麦克斯韦2D RMxprt中自动生成的转矩

在RMxprt中创建的电机模型，当在Motion Setuo中的 Machanical中勾选Consider Mechanical Transient时，在Load Torque中会出现一串默认的 if 语句。句式如下：if（条件，A，B），即当满足条件时执行A，不满足条件时执行B。

然而，通过右手定则可以发现，软件中的Load Torque 其实并不是真正意义的负载转矩，其实际意义应为驱动转矩，因为正扭矩是在正速度方向上定义的。因此，必须用负值定义实际负载转矩。

即：Tload=–Pspec/speed

其中speed是实际转子角速度，rad/s；Pspec是一个恒定值。

为了将该负载扭矩曲线应用于任何初始速度，采用RMxprt创建的模型中采用的负载扭矩曲线定义为：

Tload=if（speed<N0/2，-4*Pspec/N0/N0*speed，-Pspec/speed）

其中N0是同步电机的同步速度，或其他电机类型的额定速度，rad/s。

以上负载转矩适用于除同步电机外的任何电机。对于同步电机，官方给出的帮助文件如下：

For synchronous motors, the motor driving torque varies with torque angle which is the difference between the phase angles of the applied and the induced voltages. If the initial speed is set as the synchronous speed, and the initial torque angle is set smaller than the real value, the motor driving torque will be smaller than the specified load torque. With mechanical transient, the speed will decrease, which makes the torque angle and driving torque increase. When the driving torque equals the load torque, the speed, which is lower than the synchronous speed, will stay constant temporarily. Since the speed is lower than the synchronous speed, the torque angle continues to increase, which makes the driving torque greater than the load torque, and therefore the speed increases. When the speed reaches the synchronous speed, the torque angle will be too large, which will increase the speed to exceed the synchronous speed. Therefore, the speed will oscillate about the synchronous speed. This oscillation will decay to zero if the synchronous motor has a damper cage winding. The decaying time depends on the strength of the damping effects. In order to speed up the decaying process, an additional load torque component to model the damping effects around the synchronous speed is set for all types of synchronous motors, asexpressed below:

Tdamp = - Tst * (speed/N0 - 1)

where Tst is set as the rated torque. You may increase Tst to increase the damping effects. The damping torque curve is shown below

虽然但是，这个转矩位置的值有没有可能设置一个接口读取外部数据呢？

：

The transient motion simulator generates rotational motion solutions based on the following motion equation: 

where: 

 J is the moment of inertia, in kg.m2. 

Tem is the computed electromagnetic torque, in N.m. 

Tload is the external load torque, in N.m. 

ω is the angular speed, in rad/s. 

β is the angular acceleration, in rad/s2. 

λ is the damping factor, in N.m.s.