Patent ID: 8659248
Filing Date: 2014-02-25
Classification: H02M,H02P,H03K,Y02B

Abstract:
1. A drive device for controlling an operation of an electric power conversion circuit equipped with a plurality of pairs of switching elements, each of the pairs being comprised of a switching element in a high voltage side and a switching element in a low voltage side connected in series, at least one of the switching elements in the pair being equipped with a freewheel diode, the switching element and the freewheel diode being connected in parallel with each other, and a connection node between the switching element in a high voltage side and the switching element in a low voltage side in each pair being connected to an inductor, the drive device comprising a freewheel mode detection means and an inhibition means, wherein the freewheel mode detection means receives a detection signal regarding current information transferred from a current detection means which detects a current flowing in an electric path at a position of the inductor apart from the connection node between the switching element in a high voltage side and the switching element in a low voltage side in each pair, detects whether or not the state of the freewheel diode arranged in parallel to the switching element is in the freewheel mode on the basis of a comparison result between the received detection signal regarding the current information transferred from the current detection means and a threshold current value, wherein the threshold current value is shifted from zero toward a value at which a forward current flows in the freewheel diode, and the inhibition means inhibits the turning-on operation of the switching element equipped with the freewheel diode when the detection result of the freewheel mode detection means indicates that the state of the freewheel diode is in the freewheel mode in which a current flows in the freewheel diode.