JPS6188780A - Control constant setting method for speed controller - Google Patents

Abstract

PURPOSE:To optimally set a control gain by integrating to be hardly affected by the influence of a noise, and presuming an accurate inertia moment considered for the influence of a load torque. CONSTITUTION:The inertial moments J of a rotor of an induction motor 3 and a load unit 4 coupled with the rotor are calculated by a calculator B. Then, a torque T is calculated by an i*m/theta converter 13, an integrator 14 for integrating a torque current command signal i*8, and a torque calculator 16, and a signal DELTAomegar proportional to the rotating speed is obtained by the change width detector 15 of the speed omegar. They are input to an inertia moment calculator 17, the inertial moment of the machine system is calculated, and the gain of a speed regulator ASR10 is regulated by the output.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a control constant setting method for a speed control device for a d-motor.

[Background of the invention]

As a method of auto-engineering in a speed control device for an electric motor, for example, the method disclosed in Japanese Patent Publication No. 58-192486 is known. This method calculates the ratio of the second derivative of the rotational speed and the first derivative of the armature current to find the ratio between the motor magnetic flux and the starting time constant (moment of inertia) of the mechanical system without being affected by the load torque. , directly and automatically sets the gain of the speed adjustment section. However, since differential calculation is performed in this method, it is easily affected by pulse-like noise contained in the rotational speed and armature current detection signals, and as a result, the four-state current may contain many ripples. The difficulty is to become

[Purpose of the invention]

An object of the present invention is to provide a method for automatically and highly accurately setting control constants for speed adjustment in a speed control device for an electric motor.

[Summary of the invention]

The feature of the present invention is that the moment of inertia of the mechanical system is calculated based on the integral of the signal proportional to the torque and the variation width of the rotational speed, and the gain of the speed adjustment section is automatically set based on this before actual operation. It's what I did.

[The fruits of invention! li example]

Hereinafter, the present invention will be explained in detail with reference to the drawings.

FIG. 1 is a circuit configuration diagram for operating an induction motor in a vector control inverter. 1 and 3 are inverters and their driver circuits composed of transistors, etc.; 3 is an induction motor; 4 is a load device; and 5 is a rotational speed detector.

Part A is a general circuit for vector control, and is shown in an analog block diagram for ease of understanding. Here, 6 is an undercurrent regulator (ACR), 7 is a vector calculator, 8 is an oscillator that outputs a two-phase sine wave signal with a frequency proportional to the frequency command signal ω-, and 9 is i-, *, and T2 ( Secondary time constant a
) to calculate the slip frequency command value ω−,
10 is a speed regulator (A part), 11 is a rotation speed command device,
12 is an excitation current command device.

Section B is a section for calculating the moment of inertia J of the rotor of the induction motor 30 and the load device 4 connected thereto in the present invention. This is i-1φ converter 13, torque current command signal i-
an integrator 14 that integrates rotational speed ω, and a variation width detector 1 for the rotational speed ω.
5, torque calculator 16, and moment of inertia calculator 1
7, and the gain of A3R10 is adjusted by this output.

The principle of vector control mentioned above is =h! I! By independently controlling the magnetic flux and torque according to the excitation component and torque generation component commands 1g-i, skewer and 5- of the llI machine current, the speed of the induction motor can be controlled with high speed response and high accuracy. However, since the details are well known, a detailed explanation of the operation will be omitted here. The present invention relates to a method for automatically setting the gain of the speed regulator of such a speed 1fflj control device.

The content of the present invention will be described below.

The control loop of the speed control system is expressed as shown in FIG. 2, and its -cyclic transfer function G is given by the following equation.

・・・・・・・・・(In this case, even if the magnetic flux φ is constant, the moment of inertia J is;
When changes occur due to changes in the motive force and load equipment, the gain of the control system fluctuates, making it impossible to control the optimum response. Therefore, in the present invention, J is accurately measured before actual operation, and the gain Kl of the speed regulator is automatically set in proportion to J.

The moment of inertia J can be calculated from the following equation.

That is, the calculation unit f3Ki,'', i- and ω, in FIG.
is input, and the rotational speed is accelerated at a constant rate as shown in FIG. At this time, under the condition that φ is constant (in vector 1tlJ control, φ is kept constant with respect to torque changes), the motor generated torque T, is proportional to T,=φi−) , In addition, when the electric motor is close to no load, the generated torque can be directly regarded as acceleration torque, so the integral amount of 1, * (proportional to the integral amount of torque) during the acceleration period can be calculated as the rotational speed change width during that integral period. J can be found by dividing by .

However, in reality, it is necessary to consider the load torque Th. The acceleration torque is obtained by subtracting TL from the generated torque T, and J is given by the following equation.

However, T, > 0, Δω7. 〉OHere, T
can be estimated (i-y) as described above, but TL varies depending on the rotational speed and load conditions. Therefore, next time, J is determined when the rotational speed is decelerated at a constant rate. Since the deceleration torque is obtained by subtracting Tt from the generated torque T, J is given by the following equation in the same manner as described above.

