deemed as operating in the power generation mode if tout is between u2212 2 nm and 2 nm then it is deemed as in the zero torque mode if tout is larger than 2 nm and smaller than 3 nm then the motor is deemed as operating in the motoring mode if flag1 is zero which indicates that the output torque of the motor ever reached 3 nm or still in the zero torque mode if flag1 is other than zero and if the output torque is larger than u2212 3 nm and smaller than u2212 2 nm then the motor is deemed as operating in the power generation mode if flag2 is zero or still in the zero torque mode if flag2 is other than zero step 203 conversion between the operation modes of the motor is determined from the demanded operation mode and the current operation mode of the motor in the method for smoothing a torque of a motor according to the invention conversion between the operation modes of the motor is classified as conversion into and conversion from the idle mode particularly as depicted in table 1 and table 2 step 204 it is determined whether the demanded operation mode of the motor is stable or not in this step assuming that an operation cycle of the controller is.