An Improved Buck-Boost Converter Based on Pulse Sequence Control

Buck-Boost converters can achieve step-up and step-down easily and have been widely used in many applications because of the simple topology, easy control and can input current continuously, etc. Meanwhile, the conventional pulse width modulation (PWM) control method owns excellent steady state performance, but it cannot avoid slow transient response and difficult compensation network design. Thus, this paper combines an improved topology and a simple pulse sequence (PS) control technique to improve the performance of the system from the following three aspects. First, PS instead of PWM control technique is applied to improve the dynamic response and avoid the compensation link. Second, an improved Buck-Boost converter is put forward to effectively inhibit the low-frequency fluctuation of the PS control method when the inductor is operating in continuous conduction mode (CCM). Third, the proposed converter can achieve current sharing and reduce the energy loss of the inductor. In addition, there is almost no increase for the cost and volume. The simulation results are provided to verify the theoretical analysis.