Research And Realization Of SVPWM

Together with the continual development of all-controlled fast semiconductor self-turn-off devices and intelligent high-speed microcontroller,the digitized PWM is becoming the trend of PWM control technique development.But the analogal electric circuit cann't realize the traditional SPWM method easily.The traditional SPWM can not adapt to the development trend of the digitization of the modern power and electric. Space-vector pulse width modulation(SVPWM) a kind of superiorized PWM control technique: achieving the effective utilization of the DC supply voltage(compared with the traditional SPWM,reduced by 15.47%),having little harmonic output and the easy control method,furthermore easy to realize the digitization.The article presents the developing condition of PWM and SVPWM first.Then the theory of SVPWM is discussed in detail.The SVPWM is based on the thought of magnetic chain tracking.It makes the ideal magnetic chain circle of three-phased sysmmetry electric motor supplied by three-phased sysmmetry sine wave voltage for basis,uses the practical magnetic chain vector formed by the different switch modes of three-phased inverter to track the basic magnetic chain circle.During the course of tracking,the inverter changes the switch modes properly to form the PWM waves.Then the modulation wave of SVPWM is analyzed in detail.The modulation wave of SVPWM is implicit,but the analogous modulation wave in A-B-C axis needs to be calculated in order to expose the internal relation of SVPWM and SPWM.That is to show the implicit modulation wave of SVPWM. SVPWM actually is a transformed SPWM ruly sampled by the modulation wave which is injected by the zero prefaces based on space vectors.At the same time,the basic modulation method of SVPWM is analyzed detailly.Some improvements are carried in the existed control method of SVPWM on the basis of fore person's reserch.The improved control method is simulated dynamically by using MATLAB6.5/SIMULINK dynamic simulation sofeware.It proved the accuracy of the improved control method by analyzing the result ofsimulation.The simulated model of asynchronous machine variable frequency variable speed system fed by SVPWM inverter is set up.The dynamic performance of the system is analyzed in detail and.compared with SPWM pattern,the SVPWM pattern reduces the torque ripple,improving the speed of reacting as well as achieving the effective utilization of the DC supply voltage for the inverter.At the last,the SVPWM pattern and the system are realized by IMCD2407 which core is TMS320LF2407A DSP. The sofeware of producing raaltime SVPWM wave is designed .