The Inverter Design Based On High Frequency Isolation

In addition to the traction converter system which does not require locomotive power supply,the auxiliary converter system is also an important part of the electric locomotive and is responsible for the power supply of various other devices such as lighting systems,video detection and signal lights.Therefore,the study of auxiliary converter has an indispensable significance for the development of electric locomotives.This paper summarizes the development history of the auxiliary converter in our country.According to the technical parameters of the high-frequency converter isolated in this subject,a converter based on the high-frequency isolated converter is designed.The paper analyzes in detail process of topology selection and operational principle of main circuit.Choosing main component,depicting the control strategy of the system,and designing the Hardware Circuit of system Control Unit,then verify the feasibility of the design scheme of three inverters design based on high frequency isolation through the simulation software and experimental platform construction.First of all,according to the technical parameters of high-frequency isolation inverter,the inverter topology analysis and comparison.High-frequency isolated inverter system is divided into DC/DC converter and DC/AC inverter.Among them,the main circuit of the DC/DC converter adopting the ISOP structure can be divided into two identical modules,each of which is divided into two parts by a high-frequency isolation transformer.The primary side of the transformer is a half-bridge inverter.Since each transformer has two secondary windings,the secondary side is two full-bridge uncontrolled rectifier circuits in series.The DC/AC inverter section is a traditional two-level inverter.Second,the main circuit is divided into five parts: input front-end circuit,half-bridge inverter circuit,high-frequency isolation transformer,uncontrolled full-bridge rectifier circuit and DC/AC three-phase inverter circuit.The main part of the circuit selection calculation.The hardware circuit includes the power supply circuit,control circuit and drive circuit.Finally,assemble a prototype to build an experimental platform.Through the overload experiment of Light load and No-load switch,it is verified that the inverter design based on high frequency isolation has good performance.Voltage and current waveforms shows that the fluctuations are within the required range,and Co-operative content does not exceed 5%,and the reaction is rapidly.Secondly,due to the ISOP structure of the main circuit DC/DC conversion,a three-loop control strategy of input voltage sharing loop,current loop and current loop is proposed in order to solve the problem of voltage sharing and current sharing between modules.In this paper,Voltage ring combination.Detailed analysis.Aiming at the problem of DC/AC conversion control,this paper adopts double loop control strategy and SVPWM modulation method.Then under the conditions of input voltage stability and input voltage limit fluctuations,using matlab/simulink software to simulate the above control strategy.Finally,this article introduces the general framework of inverter control unit,and describes the design of power supply circuit,sampling circuit,protection detection circuit and drive circuit in detail.Assembled a prototype inverter,and set up the experimental platform,through the system light load test and no-load switch overload test to test this design of high-frequency isolated inverter functional parameters to meet the design requirements.In this paper,the design of high-frequency isolated inverter simulation waveforms and experimental results and theoretical analysis verify the feasibility of the design.