我的逆变波形,附图,大家帮我看看原因吧

这是我的逆变波形,带上一百w电阻的波形,我采用单片机模拟spwm,用IR2130驱动四个桥,后端输出接lc滤波,波形是方波

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后面接上100w白炽灯后波形就成这样了,高手帮我看看原因吧,感激不尽!

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