Method and apparatus for operating a starter for an internal combustion engine

A method for controlling a starter that is disposed on an internal combustion engine, the starter including a multi-phase brushless electric motor coupled to a rotatable pinion gear, a controller and an inverter, the method comprising:

• determining initial current commands for operating the electric motor in response to an activation command, wherein the activation command includes a rotational speed command concurrent with a motor torque command;
• monitoring, via current sensors, electrical current transferred from a DC power source to the electric motor, wherein the electrical current is monitored directly without an intervening current prediction step;
• monitoring, via a rotational position sensor, a rotational position of the pinion gear;
• determining feedback currents from the electric motor based upon the electrical current transferred to the electric motor and the rotational position of the pinion gear;
• determining interim voltage commands based upon the initial current commands and the feedback currents, including employing a proportional/integrator control routine to determine the interim voltage commands, wherein the integrator is subjected to a dynamic integrator clamping element and an anti-windup element from a gain saturation limiter;
• subjecting the interim voltage commands to voltage limits to determine final voltage commands;
• determining a rotational position compensation term based upon the rotational position of the pinion gear and a rotational speed of the electric motor;
• determining pulse width-modulated commands for controlling the inverter based upon the final voltage commands and the rotational position compensation term;
• and
• controlling, via the controller, operation of the inverter to control the electric motor based upon the pulse width-modulated commands.

A starter disposed on an internal combustion engine, comprising:

• a multi-phase brushless electric motor coupled to a rotatable pinion gear, a controller, a DC power source, and an inverter, the controller operatively connected to the inverter, the controller including an instruction set, the instruction set executable to:
• determine initial current commands to operate the electric motor in response to an activation command, wherein the activation command includes a rotational speed command concurrent with a motor torque command;
• monitor electrical current transferred to the electric motor from the DC power source, and a rotational position of the pinion gear;
• determine feedback current commands for the electric motor based upon the electrical current transferred to the electric motor and the rotational position of the pinion gear;
• determine interim voltage commands based upon the initial current commands and the feedback currents, including employing a proportional/integrator control routine to determine the interim voltage commands, wherein the integrator is subjected to a dynamic integrator clamping element and an anti-windup element from a gain saturation limiter;
• subject the interim voltage commands to voltage limits to determine final voltage commands;
• determine a rotational position compensation term based upon the rotational position of the pinion gear and a rotational speed of the electric motor;
• and
• control operation of the inverter in a pulse width-modulated mode to control the electric motor based upon the final voltage commands and the rotational position compensation term.