JPH01103189A - Speed/flux controller for induction motor - Google Patents

Abstract

PURPOSE:To control speed and flux stably even if q-axis flux component is not brought to 0 due to unclear induction motor coefficient or disturbance, by configuring a speed/flux controller into a non-linear multi-variable system. CONSTITUTION:Coefficient units 10, 11, 12, 13, 14, 15, 16 are provided with values of K1, K2, K3 and M. The value M represents the mutual inductance between a stator winding and a rotor winding. d-axis current command I'1d, q-axis current command I'1q and angular frequency command omegaS are outputted respectively from a d-axis root value subtractor 21, a q-axis adder 23 and the coefficient unit 16. The outputs I'1d and I'1q from a speed/flux control section are controlled non-linearly with the product of flux and speed is being fed back.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention relates to an induction motor in which a variable voltage/variable frequency voltage source is connected to the stator winding of the induction motor, and the voltage and frequency of the voltage source are controlled. The present invention relates to a speed/magnetic flux control device.

[Conventional technology]

Figure 2 shows, for example, the 1981 National Conference of the Institute of Electrical Engineers of Japan s, s-
1 "Current status and problems of AC motor vector control technology" Ei Namba (Nagaoka University of Technology), S, 8-2 "Theory of vector control" Nagashio, Hori, Okuyama (Hitachi), 8.8-3r vector control Masahiko Akamatsu (Mitsubishi Electric), or JAACE'87-5 31st System and Control Research Presentation Lecture "Disconnection control method for induction motors" Morishima (Mitsubishi Electric),
This is a configuration diagram of the basic circuit of the conventional and commonly discussed "slip frequency type vector control" shown by Yuta Ichigo-Tama (Osaka University). , a variable frequency power converter converts AC power from a normal power supply system into two desired voltages and frequencies, and supplies the converted voltage to the stator winding of the induction motor 2. 3 is a speed detector for detecting the rotor angular velocity of the induction motor 2; 4 is a three-phase alternating current 1 flowing into the stator winding of the induction motor 2;
1U *Current detector that detects IIV + IIW, 5
is a 3-phase to 2-phase converter, and the 3-phase to 2-phase converter 5 rotates the 3-phase alternating current IIU r IIV r IIW in synchronization with the frequency ωl of the alternating current voltage applied to the stator winding. Value in a two-axis rotating coordinate system (d-q coordinate system),
That is, it is converted into stator winding current 11d, Ilq.

6 is the stator winding current 11d*Il in the d-q coordinate system
a magnetic flux calculator that calculates the magnetic flux Φ2d +Φ2q interlinking with the rotor from q and the stator winding voltage vta I Vlq, 7
is the voltage command value to be generated by the power converter 1 in the d-q coordinate system, and the actual three-phase interval value v1υ* vIV +V
1w is a 2-phase to 3-phase converter that performs K conversion, and 8 is a d-axis current controller, which amplifies the difference between the d-axis component command value 11d of the stator winding current and its actual value 11 (1) and converts it to the command value. Flow current. 9 is the same < qitl + current controller,
Controls the q-axis component of stator winding current. 29 sets the d-axis component Φ2d of the rotor winding flux linkage to the desired value φ2d.
A magnetic flux controller 30 is used to control the rotor angular velocity ω of the induction motor 2.

a speed controller for controlling ω,* to a desired value,
31 is a divider, and 32 is a coefficient unit. These divider 31 and coefficient unit 32 calculate the slip frequency command ωS*. Further, 22, 24, 27, and 28 are subtracters, and 26 is an adder.

