The Research On Voriable Frequency Technology Of Blower Voriable-speed System Based On DSP

The highly developing economy requests that voriable frequency system should have higher precision, wider peed-regulating range and faster response, which can not be satisfied by general inverter. The frequency of Electric power equipment has greatly increased, which makes the influence of dead-time seriouser and the wave of output voltage and current worse. In this paper, a voriable frequency technology of blower voriable-speed system based on DSP is designed, which uses the SVPWM control technique and realizes the fuctions such as signal collection, system protection, motor speed regulation, and makes effective compensation to the dead-time influence.The work principle of inverter is introduced and several typical AC control strategies are analyzed and compared in this paper. SVPWM is used because of its excellent performance. It has simple control model and high voltage utilization, and can be conroled easily by DSP, and can reduce the current harmonic waves and torque ripples. TMS320LF2407A DSP with integrate modules for motor control developed by TI Co. is the core controller of this system, which reduces the periphery circuit greatly. The built-in protective circuits of IPM make the system more stable. The hardware structure mainly includes main circuit, control circuit, protect circuit and input and output circuit. The software system uses assemble language compile the whole program. Moreover, some measures are adopt to reduce the distortion both hardware and software.The effects of Dead-time must be settled in the design of inverter. This paper analyzes the relationship between power facor-angle, carrier-frequency, modulate ration and dead-time distortion. A new dead-time compensation method on base of the programmable dead-time control function of TMS320LF2407A is and proposed. This method realizes the combination of the software and hardware, and has low cost and highly real-time capability, and corrects current distortion effectively. The SVPWM speed regulation system proved to have reasonable designed structure, high regulating precision, good rest and dynamic performance by the experiment on an asyncronous motor.