交错并联Buck-Boost变换器模型预测控制方法

Model Predictive Control Method for Interleaved Parallel Buck-Boost Converter

对于交错并联Buck-Boost双向DC-DC变换器,以往大多采用传统移相控制方法,该方法具有变换效率提升困难、各模块电感电流不能自动均流等缺点,对此提出一种新的模型预测均流控制方法对交错并联Buck-Boost双向DC-DC变换器进行控制。该方法借鉴了模型预测控制思想,通过建立预测模型来预测下一时刻变换器中所有可能的开关状态对应的目标函数值,然后根据控制性能要求建立目标函数,最后通过最小化目标函数值确立下一时刻的开关状态,使系统控制目标达到最优。对所提出的模型预测均流控制方法进行仿真及实验验证,仿真结果显示所提出的方法可以使直流母线电压和实际电感电流准确追踪给定值,两电感电流均衡且电流纹波很小,动态过程中直流母线电压超调约为1.5%,变换器动态响应时间为8 ms左右;实验结果显示直流母线电压和电感电流有良好的静态性能,两电感电流均衡且电流纹波很小,动态过程中直流母线电压超调约为5%,变换器动态响应时间约为10 ms,证明了所提出方法的可行性。

The traditional phase-shift method is used widely for interleaved parallel Buck-Boost bi-directional DC-DC converter.This method has the faults of difficult in increasing transformation efficiency and balancing inductors current.So a new model predictive control method of balancing two inductors current was proposed.Model predictive control was introduced in this method,predicting the corresponding value of objective function with all the possible switch states for the next time of the converter.And then cost function according to the requirements for control performance was established.At last,the switch state of the next moment was selected by minimizing the value of objective function to optimize all control objectives.Simulation analysis and experimental verifications for this proposed method were carried out.The simulation results show that the proposed method can make the voltage of DC bus track the given value accurately,two inductors current are balanced and the current ripple is very small.The overshoot of DC bus voltage in dynamic process is about1.5%and the dynamic response time of converter is about0.008s.The experimental results show that the DC bus voltage and inductance current have good static performances,two inductors currents are balanced and the current ripple is very small.The overshoot of DC bus voltage in dynamic process is about5%and the dynamic response time of converter is about0.01s,which prove the feasibility of the proposed control method.