A HIGH PERFORMANCE DIRECT TORQUE CONTROL METHOD WITH PWM APPROACH OF PMSMS

摘要

The present invention provides a DTC-PWM method wherein the most appropriate voltage is selected based on a torque and a magnetic flux state by using a torque and a magnetic flux error level selector in a 12 sector voltage vector and a duty ratio of the voltage vector by using an approximate voltage function based on an angle in the selected voltage vector. The approximate voltage function is approximated by a quadratic function with respect to a d-q axis and is used as a denominator for calculating the duty ratio. A numerator for the duty ratio calculation is derived by torque, magnetic flux difference, and speed information. Unlike, an existing DTC-PWM, the speed of a motor is referred to obtain a proper duty ratio. Effectiveness of the method of the present invention is proven by an actual experiment using a commercial PMSM. In the experiment, the control method of the present invention is proven to have control performance more excellent that control performance of an existing method.