Next, the operation will be explained. First, the current control system will be explained. A three-phase alternating current 11U + IIV + IIW flowing into the stator winding of the induction motor 2 is detected by a current detector 4 . The three-phase to two-phase converter 5 converts the detected three-phase alternating current IIU*Itv, IIW into a three-phase alternating current voltage vtul vlV+ applied to the stator winding.
Stator winding current 11d + as seen from a two-axis orthogonal coordinate system (d-q coordinate system) rotating in synchronization with the frequency ω1 of VIW
Convert to Ilq. 3-phase AC current IIU + IIV
The conversion from +IIW to the stator winding current xlcl, Ilq is θ, =fωldt...
・・・・・・・・・・・・(1) is carried out. The da current controller 8 controls the stator winding d@current command value 11d and the (
1), +2) The difference between the stator winding current 11d and the stator winding current 11d obtained by the equations is amplified, and the stator winding voltage d@voltage command value Vld is output. Similarly, for the q-axis component, the q-axis current controller 9 outputs the q-axis voltage command value Vlq.

d@voltage command value v1d and q-axis voltage command value V1 q is 2
The actual three-phase adjacent voltage vIU is determined by the phase-to-three-phase converter 7.
p vIV eVIW. d-axis voltage command value v
1d, Vlq to 3-phase adjacent voltage vIU, ■1v, ■1w
The conversion to is done in . As a result, the obtained three-phase adjacent voltages VIU * vtv and viw are actually generated from the power converter 1, and a desired current can flow. Next, the slip frequency calculation will be explained. If the current control system described above is excited at a sufficiently high speed, the fixed prewinding ID
The axis and q-axis current command values are 1d = 11d111q = 1
It can be considered as 1q. At this time, stator winding current 11d + I
The equation of state of the system of the induction motor 2 when lq is considered as an input is as follows.

φ02d=-αΦ2d+ωBΦ2q+βIld
...(4)〆2q"−αΦ2q−ωSΦ2d+β
Ilq・(51Z, = r Cl1qΦ2d −11
dΦ2q) - (6) where α, β, and T are positive constants determined by the induction motor 2. Φ2d is the rotor winding magnetic flux linkage of the d-axis component (hereinafter referred to as d-axis component magnetic flux), and Φ2q is the rotor winding magnetic flux linkage of the q-axis component (hereinafter referred to as q
(referred to as the axial component magnetic flux), ωr is the rotor angular velocity, ωS
is the slip frequency and ω8=ω1−ω, (7). Now, if we assume that equation (5) becomes Me2. =-αφ2. ...(
9). Since α>0, the q-axis component magnetic flux φ2q approaches zero as time passes. After a certain time like this, φ2. It can be considered as =O. The command value ω? of the slip frequency ωS is determined by the divider 31 and the coefficient unit 32. is calculated based on equation (8). The adder 26 adds 08 slip frequency command values and the rotor angular velocity ω, and the AC voltage frequency ω1 applied to the stator winding is calculated. Actually, an AC voltage of frequency ω1 is applied to the induction motor 2.

Next, magnetic flux control will be explained. If the q-axis component magnetic flux becomes φ2q=o by the above-mentioned slip frequency control, the magnetic flux is controlled by controlling the d-axis component magnetic flux φ2d. From equation (4), assuming φ2q=0, l2d==-αΦ2
d ten βIld ... (10) and d
By manipulating the shaft stator winding current 11d, the d-axis component magnetic flux φ2
This means that d can be controlled to a desired value. In the magnetic flux controller 29, the d-axis component magnetic flux command value Φ2J and the d-axis component magnetic flux Φ
2d is amplified and a stator winding current command value xx3 is output. The value of the d-axis component magnetic flux Φ2d is determined by the fracture flux calculator 6.

Next, speed control will be explained. Φ2q = 0 by slip frequency control + φ2d = Φ2d by magnetic flux control
(Constant) If K can be controlled, equation (6) becomes ', == rΦ2d
I lq - (11) and the q-axis stator winding current 11. By operating the rotor angular velocity ω
, can be controlled to a desired value. The speed controller 30 amplifies the difference between the command value ω of the rotor angular velocity and the actual measurement value ω, and outputs a command value 11q of the q-axis stator winding current 119.

