PURPOSE: To obtain an overcurrent-takeout preventive apparatus which prevents an overcurrent exceeding the limit of a battery current from being taken out from a storage battery by a method wherein, when a duty roatio corresponding to a current instruction value is smaller then a limit value, the duty ratio is outputted to a PWM wave generation means and, when the duty ratio is larger than the limit value, the limit value is outputted to the PWM wave generation means.
CONSTITUTION: In a limit computation means 21, a current limit value which can be taken out from a storage battery is divided by the target value of a current to be supplied to a motor M or by the detection value of a current detection means 24, and a divided result is outputted as the limit value of a duty ratio. In a selection means 22, a duty ratio computed by a duty-ratio computation means 23 is compared with the limit value computed by the limit computation means 21. When the duty ratio is smaller than the limit value, the duty ratio is outputted to a PWM wave generation means 25. When the duty ratio is larger than the limit value, the limit value is outputted to the PWM wave generation means 25. Consequently, the duty ratio of generated PWM waves does not exceed the limit value.
SUENARI MASAYA
SAITO MIKIO
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