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Current control method for brushless direct current motor

A brushed DC motor and current control technology, which is applied in the direction of current controllers, etc., can solve the problems of DC side capacitance reduction, DC side capacitance reduction, etc., and achieve improved reliability, reduced volume and weight, and good current regulation effect of ability

Active Publication Date: 2017-03-29
TIANJIN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

If the energy of the AC power supply can be utilized, the energy stored in the DC side capacitor can be reduced, and the DC side capacitance may be further reduced

Method used

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  • Current control method for brushless direct current motor
  • Current control method for brushless direct current motor
  • Current control method for brushless direct current motor

Examples

Experimental program
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Effect test

Embodiment 1

[0034] In the embodiment of the present invention, in the area where the output voltage of the diode rectifier bridge cannot meet the voltage required for the normal operation of the brushless DC motor, the brushless DC motor is powered alternately by the small capacitor and the diode rectifier bridge through chopping of the switch tube on the DC side , in order to maintain the continuity and stability of the brushless DC motor current, the design steps of the control strategy are as follows:

[0035] 101: In the area where the output voltage of the diode rectifier bridge can maintain the continuous and stable current of the brushless DC motor, the duty cycle of the switch tube of the three-phase inverter bridge conducting two phases is determined by the output of the PI current controller;

[0036] 102: When the voltage output by the rectifier bridge is equal to the E+RI required for motor operation, cut in the small capacitor on the DC side;

[0037] Among them, E is the lin...

Embodiment 2

[0055] The scheme in Embodiment 1 is described in detail below in conjunction with specific accompanying drawings and calculation formulas, see the following description for details:

[0056] The brushless DC motor system that the embodiment of the present invention aims at is as figure 1 as shown, figure 1 The series structure of small capacitors and IGBTs is used to replace the large capacitors on the DC side. When the brushless DC motor is in normal operation, the average line voltage required to conduct the two phases is E+RI. E is the magnitude of the line back EMF that conducts the two phases, that is, E=e a -e b ; I is the steady-state current value of the brushless DC motor; R is the line resistance, that is, R=2R s .

[0057] The schematic diagram of the current control strategy proposed by the embodiment of the present invention is as follows figure 2 shown. The control strategy mainly includes: a speed controller, a current controller, a small capacitor cut-...

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Abstract

The invention discloses a current control method for a brushless direct current motor. The current control method comprises the steps of enabling a diode rectifying bridge to supply power for the brushless direct current motor in a region where current continuity and stability of the brushless direct current motor can be maintained by the output voltage of the diode rectifying bridge; when the output voltage of the rectifying bridge is equal to a voltage required in the operation of the motor, switching in a direct current side small capacitor; after the small capacitor is switched in, when the capacitor voltage is greater than a motor rated voltage, calculating a direct current side switching tube duty ratio when a direct current side average voltage is maintained at the motor rated voltage according to the output voltage of the diode rectifying bridge and the capacitor voltage; when the voltage capacitor is lower than the motor rated voltage, and the direct current side switching tube duty ratio is 1, maintaining the direct current side input voltage to be the motor rated voltage as far as possible; obtaining the switching-out moment of the small capacitor according to the switching-in moment and the duration in the region; and calculating the magnitude of the direct current side capacitance from the energy aspect. By adoption of the current control method, the direct current side capacitance is reduced while the reliability of the system is improved.

Description

technical field [0001] The invention relates to the technical field of brushless direct current motor control, in particular to a current control strategy of a brushless direct current motor system with a small capacitor on the direct current side. Background technique [0002] Brushless DC motors are widely used in industry due to their simple structure, reliable operation and low maintenance cost. It is very common in brushless DC motor systems to connect a large electrolytic capacitor in parallel to the DC side to maintain a constant voltage on the DC side. However, the existence of large electrolytic capacitors not only increases the volume and weight of the brushless DC motor system, but also limits its application in extreme temperature environments and reduces the reliability of the brushless DC motor system. Therefore, it is very necessary to study the brushless DC motor system with small capacitor or no capacitor on the DC side. [0003] H.K.Samitha Ransara and U....

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02P6/28
Inventor 夏长亮李佩芬李新旻陈炜史婷娜
Owner TIANJIN UNIV