Research Of The Control Instrument Of Brushless DC Motor Based On CPLD And AVR

Brushless Direct Current (BLDC) motor, which is combinations of permanent-magnet AC motors and inverters, has the virtues of not only the simplicity in their control of DC motor, but also the high efficiency and reliability of AC motor. Recently Brushless DC motor is increasingly being used in the industry area widely, especially in high-performance applications.Firstly, the basic elements and the operating principle of the control system are analyzed .The mathematic model of Brushless DC motor is also researched in this thesis. Because of brushless motor's large torque ripple during low speed and direct driving, it is the study focus of Brushless DC motor applications how to reduce torque ripples and current ripples.Furthermore, On the basis of the characters of Complex Programmed Logic Device, the paper has realized some special circuits with Verilog Hardware Description Language based on the principle of the control system. And it discusses the disadvantages when using a single Complex Programmed Logic Device chip. A new strategy using Complex Programmed Logic Device chips and MCU to control Brushless DC motor is analyzed.Finally, the paper has designed and finished Motor controller with Complex Programmed Logic Device chips made in ALTERA and AVR MCU made in ATMEL. In order to guarantee the velocity modulation's precision and quick-response, a double closed-loop control for current and velocity has been adopted and the control strategy is realized by software using PI algorithm. The whole system's hardware and software have been designed based on the system's control strategy and the reliable-designing question has been discussed in the paper.The result of the experiment show the proposed control solution is feasible, which provides the basis and useful reference for later research.