However, Ted(o , Δω, 6<O Here, considering the case where the acceleration/deceleration rate and the rotational speed change width of acceleration/deceleration are the same, under the condition that the relationship between the load torque and the rotational speed is constant, the following The ceremony will be collected.

Δω1. = Δω = Δω.

Therefore, J can be determined from the sum of equations (3) and (4), that is, from the difference in the integral amount of i- during acceleration and deceleration, without being affected by the load torque.

The multiplication described above is a system using a microcomputer.
If it is a device, it can be handled using only software processing.

FIG. 4 shows a flowchart of the calculation.

First, l♂ is taken in and φ is calculated from the mutual inductance M of the cardiac motor. Next, acceleration is performed by changing ω- at a constant rate. During this time, j, * is imported into the memory for 1 second every second, and the initial values ω, l of the rotational speed during that 1 second are
and the final value ωr2 are taken into memory. From this, find the cumulative addition (Jl, *Δt) of "it" for 1 second and the rotational speed change width Δω, and calculate fT, dt. Next, ω,
Decelerate with ~t, and do the same as above, /Ta
Find dt.

Based on the above results, J is calculated based on equation (6). Based on this J, the gain of the speed regulator ASR is set to 1.

As described above, according to the present invention, it is possible to obtain an accurate value of the moment of inertia J that is not affected by load torque, and there is an effect that speed control performance can be improved. In the above embodiment, the electric motor was accelerated or decelerated in order to eliminate the influence of load torque in calculating J, but if the measurement is performed in a range where the rotational speed changes within a small range, the load torque is almost constant regardless of the rotational speed. Therefore, calculate the load torque type f 'l', dt at a constant speed in advance, then accelerate the machine and calculate the aforementioned load torque integral from the torque integral ifT, dt at that time. Subtract stone pillar moment J
A similar result can be obtained by calculating . This relationship is (3)
It is clear from Eq. The flowchart at this time is shown in the fifth section.
As shown in the figure.

The embodiment described above is an example in which the present invention is applied to a well-known vector control device, but the present invention can be similarly applied to other control devices that can obtain signals proportional to torque and rotational speed. can. These signals may be computationally estimated signals. The well-known vector control device sets the inverter output frequency ω1 to ii+lJ (A/ζ). Also, a speed detection signal is used as a feedback signal for speed control, a speed detector attached to the motor is required, and the seven-stem configuration is complicated. be.

To solve this problem, a vector control method that does not use a speed detector was developed. , g6 shows an example of application of the present invention to this control device. The principle and operation of this system are described in Japanese Patent Application No. 58-29143, so a detailed explanation will be omitted here. 90 for electromotive force
The magnetic flux is controlled by adjusting the electric current component (excitation current) having a phase difference, and the torque is controlled by adjusting the current component (torque current) having the same phase with respect to the electromotive force. In this case as well, the torque current command it* is obtained from the speed regulator 10 as in the previous embodiment, and the excitation mixed current command i, umbrella, is obtained from the excitation current command line 12 (here, the electromotive force regulator 18 The output signal Δi− is added to 1) according to the electromotive force detection signal from the electromotive force detector 19 so as to prevent the magnetic flux from changing from the reference value, and the magnetic flux is controlled in proportion to it. ).

Also, the estimated value of rotational speed ω, ke, the electromotive force detection signal e, (
Due to the action of the electromotive force adjuster 18, e constantly matches ω-. ) is calculated by subtracting the frequency ω and the distance. As described above, since 1-9i- and ω7 are obtained which are proportional to the magnetic flux, torque, and rotational speed, the present invention can be carried out using these in the same way as in the above-mentioned real-life example, and the same effect can be obtained.

〔Effect of the invention〕

According to the present invention, an integral calculation is performed that is not easily affected by noise, instead of a differential calculation, and it is possible to estimate the moment of inertia J of crystal accuracy taking into account the influence of load torque.
This has the effect that the control gain can be set optimally.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an example of application of the control constant setting method for a fast wave control device of the present invention to a vector control device;
Fig. 3 is an explanatory diagram of the principle of the method shown in Fig. 1, and Fig. 4 is
The figures are a flowchart of software for implementing the method shown in Fig. 1, and Fig. 5 is a flowchart of software for another embodiment of the speed control device of the present invention.
The figure is a block diagram when another embodiment of the method for setting control constants for a speed control device according to the present invention is applied to a vector control device. 3...AC electric 4J, A...vector control device, 1
0... Speed regulator.

Claims (1)

[Claims] 1. In an electric motor speed control device, when the torque of the electric motor is changed and the rotational speed is changed, the integral amount of the torque proportional signal and the variation range of the rotational speed are calculated based on the signal proportional to the torque and rotational speed. A method for setting a control constant for a speed control device, characterized in that the moment of inertia of a mechanical system is calculated from the ratio thereof, and the control constant of a speed regulator is automatically set based on the result.