Dual DC-DC Power Distribution for EV Critical Load Balancing
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Solution Overview
Problem
The increasing electrification of vehicles and integration of self-driving systems lead to higher current consumption and power demands, often resulting in insufficient DCDC capacity, which can drain the 12V battery and reduce its lifespan or cause loss of functionality, especially during driving, due to the limitations in size, cost, and capacity of DCDC converters.
Innovation Solution
A power supply and distribution system for electric vehicles that includes a High Voltage power source connected to two DC-DC converters, with a dual back-to-back switch unit controlling parallel primary power supply lines to manage Variable Electrical Loads, allowing for reduced DCDC converter ratings and prioritizing power to safety-critical equipment by dynamically balancing load between the two power supply lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the DCDC converter capacity is increased to meet higher power demands from electrification and ADAS systems, then power availability to critical equipment is improved, but device cost and packaging space increase
Solution Approach 1:
The power supply system is segmented into two separate DCDC converters (first DCDC converter and second DCDC converter) that operate in parallel. Each converter serves specific critical equipment groups, allowing the system to meet total power demands without requiring a single oversized converter. This segmentation enables better utilization of packaging space and reduces the need for individual converter over-dimensioning.
Solution Approach 2:
The patent combines two DCDC converters operating in parallel to collectively serve the vehicle's power needs. The first and second primary power supply lines are merged at the busbar connection point, allowing load sharing between converters. This merging approach enables the system to achieve higher total power capacity while keeping individual converter sizes optimized for their respective loads.
2Device complexity
If the DCDC converter capacity is reduced to lower cost and weight, then device cost and packaging space are reduced, but power availability to critical equipment during high demand may be insufficient
Solution Approach 1:
The system implements dynamic load management through controllable switches (first back-to-back switch and second back-to-back switch) that can dynamically redirect loads between the two parallel power supply lines. The microcontroller unit monitors power availability and demand, dynamically adjusting switch positions to optimize power distribution. This dynamic capability ensures that critical equipment receives sufficient power even when individual DCDC converters operate at reduced capacity.
3Device complexity
If a single DCDC converter is used to simplify the system, then device complexity is reduced, but reliability and fail-safe capability are compromised
Solution Approach 1:
The power supply system is divided into two independent parallel paths, each with its own DCDC converter and control switch. This segmentation creates redundancy, as the failure of one converter or its associated switch does not completely disable power supply to critical equipment. The other converter can continue operating, maintaining system reliability.
Solution Approach 2:
The system incorporates backup capability through the parallel architecture and controllable switches. If one DCDC converter or power supply line fails, the switches can redirect loads to the remaining functional converter, providing a cushion against complete system failure. This prior cushioning ensures continuous operation of critical equipment under fault conditions.
4Ease of operation
If variable electrical loads are always connected to ensure availability, then ease of operation is improved, but power consumption increases and may drain the 12V battery
Solution Approach 1:
The system dynamically controls the connection state of variable electrical loads through the first and second back-to-back switches. These switches can connect or disconnect loads from either the first or second primary power supply line based on real-time power availability and demand conditions. This dynamic control allows the system to maintain load availability when power is sufficient while reducing power consumption by disconnecting non-critical loads when power is limited, preventing 12V battery drainage.
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
This solution reduces the cost and weight of the vehicle, enhances safety by ensuring sufficient power to critical systems, and extends the life of the 12V battery by efficiently managing power distribution and reducing the environmental footprint.
Implementation Method 1
a High Voltage power source connected to a first DC-DC converter and a second DC-DC converter, each of the first DC-DC converter and the second DC-DC converter producing Low Voltage DC
Data Source
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AI summary
The disclosure relates to a power supply and distribution system (1) for an electric vehicle, comprising: a High Voltage power source (2) connected to a first DC-DC converter (DCDC1) and a second DC-DC converter (DCDC2), each of the first DC-DC converter (DCDC1) and the second DC-DC converter (DCDC2) producing Low Voltage DC to a first primary power supply line (PS1) for a first group of critical low voltage equipment (DCDC2) and a second primary power supply line (PS2) for a second group of critical low voltage equipment (5), respectively; wherein the first primary power supply line (PS1) and the second primary power supply line (PS2) are connected in parallel to Variable Electrical Loads (VEL) via a dual back-to-back switch unit (S), the dual back-to-back switch (SW) comprising a first back-to-back switch (SW1) and a second back-to-back switch (SW2) each individually controlled by at least a first microcontroller unit (MCU1). The disclosure further relates to a method for operating a power supply system (1) for an electric vehicle.