Optimization Of Dynamic Slope Compensation For Boost Converter

There are many non-linear devices,such as inductors,capacitors and switchers,in the power converter,which causes to strong non-linearity,mainly manifested as sub-harmonic oscillation,chaos and bifurcation,etc.These phenomena make the circuit operation into unknown condition,and In severe circumstances,the system maybe paralyzed.Therefore,it is necessary to study deeply the nonlinearity of the power converter.The thesis takes the peak current DC/DC Boost converter as the research object,studies the sub-harmonic oscillation phenomenon occurring at a large duty cycle of the converter,and wants to find out a feasible solution to improve the stability of the converter.The main work of the thesis and the achieved results are as follows:(1)The working curves of the inductor current of the DC/DC Boost converter under different duty cycles are analyzed,and the source of the sub-harmonic oscillation in the peak current model converter circuit is found out,and then the traditional slope compensation for DC/DC Boost converter is studied,focusing on the problem of stabilizing control with the cost of the rated power.(2)A dynamic slope compensation method is proposed to ensure the designed power while solving instability phenomena,such as sub-harmonic oscillation,in the converter.The presented method can not only improve the stability of the converter,but also occupies good transient response ability.The simulation model for the DC/DC Boost converter is established using MATLAB/Simulink module,simulation and analysis are carried out to prove the correctness of the proposed method.(3)In order to further reduce the hardware cost of the proposed dynamic compensation,a simplified model is proposed,and the original two analog multipliers are replaced by an operational amplifier.Based on the MATLAB/Simulink module simulation,dynamic compensation and its simplification were researched and tested.The experimental results show that simplified dynamic compensation method can be achieved with stable control of the converter and lower cost,which is more useful to promote the engineering applications.The results of the thesis have certain reference value for the design of high-performance DC/DC converters.