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motor control system

A technology of motor control and control devices, applied in the direction of power factor control, etc., can solve problems such as inability to synchronize, decrease in motor power factor, and decrease in electromagnetic torque, so as to improve safety and operability, increase power factor, and increase load rate effect

Inactive Publication Date: 2016-06-15
DONGYING LINGTONG PETROLEUM MACHINERY MFG IND
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the speed of the asynchronous motor is not equal to the synchronous speed. The two speeds cannot be synchronized, and the motor speed is smaller than the synchronous speed. The ratio of the difference between the synchronous speed and the motor speed to the synchronous speed is the slip of the motor. Due to the resistance and reactance of the rotor winding Basically unchanged, the rotor current and the power factor of the rotor circuit both decrease with the decrease of the slip rate, and the power factor gradually increases when the slip rate increases gradually. When the load exceeds the rated value by a lot, the slip rate is too large, and the electromagnetic Torque drops until stalled
In practical applications, when starting and other factors are considered to be used with mechanical equipment, it is usually selected at 50-80% of the rated load of the motor, leaving a certain amount of redundancy, and the equipment cannot reach the design power in actual work, such as oil pumping. Machines, ball mills, etc., the long-term light-load operation of the motor will further reduce the power factor of the motor
[0004] Therefore, the power factor of both motors is not high

Method used

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Examples

Experimental program
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Effect test

Embodiment 1

[0044] Embodiment 1 of the present invention provides a motor control system, such as figure 1 As shown, it includes a current acquisition device 1, a control device 2, a wiring conversion device 3 and a resistor 4;

[0045] Both the acquisition device and the wiring conversion device 3 are connected to the control device 2;

[0046] The current collection device 1 is used for: collecting and sending the current information of the motor;

[0047] The control device 2 is used to: send a first control signal when the motor starts; receive the current information, and send a second control signal after confirming that the current of the motor is within its rated current range;

[0048] The wiring conversion device 3 is used to: receive the first control signal and form a closed loop between the rotor of the motor and the resistor 4; receive the second control signal and form a closed loop between the rotor of the motor and the power supply.

[0049] When the wiring conversion d...

Embodiment 2

[0052] Embodiment 2 of the present invention provides another motor control system, such as figure 2 As shown, it includes a current acquisition device 1, a voltage acquisition device, a control device 2, a wiring conversion device 3, a load ratio adjustment device 7 and a resistor 4;

[0053] The current collection device 1, the voltage collection device and the wiring conversion device 3 are all connected to the control device 2;

[0054] The current collection device 1 is used for: collecting and sending the current information of the motor;

[0055]The voltage acquisition device is used to: collect and send the voltage information of the motor;

[0056] The control device 2 is used to: send a first control signal when the motor starts; receive the current information and voltage information, and send a second control signal after confirming that the current of the motor is within its rated current range; analyzing the voltage information and generating a third control s...

Embodiment 3

[0063] Embodiment 3 of the present invention provides a motor control method, such as image 3 shown, including the following steps:

[0064] 301) forming a closed loop between the rotor of the motor and the resistor when the motor is started;

[0065] 302) collecting the current information of the motor;

[0066] 303) After confirming that the current of the motor is within its rated current range, form a closed loop between the rotor of the motor and the power supply.

[0067] When the wiring conversion device makes the rotor and the resistor form a closed loop, the rotor itself is not powered, and only the stator is powered. At this time, the motor is equivalent to an asynchronous motor, and the rotor induces the magnetic field of the stator and generates an induced current in a closed loop, thereby causing the rotor to drive the load to rotate. During the starting phase of the motor, the current is usually 3 times the rated current, and the current will drop rapidly whe...

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PUM

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Abstract

The invention relates to an electrical device, in particular to a motor control system and method. The motor control system comprises a current acquiring device, a control device, a wiring conversion device and a resistor. The current acquiring device and the wiring conversion device are connected with the control device. The current acquiring device is used for acquiring current of a motor. The control device is used for sending a first control signal during starting and sending a second control signal after the current of the motor is ensured to be in a rated current range. The wiring conversion device is used for receiving the first control signal and then enabling a rotor of the motor and the resistor to form a closed loop and receiving the second control signal and then enabling the rotor of the motor and a power supply to form a closed loop. The motor control method comprises the steps of enabling the rotor of the motor and the resistor to form the closed loop during motor starting, acquiring current information of the motor and enabling the rotor and the power supply to form the closed loop after the current is ensured to be in the rated current range. The motor control system and method can enable the power factors of the motor to be high.

Description

technical field [0001] The invention relates to power equipment, in particular to a motor control system and method. Background technique [0002] The motor is the main driving force of national production, and the annual power consumption accounts for 65% to 70% of the country's total power generation. There are generally two types of motors: synchronous motors and asynchronous motors. Both the rotor and the stator of the synchronous motor are energized, so they have the same power, so that the rotor and the stator rotate synchronously. The power factor of the synchronous motor is generally higher than that of the asynchronous motor, but the torque of this motor is small, and it cannot drive a large load at the start, and the load that can be driven at the start will fail due to the load being too small after reaching a stable rotation. resulting in low power factor. [0003] However, there is no direct electrical connection between the stator and rotor of an asynchronou...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02P23/26
Inventor 刘广东钟克新陈来平钟维军李婧菲
Owner DONGYING LINGTONG PETROLEUM MACHINERY MFG IND