基于阻尼系数的PEF系统输出方波波形特性影响因素

Influence Factors of PEF System Output Square Waveform Characteristics Based on Damping Coefficient

高压脉冲电场技术是一种新型的非热食品加工处理技术,其对输出脉冲参数有着严格的要求。基于IEEE脉冲变压器等值参数模型,研究了双极性脉冲方波脉冲电场技术（PEF）系统的阻尼系数与脉冲输出方波波形特性的关系,重点考察了负载阻抗、回路寄生参数等对系统阻尼系数的影响。理论和试验研究发现：负载阻抗越小,系统阻尼系数越大,脉冲上升时间越大;回路寄生参数影响系统上升阶段阻尼系数σrsys,输出方波上升时间增大;箝位式RCD缓冲吸收电路改变了系统分布参数能量释放通道,系统下降阶段阻尼系数σfsys减小,输出方波下降时间增大。由此可见,系统阻尼系数对PEF系统输出方波波形特性有着重要的影响,因而对于PEF系统输出方波波形优化,需基于系统阻尼系数综合考虑波形特性影响因素的作用。

High-voltage pulsed electric field technology is a new type of non-thermal food processing technology, of which the treatment performance is determined by the output pulse parameters. The relationship between the output waveform and the damping coefficient of bipolar square pulse PEF system was studied based on the IEEE pulse transformer equivalent parameter model. The effects of the load impedance and loop parasitic parameters on the system damping coefficient were studied. Theoretical and experimental results show that the damping coefficient of PEF system increases with the decrease of the load impedance, and the pulse rise time increases. Loop parasitic parameters increase the damping coefficient σrsys and then the pulse rise time. The RCD clamp circuit of the pulsed forming system changes the energy release channel of the system distribution parameters. When the σfsys decreases, the fall time of the output square pulse will increase. The experimental results prove that the system damping coefficient has an important effect on the output square waveform characteristics of PEF system, and relevant influence parameters should be considered to obtain an optimal square pulse.