Research And Development Of Equipment For Blower Frequency Conversion Adjustable-speed Based On DSP

In recent years, with the appearance of the new power electronic apparatus and high-power microprocessors, the accurate asynchronous motor models and all kinds of advanced theories, the motor control technology is developing faster than before. The frequency conversion adjustable-speed equipment of motor which haves high accuracy and control performance, wide speed regulating range can be possibly realized.Frequency conversion adjustable-speed control theory of asynchronous motor and pulse width modulation arithmetic are introduced in detail in this paper. According to working characteristic of blower, a frequency conversion adjustable-speed equipment for blower have been designed using voltage space vector pulse width modulation algorithm (SVPWM), its excellent performance, simple control model and high voltage utilization, which can be controlled easily by DSP, 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, using IGBT as primarily power component. Including main circuit, DSP control circuit, IGBT driving circuit, protection circuit, display circuit, keyboard circuit and so on have been introduced. Meanwhile, some measures are adopted to reduce the distortion. In the aspect of software, control function program of blower frequency conversion adjustable-speed, protection function program and display function program can be compiled and debugged by C language and assembly language mix programming based on CCS platform.The effect of dead-time must be attached importance to the design of inverter. A new dead-time time compensation method based on voltage space vector is proposed, combining comparison unit with the dead-time programming function of DSP to carry on the compensation, the experimental result proves its validity.Finally the experiment has been progress on the blower of 22kW (two 11KW motors, one tow two). The frequency modulation precision of the system which has realized the smoothly stepless adjustable-speed in the scope of 10Hz～50Hz is 0.5Hz. The frequency conversion adjustable-speed equipment is testified to have a reasonable designed structure, higher regulating precision, good rest and dynamic performance through the experiment on a blower.