Current control of DC motor using PI controller

[Mogambo]

Hi everybody!

I am trying to implement current control of a DC motor using a PI controller and was having a few questions.

I am supplying 19V as input voltage (and capable of supplying current upto 2A) to the H- bridge and the controlling is done via a microcontroller using PWM.
When I connect 19V (100 % duty )directly to the motor (with a small mechanical load) I measured the current through the DC motor to be 15mA. Does this mean that I can control the current only upto 15mA.
If for this same load and supply voltage, I now give a reference current of 25mA will the controller be able to take power current from the source and give it to the motor. If so, how? (as it was giving 15mA for 100% duty at 19V.)
If not, does it mean that there can be no PI control above 15mA for this case?
Is it possible to make a PI controller for any range of loads connected to the motor ?

Thanks

[fSAE-Hybrid]

Your current will vary with applied load. However, the only thing limiting the size of your motor and supply would be what you are channeling it through. The microcontroller limitations are set by the manufacturer or set-up of your motor-shield. Ultimately, this would be limited by the relay, transistor, or other switching component you are using to connect the auxiliary power source to the motor.