1、 1 摘 要 本文设计了一套用于驱动低压三相异步电机的逆变电源。 由于日常生 活中许多场合用电设备都不方便直接使用交流电网提供的电源工作， 从而 将已有的直流电进行逆变得到需要的交流电的逆变技术具有很大的应用 空间。本文设计的逆变电源由 48v 直流电压源供电，是电压型逆变电源。 电源主体电路为三相全桥逆变电路， 开关器件采用MOSFET IRF640, IRF640 的栅极控制信号为 PWM 波。电源系统利用 PIC18F2431 用软件方法生成最 初的六路 PWM 波形， 经半桥驱动 IR2103S 后输出作为三相逆变全桥电路的 六个桥臂的控制信号。 本文还设计了过电流保护电路。通过运放
2、LM358 两个管脚电平的比 较，当主电路电流过大时，LM358 送给单片机一个控制信号，单片机关闭 输出信号避免电路损坏。 通过与上位机联机调试，测取了单片机输出的 PWM 波，IR2103S 输出 的栅极控制信号以及驱动三相异步电机时电机的电压电流波形， 并进行了 分析。 关键词：逆变电源，三相异步电机，脉宽调制 2 ABSTRACT In this paper, a kind of inverter is designed to drive asynchronous motors. Because the AC supply is not always available to all
3、of the electrical equipments ,the technology of inversion has an vast application. The inverter designed in this paper is supplied by an 48-volt DC voltage source. The triphase full-bridge circuit is used as the main circuit of the inverter. Six mosfets IRF640N are took as switching devices, and the
4、ir grids are controlled by PWM signals. The system uses PIC18F2431 to create PWM waves by software. This thesis also designed a protecting circuit for excess current. By comparing two voltages on its pins, LM358 sends a signal to PIC18F2431 when the excess current appears. PIC18F2431 shut the outputs to protect the whole circuit. The waveforms, including the PWM output, the signals from IR2103S as well as the voltage waveform and current Waveform, are measured by connecting the system with comp
