L6472参数设置和步进速度之间的关系是什么？

嗨，


我是L6472的新手，通过阅读其数据表，我认为这将非常适合我的应用，它需要驱动NEMA34电机以相对较高的速度（例如每秒12转）。
我一直在阅读与L6472有关的AN4158并感到困惑
那里的一些概念，有人可以帮忙解释一下吗？

谢谢！

山姆

*）目标切换时间的概念（它设置控制系统的目标PWM频率）对我来说不清楚，这个参数和步进速度（或步进周期）之间的关系是什么？ （或者这两个参数之间是否有任何关系？）
为什么拥有固定的PWM频率更好？这个PWM频率是否与在微步模式下产生微步相电流的PWM相同？
*）它似乎使自动调整衰减和预测电流控制工作，需要正确设置6个参数：TOFF_MIN，TON_MIN，TOFF，TOFF_FAST，FAST_STEP，TSW。我不清楚这六个变量应该如何正确设置，是否有人应该为这些变量/参数设置值（或值范围）的分析步骤的概念示例？
＃l6472



以下为原文




Hi,


I'm new to L6472 here, and from reading its datasheet, I think it would be a perfect fit to my application which will need to drive a NEMA34 motor to go relative high speed (such as 12 rotations per sec.).   
I've been reading AN4158 which is related to L6472 and am puzzled by  
some of the concepts there, could someone help explain?  

thanks!

Sam

*) The concept of target switching time (it sets the target PWM frequency of the control system) is not clear to me,?what's the relationship between this parameter and the step speed (or step period)? (or is there any relationship between these two parameters?)
And why it's better to have a fixed PWM frequency? is this PWM frequency the same PWM that creates the microstepped phase currents in microstep mode?  
*) it seems to make auto adjusted decay and predictive current control work, 6 parameters need to be set properly: TOFF_MIN, TON_MIN, TOFF, TOFF_FAST, FAST_STEP, TSW. It was not clear to me how these six variables shall be set properly, is there any concete example of the analytical steps someone should take to set values (or a value range) for these variables/parameters?  
#l6472