Research On Bidirectional DC/DC Converter Control Strategy

In recent years,along with the advance of modern science and technology,the requirement of the power supply is also increasing with the demand of practical application.Hence,the traditional linear regulated power supply is hard to meet the demands.Under this background,the switching regulated power supply,such as the DC/DC converters with PWM control,which have become a key role in the field of power electronics.Nowadays,it has been widely applied in various fiel ds,such as micro grid system and electric vehicle,etc.What’s more,the classical linear control algorithm has great limitations in the controller design of switching nonlinear system.In order to further popularize the application of DC/DC converter,it is relevant to the point that focusing on nonlinear control algorithms of enhancing the performance of the DC/DC power converters.In the paper,with the purpose of further improving the overall of the system,the bidirectional DC/DC converter is selected as the research object of the control strategy.The main contents are as follows:(1)For the bidirectional DC/DC converter system,the introduction of relevant background and developing status is given briefly.And then,several dominant control methods are compared and analyzed,the traditional sliding mode control method is emphatically analyzed on its shortcomings and limitations.(2)Considering the characteristics of the circuit structure of a half-bridge bidirectional DC/DC power converter,the most common state-space average modeling method is discussed here,and,based on which the state equations in Buck mode and Boost mode are constructed respectively.Then,a brief overview of sliding mode control and the design procedures derivation of non-singular terminal sliding mode controller in bidirectional DC/DC converter are given here.(3)In order to further strengthen the dynamic response speed and static accuracy of the bidirectional DC/DC converter,a novel control strategy is proposed in this paper.The input voltage and load are measured in real time by using a finite time convergence observer,with the combination of the non-singular terminal sliding mode control method,then a composite non-singular terminal sliding mode controller is designed.In addition,the stability of the designed controller is fully proved.Finally,the simulation models under different modes are established.By contrasting with the traditional sliding mode control algorithm,it could be concluded that the proposed control strategy in this paper can effectively enhance the dynamic performance and steady-state precision of the converter system.(4)The software and hardware design of the converter system is implemented.First of all,DSP28335 was selected as the primary controller of the physical platform,and then the hardware circuits of various modules were designed more specifically;the algorithm program was written by the modular programming.Finally,the experimental comparison results with the traditional sliding mode control algorithm verify the superiority of the new control strategy proposed in this paper.