Research On Control System Of Railway Power Regulator In V/V Traction Power Supply System

Railway locomotive single-phase power supply,load imbalance,and the load and the circuit itself caused by the harmonic characteristics of the three-phase power supply system will cause a larger negative sequence,harmonics and other power quality problems.Railway Static Conditioner(RPC)as a traction transformer on both sides of the centralized control of power quality devices.Connected to the two power supply arm,can run in the work of the four quadrants,Able to take active,reactive transfer and harmonic control.In this paper,RPC device as the main research object,carried out the following work:(1)The working mode of RPC is analyzed,the mathematical model of RPC is simplified as the power supply structure of single-phase bridge arm,and the simplified mathematical model is established.The influence of isolation transformer on the system is analyzed.(2)The principle of extracting the RPC compensation instruction is deduced mathematically.Among them,single-phase software phase-locked loop and low-pass filter on the compensation signal extraction plays a major role.The pre-generalized second-order low-pass filter,in the digital domain,is more difficult to implement frequency adaptability,and needs to improve the filter structure.On the basis of this,two kinds of phase-locked loops are discussed.The discrete resonator PLL has the characteristics of convenient design of discrete domain.The reduced order resonant PLL has the advantages of small computation and flexible implementation,and can save resources when the processor performance is insufficient.Series filter structure,the structure of the filter in the extraction of DC signals when the extraction speed is faster,and the extraction of the DC signal is more smooth;(3)RPC controller design is the core of RPC functionality implementation.The realization and design of the current hysteresis control method are simple,but the uncertainty of the switching cycle is more demanding on the switch.Proportional integral controller as a more widely used controller theory is more mature,the algorithm of the control of the AC component is weak,harmonic compensation capacity is insufficient,to achieve harmonic compensation requires a lot of coordinate transformation,the digital controller requirements Higher.The repetitive controller has strong ability to control the periodic harmonics,but its dynamic performance is weak.Generally,the complex repetitive controller is used to coordinate the contradiction between the controller speed and the precision.A dynamic delay repetitive controller structure is used,But its design is more complex,more sensitive to the parameters,the idea of closed-loop design into the repeated control design,making the improvement of the controller is easy to design and implementation,repeat the controller although the global harmonic suppression is very strong,but sometimes not Requires global harmonic compensation.In order to improve the speed of the controller,used an improved poor shooting controller.In order to control each harmonic,an improved parallel quasi-resonant controller is used.The experiment shows the effectiveness of the algorithm.(4)In order to verify the function of RPC,built a 20 k W prototype system.The platform is reconstructed by focusing on the quasi-resonant controller structure.