Mechanical commutation ( graphite or precious metal brushes ) , highest efficiency , low inductance , low electromagnetic interference , multiple combination possibilities with gears , feedback devices and control electronics 機(jī)械換向器(石墨和金屬電刷) ,高效率,小電感,電磁干擾小,能與多種齒輪箱,反饋設(shè)備和控制電子元件配合使用。
The permanent magnet brushless dc motor is a dc motor using electronic commutation in place of mechanical commutation in fact , so it has excellent characteristics of dc motors , for example good start and timing performance . it simplifies the motor ' s structure and overcomes the friction disadvantages of ordinary dc motor because it does n ' t use mechanical commutation . it is extensively used in aviations , robots , digital machine tool and so on 永磁無刷直流電動(dòng)機(jī)實(shí)際上是以電子換向代替機(jī)械換向的直流電動(dòng)機(jī),因而保持了直流電動(dòng)機(jī)的優(yōu)良特性,具有較好的起動(dòng)和調(diào)速性能,又因它無需機(jī)械換向器使電機(jī)的結(jié)構(gòu)簡(jiǎn)單,可以從根本上克服一般有刷直流電動(dòng)機(jī)易于產(chǎn)生換向火花的弊病,在航天、機(jī)器人、數(shù)控機(jī)床等許多工業(yè)領(lǐng)域已得到廣泛應(yīng)用。
The chip jk3ce that is one of micro - controllers in motorola 68hc08 family is used as control unit in this system . the zero crossing point of the back emf can be obtained by comparing the terminal voltage with the virtual neutral point , then using the software of the system can figure out the commutation period . the electronic commutation replaces the mechanical commutation in this way 本系統(tǒng)采用的控制芯片為motorola系列單片機(jī)中的jk3ce ,反電勢(shì)過零點(diǎn)可以通過比較電機(jī)端電壓和虛擬中點(diǎn)電壓來得到,將過零點(diǎn)信號(hào)送往單片機(jī)捕捉端口后由系統(tǒng)軟件來確定換相時(shí)刻,這樣就可以由電子換向裝置替代機(jī)械換相裝置,有利于提高系統(tǒng)運(yùn)行的可靠性,并降低了系統(tǒng)維護(hù)的費(fèi)用。