Comprehensive Control Technology And Application Research On Power Quality Of V/v Traction Power Supply System

As the main artery of the national economy,the important infrastructure and public transport,electrified railway has an important role in the national economic and social development.With the widely use of modern power electronic technology in the railway industry,the inherent nonlinear characteristics of the power electronic equipment and the power supply driving mode of the electric locomotive have caused many kinds of pollution to the traction power supply system,which has brought the negative effect on the safety,stability,high efficiency and economic operation of the public power grid and electric locomotive.Therefore,the effective management of power quality of traction power supply system has become a major issue of railway development,which has important practical significance.The main work and innovation of this paper are as follows:(1)This paper presents an integrated control system of power quality for V/v traction power supply(V/v-PQMS).The compensation system consists of back-to-back voltage source converter(VSC)and passive fixed capacity(FC).The comprehensive control principle of the compensation system was analyzed,and the switching mode and the carrier-phase-shifted(CPS)PWM scheme for the single phase multi VSC were studied.The simulation result shows that the comprehensive compensation effect can be achieved.(2)A control strategy of V/v-PQMS in stationary coordinate system was proposed.The models of stationary abc coordinate system,the αβ coordinate system and the dq coordinate system were established respectively.The proportional integral(PI)control of two phase synchronous rotating coordinate system was discussed.Then,the typical expression and basic characteristics of quasi proportional resonant(QPR)controller in two-phase stationary coordinate system were analyzed,especially the parameter design and stability analysis of QPR controller.The frequency method was used to analyze the reason that the QPR control is superior to the traditional PI control in the dynamic performance of the system.Aiming at the problem of fast dynamic regulation and voltage fluctuation of power supply,the design method of QPR controller considering steady state characteristic and anti disturbance ability was given.The simulation result shows that compared with the PI control strategy,the QPR control strategy can effectively improve the dynamic performance of the system.(3)A new asymmetric compensation design method of V/v-PQMS was proposed.The compensation capacity of FC on two power supply arm feeders of V/v transformer was derived,and the calculation formula of asymmetrical compensation capacity of V/v-PQMS was obtained.In order to reduce the operating current and loss of V/v-PQMS,and to improve the long-term operation capability of the device,the principle of power quality parameters optimal compensation was studied,and the difference between the full compensation and the optimal compensation was compared.The relationship between the power quality parameters and the given values of compensation powers was analyzed,and the optimization model of V/v-PQMS compensation power was established.In order to meet the accuracy,rapidity and stability requirements,a simplified particle swarm algorithm hybrid leapfrog algorithm based on the big bang was proposed.The Example analysis shows the effectiveness and feasibility of the optimization calculation of the V/v-PQMS compensation power given values.(4)The principle prototype of V/v-PQMS was built.The parameter design method of the main parts of the prototype was discussed,and the calculation method of the connection reactance and the DC capacitance was analyzed.The drive circuit of the back-to-back VSC was designed,and the DSP hardware structure of the controller and the reference voltage zero capture circuit were introduced.Finally,The actual test and data analysis are carried out on the prototype,which laid the foundation for the manufacture of the engineering prototype.(5)The engineering prototype of V/v-PQMS was developed.Based on the practical design experience,the formula for calculating the key parameters of the engineering prototype was derived.According to the actual test results,the power quality parameters such as voltage unbalance,power factor,harmonic distortion and voltage fluctuation are compared and analyzed in detail.The results show that after the compensation the indexs of power quality can meet the requirements of the national standard,which verifies the effectiveness and practicability of the comprehensive treatment method.Due to the improvement of the power quality of the grid side and the traction side,the win-win situation of the electric power company and the railway enterprise has been realized.