A Study on Motor Control Method within Temperature Limit of Coil for Improving Motor Performance

In recent years, motor technology has been utilized in a wide range of fields, such as robots and automobiles. When a motor is used for electric vehicles, it is required that the motor supplies different levels of torque in different situations. For example, a motor in an electric vehicle is required to generate a higher torque when the electric vehicle suddenly stop. The braking distance can be shortened by improving the maximum torque of the motor, at the time of a sudden stop.Conventional motors have a larger safety margin of heat-resistant to avoid the motor from breakage. Therefore, it is not possible to provide the maximum torque that the motor originally has. The purpose of this research is to increase the maximum torque of the DC motors. A temperature estimation formula was used to set parameters for each current value to be supplied to the motor. We measured the actual temperature of the motor and compared the measured value to simulation value that is calculated with MATLAB/Simulink to reduce the difference in temperature between measured value and simulation value within 5 ◦C. Furthermore, we built and implemented a current control algorithm that incorporates the temperature estimation for this motor, so that a larger current can be supplied to the motor as compared with conventional motors. As a result, the maximum torque of the motor can be improved by 5.5 times.In addition, because a high-speed response is required to avoid emergency situations in automobiles, optimal feedforward control in real time was performed.