[Problem that the invention seeks to solve]

Since the conventional induction motor speed/magnetic flux control device is configured as described above, if the constant β of the induction motor 2 is unclear, the slip frequency control in equation (8) will be incomplete, and φ2q = I ? It becomes O. In this case, since the magnetic flux/speed control is also Φ2q~O, the system becomes a nonlinear system and it becomes difficult to obtain desired control characteristics. Furthermore, even if the constant β of the induction motor 2 is clear, it is necessary to return it to Φ2q=0 when it becomes φ2Q'FO due to disturbance to the system, as shown in equation (9). constant α
, and returns only with a time constant determined by K.

Therefore, the system between Φ29 and 0 is no longer a nonlinear system, and there is a problem in that the characteristics and stability of speed and magnetic flux control are not guaranteed.

This invention was made in order to solve the above problems, and it is an induction motor that can stably control the speed and magnetic flux even if the induction motor constant is unclear or becomes Φ2q"FO due to disturbance etc. The purpose is to obtain a speed/magnetic flux control device.

[Means for solving problems]

The speed/magnetic flux control device for an induction motor according to the present invention detects a difference between a rotor angular velocity and a rotor angular velocity command value of the induction motor detected by a speed detector of the induction motor, and a rotation detected by a magnetic flux calculator between the difference and the rotor angular velocity command value of the induction motor. a power converter that supplies current command values of d-axis and q-axis current controllers that control the magnitude of current flowing through the induction motor using the product with the child interlinkage magnetic flux, and further supplies variable voltage and variable frequency power to the induction motor; 1. [Operation] In this invention, the speed/magnetic flux control device for an induction motor introduces nonlinear control theory to treat the induction motor as a nonlinear multivariable system. Axial component magnetic flux φ2. is incorporated into the system as a state quantity, and the stator winding current Itd e Itq and the slip frequency ωS are simultaneously manipulated so as to simultaneously control the rotor angular velocity ωr, the d-axis component magnetic flux φ2d, and the q-axis component magnetic flux φ2q to desired values. pressure.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings.

In the drawing, the same parts as in Fig. 2 are designated by the same reference numerals.
5.16 is a coefficient multiplier, as shown in the figure, Kl e
It is given by the values K2 * K5 and M. M is the value of the mutual inductance between the stator winding and the rotor winding of the induction motor 2, and expressed by the parameters used in equations (4) and (5), M=α/β. (Here, d1 to d5 are the d-axis first to third root values, and q1 to q are the q-axis first to third root values.) Coefficient units Kl, K2
, K5 can take any negative value. 17.18 is a multiplier, 19.2G, 21.2
2.24.25 is a subtracter, and 23.26 is an adder.

(Here, 19 is a d-axis component subtractor, 20 is a q-axis component subtracter, 21 is a d-axis root value subtracter, 22 is a d-axis component subtractor, 2
3 is called a q-axis adder, 24 is called a q motion range calculator, 25 is called an angular velocity subtracter, and 12.26 is called an angular velocity adder. ) In this Figure 1, the output 11d" + Ilc of the speed/magnetic flux control section
” +ωS* is given by the formula below.

x1%=x, (Φ2d-Φra)-KzΦ2. (ω, −
ωr*)+MΦ? d...(12)11q = Kl(
Φ2q−ψ2Q)+2Φza(ωr−ωr)+MΦ2
(1-(13)ω;”K3(ω,-ωr)
- As can be seen from equations (14), (12), and (13), this is nonlinear control in which the product of magnetic flux and velocity is fed back.

Next, the operating principle of this invention will be explained. First, (1
The feedback law of equations 2), (13), and (14) is (4
1, (51.

It will be explained that the system of the induction motor 2 given by equation (6) is always stabilized as long as the value of 2*K5 in the coefficient unit Kl is set to a negative value. For that purpose, first (4
)(51, Rewrite equation (6) as follows.

