The pid control of output voltage feedback is easy to give attention to static and dynamic performance of the control system . output performance of inverter of ups is improved when rms of output voltage feedback is added to pid control system . the hardware and software is designed in order to achieve the digital pid control of inverter of ups 设计了用于逆变器数字化控制的采样调理电路,结合tms320f240的硬件资源,通过软件实现了ups系统的缓起动和市电跟踪,并改进了逆变器电压瞬时值控制,通过引入输出电流中心值检测,对反馈电压进行补偿,解决了逆变器输出的偏磁问题。