Exploration and Analysis of Brushless Driver Parameter Adjustment Rules

By understanding PID control theory and summarizing long-term manual operation experience, it is known that PID parameters should be adapted to the dynamic process of brushless driver systems based on the following points.

Adjusting Kp and Ki Values：

When the deviation of the brushless driver is large, to quickly eliminate the deviation and improve response speed while avoiding system response overshoot, Kp should be set to a large value and Ki to zero. When the deviation is small, to further reduce the deviation and prevent excessive overshoot, oscillation, and degradation of stability, the value of Kp should be reduced, and Ki should be set to a small value. When the deviation is very small, to eliminate static errors, overcome overshoot, and stabilize the system quickly, the value of Kp should be further reduced, and the value of Ki should remain unchanged or slightly increased.

Consideration of Deviation and Deviation Rate:

When the deviation and deviation rate have the same sign, the controlled quantity changes in the direction away from the set value. Therefore, when the controlled quantity is close to the set value, the opposite effect of the proportional action impedes the integral action, avoiding integral overshoot and the accompanying oscillation, which is beneficial for control. When the controlled quantity is far from the set value and changing toward it, the two effects oppose each other, slowing down the control process. When the deviation is large and the deviation rate is opposite, the value of Kp is set to zero or negative to accelerate the dynamic process of control.

Significance of Deviation Rate:

The magnitude of the deviation rate of the brushless driver indicates the rate of deviation change. The larger the ek-ek-1, the smaller the value of Kp and the larger the value of Ki, and vice versa. At the same time, the size of the deviation should be considered.

Role of Differential Action:

The differential action can improve the dynamic characteristics of the system, prevent deviation changes, reduce overshoot, eliminate oscillation, shorten the adjustment time ts, allow an increase in Kp, reduce the steady-state error of the system, improve control accuracy, and achieve satisfactory control effects. Therefore, when ek is relatively large, Kd is set to zero for PI control; when ek is relatively small, Kd is set to a positive value for PID control of the brushless driver.

In summary, understanding these adjustment rules for PID parameters enables effective control of brushless driver systems, optimizing their performance in various applications.

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