Here Town-11d pφ2d = Itd −Mφ2d
...(16) u2-114, +29=1
1Q-MΦ2.・(17) u5'''II
°−(”°ゝNow, according to Lyabunov's stability theory, the derivative (time differential) ÷ (X) of the Lyabunov function V (x) V(x) = xpx defined by a certain fixed symmetric matrix P is If so, the system is globally stable.Here, the subscript T represents transposition.The above theory of knowledge can also be rephrased for K as follows.In other words, if V has the property as shown in equation (19), If there exists a fixed symmetric matrix P forming (x), the system is stable. Therefore, the system can be expressed by equation (15).If we calculate :ui(x”(PB
l+B, P)x4-2CHPx) =・(20). Now, stator winding d-axis and q-axis current command values 11d, where stator winding current 11d, Ell, and slip frequency ωS are given by equations (12), (13), and (14),
Ilq, and slip frequency command value ω? Suppose that it is controlled by That is, Ild ” “l”d r Ilq =
Ilq, ω, = ω8. So (16), (
By substituting equations (12), (13), and (14) into equations (17) and (18), respectively, ul = 1(Φ2d-Φ'2d)- and 2Φ2Q(ωr-
”r)-Kl-Xi-Ki'Φ2qx3 -(21)u
2-Kl(Φ2q"J2q)"K2Φ2d(ω, -ω,
”)- to 1X2+ to 2φ2dXs = (Z2)u5
"K5Cω, -ωr)-5X5
”-...(23).On the other hand, let us consider a fixed symmetric matrix P.In equation (2D), (21), (Z2)
, (ku) and (24) and rearranged *(xl--2α(X engineering+x2) +2(pαγ/β10 to 3)(φ2qXl-Φ2dX2)
X5+ (2Φ2qx5 to KIXI-) (2βxl-2p
rφ2qx5)” (2ψ2(IX5) to KI X2+
(2βX2+2prφ2dX3). This can be further modified as follows.

'22? (x)−−2(α−βfl)(xl+x2)+2(p
αr/I+3−pr fl )(Φ;, x1+φ2d
X2) to X5+; (2βX1-2prφ2qxs)2/
2β+'l(2βX2'p2pTΦ2clX3
)” / 2β where KL ” r1= Kl
...(25) Kll) r = β to 2
°°°（song）※（xi is (19)
To satisfy the condition of the formula, 5-pl f 1 is added to pαr/β+
=0...(27) p * Kl l ''l should be determined so that it becomes (25).

(26), ■) Solving the equation gives 1, the value of the coefficient unit Kl l K21 K5 is negative, and the constants α, β, and γ determined by the induction motor 2 are positive values, so (29), (30) , it is clear from equation (31) that K
The condition of equation (28) is also satisfied.

From the above, the fixed logarithm matrix P can be found as follows.

Since the fixed symmetric matrix P expressed by equation (32) exists, it was shown that the system of the induction motor 2 can definitely be stabilized by the feedback law expressed by equations (12), (13), and (14).

The feedback laws of equations (12), (13), and (14) have three parameters, 1 * K2, and 5, and are always stable as long as these values are negative. The value can be uniquely determined depending on conditions such as response speed, non-interference, and optimization.

11 K2 for control parameters. As an example of a unique determination method, let the desired degree of convergence of speed control be ω, the desired degree of convergence of magnetic flux control be φ, and if non-interference between speed control and magnetic flux control is also added to the conditions, the following can be obtained. It is sufficient to select the control parameters Kl, K2, K, as follows.

Furthermore, in the above embodiment, the application to an induction motor was explained, but the present invention is applicable not only to an induction motor but also to a system (
15) Applicable to all devices expressed by formula.

