自激异步发电机变速恒压运行时电容值的计算

为保证自励异步发电机在转速和负载改变时能稳态恒压运行,采用改变机端电容值的措施,并给出了机端电容值的计算方法。以异步发电机带阻感负载稳态运行时的等值电路为基础,推导了回路阻抗方程,依据异步发电机稳态运行时同路阻抗为零这一必要条件,选择同路阻抗绝对值为目标函数,把端电压作为优化约束条件,利用单纯形法计算了不同转速和负载下的机端电容值,克服了传统方法不能处理有约束问题的弱点,计算值与实验值的一致证明了方法的有效性。此法亦可用来计算并联补偿电容值。论文还给出了恒定负载时机端电容值与转速的关系曲线,说明异步发电机恒压运行时存在临界转速。

Capacitance Requirement for Constant Voltage Operation of Induction Self-excited Generator under Variable Speeds

To keep the self-excited induction generator operating steadily at constant voltage under variable speeds and different loads,the paper presents an approach of com- puting the terminal capacitance.Based on the steady state equivalent circuit of an induction generator,the loop im- pedance is calculated,from which the terminal capacitance is determined by a direct optimizaed method with constant terminal voltage as the constrained condition.The simplex method is employed to obtain the terminal capacitance, which is advantageous over the traditional methods in deal- ing with constrained problems.That good agreement be- tween the calculated results and the experimental ones from a 2.2kW laboratory machine confirms the validity and ac- curacy of the method.This paper also gives the variation of the terminal capacitance with the speed for the specified load impedance,showing that there is a critical speed be- low which the constant terminal voltage can't be created.