Ki jan yo kòrèkteman chwazi konpozan varyateur pou endiksyon fonn gwo founo dife

Anjeneral, nan kondisyon travay ki pi wo a 400HZ, yo ta dwe konsidere aparèy KK; lè frekans lan pi wo pase 4KHz, yo ka konsidere aparèy KA. Isit la nou sitou prezante seleksyon an nan eleman nan kous la varyateur paralèl (gade Figi 1).

(1) VDRM pik vòltaj konpozan an pi devan ak ranvèse, VRRM konpozan pi devan ak ranvèse vòltaj pik yo ta dwe 1.5-2 fwa aktyèl maksimòm vòltaj pik pou pi devan ak ranvèse. Lè w sipoze vòltaj opinyon DC varyateur la se Ud ak faktè pouvwa a se cosψ, lè sa a:

VDRM/RRM=(1.5-2)πUd/(2cosψ)

(2) IT (AV) aktyèl la nan eta a nan eleman an pran an kont ke lè eleman an ap travay nan yon frekans ki pi wo, pèt chanje li yo trè enpòtan. Kouran nominal nan eta a nan eleman an ta dwe koule 2-3 fwa valè efikas li yo dapre aktyèl la Pou konsidere, sètadi

IT(AV)=(2-3)I/1.57

Sipoze ke aktyèl la D ‘inverter DC se Id, aparèy la chwazi IT (AV) se

IT(AV)=(2-3)×Id/(1.57)

(3) Turn-off time tq In the parallel inverter circuit, the turn-off time of the KK element should be selected according to the pre-trigger time tf and the commutation time tr. Generally take:

tq=(tf-tr)×

(When the power factor is 0.8, tf is about one-tenth of the period, tr is determined by the element di/dt less than or equal to 100A/μS) When the frequency is high, the commutation time tr can be reduced and appropriately sacrificed The method of power factor increase tf to select components with appropriate tq value