针对三级式同步电机在电动起动过程中，主发电机的转子励磁脉动导致输出转矩脉动较大、带载起动性能较低的问题，分析了转子励磁脉动对主发电机运行特性的影响，以及在采用矢量控制策略时，由于受到谐波电流的影响而输出的误差电压矢量的分布特点。为了提高主发电机的带载起动性能，本文提出了一种采用极坐标确定控制器调制电压矢量的起动控制方法，与传统的矢量控制策略相比，该方法在一个调节周期内不会产生电压幅值调节误差，仅会产生较小的矢量角调节误差。实验结果表明，在100 r/min转速时，传统矢量控制方法仅能拖动5 N·m的负载，新方法则能够稳定拖动40 N·m负载，说明新方法更适合电机在拖动航空发动机起动过程中低转速、大负载的运行工况。%Considering the large torque ripple and poor start performance with load which are caused by the excitation current pulsation of the main generator in the electric start process of three-stage brushless synchronous machines, the impact of the excitation current pulsation was analyzed on operating character-istics of the main generator and distribution characteristics of output voltage vector error caused by har-monic currents when vector control strategy was adopted. In order to improve the start performance of the three-stage brushless synchronous machine with load, a start control method was proposed using the polar coordinate to determine the output voltage vector. Compared with the traditional vector control strategy, this method does not produce amplitude error, but only small angle error, of the vector voltage. The ex-perimental results show that, at a speed of 100 r/min, the electric start system adopting the new method can operate steadily with a load of 40 N·m, while for the traditional vector control method, it is only 5 N·m. Therefore, the new method is more suitable for the low speed and heavy load operating condi-tions at the start mode of aircraft engines.
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