| 摘要 |
PROBLEM TO BE SOLVED: To protect an electric power unit such that if one of series input capacitors of a half bridge short-circuits, the other capacitor is protected.SOLUTION: A half bridge 40 uses an accumulated DC voltage of an input capacitor part CC comprising a series connection circuit of capacitors C2, C3 so as to generate and output an AC voltage Vbased upon the potential at a neutral point NP through switching operation. Although the AC voltage Vis normally generated by AC driving based upon AC input (V) from an AC power supply (commercial power supply) ACP, the input capacitor part CC is charged with a boosted voltage output from a storage battery 20 in a case of a power failure so as to generate the AC voltage V(DC driving). A tap 33 is provided for secondary-side winding of a transformer T1 of a boosting converter 30 and a switch SW1 is provided between the tap 33 and neutral point NP. The switch SW1 is turned on in the DC driving and turned off in the AC driving. |
