| The energy and environment issues have become the two main factors that greatly restrict the sustainable development in modern society.With the rapidly developing of the constructions of high-rise buildings,elevators are the second largest energy consumption unit after the air conditioners in building energy consumption as common special equipment in people’s daily life.So the elevator energy conservation issue becomes more and more important and cause the attentions from international experts and elevator manufacturers.Elevator energy storage system based on super capacitor is mainly used in elevator energy conservation area.This system saves a lot of energy since it stores the energy when the elevator working in generating state and release energy when the elevalor working in motor state.As the core unit,bidirectional DC-DC converter plays a very important role in transmitting energy.The converter’s performance indexes directly influence the efficiency of the elevator energy storage system,so the design and research is very important.This paper firstly does the general design and research of the elevator energy storage system,collect and research all common kinds of bidirectional DC-DC converter.After comparing the advantages and disadvantages of isolated bi-directional DC/DC converter and the non-isolated bidirectional DC/DC converter,the selection of the isolated bidirectional DC/DC converter and the analysis of the each part’s function are completed.After that,the operating principle and model research and analysis of the isolated bi-directional DC/DC converter’s boost working mode and the buck working mode is finished,bipolar control method to and shift control method are separately designed to achieve the energy flow in two dircctions.The steady state equivalent mode and AC small-signal model of bidirectional DC-DC converter are constructed and the math model analysis is finished after the analysis of the operating principle.Finally a Simulink simulation model of bidirectional DC-DC converter is built,and verified the design of topology and control methods.The whole converter of power circuit,control circuit and software are designed at last.Based on the selected parameters and the elevator working modes,an experimental platform of bidirectional DC-DC converter is built.The platform is used to achieve the experiments such as the the conversion between 540V and 56V in two directions.Experimental results show that the design of bidirectional isolated DC-DC converter can meet all the requirements of different working environment. |
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