JPH0797920B2 - Induction motor controller - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an induction motor control device that enables vector control of this induction motor without performing speed detection by a speed detector or a position detector.

[Conventional technology]

FIG. 2 shows a conventional induction motor control device shown in, for example, the Institute of Electrical Engineers of Japan, Semiconductor Power Conversion Study Group material, "Slide control control vector control method for induction motors without speed detector" (SPC-84-61). shows a block wiring diagram in FIG, 1 is an induction motor, 2 is a three-phase power amplifier, 3 voltage command vd ^e s ^*, a coordinate converter for converting the vq ^e s ^* into three-phase AC voltage of the angular velocity ω Then, this power amplifier 2 and coordinate converter 3
Constitutes a power supply device. 4 is a coordinate converter that converts an alternating current into a direct current seen on a rectangular coordinate axis (d ^e axis, q ^e axis) that rotates at an angular velocity ω. 5 is a rectangular coordinate axis that rotates at an angular velocity ω from an alternating voltage and an alternating current. thereby calculating the primary interlinkage magnetic flux seen above, the circuit for calculating a primary voltage vq ^e s on axes perpendicular to the secondary flux linkage, 6 adders, 7, 8, 9 constant multiplier, 10 , 11, 12 are subtractors, 13 is a calculator for removing the interference from the q ^e axis to the d ^e axis, 14 is a calculator of the primary angular velocity ω, 15 is an integrator, 16 is a trigonometric function generator, 17 , 18 is PI compensator, 19,20
Is a subtractor.

Next, the operation will be described. The induction motor 1 is driven by the three-phase power amplifier 2. The equation of the induction motor 1 is shown by the following equation.

Where Rs and Rr are primary and secondary resistances, Ls, Lr and M are primary inductances, secondary inductances and mutual inductances, σ is a leakage coefficient, p is the number of pole pairs, P = d / dt is a differential operator, vd ^e s, vq ^e s is d ^e , q ^e primary voltage of the axis, id ^e s, iq ^e s is d ^e , q ^e
Axis primary current, λd ^e r, λq ^e r is d ^e, q ^e axis secondary flux linkage, .omega.r
Is the rotor angular velocity, and ω is the primary angular velocity.

In vector control, the secondary interlinkage magnetic flux λd ^e r, λq ^e r is required to be on a predetermined axis that is controlled regardless of the steady state and the transient state, and if that axis is selected as the d ^e axis, Equation (2) must hold.

^{λq e r = 0 (2)} (1) is modified, two row of Formula (3) is obtained.

Where λd ^e s = σL sid ^e s + M λd ^e r / Lr and λq ^e s = σ
^{Lsiq e s + Mλq e r /} Lr respectively d ^e, is the primary flux linkage q ^e axis. .lambda.d ^e s, and? Q ^e s can be detected, vd ^e s, when given as a vq ^e s (4) below is obtained (5).

In equation (5), if ω is given as in equation (6),
Expression (7) is established.

_{(P + 1 / T 2)} λq e r = 0 (7) (7) the solution of equation is ^{_{λq e r = C 1 ε -t}} / T2 (8). Follow go-between, under the conditions of t >> T _2, it can be regarded as a λq ^e r = 0.

In this way, λd ^e s and λq ^e s are detected, and equations (4) and (6)
If the control is performed according to the equation, vector control can be performed without the calibration detector. That is, the control of the equation (4) is performed using the constant multipliers 8 and 9 and the subtractors 10 and 11, and the control of the equation (6) is performed using the calculator 14 of the primary angular velocity ω. The primary angular frequency ω output from the calculator 14 is integrated by the integrator 15 to form a phase signal, and the trigonometric function generator 16 outputs the sine and cosine of the input phase.

In addition, in order to remove the interference component from the q ^e axis to the d ^e axis in the equation (1), control is performed as vd ^{e ′} s = Vd ^{e ″} s−ωσLsiq ^e s (9). This is a circuit that calculates the second term on the right side of the equation (9) based on the output and the output of the coordinate converter 4. The biaxial current id ^e s, iq ^e s is the PI compensator 17,
Feed back control is performed by the subtractor 19, the PI compensator 18, and the subtracter 20.

d ^e, q ^e axis primary flux linkage .lambda.d ^e s, the detection of? Q ^e s by (3). A block diagram of this detection method is, for example,
As shown in the figure, integrators 29 and 30 are required, and the first-order delay filter is used instead.

[Problems to be solved by the invention]

Since the conventional induction motor control device that does not use the speed detector is configured as described above, by using the integrators 29 and 30 that substitute the first-order lag filter, λd
There was a problem that the calculation accuracy of ^e s, λ q ^e s became poor and an error occurred in the estimation of ω.

The present invention has been made to solve the above problems, and an object thereof is to obtain an induction motor control device that does not cause an error in speed estimation in principle even in a low speed region of a motor.

[Means for solving problems]

According to the present invention, an induction motor control device supplies controlled AC power to a primary winding from a power supply device, and a secondary flux linkage and a slip frequency are calculated from a primary current of the induction motor by a flux / slip frequency estimation circuit. Estimate and use the primary delay element from the voltage or the primary voltage of the search coil of the induction motor to obtain the amount equivalent to the secondary interlinkage magnetic flux by the equivalent amount calculator, and to obtain the secondary value of the magnetic flux / slip frequency estimation circuit. Based on the estimated value of the interlinkage magnetic flux, obtain an estimated value of the secondary interlinkage magnetic flux-equivalent by the estimated amount calculator, and based on this estimated value and the above-mentioned amount, the rotational angular velocity of the induction motor is estimated by the rotational angular velocity estimator. The primary angular frequency is obtained by obtaining an estimated amount and finally adding the estimated amount and the slip frequency output of the magnetic flux / slip frequency estimating circuit.

