JPS61170289A - Speed controller of motor - Google Patents

Abstract

PURPOSE:To enhance the controlling accuracy by discriminating the transient state and the normal state of a motor, and switching the function of a speed regulator in response to the state, thereby preventing the speed after the speed is recovered in the transient state from overshooting. CONSTITUTION:When a speed regulator 16, a torque regulator 20 and a state observing unit 32 for simulating a load torque are provided to control the speed of a motor 26, a switching circuit 34 for discriminating the transient state like a load abrupt variation time and the normal state is provided. To discriminate the transient state and the normal state, a speed deviation (the output of an on adder 14), is, for example, monitored, and when it is the prescribed value or higher, it is discriminated as the transient state. The regulator 16 is controlled to be switched according to the discriminated state, and operates as a P regulator at transient state time and as a PI regulator at normal state time.

Description

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

[Conventional technology]

Conventionally, motor speed control devices have been equipped with a speed regulator, a torque regulator, and a condition observation device that calculates and simulates load torque from the current and rotational speed of the motor. ) and speed recovery time (
A system configured to perform highly adaptive control with a small recovery time is known.

However, since this kind of conventional speed control device uses a PI regulator as a speed regulator, for example, as shown in Fig. Due to the time delay, the actual speed value ■ has the disadvantage of causing an overshoot.

[Problems to be Solved by the Invention] Therefore, in the present invention, by switching the function of the speed regulator between the transient state when the load suddenly changes and the steady state, the speed overshoot after speed recovery in the transient state is eliminated. An object of the present invention is to provide a speed control device for an electric motor that can prevent the above problems and achieve highly accurate control of the electric motor.

[Means for solving problems]

Therefore, in the present invention, in a speed control device for a motor equipped with a speed regulator, a torque regulator, and a state observation device that calculates and simulates load torque from the current and rotational speed of the motor, it is possible to The present invention is characterized in that a switching circuit is provided for discriminating between the speed regulator and the steady state and switching the function of the speed regulator to compensate for the delay in the integral operation of the speed regulator in the transient state.

In the speed control device described above, it is preferable that the switching circuit is configured to discriminate between a transient state and a steady state based on the deviation between the speed setting value and the detected rotational speed value, depending on whether the deviation is larger or smaller than a predetermined reference amount. It is.

In addition, the switching circuit is configured to hold the integral element of the speed regulator in a transient state and release the holding of the integral element in a steady state. It can be configured to change the proportional gain of the proportional element, release the retention of the integral element in a steady state, and return the proportional gain of the proportional element to its original state, or change the proportional gain of the proportional element of the speed regulator in a transient state. The configuration can be configured so that the proportional gain of the proportional element is restored to its original value in a steady state, and the connection of two types of output limiters connected to the speed regulator can be selectively changed in a transient state and a steady state. It can be configured to switch.

[Effect]

According to the present invention, a transient state such as a sudden load change and a steady state are appropriately determined, and in a transient state, the speed regulator is configured to function as a normal PI regulator. It is possible to effectively prevent speed overshoot due to delay in integral operation in the state, and in steady state, parameter errors and measurement errors of the state observation device can be compensated by operating as a PI regulator. Speed control of the motor in transient and steady states can be achieved with high precision.

〔Example〕

Next, embodiments of a speed control device for an electric motor according to the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a circuit diagram showing an embodiment of the speed control device of the present invention, which is a speed control device for a DC motor. That is,
In FIG. 1, reference symbol /θ is a speed setter, 7.2 is an acceleration/deceleration calculator, /g is an adder, /6 is a speed adjuster, o
g is an adder, θ is a torque adjuster, -! 1 is the ignition pulse generator, 2 is the thyristor converter 1.26 is the electric motor 1.
2g is a speed detector, 3θ is a current detector, and 3.2 is a state observer.

The above configuration is the basic circuit configuration of a conventional speed control device, and operates as follows. In other words, the speed command set by the speed setter /θ is changed to the acceleration/deceleration calculator /,! It is outputted via the speed command value n* and supplied to the adder/B. On the other hand, the electric motor detected by the speed detector, 2g! The number of rotations of O “xat” is the adder/6
The deviation from the speed command value n is calculated. The deviation signal obtained in this way is
is inputted to obtain a PI adjustment output, and this output is inputted to an adder/g, and in this adder/g, a state observer 3 is inputted.
．． 2 adds the load torque simulated by calculation and the PI adjustment output. The output signal obtained by the adder controls the ignition of the thyristor converter 2'l via the torque regulator ``θ and ignition pulse generator'', thereby controlling the motor 2' to the set rotation. Control so that it becomes a number.

However, in the circuit of this embodiment, the speed regulator /6 is not activated in a transient state such as when the load suddenly changes.
The present invention is characterized by the provision of a switching circuit 3 which operates to hold 6 integral elements. That is, this switching circuit 3 inputs a deviation signal between the speed command value obtained by the adder/g and the detected rotational speed value, and detects when the absolute value of this deviation is larger than a predetermined reference amount or is likely to become larger. In a transient state such as when the load suddenly changes, the speed regulator/6 operates to maintain the integral element I of the speed regulator/6 as a PiM moderator. Further, this switching circuit 3 is configured to: when the absolute value of the deviation based on the manual deviation signal is smaller than a predetermined reference amount;
That is, in a steady state, it operates to release the holding of the integral element I of the speed regulator/6, and sets the speed regulator/6 to P.
Operates as an I regulator.

According to the circuit of this embodiment configured in this way, by switching the function of the speed regulator/6 between a transient state such as when the load suddenly changes and a steady state, the integral operation as shown in FIG. 5 in the transient state is achieved. The speed overshoot caused by the delay can be reduced or eliminated as shown in FIG.

FIG. 2 shows another embodiment of the speed control device of the present invention. The basic configuration of the speed control system is the same as the circuit shown in FIG. 1, and the same components are given the same reference numerals and detailed explanation thereof will be omitted. The circuit of this example is
This is a modification of the operating system of the switching circuit of the embodiment shown in FIG. That is, the switching circuit 36 of this embodiment maintains the integral element I of the speed regulator/6 to operate the speed regulator/6 as a pH moderator in a transient state such as when the load suddenly changes, and also controls the proportional element P of the speed regulator/6. The device is configured to perform an operation of changing the proportional gain. Further, in a steady state, the switching circuit 36 releases the holding of the integral element I of the speed regulator/B, causes the speed regulator/6 to operate as a PI regulator, and returns the proportional gain of the proportional element P to its original state. Configure it to do so.

In the circuit of this embodiment configured in this way, as in the previous embodiment, it is possible to reduce or eliminate the speed overshoot caused by the delay in the integration operation in a transient state.

FIG. 3 shows still another embodiment of the speed control device of the present invention, in which the operating system of the switching circuit is changed in the same way as the embodiment shown in FIG. That is,
The switching circuit 3 of this embodiment operates to change the proportional gain of the proportional element P of the speed regulator/6 in a transient state such as when the load suddenly changes, and also changes the proportional gain of the proportional element P in a steady state. It is configured to perform the operation of returning to .

In the circuit of this embodiment as well, as in the embodiment described above, it is possible to reduce or eliminate speed overshoot due to delay in integral operation in a transient state.

Furthermore, FIG. y shows another embodiment of the speed control device of the present invention, in which the operating system of the switching circuit is changed in the same way as in the previous embodiments. In other words, the switching circuit yθ of this embodiment connects two types of output limit tags to the speed regulator/B, and selects the normal value of output limit tag 2 in a transient state (when the deviation is large) such as when the load suddenly changes. In a steady state (when the deviation is small), the output limit tag 2 is operated to select the value of the other output limit tag 2.

In the circuit of this embodiment as well, as in each of the embodiments described above, it is possible to reduce or eliminate speed overshoot due to delay in integral operation in a transient state.

〔Effect of the invention〕

As is clear from the embodiments described above, according to the present invention,
In an electric motor speed control system that is equipped with a speed regulator, a torque regulator, and a state observation device that simulates load torque, it is possible to distinguish between transient states such as sudden changes in load and steady states, and to adjust the speed regulator to respond to these states. By switching the functions, it is possible to effectively prevent speed overshoot due to a delay in the integral operation in a transient state. In particular, according to the present invention, since a simple switching circuit is added to a conventional device, it can be realized at low cost.

Furthermore, in a steady state, since the speed regulator is a PI regulator, it is possible to compensate for parameter errors and measurement errors of the state observation device, and it is possible to control the motor with high precision in both transient states and steady states.

Although the preferred embodiments of the present invention have been described above, it goes without saying that various design changes can be made without departing from the spirit of the present invention.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing one embodiment of the speed control device for an electric motor according to the present invention, FIGS. 2 to y are circuit diagrams showing different embodiments of the speed control device of the present invention, and FIG. A characteristic curve diagram showing the relationship between the output I and the actual speed value B when the load suddenly changes when the speed regulator of the control device is a PI regulator. FIG. 3 is a characteristic curve diagram showing the relationship between the output crab and the actual speed value 1 when the load suddenly changes in a certain case. /θ...Speed setter 7.2...Acceleration/deceleration calculator/y・0. Adder /6...Speed adjuster/
l...Adder -〇...Torque adjuster, 2
B...Electric motor, 2g...Speed detector 3θ
...Current detector 32...State observation device 3'1.
3A, 3, Gθ...Switching circuit 11.2...
・Output limiter

Claims (6)

[Claims] (1) In a motor speed control device equipped with a speed regulator, a torque regulator, and a state observation device that calculates and simulates load torque from the current and rotational speed of the motor, it is possible to distinguish between transient states such as sudden load changes and steady states. 1. A speed control device for an electric motor, characterized in that a switching circuit is provided for determining the speed regulator and switching the function of the speed regulator to compensate for a delay in the integral operation of the speed regulator in a transient state. (2) In the speed control device according to claim 1, the switching circuit is configured to control whether the switching circuit is in a transient state or a steady state depending on whether the deviation is larger or smaller than a predetermined reference amount, based on the deviation between the speed setting value and the detected rotational speed value. A speed control device for an electric motor configured to determine the state. (3) In the speed control device according to claim 1 or 2, the switching circuit holds the integral element of the speed regulator in a transient state and releases the holding of the integral element in a steady state. A speed control device for an electric motor configured to perform the following steps. (4) In the speed control device according to claim 1 or 2, the switching circuit maintains the integral element of the speed regulator in a transient state and changes the proportional gain of the proportional element, and in a steady state, A speed control device for an electric motor configured to release the retention of an integral element and restore the proportional gain of the proportional element to its original value. (5) In the speed control device according to claim 1 or 2, the switching circuit changes the proportional gain of the proportional element of the speed regulator in a transient state and changes the proportional gain of the proportional element in a steady state. A speed control device for an electric motor configured to perform a return operation. (6) In the speed control device according to claim 1 or 2, the switching circuit selectively connects two types of output limiters connected to the speed regulator in a transient state and a steady state, respectively. A speed control device for an electric motor configured to switch.