GCC world PC00054D board

Description

GCC world PC00054D board

也许不足为奇的是，在讨论电机驱动装置之前，必须先简要介绍一下电机本身，解释为什么需要这样的驱动装置。三相电机直接连接到来自电力线的60赫兹电压。当电机达到全速时，电流的交变方向完美地极化了电机外部的绕组，与速度相协调。

如果你总是计划的话，这很有用全速运行电机，但正如你可能猜到的，这种策略有两个主要问题:当电机正在加速时(尚未达到最高速度)，以及当你需要永久低于全速运行时。在这两种情况下，你都需要一个能把交流电流的频率降低到适当数量的装置。

这就是VFD的工作:它通过使用大电流半导体开关来提供目标运行速度，从而降低电机绕组的交变频率。请注意，虽然提供给电机引线的DC总线电压不会改变，但线圈电阻和电感之间的电压分布会发生变化，绕组的视在电压将作为Hz的函数发生变化，从而产生我们在VFD控制策略中常见的V/Hz比。

GCC world PC00054D board

Perhaps not surprising, before discussing the motor drive device, it is necessary to briefly introduce the motor itself and explain why such a drive device is needed. The three-phase motor is directly connected to a 60 Hz voltage from the power line. When the motor reaches full speed, the alternating direction of current perfectly polarizes the external winding of the motor, coordinating with the speed.

If you always plan, this is useful for running the motor at full speed, but as you may guess, this strategy has two main issues: when the motor is accelerating (not yet reaching maximum speed), and when you need to run permanently below full speed. In both cases, you need a device that can reduce the frequency of AC current to an appropriate amount.

This is the job of VFD: it provides the target operating speed by using high current semiconductor switches, thereby reducing the alternating frequency of the motor winding. Please note that although the DC bus voltage provided to the motor leads will not change, the voltage distribution between the coil resistance and inductance will change, and the apparent voltage of the winding will change as a function of Hz, resulting in the V/Hz ratio commonly seen in VFD control strategies.