JPH0314957Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a control device for an electric motor exciter, and in particular, even if the speed ratio between the motor shaft and the moment axis is changed, the set excitation frequency and the actually generated frequency match. The present invention relates to a control device configured as described above.

In an electric motor-type exciter, the excitation frequency is set by the speed setting device on the motor shaft, so if the speed ratio of the motor shaft and moment shaft can be varied using a pulley or gear, the speed The excitation frequency set by the setting device, that is, the excitation frequency setting device, and the frequency actually generated no longer match.

This can be explained using the synchronous motor type 4 shown in Figures 1 and 2.
This will be explained in detail using a shaft exciter as an example. In the figure, 1
a to 1d are synchronous motors, 2a to 2d are motor shafts,
3a to 3d are moments, 4a to 4d are moment axes, 5a to 5d are belts, 6a to 6d and 7a
7d is a pulley, and 8 is a bearing. In a synchronous motor-type four-axis exciter, the magnitude of the moments 3a to 3d and the rotation speed of the moment axes 4a to 4d are adjusted so that the maximum excitation force can be generated from a low frequency of about 0.3 Hz to a high frequency of about 30 Hz. It has a structure that allows for gradual changes. However, when setting a large moment with low frequency excitation, the synchronous motor 1
The motors a to 1d must be operated at low rotation speed and high torque, but this is a difficult area to use due to the characteristics of the synchronous motor. Therefore, normally the motor shafts 2a to 2d
The synchronous motors 1a to 1d are used at high rotation speeds by increasing the pulley ratio of the moment shafts 4a to 4d. However, as mentioned above, the excitation frequency is set using the speed setting device on the motor shaft, so if the pulley ratio is changed, the excitation frequency setting value on the operation panel may differ from the actual excitation frequency. The frequencies no longer matched, making it extremely difficult to use.

In view of the problems of the prior art described above, the present invention aims to provide a control device for an electric motor exciter in which the set value of the excitation frequency matches the actual excitation frequency even if the pulley ratio and gear ratio are changed. purpose. Below, the third
The present invention will be explained based on FIG.

FIG. 3 shows an embodiment of the control device of the present invention.
In the figure, 10 is a 3-digit decimal digital excitation frequency setter, 11 is a signal output circuit for the excitation frequency setter 10, and 12 is a decimal system that converts decimal to binary.
A binary conversion circuit, 13 a digital pulley ratio setter, 14 a digital memory using two read-only memory (ROM) ICs, and 15 a memory 1
16 is a read command signal for each memory 14.
A buffer circuit 17 amplifies the IC output, and a speed control circuit inputs the output of the buffer circuit 15 as a speed setting value to control the motor of the exciter.

In the embodiment shown in FIG. 3, the desired excitation frequency is set in decimal form by turning on/off switches for each digit of the setting device 10, and this set value is determined by the output circuit 11.
The data is input as decimal digital data to the conversion circuit 12, where it is converted to binary data. On the other hand, the pulley ratio setting device 13 uses 1:1, 1:4, . . . each time the pulley ratio between the motor shaft and the moment shaft is selected.
For example, pulley ratios such as ``00'', ``11'', and
Binary data like... is output. These two types of binary data are given to the memory 14 as address signals. Data obtained by multiplying the excitation frequency by various pulley ratios is preprogrammed in the memory 14, and when binary data of the set excitation frequency and binary data of the pulley ratio are given, the set excitation frequency is multiplied by various pulley ratios. Multiply the vibration frequency by the selected pulley ratio to get 10
Data of 4 decimal digits is read. This data is amplified by a buffer circuit 16 and given to a speed control circuit 17 as a speed setting value.

As a result, the motor shaft rotates at a rotational speed that takes the pulley ratio into consideration, and the set value of the excitation frequency and the actual excitation frequency always match even if the pulley ratio is changed. Figure 4 shows the setting value of the excitation frequency and memory 1.
An example of the relationship with the output of 4, that is, the rotation speed of the motor shaft, is shown, and in addition to obtaining arbitrary data corresponding to the pulley ratio, such as the characteristics of a and the characteristics of b, by using the program.
It is also possible to set limits on the set value, such as in the characteristics of Furthermore, simply by increasing the capacity of the memory 14, the setting range of the excitation frequency, that is, the number of digits, can be easily expanded.

[Brief explanation of drawings]

Fig. 1 is a block diagram conceptually showing a synchronous motor type four-axis exciter, Fig. 2 is an explanatory diagram showing the relationship between the motor and moment, and Fig. 3 is a block diagram showing an embodiment of the present invention. , FIG. 4 is a graph showing an example of the relationship between the set value of the excitation frequency and the rotational speed of the motor shaft. In the drawings, 1a to 1d are synchronous motors, 2a to 2d
is the motor shaft, 3a to 3d are moments, and 4a to 4
d is a moment axis, 6a to 6d and 7a to 7d are pulleys, 10 is a decimal digital excitation frequency setter, 12 is a decimal-to-binary conversion circuit, 13 is a pulley ratio setter, 14 is a memory, 16 is a buffer circuit, 1
7 is a speed control circuit.

Claims (1)

[Scope of utility model registration request] In a control device for an electric motor type exciter in which the speed ratio between the motor shaft and the moment axis is variable, an excitation frequency setter, a converter that converts the output of this excitation frequency setter into binary data, and a selected speed A speed ratio setter that outputs the ratio as binary data and data obtained by multiplying the excitation frequency by the speed ratio are preprogrammed.
A memory that outputs digital data of a value obtained by multiplying a set excitation frequency by a selected speed ratio by receiving binary data from the converter and speed ratio setter as an address signal, and a memory that outputs digital data of a value obtained by multiplying the set excitation frequency by the selected speed ratio; 1. A control device for a motor-type exciter, comprising: a speed control circuit that controls the motor by inputting it as a set value.