| Trolleybus combines all the advantages of tram and internal combustion engine bus,while overcomes their disadvantages at the same time.That is,it is able to drive by using the grid power without relying on the fixed-track travel.In recent years,dual-power source trolleybuses are increasingly favored by the major cities as the green public transport vehicles.Compared with pure electric bus,trolleybus needs to connect the power supply of cable network overhead,while there is a relatively high voltage between the line network and the ground.For passenger safety consideration,the corresponding standard stipulates that trolleybus shall be equipped with additional insulation between high voltage electrical appliances and vehicle body.Today the drive power system of pure electric bus is developing rapidly,this provision greatly limits the trolleybus power system progress.The application of centralized isolation technology in trolleybus will solve this problem,which has a great significance to the convergence and development of trolleybus and new energy vehicle technologies.This article has done R&D for the high-voltage power distribution system and the driving system of the dual-source trolleybus,which is based on one company's trolleybus as the research object with the purpose of improving the energy efficiency,lightweight and intelligentized of the trolleybus drive power system.The details are as follows:(1)This paper analyzes the research background,and makes a detailed analysis of the development of the whole high-voltage power supply,power distribution and driving system of the trolleybus which is the research object.(2)This paper introduces the principle of dual power source trolleybus,and elaborates the selection and matching method of each components in the whole high voltage system of dual power source trolleybus.At the same time,the typical circuit structure of several widely used isolated DC/DC converters is briefly listed,its working principle and advantages&disadvantages are analyzed as well.(3)The key technology of dual power source trolleybus' high voltage main circuit is introduced and analyzed,and the traditional design method is summarized in principle and optimized for its characteristics.(4)This paper briefly analyzes the parameters and function requirements of the isolated DC/DC converter power supply for dual power source trolleybus.At the same time,the relevant control technology is analyzed and selected.And then taking a comprehensive consideration according to the advantages and disadvantages of various types of converter power supply,the system main circuit to isolate the DC/DC power is designed.(5)The validation test has done on the key improvement design and development components of concentrated isolation dual power source trolleybus'driving system. |
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