Research On The Design Of BLDCM's Self-adaptive Control

The permanent magnet brushless DC motor is a DC motor using electronic communication in place of mechanical communication in fact, so it has excellent characteristic of DC motors, for example good start and timing performance. It simplifies the motor's structure and overcomes the friction disadvantages of ordinary DC motor because it doesn't use mechanical communication. It is extensively used in aviations, robots, digital machine tool and so on.In the paper, a new approach of designing the timing system for brushless DC motor (BLDCM) is presented, which is based on the parameter's self-adaptive PID controller combined with Fuzzy logic. At first, the principle of BLDCM is analyzed and the model is built; then a test is performed on a timing system of close loops of speed and current; Through combining Fuzzy logic with PID controller and adjusting control parameters in on-line ways, it can perfect the properties of PID controller and improve the precisions of control system. At the same time the results are given.What's more, how to reduce the torque pulsation in a wide timing range is the main discussing issue of alternating servo system. This paper simulates and analyses the torque pulsation because of the modulation frequency and speed variation under ambipolar pulse width modulation; the influence of snubber circuit, dead time effects , and modulation frequency to IGBT PWM Inverterbridge is taken into account, too. At the same time the results are given.