| US 7,457,136 B2 | ||
| Overcurrent protective device for switching element | ||
| Kiminori Ozaki, Kariya (Japan) | ||
| Assigned to Kabushiki Kaisha Toyota Jidoshokki, (Japan) | ||
| Filed on Jun. 01, 2006, as Appl. No. 11/445,857. | ||
| Claims priority of application No. 2005-162199 (JP), filed on Jun. 02, 2005. | ||
| Prior Publication US 2006/0285372 A1, Dec. 21, 2006 | ||
| Int. Cl. H02M 3/335 (2006.01) | ||
| U.S. Cl. 363—17 [363/56.03; 363/37] | 5 Claims |

| 1. An overcurrent protective device for an inverter device, the inverter device including:
a power supply having a plus terminal and a grounding terminal;
an H-bridge circuit including a group of switching elements connected to the plus terminal of the power supply and a group
of switching elements connected to the grounding terminal of the power supply, one of the groups being defined as a first
group, the other a second group;
a diode connected to each of the switching elements in a back-to-back connection manner; and
a switching frequency increase preventing section that prevents an increase of a switching frequency when an overcurrent protective
operation is performed, a load being connected to the inverter device, the overcurrent protective device comprising:
a current detecting section that detects the amount of a current flowing through the switching elements;
a control section that determines whether the inverter device is held in a first state or a second state in correspondence
with an input from the current detecting section,
wherein the amount of the current flowing through the switching elements when it is determined that the inverter device is
held in the second state is greater than the amount of the current flowing through the switching elements when it is determined
that the inverter device is held in the first state,
wherein, when it is determined that the inverter device is held in the first state, the control section performs a flywheel
operation in which drive signals for the first group of the switching elements are maintained in OFF states, and at least
one of the switching elements of the second group is maintained in an ON state so that a current circulates through the load
and the second group of the switching elements, and
wherein, when it is determined that the inverter device is held in the second state, the control section performs a regenerative
operation in which the drive signals for all of the switching elements are maintained in OFF states.
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