| The marine ventilation frequency converter realizes the variable frequency starting of the fan by controlling the three-phase asynchronous motor.Three-phase asynchronous motor has many advantages,such as simple structure,durability,easy maintenance,low price,etc.The strategies of AC variable frequency control can be divided into constant voltage-frequency ratio control(V/F),vector control(VC)and direct torque control(DTC).With the development of variable frequency speed regulation technology,this paper designs a variable frequency speed regulation system based on vector control of SVPWM modulation technology to realize variable frequency speed regulation of fan and improve the output characteristics of the system.Firstly,the mathematical model of SVPWM modulation technology used in variable frequency speed regulation system is built and verified by simulation model.Then the corresponding parameters are given through the mathematical models of the inverters,voltage loop control and output filter.Finally,the simulation model of the variable frequency speed control system is given.Secondly,aiming at the influence of dead-time on output voltage and current,on the basis of comparing the traditional dead-time compensation technology,the dead-time compensation is realized by constructing a new dead-time compensation voltage vector to change the value of the comparative register in the control chip.The feasibility of the dead-time compensation method is proved by the harmonic analysis of the current waveform by the simulation waveform.Finally,a three-phase AC converter based on DSP control and SVPWM modulation technology is designed.The whole system includes pre-charging,inverting and output filtering.Through the control of TMS320F28335 chips,dead-time setting and compensation,frequency conversion output and other functions are realized.Finally,the effectiveness of the dead-time compensation method is proved by the actual measured current waveform and harmonic data analysis. |
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