Research And Development Of Driving Power For Dual-ultrasonic Pelleting System Based On FPGA

Cellulosic fuels are regarded as an alternative to petroleum-based fuels. According to the problems of poor compression, big bulk equipment, a low sugar yield, and easily loosing during transportation of biomass pellets using traditional pelleting method. The proposal presents" Dual-ultrasonic vibration-assisted pelleting of biomass". However, a new issue has presented that two ultrasonic vibrator are driven by one power supply. A dual-ultrasonic drive power has been designed in this paper, and parallel characteristics of dual-ultrasonic transducers and ultrasonic pelleting process are studied.Firstly, according to the principle of dual-ultrasonic vibration-assisted pelleting and ultrasonic power, the control program was designed basing on FPGA,which has advantage such as low cast and good flexibility. And then the tune DC power, the high-frequency inverter circuit, the sampling circuit, the over current and the over temperature protection circuit were completed.Secondly, according to the maximum current method and phase method, the frequency automatic tracking control was designed based on FPGA, which tracking accuracy is2Hz. And then the over-current protection modules, the power control modules and the other hard-core design of FPGA were completed. Intelligent touch screen was used in human-computer interaction systems, Nios Ⅱ software and the Quartus II were used on the FPGA for secondary development, and the self-custom SOPC chip system was established to achieve that touch screen communicates with FPGA, the control of power supply’s on-off, the initial settings and the thereal-time display of current and frequency.Again, the saber software was used to simulate on performance characteristic of equivalent circuit for piezoelectric transducer. The matching inductor value influences on the phase difference between piezoelectric transducer’s current output and high transformer’s secondary voltage, under the condition of no-load and load. In the case of no-load, piezoelectric transducer’s work performance is better under the series resonance condition. However, in the case of load, piezoelectric transducer’s work performance is better under the parallel resonance condition. Finally, the Matlab software was used to analyze to impedance characteristics of the double-ultrasound transducer, and the design of parallel matching networks of double-ultrasonic was completed, the PCB board for the drive power, has been finished. Using the dual-ultrasonic vibration-assisted equipment to experimental research on the drive power, the results show that the tracking characteristic is better and achieve the desired design requirements. Through studying the effect of the presence or absence of ultrasonic, compression time, adjustable output voltage of the DC power supply on density, the results show that:the influence of dual-ultrasonic vibration-assisted on pellet density is the largest.