Changing Rated Voltage in the GUI

[derekcook]

When I change motor rated voltage (DC) in the GUI, and then load the system.h file, I do not see any change to the system.h file. Does changing motor rated voltage (DC) in the GUI have an effect on the system.h file? If so, what does it effect?

Thanks for the help,

Derek

[linestream-adam]

The rated voltage is only used in the GUI in order to help Motor Tuner automatically adjust the speed targets for situations where the motor is at a higher rated voltage relative to the dc bus.

It has no impact on the underlying control tuning.

[derekcook]

Thanks for the help Adam. I am wanting the voltage to be 200V at max torque. It looks like the current block determines the voltage reference that is sent to the SVPWM block. I see the outMax of my current block is 1.0. Does this 1.0 refer to the full scale of DC Bus voltage? Do I need to limit the current output if I want the current block to max out at 200V?

[derekcook]

Actually, would I need to lower my voltage gain? This looks to limit the modulation index from the current controller. Currently it is 0.90. I think 200V was around 0.50 for my system. 

[linestream-adam]

Correct, the output of the current block isn't voltage, it is modulation. It has already been compensated for the DC bus voltage. 

In PMSM/BLDC motors the current controllers will determine the appropriate voltage in order to establish the required current in the motor and to overcome the back emf.

Assuming you are at 200 A and have 1 Ohm of resistance, you need 200 V to establish that current. Leaving you no voltage to overcome the back emf of the motor. In that situation your motor will stall since it can't continue to produce the required torque at your speed.

In PMSM/BLDC the general rule is that current produces torque and voltage produces speed.