| 摘要 |
<p>PURPOSE:To restrain any drop in an electrification factor and the generation of an electro-magnetic wave noise so as to inhibit any large current, even when an assistant steering load is large like that in the case of a pivotal turn etc. CONSTITUTION:A battery voltage is increased by PWM control of a DC-DC coverter 21, in a controller 15. A voltage increase condition is so set that the maximum voltage can be applied between stop and about 10km/h speed and voltage can be lowered gradually in compliance with the increase of car speed. Thus, as sufficiently increased voltage is used especially in a state in which maximum assistant steering load can be generated at a low speed by car speed induction voltage increase control, only small current is allowed to flow in MOSFET 25 etc. Therefore, DC-R loss in MOSFET, motor winding, cable wire, etc., can be reduced and an electrification factor can be improved. The generation of an electro-magnetic wave noise in the motor winding by an exeiting current can be also restrained. In addition, a small current wire can be used as a power element.</p> |
