Power conversion device
View Patent ↗A power conversion device implementing an electrical-path-cutoff only if a power semiconductor element short-circuits, and to implement the cutoff at a timing earlier than when a battery fuse fuses, includes a pair of power semiconductor elements configured to be an upper arm element and a lower arm element, being connected in series between a positive-polarity electrode and a negative-polarity electrode; a short circuit detection circuit configured to detect a short circuit in the lower arm element; switching element for fusing, configured to be disposed between positive-polarity-side terminal of upper arm element on the positive-polarity electrode side, and negative-polarity-side terminal of lower arm element on the negative-polarity electrode side, and to be driven to have the positive-polarity-side terminal connected with the negative-polarity electrode when the short circuit is detected; and a cutoff part configured to be made of thin metallic wire for having the negative-polarity-side terminal connected with the negative-polarity electrode.
1. A power conversion device, comprising:
a pair of power semiconductor elements configured to be an upper arm element and a lower arm element, being connected in series between a positive-polarity electrode and a negative-polarity electrode;
a short circuit detection circuit configured to detect a short circuit in the lower arm element;
a switching element for fusing, configured to be disposed between a positive-polarity-side terminal of the upper arm element on the positive-polarity electrode side, and a negative-polarity-side terminal of the lower arm element on the negative-polarity electrode side, and to be driven to have the positive-polarity-side terminal connected with the negative-polarity electrode when the short circuit is detected; and
a cutoff part configured to be made of a thin metallic wire for having the negative-polarity-side terminal connected with the negative-polarity electrode.
2. The power conversion device, as claimed in claim 1 , further comprising:
a fuse driver circuit configured to drive the switching element for fusing to be on when the short circuit is detected by the short-circuit detection circuit.
3. The power conversion device, as claimed in claim 2 , wherein the fuse driver circuit drives the switching element for fusing to be on in a non-saturation region.
4. The power conversion device, as claimed in claim 1 , wherein the switching element for fusing is a high-voltage-tolerant, small-capacitance IGBT being tolerant for a voltage between the positive-polarity electrode and the negative-polarity electrode.
5. The power conversion device, as claimed in claim 4 , wherein the switching element for fusing is implemented to have a collector connected with the positive-polarity-side terminal, and an emitter connected with the negative-polarity-side terminal,
wherein the thin metallic wire of the cutoff part is disposed between the emitter of the switching element for fusing, and the negative-polarity electrode.
6. The power conversion device, as claimed in claim 5 , wherein the negative-polarity-side terminal is connected with the emitter of the switching element for fusing via a thin metallic wire.
7. The power conversion device, as claimed in claim 1 , wherein the short-circuit detection circuit detects the short-circuit in the lower arm element, based on a current flowing in a sense emitter when the upper arm element is driven to be on.
8. The power conversion device, as claimed in claim 1 wherein the short-circuit detection circuit detects the short-circuit in the lower arm element, based on a voltage between a collector and an emitter of the lower arm element.
9. The power conversion device, as claimed in claim 1 , wherein the pair of the power semiconductor elements are elements built in a power module having resin molding applied.
10. The power conversion device, as claimed in claim 1 , wherein the pair of the power semiconductor elements are elements constituting a booster or a step-down circuit, or an inverter circuit.