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A method for boosting energy storage control of a brushless DC motor system

A technology of brush DC motor and energy storage control, which is applied in the direction of electronic commutation motor control, single motor speed/torque control, control system, etc., to achieve the effect of reducing size, enhancing stability and improving utilization rate

Active Publication Date: 2022-05-10
TIANJIN POLYTECHNIC UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, no literature has proposed a control method that directly stores more energy for the DC link capacitor by increasing the DC link capacitor voltage.

Method used

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  • A method for boosting energy storage control of a brushless DC motor system
  • A method for boosting energy storage control of a brushless DC motor system
  • A method for boosting energy storage control of a brushless DC motor system

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] In this embodiment, the brushless DC motor adopts the three-phase six-step two-to-two conduction commutation operation mode. One electrical cycle includes six commutation cycles, and only two phase windings are energized in each commutation cycle. In this embodiment, a Take the phase commutation cycle of positive conduction and b-phase negative conduction as an example. figure 1 u in the equivalent circuit diagram shown d_link is the DC link voltage, T, T 1 -T 6 For IGBT, D, D 1 -D 6 is the freewheeling diode connected in antiparallel to the IGBT, C is the film capacitance on the DC link, L and R are the phase inductance and phase resistance of the motor, respectively, e a 、e b 、e c are the opposite electromotive forces, N is the neutral point of the motor, and O is the reference zero point of the DC link voltage.

[0031] figure 1 The DC link involved in the present invention is composed of a DC link capacitor C and a DC link switch tube T connected in series, ...

Embodiment 2

[0077] When the brushless DC motor is running in non-rated conditions, the duty cycle d(n) and capacitor voltage U cap (n) will change accordingly. Therefore, an embodiment analysis is carried out on a brushless DC motor operating under a non-rated working condition.

[0078] To verify the capacitor voltage U cap The influence of the change of the duty cycle d, according to the functional relationship of formula (11), the duty cycle d has a great influence on the capacitor voltage U cap Find the derivative:

[0079]

[0080] From equation (18), it can be seen that in region 2, the duty cycle d will increase with the DC link voltage U cap The increase increases, when n takes the maximum value U cap reaches the maximum U cm . Since each control cycle U cap unknown, assuming that U cap reach the maximum U cm , put U cm Bringing into formula (11), the maximum value of the duty cycle of each cycle can be obtained as:

[0081]

[0082] Then in region 2, satisfy:

...

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Abstract

A boosting energy storage control method for a brushless DC motor system, which is used in the rectification stage using a single-phase diode rectifier bridge, the inverter stage using a three-phase inverter bridge, and the DC link using a DC link switch tube and a DC link capacitor Control of series topology. Judging the output voltage of the single-phase diode rectifier bridge |u in each control cycle s |The area to which it belongs, when the output voltage of the single-phase diode rectifier bridge |u s |When entering areas 1 and 3, control the three-phase inverter bridge to perform PWM_ON modulation; when the output voltage of the single-phase diode rectifier bridge|u s When entering area 2, use the excess output energy of the diode rectifier bridge in this area to boost the energy storage of the DC link capacitor. In order to realize the boost energy storage, in area 2, a bipolar PWM modulation method is introduced to control the three-phase inverter The variable bridge uses the reverse vector generated by bipolar PWM modulation to realize DC link boost energy storage. The invention makes full use of the output voltage of the single-phase diode rectifier bridge to store more energy for the DC link capacitor.

Description

technical field [0001] The invention relates to a control method of a brushless direct current motor. In particular, it relates to a boosting energy storage control method of a brushless DC motor system using a small capacitor in the DC link. Background technique [0002] Brushless DC motors have the advantages of simple structure, high efficiency, and good reliability, and are widely used in aerospace, robotics, and household appliances. In a brushless DC motor system powered by a single-phase AC power supply, a large-capacity electrolytic capacitor is generally required at the DC link to maintain the stability of the DC link voltage. However, large-capacity electrolytic capacitors are bulky, and their service life is shortened with the increase of operating temperature. Therefore, the existence of large-capacity electrolytic capacitors not only increases the volume and weight of the motor drive system, but also limits its application in extreme temperature environments, ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02P6/08H02M5/458
CPCH02P6/085H02M5/458
Inventor 李新旻袁赫陈炜喻丽红谷鑫周湛清
Owner TIANJIN POLYTECHNIC UNIV