation motor.Thus, moment of inertia more accurately can be obtained, and simple to operate, realize easily, measuring cost low, can engineering practice being applied to.

Fig. 6 is the block diagram of the measurement mechanism of the moment of inertia of motor according to the embodiment of the present invention.As shown in Figure 6, the measurement mechanism of the moment of inertia of this motor comprises: acquisition module 1, sampling module 2 and control module 3.

Acquisition module 1 presets d-axis reference current and default quadrature axis reference current for obtaining in preset time period.

That is, in preset time period, i.e. t ₁~ t ₂in time period, d-axis reference current can be set with quadrature axis reference current for default d-axis reference current with default quadrature axis reference current

Sampling module 2 samples to obtain sample rate current for the electric current of default sampled point to motor in preset time period.

That is, at t ₁~ t ₂the default sampled point A of time period is to the three-phase current i of motor _sa, i _sb, i _scsample.

When motor is in zero load or light running, control module 3 is accelerated with preset angle acceleration for the rotating speed controlling motor in preset time period, the electromagnetic torque of motor is calculated according to sample rate current, and according to the moment of inertia of electromagnetic torque and preset angle acceleration calculation motor.

In one particular embodiment of the present invention, control module 3 can according to the moment of inertia of following formulae discovery motor:

$J=\frac{Y_1}{X_1}$

Wherein, J is the moment of inertia of motor, X ₁for preset angle acceleration, _y1 is pre-given electromagnetic torque.

Further, in one particular embodiment of the present invention, control module 3 is according to following formulae discovery electromagnetic torque:

Y ₁＝1.5PI _sq1[Ke+(L _sd1-L _sq1)I _sd1]

Wherein, Y ₁for pre-given electromagnetic torque, I _sq1for the quadrature axis current under two-phase rotating coordinate system, L _sd1for the d-axis inductance under two-phase rotating coordinate system, L _sq1for the quadrature axis inductance under two-phase rotating coordinate system, I _sd1for the direct-axis current under two-phase rotating coordinate system, Ke is the rotor flux of motor, and P is the magnetic pole logarithm of motor.

Further, in one particular embodiment of the present invention, control module 3 pairs of sample rate currents carry out Clark coordinate transform and Park coordinate transform to obtain quadrature axis current I _sq1with direct-axis current I _sd1.

Generally speaking, sampling module 2 obtains sample rate current i at default sampled point A _sa1, i _sb1, i _sc1after, control module 3 first carries out Clark coordinate transform and Park coordinate transform to sample rate current, obtains quadrature axis current I _sq1with direct-axis current I _sd1, and calculate electromagnetic torque Y ₁, i.e. Y ₁=1.5PI _sq1[Ke+ (L _sd-L _sq) I _sd1], wherein, Ke=ψ _f.

Thus, control module 3 is according to given preset angle acceleration X ₁with the electromagnetic torque Y that basis calculates ₁calculate moment of inertia J.

In addition, as shown in Figure 2, control module 3 is controlling the rotating speed of motor with preset angle acceleration X ₁initial preset time period i.e. 0 ~ t before accelerating ₁in time period, first the rotor of motor is positioned, namely say, obtain initial d-axis reference current and initial quadrature axis reference current, wherein, initial d-axis reference current initial quadrature axis reference current linear increase, now the rotational speed omega of rotor is zero, and rotor is fixed on specifies initial position θ ^*=θ ₀, can position rotor.It should be noted that, can not be too little, at least want to overcome the moment of resistance that motor load and friction cause.

Further, control module 3 after calculating moment of inertia J, such as, more than t ₂time, motor carries out position-sensor-free estimation by phase-locked loop, controls the motor incision speed closed loop stage, and the moment of inertia of motor calculates and terminates.

According to the measurement mechanism of the moment of inertia of the motor of embodiment of the present invention proposition, when motor is in zero load or light running, the rotating speed controlling motor in preset time period by control module accelerates with preset angle acceleration, the electromagnetic torque of motor is calculated according to sample rate current, and according to the moment of inertia of electromagnetic torque and preset angle acceleration calculation motor.Thus, moment of inertia more accurately can be obtained, and simple to operate, realize easily, measuring cost low, can engineering practice being applied to.

Fig. 7 is the block diagram of the electric machine control system according to embodiment of the present invention proposition.As shown in Figure 7, electric machine control system 701 comprises the measurement mechanism 702 of the moment of inertia of above-mentioned motor.

In the present invention's specific embodiment, as shown in Figure 8, electric machine control system 701 specifically can comprise motor 10, current sample module 20, first coordinate transferring 30, current correction module 40, direct-axis voltage module 50, quadrature-axis voltage module 60, second coordinate transferring 70, SVPWM(space vector pulse width modulation, Space VectorPulse Width Modulation) driver module 80, inverter 90 and DC power supply 100.

