Battery Electric Vehicle
1 Technical Overview of Electric Vehicle
The advantage of the EVs is the mechanical simplicity of the drivetrain. For example, an EV drive train can convert energy stores into vehicle motion, just like a conventional vehicle, and it can also reverse direction and convert vehicle motion back into energy stores through regeneration barking, which means that theirs energy/work loop is inherent bi-directional. Besides, moving parts of the electric motor in the EVs consist primarily of the armature (DC motors) or rotor (AC motors) and bearings, a relatively simple and far more efficient machine. other advantages include electric motor torque much more suited to the torque demand curve of a vehicle. EV drive train often needs only one gear ratio other than two or more. More-over, a reverse gear is unnecessary because the rotational direction of the motor itself can be reversed simply by reversing the electrical in-put polarity.
However, the function capabilities and the cost/benefits profile of electronic system are rather complicated. Electrical power is delivered to the wall outlet in the form of alternating current, and must be converted into direct current in order to charge EV batteries. In the case of EVs powered by DC motor, electricity from the battery must then be “chopped” into small bursts of variable duty cycle in order to control the speed and torque of the motor. With EVs using AC motors, the direct current from the battery must undergo complex power condition

電動自行車鋰電池管理系統(tǒng)設計
1 電動汽車技術(shù)概述
電動汽車的優(yōu)點是具有簡單的機械傳動機構(gòu)。電動汽車能夠像傳統(tǒng)的汽車一樣將本身的能量轉(zhuǎn)變成汽車的動能，但它卻還可以沿相反方向進行轉(zhuǎn)換，利用能量再生制動系統(tǒng)將動能轉(zhuǎn)換成汽車的電能儲備，這說明它的能源和工作回路是雙向的。此外，電動汽車的運動部件電動馬達主要由電樞（直流電機）或轉(zhuǎn)子（交流電機）和軸承組成，電機不僅僅具有結(jié)構(gòu)簡單效率高的優(yōu)點，而且它的輸出扭矩適合車輛的扭矩曲線。電動汽車的動力傳動系統(tǒng)往往只需要一個傳動比，不需要倒檔，因為旋轉(zhuǎn)運動方向的變換可以通過改變電力輸入的極性來實現(xiàn)。
電池系統(tǒng)的充電是相當復雜的。通過電源插座傳送的是交流電，必須轉(zhuǎn)換成直流電，才能被用來為電動汽車電池充電。如果電動汽車采用了直流電動機，來自電池的能源必須被“切”成具有一定周期的可變占空比，才能用以控制發(fā)動機的速度和扭矩。隨著電動汽車越來越多的采用交流電機，為了提供交流電和控制汽車動力輸出的能量，從電池來的直流電必須進行復雜的能源轉(zhuǎn)換。純電動汽車的主要缺點是電池能源有限，而混合電動汽車的復雜的動力系統(tǒng)是困擾其質(zhì)量提高和成本的居高不下的原因。