JPH0632581B2 - Induction motor controller - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to an induction motor controller fed by a variable frequency / variable voltage power source or the like, and more particularly to a controller based on the principle of vector control.

[Conventional technology]

FIG. 1 is a block diagram of a conventional induction motor controller shown in Japanese Patent Application No. 58-230979, for example.
(1) is a PWM inverter, (3) is a rotation speed detector of the induction motor (2), (4a), (4b), (4c) are U of the induction motor (2), respectively.
Current feedback signals i _u , i in response to primary currents of V, V and W phases
current detector that outputs _v , i _w , (5) is the current feedback signal i _u ,
i _v, synchronous angular frequency (secondary flux linkage the angular frequency of the vector) rotating coordinate system of the two-axis component that rotates perpendicular to each other with omega (d ^e axis primary current component i _w the induction motor (2) id ^e s and q ^e axis primary current component iq ^e s and referred to) is converted to a three-phase → two-phase conversion circuit (6) for the d ^e-axis primary current component id ^e s and q ^e axis primary current component iq ^e s Related to a slip angular frequency command calculation circuit that calculates a slip angular frequency command (electrical angle display) pω _s ^* , (7) is a coefficient multiplication circuit that multiplies the rotor angular frequency ω _r of the induction motor by the number of pole pairs, ( 8) adds the slip angular frequency command pω _s ^* generated as the output of the slip angular frequency command calculation circuit (6) and the output pω _r of the coefficient multiplication circuit (7) to generate the synchronous angular frequency ω An adder, (9) is a phase angle output that integrates the synchronous angular frequency ω and outputs the phase angle command θ of the secondary flux linkage vector. Arithmetic circuit, (10) is a sine wave signal sin θ and a cosine wave signal cos θ in response to the phase angle command θ
And outputs the function generator (11), (12) each of the d ^e
A shaft primary current component id ^e s, the excitation current command And q ^e- axis primary current component iq ^e s and torque current command Comparator for comparing with, and (13) and (14) are comparators (11) respectively
Excitation current deviation detected by (12) and And torque current deviation Amplifying the, d ^e axis primary current component of the induction motor (2) (excitation current) id ^e s and q ^e axis primary current component (torque current) iq
^e s is always the prescribed excitation current command And the above torque current command D ^e axis component of the primary voltage command to be equal to And an arithmetic circuit for controlling the q ^e- axis component ▲ v ^* _q es _{s of the} primary voltage command, (15) is the d ^e- axis component of the primary voltage command And q ^e axis component Is a two-phase to three-phase conversion circuit that converts the three-phase voltage commands ▲ v ^* _u ▼, ▲ v ^* _v ▼, and ▲ v ^* _w ▼.

The conventional induction motor control device is configured as described above, the current feedback signal i _u , i output by the current detector (4a), (4b), (4c)
_v, the d ^e-axis primary current component i _w the induction motor based on the equation (2) id e ^s and the q ^e axis primary current component iq ^e
s, and these are the respective exciting current components that are the respective commands. And the above torque current component The biaxial component of the above coordinate system of the primary voltage to match and Control and control them based on the formula three-phase voltage command ▲ v ^* _u
It is converted into ▼, ▲ v ^* _v ▼, and ▲ v ^* _w ▼, and the induction motor (2) is controlled via the PWM inverter (1).

However, in the induction motor control device of the embodiment as described above, the rotation speed detector (3) of the induction motor is necessary to detect the rotor angular frequency of the induction motor that is the control element, and the induction motor original The features of small size, robustness, and maintenance-free have faded.

[Outline of Invention]

The present invention has been made for the purpose of improving such a drawback, and calculates a deviation Δω _s (= ω _s ^* −ω _s ) between the slip angular frequency ω _s of the induction motor and the slip angular frequency command ω _s ^* , The present invention proposes an induction motor control device for controlling an induction motor so that the deviation becomes zero, without using a speed detector, and capable of performing control equivalent to that of a DC separately excited motor.

Example of Invention

First, the principle of the invention will be described using the voltage equation of an induction motor.

The voltage equation of the induction motor is the angular frequency ω of the secondary flux linkage.
It is given by an equation in a Cartesian coordinate system that is rotated by (referred to as a d ^e axis-q ^e axis coordinate system).

In the equation, R _s and R _r are the primary and secondary resistance values of the induction motor, L _s and L _r are the primary and secondary inductance values including the leakage inductance component, and M is the primary winding Mutual inductance between secondary windings, σ is the leakage coefficient σ = 1-M ² / L _s L _r , p is the number of pole pairs, ω _s is the slip angular frequency, and P is P = d / dt. The differential operator, Are the d ^e axis and q ^e axis components of the primary voltage, Are the d ^e axis and q ^e axis components of the primary current, Represent the d ^e axis and q ^e axis components of the secondary interlinkage magnetic flux, respectively.

