| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a technology which accurately detects the voltage of a current detecting resistor. <P>SOLUTION: An amplifier 201 amplifies the potential of a second end 107a with the potential of a first end 107a as a reference, and outputs the amplified potential of the second end 107b. An amplifier 202 amplifies the potential of the second end 108b with the potential of the first end 108a as a reference, and outputs the amplified potential of the second end 108b. A microcomputer 203 measures outputs of the amplifier 201, 202. Consequently, voltage drops generated at the current detecting resistors 107, 108 are measured. Generally, resistance values of the current detecting resistors 107, 108 are known. Accordingly, currents flowing to an active converter 103 and an inverter 105 are measured from their results. Power supplies 501, 502 are insulated from each other. Accordingly, there does not exist wiring for connecting the first end 107a of the current detecting resistor 107 to the first end 108a of the current detecting resistor 108 except for the wiring 109a. Therefore, high frequency noise is hardly transmitted to a current measuring system 2, and accurate measurement is performed. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
