EMC & synchronization in PLC810PG
Hello, i refer to the PLC810PG PFC and LLC stage controller.
The App. Note for the PLC810PG states that the synchronization of the PFC and LLC stage makes EMC compliance easier.
However, it is also known that having a NON-synchronized PFC & Downstream PWM stage means that EMC compliance will be helped since the NON synchronized stages tend to produce a "spread spectrum" effect whereby the noise is spread over multiple frequency bands, -and thus the actual peak noise frequencies are lower.
So, my question is, "which do you think is best for EMC, is it synchronized PFC & PWM stages, or NON-synchronized PFC & PWM stages?"
Also, do you have comparitive EMI reciever plots to show the difference in EMI between synchronized and non-synchronized stages.?
More specifically, if NON-synchronization causes a problem with EMC, then at which frequencies do you think the problem occurs?
Comments
Thankyou Surak,
I wondered if you have any articles on this? i cannot find anything on it. -i must confess that it has been elsewhere inferred to me that NON-synchronized operation can make common mode noise worse aswell. -since when the two stages switch within a split second of each other a high frequency "pulse" results.?
Thankyou Surak, i must confess though that i am somewhat doubtful. Out of the two noise modes (common mode and differential mode) common mode noise is by far the worst problem............this is because common mode noise is by definition, of very high frequency, and it is the high frequencies which are going to be difficult for us to filter.
Differential mode noise is typically just up to the seventh harmonic, -so in an offline supply that means differential mode noise would not likely be any higher than about 1MHz......these low frequencies are very easy to filter out with CLC filters.
If NON-synchronization makes common mode noise less of a problem, then i would recommend people to use NON-synchronized PFC & PWM stages. May i ask, Do you concur?
Anyway, may i ask of your opinion about the theory that NON-synchronized stages mean that the EMI noise spectrum tens to be different everytime you switch the power supply on....and that this makes EMC filtration of non-synchronized stages very difficult?
Using Symantec's Dynamic Multipathing (DMP) management of multiple driver select the tracks, DMP can be extended to detect the specific storage arrays feature properties. Feature-based content is not exposed on the matrix when using third-party drivers (tons per day), that is, EMC PowerPath, MPxIO, and MPIO. E20-624 VCE
Each logical can be one or more of these extended attributes. And DDL discovers extended attributes through the discovery and use of device compatibility library activity appropriate group (ASL) for a particular group.
The writing of the matrix intelligence in ASL.
Synchronizing helps differential noise by reducing ripple current. Non-synchronized may have benefits for common mode noise.