JPH048186A - Motor speed controller - Google Patents

Abstract

PURPOSE:To regulate control parameters automatically by regulating setting of control parameters at respective sections based on a speed command, obtained when the motor speed is subjected to step response, or a shift from a stepped speed response waveform. CONSTITUTION:A parameter regulating section 11 is additionally provided, and the speed waveform is stored in a waveform analyzing section 10 in order to calculate characteristic amounts such as overshoot, setting time or rising time. In the waveform analyzing section 10, the speed waveform is sampled at a sample and hold circuit 10a and stored in a memory 10b and a microprocessor 10c calculates characteristic amounts. Speed control parameters in the speed control loop of a motor 1 are then regulated so that the speed waveform satisfies specification of speed control. The operation is repeated until a judgment is made that the speed control specifications are satisfied within an appropriate allowance thus regulating the speed control parameters correctly.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to a speed control device for an electric motor.

(Prior Art) FIG. 3 is a block diagram showing an example of the functions of a conventional speed control device for an electric motor. This conventional example uses PI control with an anti-overshoot function.

In order to perform speed control that satisfies the control specifications using this speed control device, it is necessary to perform adjustment work to set the adjustment parameters of proportional gain KP, integral gain, and anti-overshoot to appropriate values.

(Problem to be Solved by the Invention) The above adjustment work is performed by, for example, an adjuster repeatedly observing the speed step response waveform and correcting the proportional gain KP, integral gain, and anti-overshoot value by trial and error. and made sure to meet the specifications. This method requires a certain amount of experience and intuition on the part of the coordinator;
And it takes time. Further, even when a large number of electric motors have to be adjusted to the same specifications, it is inevitable that the adjustment results will vary to some extent.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned problems in the prior art and to provide an electric motor speed control device having a function of automatically adjusting control parameters for controlling the speed of an electric motor.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above object, the present invention is an electric motor speed control device having the following configuration and having a function of adjusting speed control parameters of one motor.

A speed control device for an electric motor is equipped with a speed control loop based on appropriate control logic, performs speed control by giving a step input as a speed command, and has a memory that stores a speed step response waveform corresponding to this step input. ,
The quantities that define the shape of the stored speed waveform are calculated, and the speed control parameters of the motor speed control loop are adjusted so that the speed waveform satisfies the speed control specifications. The present invention is characterized by the addition of a function to repeatedly adjust the speed control control parameters to appropriate values until it is determined that the waveform satisfies the speed control specifications within an appropriate margin.

(Function) In the speed control system of an electric motor, if the control parameters are inappropriate for the specifications, the effects may be, for example, excessive overshoot in the speed step response waveform or vibration.

Alternatively, it may appear as a condition where the settling time is too long.

Therefore, the relationships between the increases and decreases in the values of the speed control parameters of each section described above and these states are understood, the actual step response waveform is analyzed to calculate the characteristics of the waveform, and the speed control parameters of each section are determined based on the above relationships. By repeatedly modifying the value of , a response that satisfies the specifications can be obtained. If the above process is executed by a computer, quick and uniform adjustment becomes possible. As a result, (the problem that the invention seeks to solve)
The problems of the prior art pointed out in the section above can be solved.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of a motor speed control device according to an embodiment of the present invention. In this figure, the same components as in FIG. 3 are given the same symbols and their explanations will be omitted.

The motor speed controller according to the present invention shown in FIG.
The elements described below are added to the conventional speed controller shown in FIG. 3 to provide a function of adjusting control parameters for speed control to appropriate values. That is, the speed controller related to the present invention.

A parameter adjustment section 11 is added. The velocity waveform is stored in the waveform analysis section 10, and feature quantities such as overshoot, settling time, and rise time are calculated. The feature quantities calculated by the waveform analysis section 10 are sent to the parameter adjustment section 1.
1, and the correction direction (increase/decrease) and amount of the speed control system proportional gain KP, integral gain, and anti-overshoot value are calculated based on the characteristic quantity, and the proportional gain set in the speed controller 5 is Gain KP, integral gain,
And the anti-overshoot value set in the feedback compensator 3 is corrected.

FIG. 2 shows an example of the configuration of the waveform analysis section IO.

The waveform of the speed ω is sampled by the sample-hold circuit 10a, stored in the memory tab, and the feature amount is calculated by the microprocessor 10c.

The following operations are performed within the microprocessor.

In the case of a response waveform with a speed ω, the memory tab stores this speed ω.
The values obtained by sampling the response waveform of 1 at an appropriate sampling period are stored. First, the set value ω of the response of speed ω
Find set. If the waveform stored in the memory 10b is a waveform until the speed response is sufficiently stabilized, the settling value ωset may be the last sampled value. In order to avoid effects such as ripples, the last sampled values may be averaged. Next, find the maximum value ωmat (of all the sampled values. ωwa
Compare ax and ωset, and if ωmaM>ωset, it is known that overshoot has occurred, and the overshoot amount OV is determined.

