# Electric Vehicles Charge

#### Skinbleu

Joined Feb 10, 2022
4
Greetings everyone

I work at a company that sells chargers for electric vehicles and I'm working on the electrical projects.
The chargers I work with, are alternating current (AC) and the main mode here is a three-phase installation 220 V, at 7.04 kW with a current of 32 amps.

If the system only had three chargers (Q01, Q02, Q03), the current for each would be 32 amps.
Using a simulator, when adding the fourth charger(Q4), the current goes to 84 amps and I wanted to understand why.
I tried to draw the three-phase circuit to make an equivalence of loads, but I couldn't get to that value.
Does an electric car behave like a delta or star load?

#### LowQCab

Joined Nov 6, 2012
3,580
Running separate Chargers on Single-Phase-Power is a tragic waste of the
Efficiency that could be had by using 3-Phase derived DC.
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#### GetDeviceInfo

Joined Jun 7, 2009
2,180
following your schematic, how many amps did you calculate with 3 chargers, before adding the 4th?
Delta or Y is irrelevant.

#### Alec_t

Joined Sep 17, 2013
14,007
Using a simulator, when adding the fourth charger(Q4), the current goes to 84 amps and I wanted to understand why.
Because, in the absence of other massive loads on all three phases (as would be found in a real-world mains supply), your fourth 32A individual load is unbalancing the phases. Try adding a few hundred Amps load to each phase and you will see approximately the same 32A in each of your four loads.

#### Skinbleu

Joined Feb 10, 2022
4
following your schematic, how many amps did you calculate with 3 chargers, before adding the 4th?
Delta or Y is irrelevant.
For three chargers I planned 32 amps for each phase. But using a simulator, the software said I need to plan 84 amps. With that all the 4 chargers will have 32 amps.

#### Skinbleu

Joined Feb 10, 2022
4
Because, in the absence of other massive loads on all three phases (as would be found in a real-world mains supply), your fourth 32A individual load is unbalancing the phases. Try adding a few hundred Amps load to each phase and you will see approximately the same 32A in each of your four loads.
I would like to know how to calculate this 84 current. My professor said I have to do a phasor diagram, but I don't know how to start it, once I don't know what's the load impedance (the load in this case it's the car).

#### Skinbleu

Joined Feb 10, 2022
4
Running separate Chargers on Single-Phase-Power is a tragic waste of the
Efficiency that could be had by using 3-Phase derived DC.
.
.
.
Where I live we use more the AC system. DC it's only for the fast chargers

#### LowQCab

Joined Nov 6, 2012
3,580
Where I live we use more the AC system. DC it's only for the fast chargers
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I think You misunderstood what I was saying ...........

ALL Chargers Output DC, because they are charging Batteries.

Getting DC from a Single-Phase-AC-Supply is less efficient and more expensive than
getting DC from a 3-Phase-AC-Supply.
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#### GetDeviceInfo

Joined Jun 7, 2009
2,180
I would like to know how to calculate this 84 current. My professor said I have to do a phasor diagram, but I don't know how to start it, once I don't know what's the load impedance (the load in this case it's the car).View attachment 260311
I wouldn’t bother with phasors. 3 chargers represent a balanced load on the 3 phase system, resulting in some line current. You know the load, the voltage, and that it’s balanced, so it’s a simple calc. The last charger is directly added to that existing load, on two phases.