Brushless motor in peak power density, efficiency, speed range, oh the reliability and operating life, structure, strong sex is better than a dc motor, controller only cost is higher than permanent magnet dc motor, brushless motor in the performance and other aspects have brush than permanent magnet dc motor has the advantage of the stronger. With the rapid development and popularity of the electronic control technology, the cost of the controller will be more low, the volume will be smaller, the power density will be bigger, believe that the brushless motor in more cases will replace the permanent magnet dc motor.