MOSFET非线性寄生电容对单管谐振正激变换器的影响及其处理  

Influence of Nonlinear Parasitic Capacitance of MOSFET on Single-switch Resonant Forward Converter and the Corresponding Treatment

作　　者：邓俊清 陈为[1] 贺宇航 DENG Junqing;CHEN Wei;HE Yuhang(College of Electrical Engineering and Automation,Fuzhou University,Fuzhou 350108,China;Center for Advanced Power-conversion Technology and Equipment,Southeast University,Nanjing 210096,China)

机构地区：[1]福州大学电气工程与自动化学院,福州350108 [2]东南大学先进电能变换技术与装备研究所,南京210096

出　　处：《电源学报》2023年第2期21-28,共8页Journal of Power Supply

基　　金：国家自然科学基金资助项目(51777036)。

摘　　要：高效的正激变换器常利用高频谐振实现磁复位及软开关。高频下,MOSFET非线性寄生电容对谐振的影响更加明显,不仅导致谐振点偏移,软开关失效,更可能令磁芯无法正常谐振复位。为计算在非线性寄生电容影响下的谐振参数,利用Simplis搭建仿真模型,并推导基本数学表达式;利用分段线性法计算谐振过程中电容充放电时间,并根据能量守恒建立谐振参数取值的约束方程组。计算所得的谐振参数可在不降低频率和占空比的条件下克服MOSFET非线性电容的影响,当激磁电感取其上限值时,磁损最小,此时可得最高效率。A high-efficiency forward converter usually utilizes high-frequency resonance to achieve magnetic reset and soft switching.At high frequencies,the nonlinear parasitic capacitance of MOSFET has a more obvious impact on resonance,which will not only cause the resonance point shift and soft switching failure,but also will make the magnetic core unable to resonate normally.To calculate the resonance parameters under the influence of nonlinear parasitic capacitance,Simplis is used to build a simulation model,and the basic mathematical expressions are derived.The piecewise linear method is used to calculate the capacitor charging and discharging time during the resonance process,and the constraint equations for values of resonance parameters are established according to the conservation of energy.The calculated resonance parameters can overcome the influence of MOSFET’s nonlinear capacitance without reducing the frequency or duty cycle.When the magnetizing inductance is set to its upper limit,the magnetic loss will be the smallest,and the highest efficiency can be obtained simultaneously.

关 键 词：寄生电容 非线性 谐振正激 MOSFET 

分 类 号：TM46[电气工程—电器]