From the first or second line of the equation, the slip angular frequency (electrical angle display) of the induction motor can be calculated by the equation or the equation.

with respect to the d ^e-axis secondary flux linkage or secondary interlinkage when the direction of the flux vector instruction slip angular frequency as to match the d ^e axis and omega _s ^*, the electrical angle display the formula from the formula Can be calculated with.

However, Represents the time that the direction of each secondary flux linkage vector is matched with d ^e axis, the d ^e-axis and q ^e axis component of the secondary flux linkage, Is.

From the equation, the slip angular frequency pω _s and its command pω _s
A deviation pΔω _{s from} ^* is given by an equation.

Also, since it can be assumed as in the formula by performing pre-excitation with an actual induction motor, Even if the deviation pΔω _s of the slip angular frequency is given by the equation, the same operation can be expected.

It was but connexion, do it by controlling the slip angular frequency deviation Piderutaomega _s given by the equation or formula, it is possible to the direction of the secondary flux linkage vector to coincide with the d ^e axis.

At this time, the torque of the induction motor expressed by the general formula is expressed by the formula.

D ^e axis component of the but connexion, secondary interlinkage flux (this is Therefore, it is also the total secondary interlinkage magnetic flux. ) Is controlled to be constant, the torque Te ′ is the above q ^e axis primary current component. And proportional constant without time factor Becomes a product, is controlled linearly by the q ^e axis primary current component iq e ^s.

The voltage equation of the induction motor has been described above, but a configuration example in which the principle of the invention obtained from this voltage equation is applied to a three-phase induction motor controller will be described next.

FIG. 2 is a block diagram of a basic embodiment of the present invention, in which (1) to (15) are exactly the same as those of the conventional device. (16) Slip angular frequency deviation (electrical angle display) pΔω _s
And (17) is a synchronous angular frequency command arithmetic circuit that integrates the slip angular frequency deviation pΔω _s to generate a synchronous angular frequency command ω, such as an integration control circuit or a proportional integration circuit. Composed of. Now, assuming that the slip angular frequency deviation pΔω _s is a positive value, the synchronous angular frequency command ω generated by integrating this will increase. Since the slip angular frequency ω _s increases accordingly, the slip angular frequency deviation pΔω _s decreases. On the contrary, when the deviation pΔω _s has a negative value, the slip angular frequency deviation pΔω _s increases.
By operating in this way, the slip angular frequency deviation p
Δω _s can be zero.

FIG. 6 is a block diagram showing an example of the synchronous angular frequency command calculation circuit (17), and FIG. 6 (a) is an integral control circuit, FIG.
(b) is a proportional-integral circuit. The integral control circuit inputs the slip angular frequency deviation pΔω _s , integrates it, and outputs it as a synchronous angular frequency command ω. Also, the proportional-integral circuit operates in the same way, but not only simply integrates,
The synchronous angular frequency command ω is configured to be able to immediately respond to changes in the slip angular frequency deviation pΔω _s .

FIG. 3 shows an example of the configuration of the slip angular frequency deviation calculation circuit of FIG. 2, which is based on the equation.

However, the biaxial component of the secondary flux linkage d ^e- axis secondary flux linkage q ^e- axis secondary interlinkage magnetic flux Is expressed by the formula derived from the first and second lines of the formula, and Is indicated by Yes equation with the values put the λq e ^{r =} 0 in the first line of expression.

Also, the biaxial component of the primary voltage command Is the expression Equivalent to. In the figure, the differential operator P is rewritten as s.

FIG. 4 is another example of the configuration of the slip angular frequency deviation calculation circuit of FIG. 2, which is based on an equation.

However, the biaxial components λ _{d er} and λ _q e of the above secondary interlinkage magnetic flux
_r is represented by a formula. In the figure, the differential operator P is rewritten as s. Further, the formula, but the formula which gives the deviation Piderutaomega _s slip angular frequency of the formula is obtained by the reference secondary flux linkage of d ^e axis and the q ^e axis to the reference secondary flux linkage In this case, the same effect can be obtained by changing the expression to the expression and the expression to the expression.

Since the induction motor controller configured as described above calculates the slip angular frequency deviation and generates the synchronous angular frequency command ω so that the deviation is zero, the rotor angular frequency ω _r of the induction motor is It is unnecessary for control, and as a result, the rotation speed detector of the induction motor is unnecessary.

FIG. 5 is a block diagram of another embodiment of the present invention, and (2) to (19) are exactly the same as those of the embodiment of the present invention. (20) is the phase command given by And a phase command voltage command calculation circuit for calculating the voltage command v ^* ,
(21) is a PAM inverter.

Therefore, the output signal of the two-phase to three-phase conversion circuit Are U-phase, V-phase, and W-phase on / off signals, respectively.

As a result, the PAM inverter can be controlled without using the rotor speed detector of the induction motor, like the PWM inverter.

