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Motor drive system, motor control method and electric conversion device

A technology of power conversion device and drive system, which is applied in the direction of AC motor control, estimation/correction of motor parameters, control system, etc. It can solve the problems of expensive speed sensor and control without considering the life of the motor, so as to suppress faults and improve Effects on maintainability and reliability

Active Publication Date: 2016-08-31
HITACHI IND PROD LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The speed sensor that can be used in such a severe environment is generally expensive, and the installation work of the sensor is also required
[0010] In addition, in the prior art described in Patent Document 1 and Patent Document 2, when an abnormal state of the motor or the motor control device is detected, the motor is only stopped urgently to ensure safety, and no consideration is given to prolonging the life of the motor. control

Method used

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  • Motor drive system, motor control method and electric conversion device
  • Motor drive system, motor control method and electric conversion device
  • Motor drive system, motor control method and electric conversion device

Examples

Experimental program
Comparison scheme
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Embodiment 1

[0029] use Figure 1 ~ Figure 3 The first embodiment will be described. figure 1 Indicates the overall structure of the motor drive system.

[0030] The power conversion device 1 drives a motor 3 via a cable 2 . The motor 3 is rotated by the three-phase AC power output from the power conversion device 1 . The cable 2 is, for example, a long cable of 500 meters or more. The electric motor 3 is sometimes used, for example, hundreds of meters to several kilometers underground, and a long cable 2 is used in such a case. When the power conversion device 1 and the motor 3 are separated, it may be difficult to confirm the motor 3 from the power conversion device 1 side.

[0031] The power conversion device 1 is installed, for example, in a building on the ground, and supplies AC power of a predetermined frequency to the electric motor 3 . The value of the predetermined frequency can be appropriately determined. The power conversion device 1 can control the motor 3 using signals...

Embodiment 2

[0066] use Figure 4 A second embodiment will be described. The following examples including this example correspond to modified examples of the first example. The description will focus on differences from the first embodiment. In this embodiment, instead of the average value of the output voltage value applied from the power conversion device 1 to the motor 3 over a predetermined time, the average value of the voltage command value used inside the power conversion device 1 is used for a predetermined time.

[0067] Figure 4 The overall structure of the motor drive system of this embodiment is shown. In the present embodiment, a change in the voltage command value V*, which is an output value of the voltage command calculation unit 13 , is detected by the voltage command change detection unit 17 . The speed command correction unit 12 corrects the speed command based on the signal from the voltage command change detection unit 17 .

[0068] In addition, in this embodimen...

Embodiment 3

[0071] use Figure 5 with Image 6 A third embodiment will be described. In this embodiment, a plurality of frequencies used for detecting signs of abnormality of the motor 3 can be set.

[0072] Figure 5 It is a flowchart showing output control processing executed by the power conversion device 1 of the motor drive system of the present embodiment. The power conversion device 1 determines whether the output frequency is any one of a preset first frequency f1 (Hz) and second frequency f2 (Hz).

[0073] When the power conversion device 1 confirms that it is any one of the monitoring target frequencies f1 and f2 (S10: YES), it calculates the average value of the output voltage at the frequency (S11A). Instead of the average value of output voltages, the average value of voltage command values ​​or the average value of current command values ​​may be calculated.

[0074] In this embodiment, the predetermined time for calculating the average value is changed for each of the ...

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PUM

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Abstract

The present invention provides a motor drive system, a motor control method and an electric conversion device. The state of the motor is determined and the occurrence of motor faults is inhibited by a simple structure. The motor drive system comprises a motor (3) configured to determine the state of the motor and the electric conversion device configured to inhibit the faults of the motor. The electric conversion device (1) outputs alternating voltage in a presetting frequency to the motor so as to drive the motor and determines whether the output voltage is larger than a presetting value or not according to the changing of the output voltage in a presetting time, when the output voltage is larger than the presetting value, it is determined that the abnormality is detected, and the presetting frequency value is reduced.

Description

technical field [0001] The invention relates to a motor drive system, a motor control method and a power conversion device. Background technique [0002] A motor drive system using a power conversion device generally called an inverter generates AC power with a variable frequency and supplies it to the motor, thereby driving the motor at a variable speed. Accordingly, the motor drive system can control the operation of rotating equipment using motors such as fans, pumps, and compressors. [0003] However, an electric motor may be used in a severe environment instead of a normal environment. For example, electric motors used in equipment such as compressors and pumps installed at depths of several hundred meters to several kilometers underground operate in severe environments such as high temperature, high humidity, and corrosive gas atmospheres. In this case, the electric motor and the power conversion device are electrically connected via cables of several hundred meters ...

Claims

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Application Information

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IPC IPC(8): H02P23/14H02P27/08
CPCH02P23/14H02P27/08
Inventor 永田浩一郎片山敏男
Owner HITACHI IND PROD LTD