Research On Repetitive Control OfEquivalent Input Disturbance For ThreeLevel Ship Shore Power Supply

With the diversification of the market economy and the intensification of competition,China's foreign trade industry has entered a new stage of vigorous development,more and more foreign merchant ships operate in China's port for transit or maintenance.For the power supply system of most foreign ships use 440VAC/60 Hz,while the standard of China's electric power industry is 380VAC/50 Hz,the ports in China need to have electrical equipment for the transform of voltage and frequency.Conventional conversion device mainly uses diesel-fueled generating units,but it has lots of disadvantages such as low efficiency,high loss and the most important is causing serious environmental pollution problems.Therefore,the proposed of the low voltage shore power supply(SPS)is timely and necessary.The SPS uses clean power electronic devices instead of the traditional diesel generators,and transfers 380VAC/50 Hz into 440VAC/60 Hz through the conversion link of AC-DC-AC directly.SPS has the advantages of high efficiency,and low pollution,so it has a broad application prospect.Some critical problems and control methods of SPS are discussed in this article.First of all,the working principle of SPS is introduced briefly,and then the part of diode-clamped three-level inverter is analyzed in detail.The working process of the three-level inverter circuit is introduced,at the same time SVPWM algorithm is used to modulate the system,and the working principle of SVPWM algorithm based on 60 °coordinate system and 90°coordinate system is analyzed and simulated.Finally the fuzzy control principle is used to modulate the phenomenon of neutral-point unbalance of midpoint clamped three-level inverter,and the Matlab simulation verify the the control principle is feasible.In addition,in order to eliminate the periodic and aperiodic interference of the SPS control system,this paper proposes to use the double closed-loop control structure to realize the interference suppression of the output voltage,which is compound control consists of repetitive control and equivalent input disturbance estimator,and a simulationmodel of double closed-loop is built.the superiority of double closed-loop control system are confirmed using Matlab,which is contrasted with the open-loop control system.Lastly,based on the theoretical analysis,the corresponding experimental platform of SPS has been set up,and software control procedures are written based on the TMS320F2812.The simulation and experimental results are consistent with the theoretical analysis,something is shown that the technical schemes provided in this article to realize SPS are feasible.