[Action]

The amount corresponding to the secondary interlinkage magnetic flux calculated using the primary delay element from the search coil voltage or the primary voltage in the present invention has a large error from the true secondary interlinkage magnetic flux in the low speed region of the motor. Since the estimated amount of the amount equivalent to the secondary interlinkage flux calculated from the estimated amount of the secondary interlinkage flux also causes an error with the true secondary interlinkage flux, if the difference between the two is taken, it is The error is canceled out, and the speed can be estimated even in the low speed range.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. First
In the figure, 31 is a circuit for coordinate-converting the output voltage of the search coil, 32 is an equivalent amount calculator for calculating an amount equivalent to a secondary interlinkage magnetic flux from the search coil voltage or the primary voltage of the motor using a primary delay element, 33 Is a magnetic flux / slip frequency estimation circuit that estimates the secondary interlinkage magnetic flux and the slip frequency from the primary current, and 34 is an estimator calculator that computes an estimated value equivalent to the secondary interlinkage magnetic flux from the estimated secondary interlinkage magnetic flux. , 35 is a rotational angular velocity estimator of the induction motor 1, and 36 is an adder.

The same blocks as those shown in FIG. 2 are denoted by the same reference numerals, and the duplicated description thereof will be omitted.

Next, the operation will be described.

First, the output voltage of the search coils on the d ^e and q ^e axes is given by equation (10).

Here, Ms and Mr are mutual inductances of the primary coil and the secondary coil and the search coil.

Since an integrator is required to calculate the secondary interlinkage magnetic fluxes λd ^e r, λq ^e r in the coordinate conversion circuit 31 using the equation (10), a primary delay circuit can be used instead of the integrator (11). It becomes an expression.

In equation (11), λd ^{e ′} r and λq ^{e ′} r are in equation (10).
Since P is replaced by P + 1 / T, this is called a quantity equivalent to the secondary interlinkage magnetic flux, unlike the secondary interlinkage magnetic flux.
The equivalent calculator 32 uses the equation (11) to calculate the above λd ^{e ′} r, λ
Output d ^{e ′} .

Further, the secondary interlinkage magnetic flux is estimated by the equation (12), assuming that the induction motor 1 is vector-controlled.

Comparing equations (10) and (11), equation (13) is derived.

Estimating the amount of the secondary flux linkage from the estimated value of the secondary flux linkage using equation (13) yields equation (14).

The estimator calculator 34 is based on the equation (14). Is output. These state equations are Eqs. (15) and (16).

here, Is an estimated amount of the motor rotation angular velocity.

Comparing equations (15) and (16), we obtain pωr By using Popov's hyperstability theory, we can obtain the asymptotically stable identification rule for the agreement of (17).

Here, pωr (0) is the initial value of the velocity at the start of identification,
k ₁ and k ₂ are gains. The rotation angular velocity estimator 35 is based on the equation (17). Is output.

The slip frequency of the induction motor 1 is estimated by the equation (18).

The magnetic flux / slip frequency estimation circuit 33 executes the equations (12) and (18), And pωs are added by the adder 36 to obtain the primary angular frequency ω
Is output.

In the above embodiment, the output voltage of the search coil is used to calculate λd ^{e ′} and λ q ^{e ′} r, but the same effect can be obtained by calculating the primary voltage.

Also, when used for applications where the speed does not change rapidly,
The first term on the right side of the equation (17) may be excluded.

〔The invention's effect〕

As described above, according to the present invention, after the estimated amount of the rotational angular velocity of the induction motor is obtained based on the difference between the estimated value output of the estimated amount calculator and the equivalent amount output of the equivalent amount calculator, this estimated amount is calculated. And the slip frequency estimated by the magnetic flux / slip frequency estimation circuit are added to obtain the primary angular frequency.Therefore, in the low-speed range of the motor, the estimated value output of the estimated amount calculator and the equivalent amount calculator are equivalent. Although the quantity output will include exactly the same error, since the difference between the two is found, the error is canceled out, and as a result, the speed can be estimated without error even in the low speed range of the electric motor. .

[Brief description of drawings]

FIG. 1 is a block connection diagram showing an induction motor controller according to an embodiment of the present invention, FIG. 2 is a block connection diagram showing a conventional induction motor controller, and FIG. 3 is a primary interlinkage magnetic flux in FIG. 3 is a block connection diagram showing the detection method of FIG. 1 is an induction motor, 2 is a power amplifier, 3 and 4 are coordinate converters, 3
1 is a coordinate converter, 32 is a considerable amount calculator, 33 is a magnetic flux / slip frequency estimation circuit, 34 is an estimated amount calculator, 35 is a rotational angular velocity estimator, and 36 is an adder. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A power supply device for supplying controlled AC power to a primary winding of an induction motor, and a magnetic flux / slip frequency estimating circuit for estimating a secondary interlinkage magnetic flux and a slip frequency from a primary current of the induction motor. A corresponding amount calculator that calculates the amount of secondary interlinkage magnetic flux using the primary delay element from the voltage or primary voltage of the search coil of the induction motor, and the secondary interlinkage output by the magnetic flux / slip frequency estimation circuit. Based on the estimated value calculator that obtains the estimated value of the amount equivalent to the secondary interlinkage magnetic flux based on the estimated value of the magnetic flux, and the difference between the estimated value output of this estimated amount calculator and the equivalent amount output of the above equivalent amount calculator. Then, the primary angular frequency is obtained by adding the rotational angular velocity estimator for obtaining the estimated amount of the rotational angular velocity of the induction motor, and the estimated amount output of the rotational angular velocity estimator and the slip frequency output of the magnetic flux / slip frequency estimating circuit. Induction motor control apparatus and an adder.