You will always be limited on available power using a VFD, if you want three phase and large motors then just buy a digital phase convertor and you can run motors greater than 4 Hp.
If you have a three phase supply at 400 volts and for whatever reason are runing a VFD to get speed control then wire the motor to Delta which is for 230 volt operation and set the VFD for 400 volt 87 Hz output and you get constant torque plus 1.7 times more power.
For anyone wondering why this works it is because a VFD has a volts per Hz output and not just variable frequency so 400 volts at 87 Hz gives 4.6 volts per Hz which is the same as 230 volts at 50 Hz.
If you have a three phase supply at 400 volts and for whatever reason are runing a VFD to get speed control then wire the motor to Delta which is for 230 volt operation and set the VFD for 400 volt 87 Hz output and you get constant torque plus 1.7 times more power.
For anyone wondering why this works it is because a VFD has a volts per Hz output and not just variable frequency so 400 volts at 87 Hz gives 4.6 volts per Hz which is the same as 230 volts at 50 Hz.