Design Of BLDCM Control System Based On DsPIC

Namely along with the rapid development of electronics technology and advanced digital signal processor, the electric transmission technology is being faced with a history revolution. Among numerous motor control strategies, Space Vector Pulse Width Modulation (SVPWM) is characterized by advance, novelty and practicability, as a motor control strategy of concern, which is based on motor unification principle, energy conversion and coordinate transformation theory. However, the output voltage of SVPWM can only achieve up to 90.7% of the square wave state. In order to achieve greater motor torque and higher DC voltage utilization ratio, the modulation factor need to be improved, this may lead to serious voltage waveform distortion and motor torque fluctuation. So it is necessary to make certain optimizations to the SVPWM Over-modulation to increase motor torque and improve voltage utilization ratio.Firstly, the mathematical model of BLDC motor is built, and after discussing some common control strategies, the paper focuses on the SVPWM principle and its implementation on the dsPIC. Based on this, the SVPWM algorithm is realized on our platform. After doing research on the Over-modulation, a new control strategy is put forward to be tested by debugging afterwards. In the aspect of software programming, paper chooses Microchip's high-performance dsPIC33FJ128MC706 as the main controller. Its rich peripherals and powerful computing capabilities have brought much convenience to operations. As for development environment, MPLAB IDE v8.5 is used for real-time simulation and debugging, C language is used for programming, the program is modular, easy to read and modify, high efficiency and compact structure. As for hardware design, the smallest system based on dsPIC is used as the control module. Then some circuits, including speed optical encoding, position signal indicator, current and voltage detection and switch circuits, are designed based on it. IGBT-IPM is selected as power module and driving and protection circuit is designed for it; In addition, multiple isolated power supplies are designed for the security of power supply.Finally, the paper summarizes at the end and makes a systematic analysis of the experimental data, the result shows that the system can effectively meet the needs of the motor control and its feasibility is confirmed. The proposed over-modulation strategy can lead the system to achieve greater motor torque and higher DC voltage utilization ratio, the effectiveness and practicability have been fully embodied.