Application of MOSFET in electric motor
Motor control applications are another application area where power MOSFETs are useful. A typical half-bridge control circuit uses 2 MOSFETs (4 for full bridge), but the shut-off times (dead zone time) for the two MOSTTs are equal. For such applications, reverse recovery time (trr) is important. When controlling inductive loads, such as motor windings, the control circuit switches THE MOSFET in the bridge circuit to the shutdown state, at which point another switch in the bridge circuit passes the body diode temporarily reverse-conducted current. As a result, the current is recirculated and supplies power to the motor. When the first MOSFET is on again, the charge stored in the other MOSFET diode must be removed and discharged through the first MOSFET, which is a loss of energy, so the shorter the trr, the smaller the loss.