Kodi Total Harmonic Distortion(THD) ndi chiyani?
Total Harmonic Distortion (THD) ndi ubale wanthawi zonse womwe umathandizira kuwerengera momwe makinawo amapangira kukopera. . Ndilo muyeso wa kusokonezeka kwa harmonic komwe kulipo mu chizindikiro ndipo kumatanthauzidwa ngati chiŵerengero cha kuchuluka kwa mphamvu za zigawo zonse za harmonic ku mphamvu yafupipafupi yofunikira. Izi zidzakhudzana ndi magetsi okha ndipo ndi gawo lokhalo lomwe limapanga ma frequency amtundu uliwonse. Kutsika kwa mtengo wa THD, phokoso lochepa kapena kupotoza muzotulutsa dongosolo.
Pamaulendo aliwonse oyesa, mtengo wa THD uli pakati pa 0 ndi 1:
ZERO - Mtengo womwe uli pafupi ndi ziro umatanthauza kuti zotulukazo zimakhala ndi kupotoza kochepa kwa harmonic. The output sine wave ili ndi ma frequency component ofanana ndi kulowa.
CHIMODZI - Mtengo woyandikira 1 umatanthauza kuti pali kusokonezeka kwakukulu mu siginecha. Pafupifupi zonse zomwe zili mu siginecha ndizosiyana ndi kuchuluka kwa sigino yolowera.
THD imathanso kufotokozedwa ngati peresenti, kuchokera ku 0 mpaka 100%, pomwe 100% imagwirizana ndi 1.
M'mapulogalamu ambiri, THD yotsika imafunika. Low THD imatanthawuza kuti kutulutsa kwadongosolo kumakhala kofanana ndi kulowetsa kwadongosolo ndi kusokoneza kochepa.
N’chifukwa chiyani kuli kofunika kwambiri?
Choyamba, monga tanthawuzo, ma harmonics ndi ma voltages kapena mafunde omwe mafupipafupi ake ndi maulendo angapo afupipafupi, ndipo Australia ndi 50 Hz: 100, 150, 200 Hz, etc. Total Harmonic Distortion (THD) ndi chiwerengero cha zigawo zonse za harmonic za ma frequency ofunikira omwe amapezeka pazida zamagetsi ndi zamagetsi zopanda mzere.
Madalaivala a LED ndi magwero amagetsi amagetsi mu zounikira za LED zomwe zimakhala ndi zida zopangira inductive (reactance and capacitive components). Ndizida zopanda mzere chifukwa zimasintha mawonekedwe a mafunde apano omwe amatengedwa kuchokera pamagetsi omwe amaperekedwa ndikuwoneka ngati sinusoidal yochepa.
Madalaivala ambiri a LED amaphatikizanso mlatho wa diode wowongolera chizindikiro cha AC chogwiritsira ntchito gawo la DC LED. Kusintha kwa milatho ya diode iyi kumapangitsa kuti pakhale mpweya wosasunthika womwe pamapeto pake umasokoneza mafunde a sine.
Choncho, pamene dalaivala wa LED akugwirizanitsidwa ndi mphamvu yaikulu yamagetsi, imapanga mafunde a harmonic omwe amasokoneza magetsi. Ndipo zowunikira zambiri (zokhala ndi madalaivala osagwirizana ndi ma LED) m'derali, zimasokoneza kwambiri njira yogawa magetsi, zomwe zimapangitsa kuti zikhale zopanda ntchito, zomwe zimakhudza magwiridwe antchito a zida zina ndikuwotcha waya.
Ichi ndichifukwa chake mafotokozedwe amagetsi pazida zowunikira m'malo atsopano nthawi zambiri amafuna kuti THD yayikulu ya nyali ikhale yosakwana 15%.