Wherein, current sample module 20 is for the three-phase current i of sample motor 10 _sa, i _sb, i _sc.First coordinate transferring 30 is for according to initial position θ ₀to three-phase current i _sa, i _sb, i _sccarry out Clark coordinate transform and Park coordinate transform to obtain direct-axis current I _sdwith quadrature axis current I _sq.Current correction module 40 is for according to d-axis reference current with quadrature axis reference current respectively to direct-axis current I _sdwith quadrature axis current I _sqcarry out current correction to obtain direct-axis voltage changing value △ V _dwith quadrature-axis voltage changing value △ V _q.Direct-axis voltage module 50 is for adjusting direct-axis voltage u according to rotor angular rate _sd, i.e. u _sd=R _si _sd-ω _rl _sqi _sq; Quadrature-axis voltage module 60 is for adjusting quadrature-axis voltage u according to rotor angular rate _sq, i.e. u _sq=R _si _sq+ ω _rl _sdi _sd+ ω _rψ _f.Second coordinate transferring 70 is according to initial position θ ₀to direct-axis voltage u _sdwith direct-axis voltage changing value △ V _dsum and quadrature-axis voltage u _sqwith quadrature-axis voltage changing value △ V _qsum carries out Clark coordinate inverse transformation and Park coordinate inverse transformation to obtain three-phase voltage u _sa, u _sb, u _sc.SVPWM driver module 80 is for according to three-phase voltage u _sa, u _sb, u _scoutput drive signal.Inverter 90 is for controlling the electric current of motor 10 according to drive singal.DC power supply 100 is for powering for inverter 90.

Like this, based on above-mentioned electric machine control system 701, when motor 10 is in zero load or light running, in preset time period according to given default d-axis reference current with default quadrature axis reference current vector control is carried out to motor, and the rotational speed omega controlling motor is with preset angle acceleration X ₁accelerate, namely control the rotor angular rate ω in direct-axis voltage module 50 and quadrature-axis voltage module 60 _rwith preset angle acceleration X ₁accelerate.Next, the measurement mechanism 702 of the moment of inertia of motor is according to electromagnetic torque Y ₁, preset angle acceleration X ₁calculate the moment of inertia J of motor.

To sum up, according to the electric machine control system that the embodiment of the present invention proposes, moment of inertia more accurately can be obtained, and simple to operate, realize easily, measuring cost low, can engineering practice being applied to.

Describe and can be understood in flow chart or in this any process otherwise described or method, represent and comprise one or more for realizing the module of the code of the executable instruction of the step of specific logical function or process, fragment or part, and the scope of the preferred embodiment of the present invention comprises other realization, wherein can not according to order that is shown or that discuss, comprise according to involved function by the mode while of basic or by contrary order, carry out n-back test, this should understand by embodiments of the invention person of ordinary skill in the field.

In flow charts represent or in this logic otherwise described and/or step, such as, the sequencing list of the executable instruction for realizing logic function can be considered to, may be embodied in any computer-readable medium, for instruction execution system, device or equipment (as computer based system, comprise the system of processor or other can from instruction execution system, device or equipment instruction fetch and perform the system of instruction) use, or to use in conjunction with these instruction execution systems, device or equipment.With regard to this specification, " computer-readable medium " can be anyly can to comprise, store, communicate, propagate or transmission procedure for instruction execution system, device or equipment or the device that uses in conjunction with these instruction execution systems, device or equipment.The example more specifically (non-exhaustive list) of computer-readable medium comprises following: the electrical connection section (electronic installation) with one or more wiring, portable computer diskette box (magnetic device), random-access memory (ram), read-only memory (ROM), erasablely edit read-only memory (EPROM or flash memory), fiber device, and portable optic disk read-only memory (CDROM).In addition, computer-readable medium can be even paper or other suitable media that can print described program thereon, because can such as by carrying out optical scanner to paper or other media, then carry out editing, decipher or carry out process with other suitable methods if desired and electronically obtain described program, be then stored in computer storage.

Should be appreciated that each several part of the present invention can realize with hardware, software, firmware or their combination.In the above-described embodiment, multiple step or method can with to store in memory and the software performed by suitable instruction execution system or firmware realize.Such as, if realized with hardware, the same in another embodiment, can realize by any one in following technology well known in the art or their combination: the discrete logic with the logic gates for realizing logic function to data-signal, there is the application-specific integrated circuit (ASIC) of suitable combinational logic gate circuit, programmable gate array (PGA), field programmable gate array (FPGA) etc.

Those skilled in the art are appreciated that realizing all or part of step that above-described embodiment method carries is that the hardware that can carry out instruction relevant by program completes, described program can be stored in a kind of computer-readable recording medium, this program perform time, step comprising embodiment of the method one or a combination set of.

