| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a motor-driven power steering device having a failure diagnosing system of a motor current detecting means capable of highly accurately diagnosing failure. <P>SOLUTION: Both semiconductor switching elements (hereinafter referred to as an element) T<SB>1</SB>and T<SB>4</SB>of an H bridge circuit for constituting a motor driving circuit are turned off, an element T<SB>2</SB>is turned on, an element T<SB>3</SB>is driven by a PWM signal on the basis of a current command value at failure diagnosing time, the elements T<SB>3</SB>and T<SB>2</SB>are simultaneously driven, an electric current is made to flow to a current detecting resistance R without making an electric current flow to a motor M, and an electric current value is detected by a current detecting circuit C. A detected current value is compared with a predictive current value on the basis of the current command value at failure diagnosing time, and when the detected current value is outside a range of the predictive current value, it is determined as failure of a motor current detecting circuit. <P>COPYRIGHT: (C)2004,JPO |
