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Method and device for soft stop control for pump loaded motor

A control method and technology for pump loads, applied in motor generator control, AC motor control, control systems, etc., can solve problems such as pump load surge and pump load, improve stability and solve pump load surge The effect of vibration and descent is stable

Inactive Publication Date: 2010-06-02
YANGZHONG FENGSHUN ELECTRIC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0015] The purpose of the present invention is to provide a soft stop control method and device for pump load motors. The invention controls the phase shift angle of the main circuit to make the motor decline according to a predetermined ideal curve, thereby solving the problem of pump failure during the motor shutdown process. Such loads are likely to cause pump load surge problems

Method used

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  • Method and device for soft stop control for pump loaded motor
  • Method and device for soft stop control for pump loaded motor
  • Method and device for soft stop control for pump loaded motor

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Embodiment 1

[0044] Embodiment 1: In order to solve the above technical problems, a soft stop control method of a pump load motor in the present invention includes the following steps:

[0045] 1.1. After entering the soft stop process, connect the working voltage to the main circuit and then output to the motor;

[0046]1.2. Control the conduction angle of the thyristor of the main circuit according to the predetermined motor voltage drop curve;

[0047] 1.3. Collect the voltage and current output from the main circuit to the motor;

[0048] 1.4. Set the voltage and current according to or Establish a mathematical model to calculate the real-time active power of the motor; for a single-phase AC asynchronous motor, the average active power consumed in one cycle can be defined as:

[0049] P = ∫ t 0 t 0 + ...

Embodiment 2

[0065] Embodiment 2: In the process of reducing the motor speed, due to the inherent characteristics of the asynchronous motor, when the load is large, the peak current of the motor can reach several times of the rated current. This situation is undesirable. Therefore, on the basis of active power closed-loop control, it is also necessary to add current limiting to ensure that the motor current will not exceed the allowable current value during the soft stop process.

[0066] In order to increase the current limiting control, the real-time active power is compared with the predetermined active power, and the current difference between the two is obtained as the predetermined current, which is compared with the motor current obtained by sampling to generate a current error signal, which is used by the current PID regulator This current error signal is used as an input to control the phase shift angle of the main circuit.

[0067] A soft stop control method for a pump load moto...

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Abstract

The invention discloses a method and a device for soft stop control for a pump loaded motor. A soft stop control scheme of active power closed-loop control can be designed by measuring the active power of the motor in real time, the constant power adjustment can be performed by adopting the adjustment for the active power, the predetermined active power produced by a soft stop control rule function is compared with the real-time active power to generate a power error signal, a phase-shifting angle of a main circuit is changed through the error signal so that the active power of the motor is changed according to the set soft stop control rule, and finally the motor is steadily stopped. The method and the device solve the problem that the pump loaded surge is easy to cause during pump loaded soft stop.

Description

technical field [0001] The invention relates to a soft-stop control method and device for a motor, in particular to a soft-stop control method and device for a pump load asynchronous motor, and belongs to the technical field of motor control devices. Background technique [0002] Motors are widely used in metallurgy, chemical industry, construction, mining and other industrial fields. Among them, AC asynchronous motors are the most commonly used, and the motors are back EMF-based loads. When the motor starts, the back electromotive force will gradually increase with the increase of the rotor speed, so the inrush current when the motor starts is very large, so it will cause damage to the load, especially the pump load. Due to the mismatch between the load torque characteristics of the load in the pump system and the torque characteristics of the asynchronous motor, the sudden change in torque caused by the direct start and stop of the motor will cause liquid flow impact, whic...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02P3/18H02P27/02
Inventor 尹祥顺李军民
Owner YANGZHONG FENGSHUN ELECTRIC
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