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An active damping method for a buck circuit brushless DC motor control system

A brushed DC motor and control system technology, applied in the direction of DC motor speed/torque control, control system, electrical components, etc., can solve the problems of capacitor boost, unstable motor phase current waveform, etc. Damping effect, the effect of suppressing system resonance

Active Publication Date: 2018-01-16
SUZHOU SEIDAL INTELLIGENT TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] However, when the value of the Buck capacitor is small, there will be a phenomenon that the capacitor boosts the voltage during the commutation of the brushless DC motor.
And during the commutation period of the motor, the inductor current is considered constant, which is equivalent to the parallel connection of the current source Buck capacitor and the motor impedance to the constant current source. When the motor impedance is fixed and small, it will cause strong current resonance, making the motor phase current waveform unstable.

Method used

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  • An active damping method for a buck circuit brushless DC motor control system
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  • An active damping method for a buck circuit brushless DC motor control system

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0074] Example 1: Buck capacitors connected in parallel with virtual resistors

[0075] (1) Figure 5 is the equivalent circuit diagram after adding the damping resistor. Such as Figure 5 As shown, the inductor current keeps constant at the moment of commutation of the motor, which can be regarded as a constant current source, and its current value is i L . Capacitance C f It is connected in parallel with the motor phase winding at both ends of the inductance, r m is the motor phase resistance, L m is the motor phase inductance. R is the resistance value of the added virtual resistance, which is equivalently connected in parallel at both ends of the capacitor. according to Figure 5 , write the circuit equation in the complex frequency domain as follows:

[0076]

[0077] i R (s).R=u cf (s)

[0078] i phase (s).(L m s+r m ) = u cf (s)

[0079] i Lfed (s)=i cf (s)+i R (s)+i phase (s)

[0080] In the formula, i cf (s) is the capacitive current in the c...

Embodiment 2

[0092] Example 2: Buck capacitor in series with virtual resistor

[0093] (1) Figure 9 is the equivalent circuit diagram after adding the damping resistor. Such as Figure 9 As shown, the inductor current keeps constant at the moment of commutation of the motor, which can be regarded as a constant current source, and its current value is i L . Capacitance C f It is connected in parallel with the motor phase winding at both ends of the inductance, r m is the motor phase resistance, L m is the motor phase inductance. R is the resistance value of the added virtual resistance, which is equivalently connected in series with the capacitor branch. according to Figure 9 , write the circuit equation in the complex frequency domain as follows:

[0094]

[0095] i phase (L m s+r m ) = u cf

[0096] i Lfed = i cf + i phase

[0097] In the formula, i cf (s) is the capacitive current in the complex frequency domain;

[0098] R is the resistance value of the resistor...

Embodiment 3

[0107] Embodiment 3: Inverter bus bar series virtual resistance

[0108] (1) Figure 13 is the equivalent circuit diagram after adding the damping resistor. Such as Figure 13 As shown, the inductor current keeps constant at the moment of commutation of the motor, which can be regarded as a constant current source, and its current value is i L . Capacitance C f It is connected in parallel with the motor phase winding at both ends of the inductance, r m is the motor phase resistance, L m is the motor phase inductance. R is the resistance value of the added virtual resistance, which is equivalently connected in series on the inverter bus branch. according to Figure 13 , write the circuit equation in the complex frequency domain as follows:

[0109]

[0110] i bus (L m s+r m ) = u cf

[0111] i Lfed = i cf + i bus

[0112] In the formula, i cf (s) is the capacitive current in the complex frequency domain;

[0113] R is the resistance value of the resistor ...

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Abstract

The invention discloses an active damping method for a Buck circuit brushless DC motor control system. The method has three implementation modes, which are Buck capacitor parallel connection virtual resistance, Buck capacitor series virtual resistance, and inverter bus bar series virtual resistance; The system adopts double closed-loop control of speed and current. The outer loop is the speed loop, which is controlled by a PI regulator; the inner loop is the current loop. In order to make the inductor current better follow the given value, the current inner loop adopts single-cycle control; When the value is small, this method can increase the damping of the control system, and can quickly stabilize the output voltage of the Buck bus during the commutation period, so that the motor phase current can quickly return to the steady state value during the commutation period, and suppress the current resonance. The invention realizes the damping effect through the control algorithm of the system, effectively increases the system damping, suppresses the resonance of the phase current of the motor, and improves the stability of the control system without increasing the system loss.

Description

technical field [0001] The invention relates to an active damping method for a Buck circuit brushless DC motor control system, belonging to the field of DC converter-motor drive. Background technique [0002] The rotor of the brushless DC motor is excited by permanent magnet materials. Due to its small size, high power density, strong dynamic adaptability, and easy control, it has been widely used in various fields of production and life. However, the speed regulation range of brushless DC motors under various traditional PWM control methods is limited by the frequency of the switching tube of the inverter, and high-frequency PWM chopping will greatly increase the switching loss. [0003] With the development of power electronics technology, Buck circuit is more and more used in the occasion of motor speed regulation. The output voltage of the Buck circuit can be adjusted by controlling the duty cycle of the switching tube, which is very suitable for some occasions that req...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02P7/288
Inventor 单涛王晓琳倪拓成
Owner SUZHOU SEIDAL INTELLIGENT TECH CO LTD