Ships Using The If Power Developed

The thesis studies 400Hz medium frequency power supply in naval vessels. It is very important that how medium frequency power supply keeps output waveform sine wave and output frequency stable. The thesis tries to solve the problems in two ways: carrier wave modulation control methods and deadbeat control methods as well as some theoretic problems discussed.In chapter 3, on the basis of analyzing and comparing with some common PWM modulation methods, a step reference waveform modulation strategy is proposed. Via theoretical analyzing, we can find that the step reference waveform modulation strategy is an ideal one when frequency modulation ratio is not very high.In chapter 4, designing methods of filters in medium frequency power supply and negative effects that filters impact on the running system are discussed. After detailed designing method with some examples are proposed, the problem that running system with asymmetric load is studied theoretically and some feasible schema are proposed.Ralated software system and hardware system of the power supply are introduced in chapter 5 and chapter 6 respectively. At the end of chapter 6, experiment waveforms are given. The results show that system design is satisfactory.In chapter 7, deadbeat control methods of medium frequency power supply are proposed. A deadbeat control algorithm based on resistive load as well as its realization scheme and experiment results are given. To overcome its shortcomings, a disturbance prediction based deadbeat control algorithm is presented. The result ofsimulation shows that it is an ideal deadbeat control method.