A power conversion device, such as an inverter, includes a pair of switching elements serially connected to each other for supplying power to a load, and a pair of free-wheeling diodes respectively connected in reverse parallel with the pair of switching elements. The free-wheeling diodes allow energy accumulated in the load to flow in a forward direction through one of the diodes as a free-wheeling current when a corresponding one of the switching elements is turned off.
However, if the other one of the switching elements is turned on when the free-wheeling current flows, a DC link voltage can be applied to the free-wheeling diode as a reverse bias. At this time, the free-wheeling diode is interrupted after allowing a reverse current (hereinafter, also referred to as a reverse recovery current) to flow by residual charge. Such a reverse recovery current causes large heat generation in the free-wheeling diode.
In order to prevent such heat generation, it is desired to reduce the reverse recovery current of the free-wheeling diode.
USPTO Backgrounds
USPTO Backgrounds