中文摘要：

电力机车功率大、直流侧电压高、开关频率低、运行速度快，针对牵引状态下电机电流谐波含量大、转矩脉动大、定子发热等问题，研究了电力机车在整个运行速度范围内的调制策略。提出了电力机车调制方式由异步调制切换至同步SHEPWM调制然后再到最大电压利用区（方波调制）的策略。理论上分析推导了减小切换电流畸变的方案，针对该策略和方案进行了仿真研究并在异步电机小功率实验平台上进行了实验验证。仿真和实验结果表明，所提出的调制策略可以作为电力机车全速度范围调制策略，切换方案能够减小电流谐波含量，提高电压利用率，使电力机车在全速度范围内平稳运行。

英文摘要：

The electric locomotive has high power, high DC power, low switching frequency, high speed and so on. When running in traction state, large current harmonic, torque ripple, the stator radiation and other problems are existed. The electric locomotive modulation strategy within the whole speed range was studied. Meanwhile the scheme from asynchronous modulation to synchronous SHEPWM modulation and then to the maximum voltage utilization area （square wave area） was proposed. The reducing switching current programs were the oretically deduced. The simulation and experiments on small power induction motor platform for experimental verification were done. The simulation and experimental results show that the modulation strategy can be used as electric locomotives whole-speed range modulation strategy. The cutover methods can reduce the current harmonic, and improve the voltage utilization. The electric locomo-tive can run smoothly in the whole speed range.