neilh10
commented
1 year ago My take is you are designing power for 220V - 110V two phase and need to do at least paper specifications for 40A for each J1772. That is you need to design for the useable power rails of say nominal V12DC (though +/- ?V) to be derived from both the 110V Since it can operate on two 110VAC, should be able to detect if either one is not there, assuming the other one is powering - a fault condition. This is then switched to rail V12DC, that everything else runs off Possibly look on Digikey for AC-DC modules ~ 10-50W, Enclosed Frames (safety) https://www.digikey.com/en/products/filter/ac-dc-converters/923?s=N4IgjCBcpgHAzFUBjKAzAhgGwM4FMAaEAeygG0R4AWKgJjCpAF0iAHAFyhAGV2AnAJYA7AOYgAvkTABWWtKQhUkTLkIlyIWAHYtcZm06Qe-YWMngAnLAsKlK-EVKQKABmbn622%2BmwP1z8BcAAgB1ECkwUPDwWiipaTjwADZEsAtE2mCwolpY7JBaKgyE-Pgs6PhI0pT8qnKiKhLoqhro6XqQJI6kpqItDtgOsBdylhAOLgBVIQF2AHk0AFk8DBwAVz48CSIAWlpvSH41tScKeSZzHZtoRSgjk40IC48NAEEAYR2AEXeggFtiAATNZYPA4fSdBQCQFcHbDCAGLjRdgAT1YWyMq1Q4nEQA
However for safe testing and hardware verification, there may be benefits to having a TEST RIG at 24VAC- two out of phase created total 48VAC. Possibly use 24VAC transformers at 6A for also testing current passing through.
The TEST RIG may also need to generate the V12VDC as ac-dc converters can runoff a lowly 24VAC.
Eg Low-Current Transformer , Screw Terminal Output and Auto-Reset, 120V AC to 24V AC but only 40VA
Part number 5600K18
https://www.mcmaster.com/products/power-supplies/output-voltage~24v-ac/
This gives more power 96VA - https://www.functionaldevices.com/product/tr100va001/ - may need to get a quote for two and see where they can be bought
I suggested relay https://www.digikey.com/en/products/detail/american-zettler/AZ2800-2A-12DE/12171621 need to check how well it switches power , and its got built in monitoring capability?
Surge protection can be meaningless at 40A
The current transformer is analog ~ $10ea (seems costly) could assume one per line- so if using, need to determine range of measurement and what is the minimum current needed to measure. Then measure RMS current?
NEC 625 (Page 23) specifies no back-feeding when grid loses power
Do We Want to Use 220V or 48V or 24V?: a) Use 208V from school outlet to test if it can operate at 208V. Use 24V to test 40 amps, (if we even have equipment that can generate 40 amps) b) Considerations: b.1) Price b.2) Time b.3) Ease of testing b.4) How much does it matter that we parallel real world specifications? b.5) Whichever voltage we choose, how many amps do we want for daily testing?
Possible Actuators for Mains: a) Relay a.1) Mechanical or solid state? {Page 21 says that SSRs are not the right type} a.2) Is trigger voltage ac or dc? a.3) Is trigger voltage 3.3V or 24V or 48V? 3.3V reduces the need for amplification and reduction but also moves the product farther away from regulation b) Contactor b.1) same questions as 3.a c) Thyristor d) TRIAC
How Long Does it Take to Switch Amperages?: a) Could this be found in J1772 documentation? b) Can our actuators match this required time? c) Does it even matter in this application? (relatively low performance application)
Surge Protection: a) This will not be considered for this project
Ground Protection: a) Do we want to include this in our scope?
Stuck Relay Protection (if applicable): a) Do we want to include this in our scope? b) EDM (external device monitoring) is a simple way to achieve this safety while avoiding additional software. It requires force-guided relays.
Power Pins are Not Energized Until EV Demands It:
Current Sensor: Current Transformer 50A | 50Hz/60Hz | 2500VAC Isolation | 5V Output (Is it billable quality? Is the diameter large enough for cable size?)
Inverter to power the controller a) Controller likely needs 5V b) Control pilot signal needs 12V c) Proximity pilot needs 5V (I think)