Design Of The DC-DC Converter And Snubber For Fuel Cell Generation System

Global energy crisis,environmental pollution and ecological problems lead to increasing attention to the development of new energy.Fuel Cell which can transform chemical energy directly into electric energy by the way of electrochemical reaction will be the major energy in the near future and widely applied with its high efficiency and cleansing.But in order to get to meet the requirements of DC or AC,a power converter must be used to improve the output power because of the soft feature of the output volt-ampere characteristics and the power design problem.So,Fuel Cell power converter should be included in a one-way DC-DC converter,a snubber based on auxiliary power supply and an inverter(AC Load).Firstly,The article analyses in detailed the operating principle and working process of the push-pull forward converter used to Fuel Cell DC-DC converter,and draw the comparative advantages of push-pull forward converter,compared with push-pull converter and forward converter.The push-pull forward converter has the excellence both of the push-pull converter and of the forward converter because of the clamp capacitor linked between the IGBTs,and overcomes their disadvantages.Therefore it shows significant applications in the fields of Fuel Cell generations.Second,the principle of indirect current mode control and the applicability in the push-pull forward converter are analyzed in detail,and more,the stability of the control strategy performance is analyzed via the bode plots.An improvement for peak current mode control,the indirect current mode control based the integration of the inductor voltage makes the alternating voltage waveform to triangle wave,expressing the inductance current waveform for the current loop to implement the modulation of the duty cycle.And then,hardware and software design based DSP for the Fuel Cell DC-DC converter are made.The hardware includes the DC power supply,high frequency transformer,drive circuit, detection circuit,and the software includes the sampling and main procedure.Result, experimental measurements are similar with the simulation analysis and prove the feasible and rationality.The snubber for Fuel Cell based on battery or super capacitor is to solve the dynamic response speed and to achieve maximum power point tracking.A bi-directional DC-DC converter is used to achieve two-way flow of power.At last,the article establishes the Fuel Cell model and analyzes the process of buck-boost bi-directional DC-DC converter and maximum power point tracking algorithm-- perturbation and observation method.Then, simulation model of snubber is established and analyzed.