| 摘要 |
PROBLEM TO BE SOLVED: To make uniform thermal stress among a plurality of capacitors. SOLUTION: DC power from a battery 10 is fed through a smoothing circuit 12 to an IGBT module 14 where it is converted into a specific AC current. The smoothing circuit 12 comprises three smoothing capacitors C1, C2 and C3 connected in parallel and the capacitance thereof is set depending on the impedance Z of an current passage up to the IGBT module 14 to satisfy a relation; C1:C2:C3=Z(Lc3):Z(Lc2):Z(Lc1). Since thermal stress is balanced among the capacitors C1, C2 and C3, generation of heat is not concentrated to any particular capacitor and breakdown or deterioration thereof can be avoided. |
