求助:用SG3525作逆变,驱动推挽变压器,空载时PWM输出波形很好,带载后MOSFET很快发烫PWM输出波形也变差

我做了一个 1KW 的 DC24V -- DC350V  的逆变电源,推挽变压器是两对EE55的磁芯,变比 2:2:36 ,用了 3 对 IRF3808 的管子! 电路图如下

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空载电流0.31A ,SG3525的11脚(OUT A)和14脚(OUT B)输出的PWM波形很好,电源和地线上都比较干净.MOSFET也不热.
当我接一个25W的灯泡时,用示波器测量,DC350V输出比较稳定,但是11脚和14脚占空比调整频繁,而且11脚(OUT A)输出的PWM波形变差(出现一个和OUT B同相位的干扰信号,见下图).电源和底线上也出现同样的干扰信号.OUT A对应的MOSFET稍微有点发热.
当我接150W的负载时,OUT A对应的MOSFET发热很严重,一会就烧了. OUT B对应的MOSFET微热.

请问大家遇到过类似的问题没有?我该从哪方面下手?

下面是部分波形记录:
(1)接25W灯泡时, SG3525的11脚和14脚波形

静态波形图
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展开
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动态波形图
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展开
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(2)11脚和13脚(VC)波形对比图

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(3)15脚(VCC)和12脚(GND)波形对比图

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