Robust Controller Design For Railway Static Power Conditioner

In power control system of electrified railway,it is difficult to describe dynamic characteristics by accurate mathematic model.And the variation of parameter produces the uncertainty for some factors such as environment.in addition,necessary reduction could not be avoided for controller design,ever when the accurate mathematic model could be derived from the control plants in some case.Robust control theory is effective for the control problem of uncertainty system.The theory is applied in Railway static Power Conditioner system,which is the typical control system with the disturbance and uncertainties.The controllers are designed separately and simulation for Railway static Power Conditioner system base on ?-synthesis control theory andH_? control theory,At the same time,the simulation experiment is also carried out in this thesis.The main work is described as follow:(1)According to the structure and work principle of RPC power supply system,The vector analysis method is used to analyze the transformation relation of each variable in the power grid.At the same time,the mathematical model is obtained.(2)This paper puts forward a RPC system compensation method based on improved particle swarm optimization algorithm,In order to solve the problem that traditional PSO is easy to fall into the local optimum because of reducing particle diversity and lacking mechanism to jump out of local optimal value region,Improved particle swarm optimization has multi-swarm and multi-speed update mode.The total harmonic distortion rate of a phase supply arm current,the integrated absolute error of a phase supply arm current and the integrated absolute error of DC voltage are selected to form the optimal objective function in the RPC compensation power supply system,The optimization model of RPC controller based on improved particle swarm optimization algorithm algorithm is established,and the experimental results show that the improved method can improve the dynamic performance of PRC system by reducing the overshoot of the system and improving the response speed.(3)A ?-synthesis robust control method based on model matching for RPC system is proposed.The model aimed at describing the problem of component parameter perturbation which was caused by that was difficult to measure the AC side inductor L in the RPC structure of the actual system,and it will change with time and so on.Model matching problem including the actual controlled object was transformed into a generalized system with abstracted uncertainty block and solved by DK iteration.The ?-synthesis simulation results show that the ?-synthesis controller can assure the nominal performance and robust performance of RPC system and improve the dynamic performance of the railway static power conditioner,which is beneficial to the stable operation of the device.(4)This paper presents aH_? robust controller design method for railway power conditioner based on cat swarm optimization algorithm.The weighting function plays a decisive role in the design of robustH_? control,This method is used to solve the problem that there is no unified formal method for weighting function construction.Cat swarm optimization algorithm has those features that swarm intelligence optimization and random search to achieve the best global optimum,TheH_? controller is designed through the cat swarm optimization algorithm is used to construct the weighting function.The simulation results show that theH_? controller can make the RPC system achieve the compensation effect quickly.