Researching the high performance transporting, metering and dropping system to boost the drop frequency has been a hotspot of farming machine.
研究开发性能良好的输送、分苗、落苗系统，提高投钵频率已成为农业机械领域一个热点问题。
This paper describes the basic working principles and control methods of three-phase high- frequency boost & buck IGBT SPWM rectifiers.
文中介绍了IGBT升压与降压式三相高频SPWM整流器的基本工作原理和控制方法。
It consists of high frequency PWM boost chopper and digitalized SPWM inverter. It features IGBT multiple protection and special design for the protection of locomotive from EMI.
该电源由PWM高频升压斩波器及数字化控制SPWM逆变器组成，具有IGBT多重保护及机车抗emi特殊设计。
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