〔Effect of the invention〕

As described above, according to the present invention, the speed of the induction motor
Since the magnetic flux control device is configured as a nonlinear multivariable system, the q-axis component rotor linkage magnetic flux Φ2. does not require the condition that Φ2q=0, and has the effect that a highly stable control system can be constructed with any Φ2q. In addition, 1. K2. K,
It is only necessary to apply the droplet only on the condition that is negative, and there is no need to determine it according to the motor constant, which has the effect of providing a highly stable and reliable control system even when the motor constant is unclear or fluctuates.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a speed/magnetic flux control device for an induction motor according to an embodiment of the present invention, and FIG. 2 is a block diagram showing a conventional speed/magnetic flux control device for an induction motor. In the figure, 1 is a power converter, 2 is an induction motor, 3 is a speed detector, 4 is a current detector, 5 is a 3-phase to 2-phase converter, and 6
is a magnetic flux calculator, 7 is a 2-phase to 3-phase converter, 8 is a d@current controller, 9 is a q-axis current controller, 19 is a d-axis component subtractor, 20 is a q-axis component subtractor, 21 is a d-axis route 22 is a d-axis subtracter, 23 is a q-axis adder, 24 is a q-range calculator, 25 is an angular velocity subtractor, and 26 is an angular velocity adder. Note that in the figures, the same reference numerals represent the same parts.

Claims (3)

[Claims] (1) A power converter that supplies variable voltage and variable frequency power to an induction motor, and fixation of the induction motor as seen from a d-q coordinate system that rotates in synchronization with the frequency of AC power supplied by the power converter. a current detector that detects the d-axis component and the q-axis component of the current flowing in the stator winding;
a d-axis and q-axis current controller that controls the magnitude of the axial component through a d-axis subtracter and a q-axis subtracter, respectively; a speed detector that detects the rotor angular velocity of the induction motor; In the speed/magnetic flux control device for an induction motor, the device includes a magnetic flux calculator that detects d-axis magnetic flux and q-axis magnetic flux of the magnetic flux interlinking with the rotor of the induction motor as seen from a coordinate system, and an input of the d-axis current controller. The desired value of the rotor winding flux linkage as a condition determining element, the d-axis and q-axis components output from the magnetic flux calculator, and the result of subtraction between the desired value of the rotor angular velocity and the rotor angular velocity are input. a first arithmetic circuit; a d-axis subtracter that inputs the result of subtraction between the output of the first arithmetic circuit and the d-axis stator winding current seen from the orthogonal coordinate system; and an input of the q-axis current controller. A second operation that receives as input the desired value of the rotor winding flux linkage as a condition determining element, the q-axis component output from the magnetic flux calculator, and the result of subtraction between the desired value of the rotor angular velocity and the rotor angular velocity. a q-axis subtracter inputting the result of subtraction between the output of the second arithmetic circuit and the q-axis rotor winding current seen from the orthogonal coordinate system, and a desired value of the rotor angular velocity and the speed detector. An angular velocity subtracter calculates the obtained rotor angular velocity, and a predetermined coefficient value is given to the output of the angular velocity calculator to calculate the rotor angular velocity.
A speed/magnetic flux control device for an induction motor, comprising a phase converter and an angular velocity adder input to a two-phase to three-phase converter. (2) The configuration of the first arithmetic circuit includes a d-axis component subtracter that subtracts a desired value of the rotor winding flux linkage from the d-axis component of the magnetic flux calculator, and a desired value of the rotor winding flux linkage. A d-axis first root value outputted by giving a predetermined coefficient to the value, a d-axis second root value outputted by giving a predetermined coefficient value to the output of the d-axis component subtracter, and the angular velocity subtracted from the q-axis component. The d-axis third
Claim 1 is constructed with a d-axis root value subtracter that inputs and subtracts the root value.
A speed/magnetic flux control device for an induction motor as described in . (3) The configuration of the second calculation circuit includes a q-axis component subtracter that subtracts a desired value of the rotor winding flux linkage from the q-axis component of the magnetic flux calculation unit, and a d-axis component of the magnetic flux calculation unit and the Multiply by the output of the angular velocity subtracter, give a predetermined coefficient, and output q
The axis first root value, the q-axis second root value which is output by giving a predetermined value to the output of the q-axis component subtracter, and the q-axis second root value which is output by giving a predetermined coefficient to the predetermined value of the rotor winding flux linkage. q-axis 3rd
The speed/magnetic flux control device for an induction motor according to claim 1, characterized in that it is constructed with a q-axis adder for adding the route value.