模型中明显地体现出模型设计主要有电流调节器和转速调节器两个负反馈闭环组成，
把转速调节器的输出当成电流调节器的输入，在通过电流调节器的输出控制后面的电路。
在这里电流环为内环，电压环为外环，所以形成了转速电流双闭环控制的直流调速系统。(The model obviously shows that the design of the model mainly consists of two negative feedback loops: current regulator and speed regulator,

Take the output of the speed regulator as the input of the current regulator, and control the circuit behind it through the output of the current regulator.

Here, the current loop is the inner loop and the voltage loop is the outer loop, so a DC speed regulation system with speed current double closed loop control is formed.)