SPWM的FPGA实现方法

The Method of SPWM with FPGA

本文主要描述利用FPGA现场可编程门阵列器件作为控制核心,结合DDS数字频率合成技术直接形成SPWM脉宽调制波。首先将一个周期的正弦函数进行1024点的离散,并将离散后的数据按顺序存储到FPGA的RAM中。然后使用VHDL语言编程实现可逆计数器,利用可逆计数器完成三角函数的上升与下降,形成一个完整的三角函数,频率为正弦周期的N倍,并可调。其次将同一时刻的正弦函数值与三角函数制比较(即正弦调制),形成一路脉冲调制波。最后为防止同相桥臂功率器件的同时导通,采用按时关断、延时开通的单边不对称设置完成调制脉冲波的死区延时,形成最终的SPWM脉宽调制波,并用于电力电子逆变装置,使得系统设计简化,提高设备的可靠性。

Combine with the direct digital synthesizer （DDS） technology, use field programmable gate array （FPGA） chip as control unit, directly generate the sine pulse width modulation （SPWM）.In order to generate the SPWM, first the sinusold which has been divided 1024 points should be stored into the RAM of FPGA. Then use reversiide counter form the triangle that program by VHDL hnguage. The frequencies of triangle are more than sinusoid and should be adjust. Then, Compare the sinusoid and triangle at same time to generate the SPWM, but in case of circulate at same time in one bridge power component, apply misbalance method to resolve it. We use the final SPWM to the power covert should make the system steadily and simply.