Boost变换器既有开关动作上的离散性,又有连续子系统,是典型的混杂动态系统。根据混杂切换理论建立Boost功率变换器的混杂模型,分别讨论变换器在CCM和DCM两种工作模式下的切换控制策略。在固定的系统工作频率下,通过检测电感纹波电流与理论值相比较来控制功率开关器件导通或关断,由此得到所需的占空比信号,从而实现Boost功率变换器的混杂切换的控制。根据电容电荷平衡原理,对负载电流进行估算,减少电路中被检测量,简化控制器的设计并提高了效率。最后,在Matlab/Simulink环境下进行仿真实验,验证了所提控制算法的有效性。
Boost converter is a typical hybrid dynamic system including both discrete and continuous subsystems. Based on hybrid switching control theory, the hybrid model of Boost converter was built. And then this paper discussed the switching control strategies of the converters working in continuous current mode(CCM)and DCM modes. On condition that the switching frequency was fixed, the duty cycle was obtained by comparing the inductor current with its theoretical value, which achieved the hybrid switching control of the Boost DC-DC converter. Meanwhile, according to the principle of capacitor charge balance, the load current was estimated instead of by detection which simplified the design and improved the efficiency. Finally, the simulation results show that the proposed algorithms are effective.