〔The invention's effect〕

INDUSTRIAL APPLICABILITY As described above, the present invention can control the induction motor without using the speed detector, and can control the induction motor in the same manner as the separately excited DC motor. When used, it has the effect of being able to construct a system with improved performance over the separately excited DC motor, making full use of the original features of the induction motor, such as small size, robustness, and maintenance-free.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a conventional controller for an induction motor, and FIGS. 2 and 3 are block diagrams showing an embodiment of the present invention, FIGS. 4 and 5. 6 is a block diagram showing another embodiment of the present invention, and FIG. 6 is a block diagram showing an example of a synchronous angular frequency command calculation circuit. In the figure, (9) ... phase angle calculation circuit, (10) ... function generator, (5) ... coordinate converter, (16) ... slip angle frequency deviation calculation circuit, (17) ... synchronization angle Frequency command calculation circuit, (6)
...... Slip angular frequency command arithmetic circuit, (18) …… Slip angular frequency arithmetic circuit, (19) …… Adder. The same reference numerals in the drawings indicate the same or corresponding parts.

Claims (2)

[Claims] 1. An apparatus for controlling the induction motor using a primary voltage command or a primary current command of an induction motor composed of biaxial components of a rotating coordinate system as a manipulated variable, in a phase responding to a synchronous angular frequency command ω of the induction motor. A phase angle calculation circuit that generates an angle command θ, a function generator that generates a sine wave signal sin θ and a cosine wave signal cos θ that respond to the phase angle command θ, and a function that generates a signal that responds to the primary current of the induction motor. by using the sine wave signal and the cosine wave signal generated from the vessel biaxial (d ^e axis, q ^e axis) of the rotating coordinate system that are orthogonal to each other and rotating at the synchronous angular frequency command ω component id e ^s, iq
coordinate converter for converting the ^{e s,} primary resistance Rs of the induction motor unit, primary inductance Ls, leak factor sigma, secondary inductance Lr, the mutual inductance M, the synchronization angular frequency command omega, primary voltage command vd ^e s ^* , ^vq e ^{s *,} and the primary current ^{id e} s, iq e s Tokara biaxial components of the rotating coordinate system of the secondary flux linkage that is calculated based on the equation 1 .lambda.d ^e r, and? Q ^e r, Using the primary current and the reference of the secondary interlinkage magnetic flux as one of the components of the two axis components of the rotating coordinate system, the slip angular frequency command pω _s ^* of the induction motor is expressed by Equation 2. The slip angular frequency calculation value pω _s is calculated by Equation 3, and the deviation pΔω _s thereof is calculated.
(= Pω _s ^* −pω _s ), a slip angular frequency deviation calculation circuit, and a synchronization angular frequency command calculation circuit that integrates the deviation p Δω _s to generate the synchronization angular frequency command ω. The synchronization angular frequency command ω generated by the synchronization angular frequency command calculation circuit increases or decreases depending on the positive or negative value of p Δω _{s, and} the slip angular frequency ω _s increases or decreases accordingly, so that the deviation pΔω _s becomes zero. An induction motor control device characterized in that 2. An apparatus for controlling the induction motor by using a primary voltage command or a primary current command of an induction motor composed of biaxial components of a rotating coordinate system as a manipulated variable, in a phase responding to a synchronous angular frequency command ω of the induction motor. A phase angle calculation circuit that generates an angle command θ, a function generator that generates a sine wave signal sin θ and a cosine wave signal cos θ that respond to the phase angle command θ, and a function that generates a signal that responds to the primary current of the induction motor. by using the sine wave signal and the cosine wave signal generated from the vessel biaxial (d ^e axis, q ^e axis) of the rotating coordinate system that are orthogonal to each other and rotating at the synchronous angular frequency command ω component id e ^s, iq
coordinate converter for converting the ^{e s,} primary resistance Rs of the induction motor, the primary inductance Ls, leak factor sigma, secondary inductance Lr, the mutual inductance M, the synchronization angular frequency command omega, primary voltage command Vd ^e s ^*, vq ^e s ^*, and the primary current ^{id e} s, iq e s Tokara biaxial components of the rotating coordinate system of the secondary flux linkage that is calculated based on the equation 1 .lambda.d ^e r, and? Q ^e r, the Using the primary current, the slip angular frequency deviation pΔω _s of the induction motor is calculated by Equation 4 using the reference of the secondary interlinkage magnetic flux as one of the two axial components of the rotating coordinate system. slip angular frequency deviation calculation circuit, and by integrating the deviation Piderutaomega _s, with a synchronous angular frequency command calculation circuit for generating the synchronous angular frequency command omega, the positive and negative value of the deviation Piderutaomega _s, the synchronizing angular frequency The synchronous angular frequency command omega increases or decreases generated in decree arithmetic circuit, which as by the slip angular frequency omega _s is increased or decreased, the induction motor control device is characterized in that so as to zero the deviation Piderutaomega _s .