I have been mucking about with my solar setup, initally playing with buck modules in paralell but that is another thread...
Anyway I needed to put something in place that actually worked so decided to go with 'simple' pwm
I should have known better, simple.... Not
The PWM signal is from an arduono, no problem altering freequency or duty cycle.
I have 5 Fets in paralell, P-Type with an RDSOn of arround 0.06 Ohms.
The gate is level shifted with transistors to around S-0.4 / S-11.8, Off and On respectively.
Maximum current from the PV is about 32A right now althouh I am about to add another 600W , the system is 12V.
The gate drive works well, so far as I can tell and fets only require a modest heat sink to handle the heat dissipated.
To be honest I was chuffed when it all did what I had hoped but then I realised it was also causing my broadband to drop out...
I have tried freequencys between about 250Hz and 20kHz and the DSL drops out fairly consistantly.
The PWM duty cycle is limmited to between 10% and 90%, aproximatly
I suspect the issue is RFI as opposed to there being anything superimposed on the DC. The router is down streame of a boost buck combination which stabilises its 12V supply, allong with the satellite box and the phone. Neither converter is isolated so I suppose noise could conceevacly pass through on the ground line but I am struggling with the mechanisme.
Interestingly the DSL occasionally drops out when the genny powered charger is on... more PWM I suspect!
So the question is... How do I fix it without resorting to long slow pulses which is possible but hardly optimal.
I literally have no idea, apart from proxcimity, which isnt going to be easy to change.
Thoughts?
Cherrs,
Al
Anyway I needed to put something in place that actually worked so decided to go with 'simple' pwm
I should have known better, simple.... Not
The PWM signal is from an arduono, no problem altering freequency or duty cycle.
I have 5 Fets in paralell, P-Type with an RDSOn of arround 0.06 Ohms.
The gate is level shifted with transistors to around S-0.4 / S-11.8, Off and On respectively.
Maximum current from the PV is about 32A right now althouh I am about to add another 600W , the system is 12V.
The gate drive works well, so far as I can tell and fets only require a modest heat sink to handle the heat dissipated.
To be honest I was chuffed when it all did what I had hoped but then I realised it was also causing my broadband to drop out...
I have tried freequencys between about 250Hz and 20kHz and the DSL drops out fairly consistantly.
The PWM duty cycle is limmited to between 10% and 90%, aproximatly
I suspect the issue is RFI as opposed to there being anything superimposed on the DC. The router is down streame of a boost buck combination which stabilises its 12V supply, allong with the satellite box and the phone. Neither converter is isolated so I suppose noise could conceevacly pass through on the ground line but I am struggling with the mechanisme.
Interestingly the DSL occasionally drops out when the genny powered charger is on... more PWM I suspect!
So the question is... How do I fix it without resorting to long slow pulses which is possible but hardly optimal.
I literally have no idea, apart from proxcimity, which isnt going to be easy to change.
Thoughts?
Cherrs,
Al