Patent ID: 6956349
Filing Date: 2005-10-18
Classification: F01L,H02M

Abstract:
1. A valve opening and closing control device making use of a rotational torque of a motor driven by a motor drive apparatus to control valve opening and closing of an internal combustion engine, the motor drive apparatus comprising: an electric source; a bridge circuit comprising a plurality of rows of arms comprising two switching elements connected in series to each other and two diodes connected in parallel to corresponding switching elements, the respective arms being connected in parallel to the electric source, the motor having windings thereof connected to points of interconnection of the two switching elements on the respective arms, and control means for controlling ON/OFF of the switching elements, and wherein after putting the switching element on one of the two rows of arms in an ON state to carry an electric current to the windings, the control means causes an electricity introduction stoppage element that is one of the two switching elements put in an ON state, to be put in an OFF state and causes the separate switching element on the same arm as that, on which the electricity introduction stoppage element is disposed, to be put in an ON state, wherein after putting the switching element on one of the two rows of arms in an ON state to carry an electric current to the windings, the control means controls ON/OFF of the switching element selected as the electricity introduction stoppage element by means of a pulse-width modulation method.