自励异步发电机负载对端电压和频率的影响

从异步发电机稳态运行的等效电路数学模型出发，推导了回路阻抗方程，令回路阻抗值为零，作为异步发电机稳定运行的条件。利用变量轮换直接优化方法计算励磁电抗和定子频率，进而计算出不同负载下的端电压值。此法稳定性好且编程简单。给出了异步发电机的端电压和定子频率随负载变化的曲线以及外特性曲线。计算结果说明负载对异步发电机的端电压影响较大，而对定子频率影响较小，且影响随负载性质改变而不同。计算结果与实验结果的一致性说明了分析方法的准确性。

Effect of the Load on Terminal Voltage and Frequency of a Self-excited Asynchronous Generator

Based on the steady-state equivalent circuit of a self-excited asynchronous generator referred to the base frequency, the loop impedance is derived. Equating the loop impedance to zero is the prerequisite for predicting the steady-state performance of the asynchronous generator. As a direct search optimization method, variable-shifting method that is of the advantages in stability and feasibility is utilized to calculate the magnetizing reactance and stator frequency, thus determining the terminal voltages under different loads. The variations of terminal voltage and stator frequency with the load impedance and the load current are given out. The computed results indicate that the terminal voltage is affected by the loads greatly while the stator frequency is not so sensitive to them. The phenomenon that different kinds of loads have different influences on the voltage and frequency is also shown. The agreement between the calculated results and the experimental results verifies the accuracy of the presented method.