I'd like to make a PWM diversion load controller with an arduino Mega 2560. The standard frequencies are 490 and 980 hz. If the PWM diversion load of about 1KW is powered by a 2.8 kw 120v pure sinewave inverter (Outback 2812), will the inverter have problems with the PWM nature of the load? I ask because the inverter has had problems with a Watlow Din A Mite controller using a single cycle variable time base scheme - the CFL lights would flicker because the output voltages was 10 volts different between on and off cycles. See the waveform in the file below.
Can anyone offer an opinion if the PWM load can be successfully powered from an inverter?
Let's step back and help me determine what your current setup is now ...
You have an Outback 2812 2.8KW Pure Sine Wave inverter.
You have a 1 KW Water Heater, the Diversion Load.
You tried inserting a Watlow Din A Mite controller between the Outback Inverter and the Diversion Load.
But the Watlow used a "weird" variably timed single cycle method to control the output.
This cause flicking in the lights.
Am I correct, so far?
So, you want to replace the Watlow Din A Mite controller with an Arduino running PWM Software.
The PWM will pulse at 490 Hz or 980 Hz.
This Arduino will be connected between the Outback AC output and the Diversion Load.
Now, you want to now know if the Outback Inverter can properly drive a PWM type Diversion Load.
First, did you contact OUTBACK regarding a PWM type Diversion Load on their Inverter?
Second, Yes I do think the Outback Inverter can support the PWM Load.
May I ask why PWM?
Is there a need for 10%, 25%, 50%, 75%, 100% type of loading scheme on the inverter?
Are you diverting the Power after your Batteries are fully charged?
These guys are quite good regarding Outback Inverters!
I think an (ex) Outback Employee hangs here ...
some really smart guys here too ...
This is an Arduino forum so my answer is "YES the Ardudino will work".
But that is not the answer you are looking for.
You really have an OUTBACK Inverter question so you really need OUTBACK support.
I prefer you do not use 490 Hz , too slow.
My gut tells me, "Yes the Outback could drive a 980hz PWM type Diversion Load"
At 980 Hz / 60 Hz = only 16 PWM pulses per AC Cycle (maybe not enough pulses per sine wave?)
I prefer to see a HIGHER PWM frequency, like around 2,000 Hz or more!
But with software you can always modify PWM code later, IF the CPU is fast enough.
But you ain't changing the WIDTH of the Pulses very often, right?
So the PWM is doing ALL the work and CPU is only changing the Width quite infrequently, right?
No, I do not think you need to sync to zero-crossing either - that makes it much easier.
PWM and AC for as Resistive Diversion Load will "mix" just fine.
Let us know what you find out .
Good Luck ...