Multi-Scale Modeling Method Of DC/DC Convertor

In order to analyze the scale-phenomena occurring in the nature, a multi-scale modeling method is proposed as required. The core idea is to build the mathematic models of different scales for a system, then analyzing the system based on these models, finally integrating the analysis results. As a result, the essential characteristics of scale-phenomena can be shown better by utilizing the multi-scale modeling method.As a complex system, many physical phenomena are featured with multi-scale in DC/DC convertor. Meanwhile, people always observe the operation process of the system on different scales in engineering practice. At present, the modeling method of DC/DC convertor is on a single scale, thus some physical phenomenon can't be directly observed through a single scale model, such as the overshoot phenomenon of switch tube voltage or current. Therefore, to analyze the scale-phenomena of DC/DC convertor in deeply, it's important for us to investigate the multi-scale modeling method.For the multi-scale characteristics analysis of a DC/DC convertor, this paper is devoted to proposing a multi-scale modeling method for analyzing some physical phenomena of a DC/DC convertor, and the method is applied in a BUCK convertor.The main works of this paper are as follows.Firstly, the principal theory of multi-scale system is elaborated in this paper. Then, we analyzed the multi-scale system from four aspects including the scale concept,time and space scale concept, multi-scale system concept and phase space concept. Also, taking a signaling system as an example, the multi-scale stochastic system is introduced.Secondly, the power electronic system is divided into different scales, which meanings are explained respectively, so we proposed a framework of multi-scale model for the power electronic system. Then, the multi-scale modeling method of DC/DC convertor is analyzed and also its core idea is proposed. A framework of multi-scale model of DC/DC convertor is constructed, and based on which we studied the handover strategy.Thirdly, the operating principle of BUCK convertor is investigated. A circuit scale model is constructed based on the hybrid automata theory according to the hybrid system characters of BUCK convertor. Then a hybrid control strategy is investigated for a BUCK convertor, and we presented some simulations to demonstrate our theoretical results. Taking the operating principle of IGBT(Insulated Gate Bipolar Translator) into account, a device scale model is constructed for an IGBT based on Hefner model. Both simulation and experiment results are verified by the proposed model methods.Finally, a correlation function is established according to analyze the relationship between the circuit scale model and the device scale model, based on which the multi-scale model of BUCK convertor is constructed. A simulation model is built to analyze the consistency and handover strategy. The model proposed this paper is compared with the traditional models.