Electric driving device and electric power steering system including the same

摘要

A control device (3) controlling an electric motor (2) is disposed on an axial line of a rotor shaft (30) of the electric motor (2). The control device (3) includes semiconductor switching devices (15) forming a three-phase bridge circuit that controls a current of the electric motor (2) and capacitors (13) that suppresses a ripple component of a current flowing to the electric motor (2). The semiconductor switching devices (15) and the capacitors (13) are provided in pairs for respective arms of the three-phase bridge circuit and disposed concentrically. Hence, impedance across the three-phase circuit controlling a current flowing to the electric motor is reduced. Consequently, not only can ripples be absorbed efficiently but also power efficiency of a driving device can be enhanced.

主权项

1. An electric driving device comprising: an electric motor and a control device disposed on an axial line of a rotor shaft of the electric motor and controlling driving of the electric motor, wherein the control device includes:
semiconductor switching devices forming a three-phase bridge circuit that controls a current of the electric motor; capacitors suppressing a ripple component of a current flowing to the electric motor; a coil reducing noises generated during a switching action of the semiconductor switching devices; a power circuit portion including the semiconductor switching devices, the capacitors, and the coil; a heat sink on which the power circuit portion is mounted and which releases heat generated from the power circuit portion; a control board on which is mounted a microcomputer that generates a drive signal to drive the semiconductor switching devices; and a plurality of electrical conducting plates insert-molded with an insulating resin, are disposed parallel to each other and concentrically with the rotor shaft in a ring shape which electrically connect the respective arms of the three-phase bridge circuit in a shortest distance and electrically connect the capacitors which are disposed along the respective arms of the three-phase bridge circuit while a positive wiring and a negative wiring of a DC power supply are aligned parallel to each other on a same plane so as to reduce electromagnetic noise in the electrical conducting plates and facilitate a connection between the arms and the capacitors of the three-phase bridge circuit, the electrical conduction plates comprising a pad connected to a power board and a welding portion exposed from the insulating resin, and a portion of the electrical conducting plates are embedded within a circuit case of the control device wherein: the semiconductor switching devices and the capacitors are provided in pairs for respective arms of the three-phase bridge circuit and disposed concentrically with the rotor shaft, and the welding portion electrically connected to the electrical conducting plate is exposed from the insulating resin.