DEVICE AND METHOD FOR CONTROLLING PRIME MOVER

When an angular acceleration alpha of a rotating shaft of a motor connected with a drive shaft exceeds a preset threshold value alpha slip, which suggests the occurrence of a skid, the torque control procedure sets a maximum torque Tmax by referring to a map, which gives a smaller maximum torque Tmax with an increase in angular acceleration alpha , and restricts the motor torque to the maximum torque Tmax. The maximum torque Tmax is fixed to a value corresponding to a peak value of the angular acceleration alpha at the time of occurrence of a skid. The torque control procedure then integrates the angular acceleration alpha to give a time integration thereof over an integration interval when the angular acceleration alpha once exceeds the preset threshold value alpha slip and decreases again below the preset threshold value alpha slip by the motor torque restriction. When the motor torque restriction practically converges the skid, the torque restricted to the maximum torque Tmax corresponding to the peak value of the angular acceleration alpha is restored to the new setting of the maximum torque Tmax corresponding to the time integration of the angular acceleration alpha .