含有右半平面零点的开关DC-DC变换器暂态性能分析及频域法设计

Transient Performance Analysis and Frequency Domain Design of Switched DC-DC Converters with Right Half Plane Zero

含有右半平面零点(RHPZ)的开关DC-DC变换器发生占空比突变时,暂态过程会出现负调现象,该现象会导致系统暂态性能变差,负调持续时间段系统易形成正反馈而出现不稳定现象,传统的频域法无法直接进行控制器设计,因此对其进行控制较最小相位系统困难的多。该文以含有RHPZ的Buck-Boost变换器为例,建立负调电压暂态数学模型,推导出衡量负调电压性能的表达式,依据该表达式与变换器参数之间的关系,给出抑制负调电压的参数设计方法。根据负调电压抑制后的系统暂态性能特点,并结合含有RHPZ开关DC-DC变换器电路拓扑的特点,提出限制占空比和频域法相结合的控制策略。实验结果表明,该控制策略具有良好的暂态和稳态性能。

When the duty cycle of switched DC-DC converter with right half-plane zero(RHPZ) changes abruptly, negative tuning will occur in the transient process. This phenomenon will lead to the deterioration of the transient performance of the system. The negative tuning duration period system is prone to form positive feedback and instability. The traditional frequency domain method cannot directly design the controller, so it is necessary to improve the performance of the system. Row control is more difficult than minimum phase system. Taking Buck-Boost converter with RHPZ as an example, this paper establishes a transient mathematical model of negative voltage, derives an expression to measure the performance of negative voltage, and gives a parameter design method to suppress negative voltage based on the relationship between the expression and the parameters of the converter. According to the characteristics of system transient performance after negative voltage regulation suppression and the characteristics of circuit topology of DC-DC converter with RHPZ switch, a control strategy combining limited duty cycle and frequency domain method is proposed. The experimental results show that the control strategy has good transient and steady-state performance.