System and methods using a motor drive circuit to both drive a battery operated motor and to recharge the battery

摘要

A battery-operated motor system includes a rechargeable battery, a motor and circuitry for recharging the battery. The recharging circuit processes externally applied energy to provide a source of recharging current. The recharging current is applied to a winding in the motor in the form of periodic current pulses. Following each pulse, energy thus stored in the motor winding is allowed to discharge into the battery, thereby recharging it. Use of the motor winding in this manner avoids the need to provide a separate inductance for recharging the battery and results in reduced weight, fewer components and greater manufacturing economy. The large inductance of the motor winding also enables recharging at a rate well suited to the particular motor/battery combination. By using existing components of a known H bridge motor drive to perform the various switching functions, further savings in these areas can be realized.