MOTOR DRIVE CONTROL SCHEME FOR REDUCING NEGATIVE CURRENTS

A tool is provided including a motor powered by a battery, a power switch circuit, and a controller that controls the power switch circuit using a multi-phase trapezoidal commutation scheme including at least six commutation sectors for each rotation of the motor. The power switch circuit includes high-side power switches and low-side power switches configured as an inverter circuit. Within at least one phase of the motor that includes a first sector and a second sector driven by pulse-width modulation (PWM) control, a dissipation current path is provided through at least two of the high-side or two of the low-side power switches, for a current dissipation period that starts immediately after a motor commutation from the first sector to the second sector, for dissipation of the motor current associated with the first sector to avoid negative flow of motor current into the bus line.