Control scheme to increase power output of a power tool using conduction band and advance angle

A control system for a power tool, the control system comprising:

• an input unit capable of moving between a first position and a second position and output a signal indicating an amount of power output to be delivered to a brushless direct current (BLDC) motor of the power tool, wherein the BLDC motor has a stator defining a plurality of phases;
• and
• a control unit configured to, for each phase:
• generate a control signal to drive one or more of a plurality of switches;
• control the amount of power output to the BLDC motor by varying one or more parameters of the control signal and the one or more of the plurality of switches based on movement of the input unit;
• control the amount of power output to the BLDC motor between a first power level and a second power level by varying a first parameter of the control signal between a first value and a second value while maintaining a second parameter of the plurality of switches at a predetermined value in response to the input unit moving between the first position and a predetermined position between the first and second positions;
• and
• increase the amount of power output to the BLDC motor to greater than the second power level by increasing the second parameter to greater than the predetermined value while maintaining the first parameter at the second value in response to the input unit moving between the predetermined position and the second position.

A power tool, comprising:

• a brushless direct current (BLDC) motor having a stator and windings configured to operate in a plurality of phases;
• a switching arrangement having a plurality of motor switches connected electrically between a power source and the BLDC motor and operates to deliver electric power to the BLDC motor;
• an input unit operable within a range to output a speed signal indicating of an amount of power delivered to the BLDC motor;
• and
• a controller interfaced with the input unit and the plurality of motor switches, the controller operates to output drive signals to the plurality of motor switches in accordance with the speed signal, wherein below a predetermined level of the speed signal the controller controls the drive signal using a first commutation control mechanism, and above the predetermined level of the speed signal the controller controls the drive signal using a second commutation control mechanism different from the first commutation control mechanism.