Zhangyichao and Wang Dong, researchers of the National Defense Science and Technology Key Laboratory of Ship Integrated Power Technology of the Naval Engineering University, wrote in the 24th issue of the Journal of Electrical Technology in 2018 that the rotor groove harmonic method is an important motor speed estimation method. The influence of motor parameters is small. It has a strong parameter robustness and has a good prospect in the field of speed sensorless control of induction motor. The traditional rotor groove harmonic method is mostly based on stator current analysis, and the rotor groove harmonic in stator current is easily limited by the motor structure, and the amplitude is small, and the signal-to-noise ratio is weak, which affects the accuracy of generalization and rotation speed estimation.
In view of the above problems, the rotor groove harmonics in the induction air gap magnetic field of the coil arranged inside the motor are proposed. By studying the factors affecting the rotor groove harmonic signal-to-noise ratio in the induction coil, an optimal design method for the induction coil layout is proposed. The results of simulation and experimental research on a 15 phase electric machine show that the designed induction coil can greatly improve the rotor groove harmonic signal-to-noise ratio, and the speed estimation method has good accuracy.
Induction motor vector control needs accurate speed value to achieve closed-loop control. In practice, rotating speed sensors are generally used to measure motor speeds, such as rotating Transformers and photoelectric encoders. These devices are mature in technology and have high measurement accuracy, but in some cases where environmental, spatial, and reliability requirements are harsh, There are problems such as declining measurement accuracy and difficult line maintenance, especially when water immersion, vibration eccentricity and other conditions can not work normally. These problems will reduce the reliability of the motor system and limit its application range.