Supposed I have a motor with the following ratings:
Power: 7 kW
Torque 14.8 Nm
Speed: 4500 rpm
Voltage 55.5 V (IP 54)
Current: 90 A (Duty S1 -EN 60034)
Ke: 11.2 V/1000rpm
Assuming that this motor would be driven by a controller that monitors DC bus voltage, phase current, employs FOC, and can reliably limit the current delivered to the motor at any time.
What would happen if I would decide to go with a much higher battery voltage around 120 V and an IGBT power stage. That power stage could easily handle the currents required to drive the motor at its 18 kW peak power level and would also be able to drive substantially more powerful motors if so desired later. OTOH, getting 18 kW out of 55ish Volt with MOSFETs is a challenge.
If I limit the current on my bench power supply and hook it up to a low resistance load, the voltage across the load will sag down to what would generate the desired current according to Ohms law. Would not the same happen (at least up to the speed where BEMF exceeds rated voltage) in a motor that is driven with a higher than rated voltage but with limited current?
Power: 7 kW
Torque 14.8 Nm
Speed: 4500 rpm
Voltage 55.5 V (IP 54)
Current: 90 A (Duty S1 -EN 60034)
Ke: 11.2 V/1000rpm
Assuming that this motor would be driven by a controller that monitors DC bus voltage, phase current, employs FOC, and can reliably limit the current delivered to the motor at any time.
What would happen if I would decide to go with a much higher battery voltage around 120 V and an IGBT power stage. That power stage could easily handle the currents required to drive the motor at its 18 kW peak power level and would also be able to drive substantially more powerful motors if so desired later. OTOH, getting 18 kW out of 55ish Volt with MOSFETs is a challenge.
If I limit the current on my bench power supply and hook it up to a low resistance load, the voltage across the load will sag down to what would generate the desired current according to Ohms law. Would not the same happen (at least up to the speed where BEMF exceeds rated voltage) in a motor that is driven with a higher than rated voltage but with limited current?