Electric power converter to reduce or eliminate erroneous power module abnormality indication

摘要

A processor unit in an electric power converter executes detection of an overheating predicted state that is a stage prior to overheating of the IGBTs, a short circuit predicted state that is a stage prior to a short circuit in the arms, and a voltage drop predicted state that is a stage prior to a drop in a control voltage to be supplied to a driver circuit. When none of these predicted states is detected, a determination that an abnormality is not caused in the power module based on a latch signal is made by the processor unit. When an overheating predicted state is detected, the processor unit lowers the duty ratio of a motor control signal. When a short circuit predicted state is detected, the processor unit prolongs the dead time in which the upper IGBTs and the lower IGBTs are both maintained in the off-state.

主权项

1. An electric power converter comprising:
a processor that outputs control signals; and a power module that converts direct-current power supplied from a driving electric power source, into alternating-current power based on the control signals, the power module including:
an inverter circuit in which multiple arms each having power semiconductor devices connected in series are connected in parallel,a driver circuit that outputs drive signals obtained by amplifying the control signals based on a control voltage, to the power semiconductor devices, andan abnormality detection circuit that executes detection of at least one of a plurality of abnormalities including overheating of the power semiconductor devices, a short circuit in the arms, and a drop in the control voltage to be supplied to the driver circuit, and that outputs an abnormality detection signal indicating a result of the abnormality detection to the processor, wherein the processor executes detection of a predicted state that is a state prior to occurrence of the at least one of the plurality of abnormalities, and the processor makes a determination that the at least one of the plurality of abnormalities is not caused in the power module when the predicted state is not detected, even if the at least one of the plurality of abnormalities is detected.