| In recent years, with the application of advanced digital chips and control technology, power converter has been a qualitative improvement in intelligent level, reliability and flexibility. However, at the same time the performance of power converter being improved, analysis and design methods of power converter are facing new challenge. For example, some traditional parameters are short of practical significance for modern digital power converters. With the increase of the switching frequency, traditional parameters such as Ripple Coefficient, Power Factor, Total Harmonic Distortion are becoming more and more unsuitable for describing the features of power conversion circuits. There are many power’s modeling analysis methods with different performance. But most of these methods will be facing the problems of high degree of complex and poor flexibility when analysis high switching frequency and multi- element power conversion circuits. On the other hand, the frequently used digital PID control method also has many disadvantages. For example, the steady state error is difficult to eliminate, the transient response is slow, and the parameters’ selection is not flexible and precise. This thesis chose digital power conversion technology as the research object, and the widely used digital low power dcdc converter as the object of study. In view of the traditional methods’ shortcomings in the application of digital converter, thesis innovatively proposed a kind of modeling method and digital control method based on energy.From the energy point of view, the power conversion circuit is a kind of passive, dissipation and positive qualitative regional system. Firstly, the energy of power conversion circuits was detailed analysis. Thesis theoretically derived the involved several parts of energy, and analyzed the stored energy’s influence on power conversion circuits. New parameters, Oscillation Factor and Transient Time Constant were proposed based on the stored energy. Study showed that Oscillation Factor and Transient Time Constant could be used to characterize the transient response’s wave and speed. On the basis of this conclusion, thesis defined new parameters, Magnetic Damping Time Constant and Electric Damping Time Constant, and proposed a power converter circuit’s modeling analysis method based on energy. Then a detailed theoretical analysis, derivation and software simulation were given. Thesis showed that the proposed method can simplify the process of analyzing power converter’s power stage circuit. For the control stage of power converters, thesis proposed a fuzzy feedforward proportional control method based on energy, on the analysis of energy and the disadvantages of PID control. According to the control method, thesis designed a digital controller of digital power conversion circuit, and simulated it by software. By comparing the simulation results, it can be seen, the proposed digital control method can be well applied to control the power converter circuit, and the transient response speed, output stability have obvious advantages over traditional PID control method. In addition, thesis verified the research by means of experiment further. |
