Kusiyana kwakukulu pakati pa mota yomwe imayendetsedwa ndi mphamvu yosinthira ma frequency ndi mota yomwe imayendetsedwa ndi mafunde amphamvu ya sine frequency ndikuti mbali imodzi, imagwira ntchito m'ma frequency osiyanasiyana kuyambira pa ma frequency otsika mpaka ma frequency apamwamba, ndipo kumbali ina, mawonekedwe a mafunde amphamvu si a sinusoidal. Kudzera mu kusanthula kwa mafunde a magetsi a Fourier, mawonekedwe a mafunde amagetsi ali ndi ma harmonics opitilira 2N kuwonjezera pa gawo loyambira la mafunde (mafunde olamulira) (chiwerengero cha mafunde osinthasintha omwe ali mu theka lililonse la mafunde olamulira ndi N). Pamene SPWM AC converter itulutsa mphamvu ndikuyiyika pa mota, mawonekedwe amagetsi pa mota adzawoneka ngati mafunde a sine okhala ndi ma harmonics opitilira. Mphamvu ya harmonic idzapanga gawo la pulsating magnetic flux mu magnetic circuit ya asynchronous motor, ndipo gawo la pulsating magnetic flux limayikidwa pamwamba pa main magnetic flux, kotero kuti main magnetic flux ili ndi gawo la pulsating magnetic flux. Gawo la pulsating magnetic flux limapangitsanso kuti maginito azikhala odzaza, zomwe zimakhala ndi zotsatira zotsatirazi pakugwira ntchito kwa mota:
1. Kuthamanga kwa maginito kumapangidwa
Kutayika kumawonjezeka ndipo magwiridwe antchito amachepa. Chifukwa kutulutsa kwa mphamvu yamagetsi yosinthasintha kumakhala ndi ma harmonics ambiri apamwamba, ma harmonics awa amapanga kugwiritsa ntchito mkuwa ndi chitsulo koyenera, zomwe zimachepetsa magwiridwe antchito. Ngakhale ukadaulo wa SPWM sinusoidal pulse width, womwe umagwiritsidwa ntchito kwambiri pakadali pano, umangoletsa ma harmonics otsika ndikuchepetsa torque ya pulsating ya mota, motero kukulitsa magwiridwe antchito okhazikika a mota pa liwiro lotsika. Ndipo ma harmonics apamwamba sanangotsika, komanso adawonjezeka. Kawirikawiri, poyerekeza ndi mphamvu yamagetsi ya frequency sine, magwiridwe antchito amachepetsedwa ndi 1% mpaka 3%, ndipo mphamvu yamagetsi imachepetsedwa ndi 4% mpaka 10%, kotero kutayika kwa harmonics kwa mota pansi pa mphamvu yamagetsi yosinthira ma frequency ndi vuto lalikulu.
b) Kupanga kugwedezeka kwa maginito ndi phokoso. Chifukwa cha kukhalapo kwa ma harmonics angapo apamwamba, kugwedezeka kwa maginito ndi phokoso zidzapangidwanso. Momwe mungachepetsere kugwedezeka ndi phokoso ndi vuto kale pama mota oyendetsedwa ndi sine wave. Pa mota yoyendetsedwa ndi inverter, vutoli limakhala lovuta kwambiri chifukwa cha mphamvu yamagetsi yomwe siili ya sinusoidal.
c) Mphamvu yothamanga ya ma frequency ochepa imachitika pa liwiro lotsika. Mphamvu ya ma magnetomotive ya harmonic ndi rotor harmonic current synthesis, zomwe zimapangitsa kuti torque ya ma electromagnetic ya harmonic ikhale yokhazikika komanso torque ya ma electromagnetic ya harmonic alternating, torque ya ma electromagnetic ya harmonic alternating ipangitsa kuti mota ipule, motero imakhudza ntchito yothamanga pang'ono. Ngakhale njira ya SPWM modulation ikugwiritsidwa ntchito, poyerekeza ndi mphamvu ya frequency sine power supply, padzakhalabe ma harmonics otsika, omwe apanga torque ya ma pulsating pa liwiro lotsika ndikukhudza ntchito yokhazikika ya mota pa liwiro lotsika.
2. Pangani mphamvu yamagetsi ndi mphamvu yamagetsi ya axial (yamakono) ku insulation
a) Mphamvu yamagetsi imachitika. Pamene mota ikugwira ntchito, mphamvu yamagetsi yomwe imagwiritsidwa ntchito nthawi zambiri imayikidwa pamwamba pa mphamvu yamagetsi yomwe imapangidwa pamene zigawo zomwe zili mu chipangizo chosinthira ma frequency zimasinthidwa, ndipo nthawi zina mphamvu yamagetsi imakhala yokwera, zomwe zimapangitsa kuti coil igwedezeke mobwerezabwereza komanso kuti chotenthetseracho chiwonongeke.
b) Kupanga magetsi a axial ndi axial current. Kupanga magetsi a shaft kumachitika makamaka chifukwa cha kusalingana kwa maginito ndi electrostatic induction, zomwe sizili zovuta kwambiri m'magalimoto wamba, koma zimaonekera kwambiri m'magalimoto omwe amagwiritsa ntchito mphamvu yamagetsi yosinthasintha. Ngati magetsi a shaft ndi okwera kwambiri, mafuta omwe amalowa pakati pa shaft ndi bearing adzawonongeka, ndipo nthawi yogwira ntchito ya bearing idzafupikitsidwa.
c) Kutaya kutentha kumakhudza mphamvu ya kutentha ikamayenda pa liwiro lotsika. Chifukwa cha kuchuluka kwa mphamvu ya injini ya ma frequency osinthasintha, nthawi zambiri imayenda pa liwiro lotsika pa liwiro lotsika. Pakadali pano, chifukwa liwiro ndi lotsika kwambiri, mpweya woziziritsa womwe umaperekedwa ndi njira yoziziritsira yokha yomwe imagwiritsidwa ntchito ndi injini yanthawi zonse sikokwanira, ndipo mphamvu ya kutentha imachepa, ndipo kuziziritsa kwa fan yodziyimira payokha kuyenera kugwiritsidwa ntchito.
Mphamvu ya makina imakonda kugwedezeka, nthawi zambiri, chipangizo chilichonse cha makina chimapanga phokoso. Komabe, injini yomwe ikuyenda pafupipafupi komanso liwiro losasintha iyenera kupewa kugwedezeka ndi liwiro lachilengedwe la makina la 50Hz. Pamene injiniyo ikugwiritsidwa ntchito ndi kusintha kwa pafupipafupi, liwiro logwirira ntchito limakhala ndi mitundu yosiyanasiyana, ndipo gawo lililonse limakhala ndi liwiro lake lachilengedwe, zomwe zimakhala zosavuta kuti lizigwedezeka pafupipafupi.
Nthawi yotumizira: Feb-25-2025