Bidirectional Isolation Bus Power Supply for Fault-Tolerant EV Loads
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Solution Overview
Problem
The increasing complexity of power systems in new energy vehicles, particularly due to higher autonomous driving levels, poses challenges in ensuring functional safety and redundancy, as faults in power supply systems can lead to unexpected voltage fluctuations and system instability, threatening vehicle safety and functionality.
Innovation Solution
A power supply apparatus and system utilizing bidirectional isolation units with control mechanisms to manage power distribution between voltage conversion units and batteries, ensuring stable bus voltage by disconnecting faulty branches and maintaining power supply through redundant pathways, meeting ASIL B and D safety standards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the power supply system uses conventional direct connection between voltage conversion unit and load, then the device complexity is reduced, but the reliability and functional safety deteriorate due to voltage fluctuations and faults affecting the load
Solution Approach 1:
The patent introduces bidirectional isolation units as intermediary components between the voltage conversion unit and the load. These isolation units include switching elements and isolation circuits that mediate the power transmission, allowing the system to maintain reliability by isolating faults while managing the added complexity through controlled isolation mechanisms.
Solution Approach 2:
The power supply system is segmented into distinct functional modules: voltage conversion unit, bidirectional isolation units, and load circuits. This segmentation allows independent control and isolation of each module, improving functional safety by preventing fault propagation while maintaining manageable system complexity through modular architecture.
2Reliability
If the power supply system adds redundancy components to prevent faults, then the reliability improves, but the device complexity and power consumption increase
Solution Approach 1:
The bidirectional isolation units incorporate dynamic switching elements that can change their state based on system conditions. This dynamic capability allows the system to activate redundancy only when needed, maintaining high reliability while reducing the impact on device complexity and power consumption during normal operation.
Solution Approach 2:
The bidirectional isolation units serve multiple functions: normal power transmission, fault isolation, and redundant pathway activation. This multi-functionality reduces the need for separate dedicated redundancy components, thereby improving reliability while minimizing the increase in device complexity.
3Stability of the object's composition
If bidirectional isolation units are introduced to isolate faulty branches, then the stability of bus voltage improves, but the device complexity increases due to additional switching components
Solution Approach 1:
Bidirectional isolation units are introduced as intermediary components between the voltage conversion unit and the load. These isolation units include switching elements and isolation circuits that mediate the power transmission, allowing the system to maintain reliability by isolating faults while managing the added complexity through controlled isolation mechanisms.
4Reliability
If multiple isolation units and switching components are added to ensure functional safety, then the power consumption increases, but the reliability and safety performance improve
Solution Approach 1:
The bidirectional isolation units incorporate dynamic switching elements that can change their state based on system conditions. This dynamic capability allows the system to activate redundancy only when needed, maintaining high reliability while reducing the impact on device complexity and power consumption during normal operation.
Data Source
AI summary
This disclosure discloses a power supply apparatus, a power supply system, and a method. The apparatus includes: a power supply bus connected to an output end of a voltage conversion unit and a low-voltage battery through separate bidirectional isolation units. The bidirectional isolation units control connection and disconnection between the bus and the voltage conversion unit or the low-voltage battery. The bidirectional isolation unit includes two switches connected in series. The two switches connected in series each are connected in parallel to one diode, and the two diodes are disposed back to back. The power supply apparatus further includes another circuit, where the circuit is electrically connected to the bus, and is configured to supply power to a load. Solutions in embodiments are applied to new energy vehicles such as an electric vehicle and a hybrid electric vehicle, to improve functional safety performance of power supply of the vehicles.