Method and device for limiting DC bus current of DC brushless motor

Abstract

The invention provides a DC bus current limiting method and device for a DC brushless motor. The method includes calculating the modulus length of the expected output voltage vector according to the expected output direct-axis voltage and quadrature-axis voltage; according to the preset DC bus current To limit and actual bus current, adjust the modulus length of the limited output voltage vector through PI controller; according to the relationship between the modulus length of the expected output voltage vector and the modulus length of the limited output voltage vector, determine the voltage limit coefficient, and use the voltage limit coefficient Limit the output direct-axis voltage and quadrature-axis voltage. According to the principle of conservation of input power and output power of the controller, when other parameters remain unchanged, the direct-axis voltage and the quadrature-axis voltage are positively correlated with the DC bus current. Limiting the direct-axis voltage and the quadrature-axis voltage can indirectly limit the DC bus current, and then It realizes that the DC bus current can be limited under any working condition.

Description

technical field [0001] The present invention relates to the field of DC brushless motors, more specifically, to a method and device for limiting the DC bus current of DC brushless motors. Background technique [0002] Brushless DC motors include DC power supplies, controllers and motors, such as figure 1 shown. The DC power supply outputs DC power to the controller through positive and negative wires, and the current flowing through these two wires is the DC bus current of the brushless DC motor. The three-phase interfaces a, b, and c of the controller are connected to the phase lines of the motor through wires, and the current flowing through these three wires is the phase current of the DC brushless motor. When the DC bus current is too large, it will cause abnormal failures such as burnout of the internal devices of the controller due to overcurrent. Therefore, a solution to limit the DC bus current is urgently needed. Contents of the invention [0003] In view of th...

AI Technical Summary

Problems solved by technology

When the DC bus current is too large, it will cause abnormal faults such as burning of the internal devices of the controller due to overcurrent. Therefore, a solution to limit the DC bus current is urgently needed.

Images