Hey guys
Still my age old project, but circumstances require i focus on it again.
You guys were invaluable while i was finishing my degree and really did save me during numerous breakdowns.
Thanks for that AAC! - i owe my degree classification to the sanity instilled here.
Genuinely - Thank those that helped, the common culprits and those less so.
Now down to business - i am using PWM to control a 100W load at 24V, so the RMS load current would be around 4.2A.
I am aiming to produce a design that will minimise EMI emission to make CE certification more achievable in the future (beyond me at the moment).
Currently i am PWM'ing 24V AC with no filter stage, and designed for AC to this point as i know AC can be filtered to recover the sinusoid and effect variable amplitude sine-wave dimming. Thus converting my PWM output into a nice smooth AC with little EMI to consider.
Although it seems that it may not be so simple to filter at these power levels (or so i am lead to believe), please tell me i am wrong - i hope so haha.
My other option is to use DC, but again i still have high pulsated load currents producing unacceptable EMI, and .... unless i'm missing something - i cant think of a way to filter DC.
So before i can progress, i need to determine how i can reduce the EMI output of a 100W+ load controlled with PWM.
If i was in the US i could get away with a-lot more, but being where i am - i believe i need to over-engineer things. Which is fine by me.
As always AAC - any help is greatly appreciated.
Still my age old project, but circumstances require i focus on it again.
You guys were invaluable while i was finishing my degree and really did save me during numerous breakdowns.
Thanks for that AAC! - i owe my degree classification to the sanity instilled here.
Genuinely - Thank those that helped, the common culprits and those less so.
Now down to business - i am using PWM to control a 100W load at 24V, so the RMS load current would be around 4.2A.
I am aiming to produce a design that will minimise EMI emission to make CE certification more achievable in the future (beyond me at the moment).
Currently i am PWM'ing 24V AC with no filter stage, and designed for AC to this point as i know AC can be filtered to recover the sinusoid and effect variable amplitude sine-wave dimming. Thus converting my PWM output into a nice smooth AC with little EMI to consider.
Although it seems that it may not be so simple to filter at these power levels (or so i am lead to believe), please tell me i am wrong - i hope so haha.
My other option is to use DC, but again i still have high pulsated load currents producing unacceptable EMI, and .... unless i'm missing something - i cant think of a way to filter DC.
So before i can progress, i need to determine how i can reduce the EMI output of a 100W+ load controlled with PWM.
- I could use 240V to reduce the load currents if this would ease filter design, though it imposes other issues with my load choice.
- A user of another forum suggested DC however i cannot see how this can be filtered to negate the load current pulsations.
- Another option is to investigate other control methods such as phase-angle control and cutting conduction on the trailing edge, though i am hoping this isn't the go to answer of the best educated here as i know the least about this option - but if its superior then i will embrace it.
If i was in the US i could get away with a-lot more, but being where i am - i believe i need to over-engineer things. Which is fine by me.
As always AAC - any help is greatly appreciated.