串联谐振变换器的稳态模型

谐振变换器是依靠改变开关网络的工作频率实现对输出量的控制的,因此它是一种变频控制的开关调节系统。像PWM型开关调节系统一样,这种开关调节系统也是一种强非线性、离散的病态系统,要精确的建立其数学模型并从理论上得到系统的瞬态解和稳态解是较为困难的,更不能用经典控制理论设计控制器并研究其稳定性。因为在传输能量方面,PWM型变换器是靠平均值传输能量的,而谐振型变换器是靠"基波"传输能量。所以在稳态分析时,PWM型变换器采用平均值分析法,而谐振变换器采用了基波分析法。本文详细介绍了串联谐振变换器稳态模型的建立方法。

Steady State Model for Series Resonant Converter

The output voltage of resonant converter is controlled depending on the changes of the switch network's frequency.Hence it is called pulse frequency modulation (PFM) system,which is the same nonlinear and discrete ill-conditioned system as the pulse width modulation (PWM) system.It is difficult to model the accurate mathematical building and analyze the transient response as well as the steady state response from the theories.Even worse,the compensating networks design and the converter's stability's study is hard u- sing the classical control theories.The average method is employed to analyze the energy transmission mode of PWM system while the equivalent fundamental wave method is applied in resonant converter,thus PWM converter is modeled by average method while reso- nant converter is modeled by equivalent fundamental wave method.The steady state model for series resonant converter using this method is introduced detailedly in this paper.