40W电源请求帮忙

本人用TOP225+EFD30磁芯设计一个开关电源,功率=40W 输出电压180V  电流0.2A
但效率不高,带负载20瓦时变压器温度已经很高,效率小于80%,
电路如下图
并附次级线圈波形图, 波形不是方波,估计是造成效率低的原因,
请问怎样改可以提高效率,
请帮帮忙,谢谢!!!!!!!!!
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