| 摘要 |
PROBLEM TO BE SOLVED: To provide a power converter having a high-precision control property at low cost, by enabling the detection of a load current precisely and easily by a shunt resistor-type current detector. SOLUTION: A power converter which inputs a voltage between both ends of a shunt resistor 6 connected in an electric DC line between a converter portion 2 and an inverter portion 3 of a PWM control system to a computer 7 as a detected value of the load current, and PWM-controls the inverter portion 3, is fitted with an error detection circuit. The detection circuit 12 determines that detection is wrong when it learns from an S and H control signal, that the pulse width of a PWM signal has become equal to or narrower than a specified value. Its error detection signal is inputted to an overcurrent protecting circuit 13 and the computer 7 for a PWM control, and an influence by high-frequency noise is removed so that the output data of an S and H circuit 8 is not used for controlling the inverter portion 3. |