It is.

If ω, □ ωset, no overshoot has occurred and ○v=0. In this case, other features include settling time Tse
Find t. This checks the sampled values sequentially from the beginning, and if the value is 0.95 *ω from the beginning of the response.
All you have to do is find the time until it exceeds set for the first time.

Similarly, the rise time can be calculated according to the definition.

An example of the configuration of the parameter adjustment section 11 is a microprocessor and memory, similar to the waveform analysis section 1o. This is a sample-
This is the same as FIG. 2 except that there is no hold circuit, so the illustration is omitted. In this case, adjustment rules based on the feature amounts are stored in the memory.

Examples of adjustment rules are explained below.

Generally, once the settling time and return time are determined, the broken wave number ω determines the response characteristics. is found. In this embodiment, due to pole-zero cancellation, the broken fish waste wave number ωpx of the speed system PI and the broken fish waste wave number ωAND of the anti-overshoot are set to ω. match,
This ω. Improve anti-overshoot gain, etc. It would be better to determine the proportional gain KP in that state, but since the inertia of the motor and load is uncertain, the phase will shift.
An overshoot appears in the speed response waveform depending on the value of the proportional gain KP. This is made into a step-like waveform without overshoot by adjusting the proportional gain KP. That is, if an overshoot occurs in the response waveform of the speed command, the proportional gain KP is increased; otherwise, the proportional gain KP is decreased. At this time, the value of ωpx ”Kr/ is also determined from P to the integral gain. As explained above, incorrect setting of the values of the proportional gain KP, integral gain and anti-overshoot can be caused by: 1) Speed command 2) If an overshoot occurs in the speed command response during that time, increase the proportional gain KP, and 3) If the speed command response during that time is delayed and the settling time becomes longer. , reduce the proportional gain KP.

4) Make the speed command response waveform close to a step-like waveform within an appropriate margin.

5) Finely adjust the proportional/integral control system broken fish waste wave number and anti-overshoot broken fish waste wave number by the value of TQet.

This can be corrected using the adjustment rule.

In this way, the proportional gain KP is corrected and the step response of the motor speed described above is performed again.

The above steps are repeated until it is determined that the adjustment has been completed. Various methods can be considered for determining whether adjustment has been completed, and any method that can confirm this may be used.

For example, 1 there is no overshoot and T8et'-tolerance <
T set < T set ”Ten margin.

2 Overshoot is within a predetermined margin (for example, 1%).

3. The time integral of the error between the predetermined step waveform and the response waveform of the adjustment process becomes smaller than a predetermined value. (In addition to a simple error, the absolute value of the error, the square value of the error, etc. can be considered as the quantity to be integrated over time.) There are methods such as the following.

In the above embodiment, overshoot and settling time were used as the characteristic values of the speed command or the speed response waveform, but the characteristics may be changed as long as incorrect settings of the proportional gain KP, integral gain, and anti-overshoot can be reflected. Any amount may be used.

〔Effect of the invention〕

As explained above, in the present invention, the influence of incorrect settings of control parameters of various parts related to the speed control device of the electric motor can be suppressed by adjusting the speed command or the speed response waveform when the speed of the electric motor is caused to respond in a step-like manner. The deviation from the step-like waveform is quantified, and the settings of the control parameters for each section are adjusted based on the results. Thereby, it is possible to provide a speed control device for an electric motor that has a function of automatically adjusting control parameters related to the speed control device for an electric motor.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an electric motor speed control device according to a first embodiment of the present invention, and FIG. 2 is a waveform analysis section 10 of FIG.
FIG. 3 is a block diagram of a conventional motor speed control device. 1...Electric motor, 2:...Speed detector, 3...
- Feedback compensator, 4... Subtractor, 5... Speed controller. 6... Current detector, 7... Subtractor, 8... Current controller, 9... Control power supply, 10... Waveform analysis section, 11... Parameter calculation section. Agent Patent Attorney Noriyuki Chika

Claims (1)

[Claims] A speed control device for an electric motor equipped with a speed control loop that calculates a deviation between a speed command value and a detected speed value and issues a control command based on appropriate control logic, in which a step input is given as a speed command. Perform speed control, prepare a memory that stores the speed response waveform corresponding to this step input, calculate the amount that defines the shape of this stored speed waveform, and make sure that the speed waveform satisfies the speed control specifications. This function adjusts the speed control parameters to appropriate values by adjusting the coefficients of each part of the motor and repeating the above process until it is determined that the speed waveform satisfies the speed control specifications within an appropriate margin. A speed control device for an electric motor, characterized by adding: