JPH0522974A - Motor speed controller - Google Patents

Abstract

PURPOSE:To enhance trackability of speed for acceleration and deceleration by previously obtaining a mechanical loss torque for acceleration and deceleration and a multiple of acceleration/deceleration torque. CONSTITUTION:A mechanical loss torque of a mechanical load 1 and a motor 2 which is a factor of a load torque output is previously measured with a mechanical loss torque function generating means 11. Moreover, a multiple of acceleration/deceleration torque is measured with an acceleration/deceleration torque measuring means 12 to obtain an acceleration/deceleration torque and gives a mechanical loss torque and acceleration/deceleration torque as an acceleration/deceleration compensation signal of a load torque TL at the time of accelerating or decelerating the speed reference WS. Therefore, when there is no disturbance an output of a speed control amplifier 6 may be set to zero. Thereby, the torque control amplifier 7 can control a generated torque of the motor 2 based on the accurate torque reference T and also controls the speed of motor 2 with good trackability during acceleration and deceleration of speed reference.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a speed control device for an electric motor having an improved acceleration / deceleration compensation function for the electric motor during acceleration / deceleration.

[0002]

2. Description of the Related Art In a speed control device for an electric motor of this type, as shown in FIG. 2, a feedback control for executing feedback control based on a rotational speed of an electric motor 2 for driving a mechanical load 1 (hereinafter referred to as an actual speed). It is composed of a control system 3 and an acceleration / deceleration compensation system 4 for compensating the acceleration / deceleration torque during acceleration / deceleration based on the speed. Among them, the feedback control system 3 is composed of a speed detector 5 for detecting the actual speed of the electric motor 2, a speed control amplifier 6 for obtaining a load torque, a torque control amplifier 7, a power converter 8 and the like. System 4
Is composed of a differentiating means 9 for obtaining an acceleration from the rate of change of the speed reference, and a multiplying means 10 for multiplying the acceleration from the differentiating means 9 by the total moment of inertia of the mechanical load 1 and the electric motor 2 to obtain an acceleration / deceleration torque. Multiplication means 1
The acceleration / deceleration torque obtained by
After the torque reference is obtained by adding it to the load torque which is the output of the above, it is introduced into the torque control amplifier 7.

Therefore, according to the above-mentioned structure, the speed control amplifier 6 receives the deviation between the speed reference Ws and the actual speed Wp detected by the speed detector 5, and the speed control amplifier 6 performs the proportional / integral calculation to obtain the load torque T. _{After obtaining L} , it is introduced into the torque control amplifier 7 as a torque reference T.

On the other hand, in the acceleration / deceleration compensation system 4, the differentiating means 9 obtains the differential of the speed reference Ws, that is, the acceleration S = dWs / dt, and then sends this acceleration dWs / dt to the multiplying means 10. In the multiplication means 10, the total inertia moment J of the mechanical load 1 and the electric motor 2 is added to the acceleration from the differentiating means 9.
To obtain the acceleration / deceleration torque Ta = J · dWs / dt, and then the acceleration / deceleration torque Ta is added to the load torque _TL from the speed control amplifier 6 to obtain the torque reference T to obtain the torque control amplifier 7. Supply to. Here, the torque control amplifier 7 controls the torque generated by the electric motor 2 via the power converter 8 based on the torque reference T.

Therefore, in this speed control device, since the acceleration / deceleration compensation is not performed for the load torque TL in advance, a slight deviation may occur between the speed reference Ws and the actual speed Wp during acceleration / deceleration. As a result, the load control torque TL is output from the speed control amplifier 6.

[0006]

Therefore, in the speed control device for an electric motor as described above, the load torque TL is output from the speed control amplifier 6, and the output factor of this load torque TL is shown in FIG. As described above, in addition to the mechanical loss torque of the mechanical load 1 and the electric motor 2 (hereinafter referred to as mechanical loss torque), the acceleration / deceleration torque compensation error due to the fact that the actual moment of inertia GD ₂ of the mechanical load 1 and the electric motor 2 is different from the design value Minute torque, load fluctuations that occur suddenly in the mechanical load 1, so-called disturbance torque, etc. are increased.

However, the output of the torque corresponding to the error in the acceleration / deceleration torque compensation and the mechanical loss torque of the mechanical load 1 causes a difference between the speed reference and the actual speed, and the electric motor during acceleration / deceleration is increased. Considering the followability of the rotational speed of No. 2, it is not desirable that a non-negligible deviation occurs, and it should be output only for the torque of the disturbance that is originally unpredictable.

The present invention has been made in view of the above circumstances, and the actual speed of the electric motor always matches the speed reference during acceleration / deceleration regardless of the actual values of mechanical loss, mechanical load, and inertia moment of the electric motor. It is an object of the present invention to provide a speed control device for an electric motor, which can perform mechanical loss torque compensation and acceleration / deceleration torque compensation, and thus can sufficiently enhance the speed followability of the electric motor during acceleration / deceleration.

[0009]

In order to solve the above problems, the present invention provides a mechanical loss torque generating means for measuring and storing the mechanical loss torque from the output of the speed control amplifier while changing the speed reference in advance. Similarly to the mechanical loss torque generating means, an acceleration / deceleration torque measuring means for obtaining the acceleration / deceleration torque multiple by previously taking in the rate of change of the speed reference is provided, and during the speed control of the electric motor, the mechanical loss torque with respect to the speed reference is provided. Speed control of an electric motor for performing torque control of the electric motor by giving a mechanical loss torque from a generating means and an acceleration / deceleration torque obtained by multiplying a rate of change of the speed reference by the acceleration / deceleration torque multiple to the torque reference. It is a device.

[0010]

Therefore, according to the present invention, since the mechanical loss torque and the acceleration / deceleration torque multiple for acceleration / deceleration are obtained in advance by taking the above-mentioned means, the appropriate mechanical torque can be obtained during the actual acceleration / deceleration control. Loss torque compensation and acceleration / deceleration torque compensation can be performed, whereby the speed of the electric motor can be controlled based on an accurate torque reference, and the speed followability with respect to acceleration / deceleration can be improved.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the device of the present invention will be described below with reference to FIG. In the figure, the same parts as those of the device of FIG. 2 are designated by the same reference numerals, and detailed description thereof will be omitted.
Hereinafter, only different parts will be described. That is, the different point of this device is that the acceleration / deceleration torque multiple K required for obtaining an accurate acceleration / deceleration torque on the output side of the differentiating means 9 is obtained.
In addition to the multiplication means 10 'having a memory for storing the value of, the mechanical loss torque functionalized beforehand based on the speed reference is stored in advance, and the mechanical loss torque functionalized with respect to the change of the speed reference is generated. The mechanical loss torque function generating means 11 is provided, and the acceleration / deceleration torque measuring means 12 is further provided.

The acceleration / deceleration torque measuring means 12 has a function of receiving the acceleration / deceleration torque measurement command 13, measuring the acceleration / deceleration torque multiple (initial value) K during acceleration / deceleration, and setting it in the memory of the multiplication means 10 '. ..

Next, the operation of the apparatus configured as described above will be described. First, in order to improve the speed followability during acceleration / deceleration without being influenced by the actual values of the mechanical loss torque and the inertia moment GD ₂ , the actually required values of the mechanical loss torque and the acceleration / deceleration torque are required. Need to be measured in advance.

Therefore, description will be made below in the order of (1) measurement of mechanical loss torque, (2) measurement of acceleration / deceleration torque multiple for obtaining accurate acceleration / deceleration torque, and (3) original speed control of the electric motor. (1) Measurement of mechanical loss torque

The mechanical loss torque is measured in advance prior to the normal speed control of the electric motor and stored in the function table of the mechanical loss torque function generating means 11. Therefore, in this device, the speed reference Ws is gradually changed stepwise within the range of the operating speed in a state where the differentiating means 9 and the multiplying means 10 are removed, and the torque reference T is generated only by the speed control amplifier 10. At this time, when the speed reference Ws and the actual speed Wp of the electric motor 2 are constant, the value of the reference torque T corresponds to the value of the mechanical loss torque T _{M at} the speed reference Ws (see FIG. 3). Therefore, if the torque reference T output from the speed control amplifier 6, that is, the mechanical loss torque T _M is stored in the mechanical loss torque function generating means 11 via the dotted line 21 shown in the figure while sequentially changing the speed reference Ws.
The mechanical loss torque T _M for each speed reference Ws can be acquired in advance. (2) Measurement of acceleration / deceleration torque multiples

As described above, the mechanical loss torque T
After the measurement of _M is completed, the acceleration / deceleration torque measuring means 12 measures the acceleration / deceleration torque Ta based on the acceleration / deceleration torque measurement command 13. That is, the acceleration / deceleration torque measuring means 12 takes in the torque reference T when the electric motor 2 is accelerated at the acceleration rate through the dotted line 22 shown in the drawing, and the speed reference from the mechanical loss torque function generating means 11 and the differentiating means 9, respectively. Mechanical loss torque T _M at Ws,
After capturing the acceleration S, K = (T−T _M ) / S

Accurate acceleration / deceleration torque Ta
Then, the multiple K required to obtain is obtained. That is, the mechanical loss torque T _M is subtracted from the total torque T required for acceleration, and the acceleration S, which is the output of the differentiating means 9, is added.
After obtaining the acceleration / deceleration torque multiple K by dividing by
Store at 0 '. (3) Speed control of electric motor

However, if the mechanical loss torque T _M and the acceleration / deceleration torque multiple K are previously measured and stored as described above, thereafter, the acceleration / deceleration torque measuring means 12 is disconnected and the original speed control of the electric motor 2 is performed. To execute. In this case, a deviation between the speed reference Ws and the actual speed Wp detected by the speed detector 5 is introduced into the speed control amplifier 6, where a proportional / integral calculation is performed based on the deviation to calculate the load torque T.
Output _L. On the other hand, the mechanical loss torque function generating means 11
Then, the mechanical loss torque T _M measured in advance based on the speed reference Ws is generated, and the acceleration S determined by the differentiating means 9 is further multiplied by the acceleration / deceleration torque multiples previously measured and stored in the multiplying means 10. Accurate acceleration / deceleration torque Ta is obtained by multiplying K. Then, the torque reference T is obtained by adding the mechanical loss torque T _M and the acceleration / deceleration torque Ta to the load torque T _L , and the torque reference T is supplied to the torque control amplifier 7, where the torque reference T is supplied via the power converter 8 as in the conventional device. The generated torque of the electric motor 2 is controlled.

Therefore, according to the configuration of the above embodiment, the mechanical loss torque T _M of the mechanical load 1 and the electric motor 2 which are the load torque output factors are measured in advance by the mechanical loss torque function generating means 11, and The acceleration / deceleration torque measuring means 12 measures the actual acceleration / deceleration torque multiple K to obtain the acceleration / deceleration torque Ta, and at the time of acceleration / deceleration of the speed reference Ws, these mechanical loss torque T _M and acceleration / deceleration torque Ta are compared with the load torque _TL . Since it is given as an acceleration / deceleration compensation signal,
When there is no disturbance, the output of the speed control amplifier 6 can be made zero. As a result, the torque control amplifier 7 can control the generated torque of the electric motor 2 based on the accurate torque reference T, and the speed of the electric motor 2 can be controlled with better followability during speed-based acceleration / deceleration.

In the above embodiment, the mechanical loss torque function generating means 11 and the acceleration / deceleration torque measuring means 12 are described as hardware, but the mechanical loss torque TM and the acceleration / deceleration torque multiple K can be obtained by software. Is. Besides, the present invention can be variously modified and implemented without departing from the scope of the invention.

[0021]

As described above, according to the present invention, the mechanical loss torque and the acceleration / deceleration torque multiple, which are factors of the load torque output from the speed control amplifier at the time of speed-based acceleration / deceleration, are measured in advance, and the electric motor Since the mechanical loss torque and the acceleration / deceleration torque obtained from the acceleration / deceleration torque multiple are compensated for during speed control of the motor, the motor is always operated during acceleration / deceleration regardless of the actual values of mechanical loss, mechanical load, and the motor inertia moment. It is possible to perform mechanical loss torque compensation and acceleration / deceleration torque compensation so that the actual speed of the above-mentioned becomes equal to the speed reference, and it is possible to provide a speed control device for an electric motor capable of sufficiently improving the speed followability during acceleration / deceleration.

[Brief description of drawings]

FIG. 1 is a configuration diagram illustrating an embodiment of a speed control device for an electric motor according to the present invention.

FIG. 2 is a configuration diagram of a conventional device.

FIG. 3 is a diagram showing operating characteristics of the device of the present invention and the conventional device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Mechanical load, 2 ... Electric motor, 5 ... Speed detector, 6 ... Speed control amplifier, 7 ... Torque control amplifier, 9 ... Differentiation means, 1
0 '... multiplying means, 11 ... mechanical loss torque function generating means,
12 ... Acceleration / deceleration torque measuring means.

Claims (1)

Claim: What is claimed is: 1. A speed control device for an electric motor, comprising: controlling a torque of the electric motor using a torque reference output from a speed control amplifier in response to a deviation between the speed reference and an actual speed of the electric motor; Mechanical loss torque generating means for measuring and storing mechanical loss torque from the output of the speed control amplifier while varying the speed reference in advance, and acceleration / deceleration torque measuring means for acquiring the acceleration / deceleration torque multiple by previously taking in the rate of change of the speed reference. And, during the speed control of the electric motor, the mechanical loss torque with respect to the speed reference generated from the mechanical loss torque generating means and the acceleration / deceleration torque obtained by multiplying the rate of change of the speed reference by the acceleration / deceleration torque multiple. And an acceleration / deceleration compensating means for controlling the torque of the electric motor by applying the speed of the electric motor to the speed of the electric motor. The control device.