In addition, each functional unit in each embodiment of the present invention can be integrated in a processing module, also can be that the independent physics of unit exists, also can be integrated in a module by two or more unit.Above-mentioned integrated module both can adopt the form of hardware to realize, and the form of software function module also can be adopted to realize.If described integrated module using the form of software function module realize and as independently production marketing or use time, also can be stored in a computer read/write memory medium.

The above-mentioned storage medium mentioned can be read-only memory, disk or CD etc.

In the description of this specification, specific features, structure, material or feature that the description of reference term " embodiment ", " some embodiments ", " example ", " concrete example " or " some examples " etc. means to describe in conjunction with this embodiment or example are contained at least one embodiment of the present invention or example.In this manual, identical embodiment or example are not necessarily referred to the schematic representation of above-mentioned term.And the specific features of description, structure, material or feature can combine in an appropriate manner in any one or more embodiment or example.

Although illustrate and describe embodiments of the invention, for the ordinary skill in the art, be appreciated that and can carry out multiple change, amendment, replacement and modification to these embodiments without departing from the principles and spirit of the present invention, scope of the present invention is by claims and equivalency thereof.

Claims (9)

1. a method of measurement for the moment of inertia of motor, is characterized in that, comprises the following steps:

When described motor is in zero load or light running, obtain in preset time period and preset d-axis reference current and default quadrature axis reference current, and the rotating speed controlling described motor accelerates with preset angle acceleration;

Sample to obtain sample rate current at the electric current of default sampled point to described motor of described preset time period, and calculate the electromagnetic torque of described motor according to described sample rate current;

The moment of inertia of motor according to described electromagnetic torque and described preset angle acceleration calculation.

2. the method for measurement of the moment of inertia of motor as claimed in claim 1, is characterized in that, the moment of inertia of motor according to following formulae discovery:

$J=\frac{Y_1}{X_1}$

Wherein, J is the moment of inertia of described motor, X ₁for described preset angle acceleration, Y ₁for described pre-given electromagnetic torque.

3. the method for measurement of the moment of inertia of motor as claimed in claim 1, it is characterized in that, described electromagnetic torque obtains according to following formulae discovery:

Y ₁＝1.5PI _sq1[Ke+(L _sd-L _sq)I _sd1]

Wherein, Y ₁for described pre-given electromagnetic torque, I _sq1for the quadrature axis current under two-phase rotating coordinate system, L _sdfor the d-axis inductance under two-phase rotating coordinate system, L _sqfor the quadrature axis inductance under two-phase rotating coordinate system, I _sd1for the direct-axis current under two-phase rotating coordinate system, Ke is the rotor flux of described motor, and P is the magnetic pole logarithm of described motor.

4. the method for measurement of the moment of inertia of motor as claimed in claim 3, is characterized in that, wherein,

Clark coordinate transform and Park coordinate transform are carried out to obtain described quadrature axis current I to described sample rate current _sq1with described direct-axis current.

5. a measurement mechanism for the moment of inertia of motor, is characterized in that, comprising:

Acquisition module, described acquisition module is used for obtaining in preset time period presetting d-axis reference current and default quadrature axis reference current;

Sampling module, described sampling module is used for sampling to obtain sample rate current at the electric current of default sampled point to described motor of described preset time period;

Control module, when described motor is in zero load or light running, the rotating speed that described control module is used for controlling in described preset time period described motor accelerates with preset angle acceleration, calculate the electromagnetic torque of described motor according to described sample rate current, and according to described electromagnetic torque and described preset angle acceleration calculation the moment of inertia of motor.

6. the measurement mechanism of the moment of inertia of motor as claimed in claim 5, is characterized in that, the moment of inertia of described control module motor according to following formulae discovery:

$J=\frac{Y_1}{X_1}$

Wherein, J is the moment of inertia of described motor, X ₁for described preset angle acceleration, Y ₁for described pre-given electromagnetic torque.

7. the measurement mechanism of the moment of inertia of motor as claimed in claim 5, it is characterized in that, described control module is electromagnetic torque according to following formulae discovery:

Y ₁＝1.5PI _sq1[Ke+(L _sd1-L _sq1)I _sd1]

Wherein, Y ₁for described pre-given electromagnetic torque, I _sq1for the quadrature axis current under two-phase rotating coordinate system, L _sd1for the d-axis inductance under two-phase rotating coordinate system, L _sq1for the quadrature axis inductance under two-phase rotating coordinate system, I _sd1for the direct-axis current under two-phase rotating coordinate system, Ke is the rotor flux of described motor, and P is the magnetic pole logarithm of described motor.

8. the measurement mechanism of the moment of inertia of motor as claimed in claim 7, is characterized in that, described control module carries out Clark coordinate transform and Park coordinate transform to obtain described quadrature axis current I to described sample rate current _sq1with described direct-axis current.

9. an electric machine control system, is characterized in that, comprises the measurement mechanism of the moment of inertia of the motor according to any one of claim 5-8.