High current production  testing of our EV chargepoint - Page 1
Forum section: electronics / projects

author: Faringdon
author_rank: Super Contributor
timestamp: June 08, 2022, 10:56:23 am
content: Hi,Please help us save energy when dummy load testing our chargepoint in production….We’ve just designed a 3.6kW EV chargepoint for 230VAC.We dummy load them in production test, but this is wasteful of energy.So instead we will simply put an isolated 50Hz , 16A AC current from a current source through the live of the product.However, there’s an RCD in it. So it will detect a difference in current because there’ll be no current in the neutral. We dont want the RCD to trip during high current test.So what we’ll do, is put another AC current source through the neutral…..we will sense the live one, and make the neutral one the same, so that the RCD doesn’t get tripped.Is this a good ploy?...or is it simply better for us to simply disable the RCD for the high current test? (We actually already disable the RCD for other tests anyway.)(BTW, the product does need to be connected to the mains for this test, for various reasons, hence the “isolated” AC current source]

author: NiHaoMike
author_rank: Super Contributor
timestamp: June 08, 2022, 01:41:51 pm
content: Quote from: Faringdon on June 08, 2022, 10:56:23 amYes.

author: SeanB
author_rank: Super Contributor
timestamp: June 08, 2022, 02:04:42 pm
content: How about simply having a toroidal transformer with 2 16A secondaries, one for live, one for neutral, and then control the primary to get the current flow. That way both lines have current flow, and thus both line and neutral get tested, but your toroid should be able to provide a balanced current. Just have to have the 2 secondaries wound using insulated copper wire with robust insulation, so they have 1kV of isolation between each other. Pretty much easy to do, and a standard wire for most custom transformer winders as well, using 16 SWG wire on an existing toroidal core.

author: Faringdon
author_rank: Super Contributor
timestamp: June 08, 2022, 02:38:39 pm
content: QuoteThanks, yes, this was considered, but the size and weight of the torroid seemed prohibitive.Specially since we also intend this for our soon-2-come 32A EV chargepoint.

author: TheMG
author_rank: Frequent Contributor
timestamp: June 08, 2022, 04:28:05 pm
content: Does the device distinguish between real power and reactive (apparent) power?If not, then a sufficiently sized AC capacitor bank will pull current while drawing very little real power and would work to "load" the charge point at least as far as current is concerned.

author: Faringdon
author_rank: Super Contributor
timestamp: June 08, 2022, 04:59:42 pm
content: Thanks, yes it does detect the Power factor, and needs it to be unity.

author: jonpaul
author_rank: Super Contributor
timestamp: June 09, 2022, 05:19:29 am
content: Bonjour cher FarringtonThe US experience with EV charge points in high EV California....Recent Official survey results75 %'of all charging stations in California are unusable, 25 % are in service!Defective electronics, plug, cable, mechanical defect, contrôle system / billing / internet issues.Some plugs were incompatible or poor quality, some cables were too short to reach the auto receptacles.I am certain that a lot of out of service points have poorly designed or cheaply manufactured power electronics.Bon chanceJon