DC Converter Output Protection for Short-Circuit and Polarity Reversal
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Solution Overview
Problem
Existing DC converters in electric and hybrid electric vehicles lack effective protection against short-circuit conditions and polarity reversals, leading to reduced power supply reliability, increased costs, and potential accidents due to damage to low-voltage batteries and devices.
Innovation Solution
An output power protection apparatus comprising a DC conversion unit, an output protection unit with parallel protection circuits, a high-voltage battery, a low-voltage battery, and a control unit that generates signals to disconnect the low-voltage battery and device when a short-circuit or polarity reversal is detected, preventing damage and ensuring safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a non-isolated DC converter is used to convert DC power, then the circuit structure is simple and cost is low, but the system lacks protection against short-circuit conditions and polarity reversal
Solution Approach 1:
The patent divides the DC converter system into isolated and non-isolated converter modules, allowing selective deployment based on protection requirements. The isolated converter segment provides inherent galvanic isolation for short-circuit and polarity reversal protection, while the non-isolated segment maintains simplicity for applications where protection is handled by other means.
Solution Approach 2:
The patent introduces an isolation converter as an intermediary component between the high-voltage battery and low-voltage devices. This intermediary provides galvanic isolation, blocking short-circuits and polarity reversal from propagating through the system, thereby protecting downstream components while allowing power transfer.
2Reliability
If protection circuits are added to prevent short-circuit and polarity reversal, then power supply reliability is improved, but device complexity increases
Solution Approach 1:
The patent merges the protection function with the power conversion function by using the isolation converter itself as the protection mechanism. The galvanic isolation inherent in the isolated DC-DC converter design provides both power conversion and short-circuit/polarity reversal protection in a single integrated component, eliminating the need for separate protection circuits.
3Reliability
If protection against short-circuit and polarity reversal is implemented, then damage to low-voltage battery and devices is prevented, but additional costs are incurred
Solution Approach 1:
The patent designs the isolated DC-DC converter to serve multiple functions: power conversion, galvanic isolation, and protection against short-circuits and polarity reversal. This multi-functionality allows a single component to provide protection that would otherwise require additional dedicated protection circuits, reducing overall system cost despite the higher per-unit cost of the isolated converter.
Data Source
AI summary
An output power protection apparatus includes a DC conversion unit, an output protection unit, a high-voltage battery, a low-voltage battery, and a control unit. The DC conversion unit converts an input DC power into an output DC power. The output protection unit is connected in series to the DC conversion unit, and the output protection unit has a plurality of protection circuits connected in parallel to each other. When a short-circuit condition occurs between the high-voltage battery and the low-voltage battery or the low-voltage battery is reversely connected in polarity, the control unit generates a control signal to control the protection circuits to disconnect the connection between the low-voltage battery and a low-voltage device, and the DC conversion unit.