【正文】 式。串聯(lián)在變壓器旁的電容主要起到“隔直流通交流”的作用。在整流方式和濾波電容的選擇方面，主要考慮兩個(gè)因素：①用于構(gòu)成整流電路的二極管所承受的反向電壓，②電路處于高頻工作環(huán)境還是低頻工作環(huán)境。開關(guān)電源一般由脈沖寬度調(diào)制（PWM: Pulse Width Modulation）來(lái)進(jìn)行控制。綜合考慮，決定在三段式充電的基礎(chǔ)上分別增加一個(gè)恒流階段和恒壓階段，構(gòu)成五段式充電模式，其充電特性曲線如下圖所示：圖 五段式充電特性曲線①曲線為充電電池接收特性曲線②曲線為充電過程中電流變化曲線，即充電特性曲線③曲線為充電過程中電壓變化曲線充電過程分為以下五個(gè)階段：30A 恒流充電直至電壓升至 ，切換為恒壓充電模式。電池放電越深，恒流充電的時(shí)間越長(zhǎng)，反之則較短?，F(xiàn)在大多數(shù)接入直流電源系統(tǒng)的蓄電池，在完全充電后都會(huì)進(jìn)入涓流充電狀態(tài)，以備放電時(shí)使用?！　『銐撼潆婋娊馑苌?，避免了由于硫酸鉛濃度上升而造成的電池老化。但是現(xiàn)階段的充電方式往往都只能單純的滿足減少充電時(shí)間或保護(hù)電池性能的要求，因此，研究處于兩者平衡點(diǎn)的充電方式是必然的發(fā)展趨勢(shì)。本文首先對(duì)幾種常見充電方式進(jìn)行介紹分析，并在其基礎(chǔ)上進(jìn)行優(yōu)化改進(jìn)，引出五段式充電模式的概念。同時(shí)，相較于傳統(tǒng)汽車，電動(dòng)汽車除了在環(huán)境保護(hù)方面占據(jù)優(yōu)勢(shì)之外，與不斷上漲的油價(jià)相比，低廉的電費(fèi)也正是吸引眾多潛在消費(fèi)者的最大賣點(diǎn)之一。關(guān)鍵詞：電動(dòng)汽車，充電器，比例電路，PI調(diào)節(jié)器，仿真 Abstract：With the rapid development of electric automobile industry, the design requirements to all part of it have been improved greatly and power system should be the core part. All performance indexes of rechargeable batteries could have great influence on the performance of the whole system. As to the consumers who are short in professional knowledge, the service life of rechargeable batteries would be the most direct standards of judgment. And therefore, except the irresistible influence caused by the physical characteristics of batteries, extending the service life through changing charge methods has already bee the research emphasis in recent years. The thesis analyzes and contrasts the existing working principle of charging method, adds more elements as constantcurrent charging and constantvoltage charging on the basis of 3stage charging mode, proposes the 5stage charging mode which would be more suitable for the receiving characteristics of rechargeable batteries. The research core of this thesis – control circuit through the application of PI regulator, output amplifier of charging current, voltage sampling value and the relative differences of constantcurrent and constantvoltage values on the control chip SG3525 of PWM, lead to the adjustment of output current and voltage in frontend circuit, reduce the difference gradually and reach the steady output. The biggest characteristics is that shift the constantcurrent charging and constantvoltage charging automatically under the help of peripheral circuit, and keep the steady current and voltage values in every charging stage. The biggest innovation of this thesis lies in taking advantage of the unilateral conduction of diode, through the reasonable settings of circuit parameters and a SG3525 chip, achieve the control in constantcurrent and constantvoltage stages. Key Words: Electric automobile, Charger, Proportional circuit, PI regulator, Simulation目錄前言 ....................................................................................................................................................11 蓄電池的充電方式 ......................................................................................................................2 蓄電池充電特性曲線 ...........................................................................................................2 幾種常見充電方式 ...............................................................................................................3 恒壓充電 ........................................................................................................................3 恒流充電 ........................................................................................................................4 涓流充電 ........................................................................................................................4 三段式充電 ...........................................................................................................................4 五段式充電 ...........................................................................................................................52 前端電路開關(guān)電源介紹 ..............................................................................................................6 選用開關(guān)電源的原因 ...........................................................................................................6 開關(guān)電源工作原理 ...............................................................................................................6 前期整流濾波部分 ........................................................................................................7 IGBT 部分 .....................................................................................................................7 后期整流濾波部分 ........................................................................................................73 控制電路的設(shè)計(jì) ..........................................................................................................................8 設(shè)計(jì)思路與理念 ...................................................................................................................8 電路模塊介紹 .....................................................................................................................10 采樣模塊 ......................................................................................................................11 PWM 信號(hào)模塊 ...........................................................................................................11 比例放大模塊 ..............................................................................................................11 PI 調(diào)節(jié)模塊 .................................................................................................................12 關(guān)鍵元器件—— 集成運(yùn)放的選擇 .....................................................................................14 電路的設(shè)計(jì)細(xì)節(jié)及參數(shù)選擇 .............................................................................................16 分壓電路 ......................................................................................................................16 比例放大電路 ..............................................................................................................18 運(yùn)放調(diào)零電路 ...............................................