電動公車電力分配系統之模擬與實驗

Abstract

本研究對於電動公車的電力分配系統，採用分散式電源系統的概念，以多電池模組並聯的方式來提供512伏特的電壓給空壓機、空調、動力方向盤、主馬達等負載。電池模組多組並聯使用，可以提供負載高可靠度和大電流輸出。對於以磷酸鋰鐵電池為電源的電動公車，本研究用四組電池模組並聯，首先使用繼電器和預充控制板，成功使電壓送給負載端。此外，為了可以剎車回充而配置功率半導體IGBT。最後依照車子行駛的情況，控制繼電器和IGBT是否導通，以達到行駛時電池放電，剎車時電池充電的目的。本研究使用模擬軟體Simulink模擬IGBT切換狀態加上snubber電路，成功減少突波電壓。並且執行電腦模擬雙向直流轉換器，成功升降壓轉換。實作方面，使用8051實驗板，依照公車的三種行駛情況，也成功控制四個繼電器和四個IGBT。

The purpose of this thesis is to design a power distribution system for electric buses in mass transportation. The power distribution system provides 512 volts to the air compressor, air conditioning, power steering, main motor and other loads by multi-battery modules in parallel way. The parallel use of multi-battery modules can provide loads with demand of high reliability and high current output. For lithium iron phosphate battery-powered electric vehicles, this study uses four battery modules in parallel. At first, using relays and pre-charge control board transmit voltage to the load. In order to charge battery when breaking, we use power semiconductor (IGBT). At last, according to car driving, we control relays and IGBT whether turned on or turned off. It can achieve battery discharges when driving and battery charges when breaking. This study uses a software Simulink to simulate IGBT switching state with a snubber circuit that indeed reduces surge voltages. Computer simulation is also carried out for power distribution with bidirectional DC-DC converter to yield voltage boost or drop. This study uses 8051 breadboards, according to three car-driving conditions, to control four relays and four IGBTs in experiments.