Hello, I own a 2019 Hyundai Kona electric. I want to know if I can use a 400 VAC to 230 VAC transformer to charge the electric car through a Huawei charging station, a station that can operate powered by an IT network, without a working neutral. I want to specify that in the secondary of the transformer I will not have a neutral from the electrical network.
400 VAC 3-ph is 230 phase to neutral, what we use here in NZ for domestic distribution. If you have no neutral available and instead draw off two phases of the 400 to a single-phase transformer (with isolated windings) and produce 230V, you'd only need to bond to ground one side of the output to limit the 'float' of the 230V to within the typical dielectric ratings of the connected parts. Then it would look like a typical domestic feed. The EVSE may also need to 'see' a very small current path from either wire to its GND connection in order to operate. I know mine does, intentionally leaking 0.2mA in the expectation that the neutral is grounded somewhere. So in my case it won't work connected to a generator with a floating output for example. Other than adding breakers or fuses as appropriate for sensible design and complying with local regulations (if applicable) I don't see any problems in principle.
Finally I ordered a 400/230 VAC transformer and it works in the first tests. I will equip the panel where the transformer will be mounted and the final tests with 7.5 KW. For now I have only loaded with 5 KW and the current per phase was 12.8A. I will come back with the electrical diagrams and some pictures after I complete the project.
