1)  twin inverter-motor reciprocal power fed test system

2)  doubly-fed induction generation system

3)  doubly-fed induction generator

1.
Based on comparative analysis of several wind farm models for power flow calculation,an improved model of wind farm with the variable speed constant frequency doubly-fed induction generator is proposed.

2.
In this paper,the authors compare the difference between an asynchronous generator and doubly-fed induction generator,and according to the steady state mathematical model of this two kinds of generators,the authors put forward methods which can be used to deal with wind farms in power flow calculation.

3.
The mathematical model of doubly-fed induction generator was analyzed and established.

4)  doubly-fed induction generator (DFIG)

1.
By means of detailed analysis on both reactive power limit of doubly-fed induction generator (DFIG) and impact of stator output reactive power on generator loss,two methods to determine reactive power reference value of DFIG set are proposed.

5)  doubly fed induction generator

6)  doubly-fed asynchronous machine

1.
Based on the theory of vector control and automatic control system,the vector control system of current model for doubly-fed asynchronous machine with field-oriented rotor was established.

 异步电机asynchronous machine   利用气隙旋转磁场与转子绕组中的感应电流相互作用产生电磁转矩，从而实现能量转换的交流电机。主要作电动机用。异步电机的转子实际转速总是低于（作电动机运行）或高于（作发电机运行）旋转磁场的转速，两者始终存在一定差异，故称异步。异步是这种电机产生电磁转矩的必要条件。由于转子绕组电流是感应而生的，所以异步电机也称为感应电机。如果旋转磁场和转子的转速分别为ns和n  ，则异步电机的转差率s为      它代表转子导体与旋转磁场之间的相对运动速度。在电源电压和频率一定的条件下，转子导体中的电动势、电流及异步电机的运行状态都由转差率决定  。当转差率s不同时，异步电机有3种不同的运行状态：   0＜s≤1，nS＞n≥0 电动机运行   s＜0，n＞nS 发电机运行    s＞1，n＜0 反接制动运行