Patent ID: 7550945

Claim:
A voltage measurement device, in a plurality of voltage sources in series connection that are divided into a plurality of blocks each having at least one voltage source, for measuring respective voltages of the blocks, the voltage measurement device comprising: a measuring capacitive element connected to the blocks; a first group of switches each arranged between the blocks and the measuring capacitive element to connect the voltages of the blocks to the measuring capacitive element; a measuring output terminal connected to the measuring capacitive element; a second group of switches each arranged between the measuring capacitive element and the measuring output terminal to connect the voltage of the blocks accumulated in the measuring capacitive element to the measuring output terminal; and calculating means connected to the measuring output terminal and adapted so as to perform the operations of: measuring a stray capacitance including parasitic capacitances of the second group of switches in advance; calculating an erroneous voltage due to electrical charges accumulated in the stray capacitance; and subtracting a calculated value of the erroneous voltage from a measured value of a terminal voltage of the measuring output terminal, thereby calculating a true value of a measured voltage of each of the blocks.