Power Redundancy System for 48 V Backup Loads
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Solution Overview
Problem
Existing power supply redundancy systems fail to ensure continuous power supply to loads when a ground fault or short circuit occurs in one of the power systems, particularly the 48 V system, as the voltage does not rise sufficiently for the 48 V backup load when relying on a DCDC converter from the 12 V system.
Innovation Solution
A power supply redundancy system with a DCDC converter, first and second switches, and a controller that monitors the 48 V battery voltage, switching off the first switch when the voltage drops below a reference value and switching on a semiconductor second switch when the DCDC converter output voltage reaches a certain level, allowing power from the 12 V system to be boosted to the 48 V backup load through a parasitic diode, with an optional capacitor to prevent instantaneous interruption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a DCDC converter is used to supply power from the 12 V system to the 48 V backup load during a ground fault or short circuit in the 48 V battery, then power supply redundancy is achieved, but the voltage does not rise sufficiently to power the 48 V backup load
Solution Approach 1:
A capacitor is introduced as an intermediary energy storage device between the DCDC converter and the 48 V backup load. The capacitor accumulates energy during normal operation and releases it during voltage drops, acting as a buffer that maintains sufficient voltage for the backup load even when the DCDC converter output is insufficient.
Solution Approach 2:
The capacitor is pre-charged during normal operating conditions before a fault occurs. This preliminary energy storage ensures that when a ground fault or short circuit happens, the capacitor can immediately provide the necessary voltage boost without waiting for the DCDC converter to respond, solving the timing and voltage magnitude problem.
2Adaptability or versatility
If the first switch is turned on to allow power flow from the 12 V system through the DCDC converter, then power supply path is established, but the voltage rise is insufficient during ground fault or short circuit conditions
Solution Approach 1:
The capacitor serves as an intermediary that receives power from the DCDC converter through the first switch during normal operation, storing energy that can be quickly discharged to supplement voltage during fault conditions, thereby enhancing the overall power delivery capability beyond what the DCDC converter alone can provide.
Solution Approach 2:
The system merges two power delivery paths: the direct DCDC converter path and the capacitor discharge path. During ground faults or short circuits, both paths operate simultaneously to combine their power output, ensuring sufficient voltage reaches the 48 V backup load despite the limitations of the DCDC converter alone.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables reliable power supply to the 48 V backup load even during a ground fault or short circuit in the 48 V battery by effectively switching to the 12 V system's power via the DCDC converter, ensuring continuous operation of critical functions like steering and other essential vehicle systems.
Implementation Method 1
A DCDC converter 350 is provided between the 12 V power supply system and the 48 V power supply system
Implementation Method 2
allowing power from the 12 V system to be boosted to the 48 V backup load through a parasitic diode
Data Source
AI summary
Provide is a power supply redundant system in which power supply systems of different voltages coexist, which allows electric power to be supplied to a load even if a ground fault or short circuit occurs therein. The system includes a DCDC converter, a first side of the DCDC convertor being connected to a first battery having a first voltage, a first switch provided between a second battery having a second voltage different from the first voltage and a second side of the DCDC converter, a load operating with the second voltage, separately connected to the second battery and the second side of the DCDC converter, and a controller monitoring a voltage of the second battery by turning on the first switch, and when the voltage of the second battery becomes equal to or lower than a first reference value, switching off the first switch and allowing the DCDC converter to output the second voltage from the second side.