Filter problem with three phase inverter with IPM

[akademi]

Hello

I have used Fuji IPM 6MP100RA120 for my three phase inverter. My load is a three phase motor. The current signals at the output are very noisy. How can I eliminate these?
I used a RCD snubber one input of IPM (between P - N). Is it right?
My switching frequency is 18 kHz. My snubber circuit values are C -- 0.22 uF 1250 V, R--22R 50W, nad D -- DSEI 120-12. Is it appropriate?
The most important question is how I can use output filter. I haven't got a neutral line. So I don't know how I will connect a L - C filter. To make a neutral line I found a way. Between P - N input of IPM, if I connnect two split capacitors and take a line between capacitors it is neutral line. But if I do so, the input DC voltage must be very high. I haven't got so much DC voltage. Is there a way to connect L - C filter without neutral line? If it is possible how can I do?

Or to eliminate the noise from the output signals is there another way?

Thank you....

 

[happy2005]

Use low esr and high ripple current capacitors at P-N inputs. Connect the capacitor directly the P-N pins. It filters sharp voltage spikes created by switching action.

About output filter connection: connect to each phase an inductor serially. After inductor connect a capacitor parallely. Other pin of capacitor at each phase are connected together (like star connection). I think it will works.
Regards,