Question

(c) The dual-switch forward converter in Fig. Q4(c) is supplied from an input voltage Vin of 42V, and switches at 100kHz with a duty factor of 0.35. The transformer T1 carries 50 primary turns and 34 secondary turns. The core used in T1 has an effective area of 45mm2 and an effective length of 72mm. The relative permeability of its core material is =1790. [NB: The permeability of free space IS μ.-1.257×10-94/m.] V.D D, L1 TRI - 01 N1 N2 7 T1 D2즈 I TR2 0V Fig. Q4 (c) (i) Calculate the output voltage Vout Assume that all the components are ideal (i) Calculate the peak flux density excursion appearing in the core material of and that the circuit operates in the CCM T1 (ii) Calculate the peak magnetising current drawn by the transformer (iv) Explain why the dual-switch forward converter cannot be operated at duty factors above 50% 10 marks

Answer 1

oud put -voltage. Nauf. sume tat all, the Components op ante-.ideo」一牟 _couruets Collocoine &r uation .. extracted ng fsom the unning in continuous crurent mode C ccm output voltage, inpu veltage Tasugered Efticiency uay_ 34

Peak fluy densiy I vn) here Vfn-2-42V 100 kHz. 2 on Bmax 2 c-0.046 Tes la. Lp toN.--ㄧㄏㄧㄧ = To 00kH2 10 see ウー"To calculate LP

Hn As GivenEffeative lengte- チ2 x10 0.0- : U6 LP = 2500 -S

V) Reason to Not opesiated at above So ofo oluut eft to Reset fully Less duty 丫一一年 matia-means ,Less powen To he output if duty ratio tncreased the vottage