求助 电动工具谐波问题
小弟有一带调速的电锤在EMC测试中谐波电流超了，调速器厂家说没有办法，我自己也不知从何下手整改，求助各位前辈能指点一二。2次和4次谐波电流超，其余的都是可以的，
产品接了1个0.22+2*2200的三角电容和1个20-30uH的电感，电机参数是0.53/16+0.65/130，调速器据说是全波整流的。 2次诣波值1.696，超4.5%
4次谐波值0.822，超27.5% Your product is portable tool and classified as Class B in EN61000-3-2. The corresponding limits should be 1.5 x Table 1 (Class A limit). Hence, it is rarely failed in the harmonic tests because the symmetric control is normally used.
In view of your data, your speed control is most likely using the TRIAC to change the Fire Angle.And, the motor is fairly high power. Otherwise, the 2nd and 4th harmonics should not be as high as yours. If that is the case, your supplier is correct that the harmonic problems are difficult to be solved in the circuit design.
As my motor-driven product is usually of low power type, I also not sure whether my suggestion is workable or not. Perhaps, you may consider
- changing your motor to be a less power one, or
- change the control method from Fire-angle control to PWM control
Hopefully, it may help.
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