SVPWM abnormal current under inductive load

I desing three phase inverter with SVPWM with matlab&simulink 2024a

It works perfectly under resistive load.

When I add 450VAR inductive load to 450W resistive load at 0,02 second, phase a and b currents shift up and phase c current shift down. why?

All loads is balanced. Why does current behavior like that? How can ı solve it?

Answer 1

[David Goodmanson]

Hi Bahdir,

I believe the effect is real and can't be 'solved'. When the loads are purely resitive, the current and voltage are exactly in phase. With a resistive+reactive load, the current and voltage are no longer exactly in phase. The age-old mnemonic ELI the ICE man says that for an inductor, current lags voltage. Accordingly, in the lower plot you can see the current peaks all occur later than in the upper plot.

When you change the loads all of a sudden, there will be some transients involved in shifting the phases from the old values to the new. The transients die down due to the resistances in the circuit and you end up with a steady state, different from the original steady state.

[Bahadir]

@David Goodmanson thank you so much. When I add inductive load, the load current lags from voltage.

I think that phase a, b, c currents shift up and down owing to transients behavior of inductive load. Charging of inductive load. How can I explain this transient behaviour of charging inductive loads.