Battery Pack Round-Robin Pre-Charging for DC Bus Resistor Protection
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Solution Overview
Problem
In electric or hybrid vehicles with multiple battery packs connected in parallel, repeated rapid pre-charging of the high-voltage DC bus can lead to premature burnout of the resistor in the pre-charge circuit, resulting in costly and complicated battery pack failures.
Innovation Solution
A round-robin architecture is implemented where a controller assembles a queue based on the usage of battery packs to pre-charge the DC bus, ensuring that no battery pack is repeatedly selected for rapid pre-charging, thus preventing resistor burnout. This system is scalable, requires no additional hardware, and is cost-effective.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the same battery pack is used repeatedly for pre-charging the DC bus, then the pre-charging function is maintained, but the resistor in the pre-charge circuit burns out due to excessive heat dissipation
Solution Approach 1:
The system divides the single pre-charging function across multiple battery packs. Instead of one battery pack performing all pre-charging operations, the controller distributes pre-charging tasks among multiple battery packs in a round-robin fashion, segmenting the thermal and electrical stress burden across multiple resistors rather than concentrating it on one.
Solution Approach 2:
The controller implements periodic rotation through the queue of battery packs, selecting different battery packs for pre-charging in sequential cycles. This periodic action ensures that no single battery pack's resistor is subjected to continuous repeated stress, allowing each resistor adequate recovery time between pre-charging events.
2Reliability
If additional hardware or software solutions are implemented to prevent resistor burnout, then resistor protection is improved, but system complexity and cost increase
Solution Approach 1:
The existing controller, which already manages battery pack selection and charging operations, is extended to implement the round-robin queue management. The same controller hardware performs multiple functions: monitoring battery states, managing the pre-charging queue, selecting battery packs, and coordinating pre-charging operations. This multi-functionality approach avoids adding dedicated protection hardware.
Solution Approach 2:
The system uses its own existing resources (the controller and the array of battery packs) to protect itself from resistor burnout. Rather than requiring external protection devices, the controller intelligently manages the pre-charging distribution among battery packs, making the system self-protecting through software-based load balancing.
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
The solution effectively prevents resistor burnout and battery pack failure by ensuring that battery packs are used alternately for pre-charging, thereby extending the lifespan of the battery packs and reducing replacement costs.
Implementation Method 1
Each battery pack includes one pre-charge circuit comprising a resistor, which dissipates power through heat.
Data Source
AI summary
The present disclosure provides a system and method for selecting a battery pack that is used to pre-charge a high-voltage DC bus of an electric vehicle. A round-robin architecture is disclosed that prevents repeat selection of battery packs in order to prevent burnout of a resistor of the battery pack resulting from rapid subsequent pre-charging events. The system and method provided includes an easy solution that is scalable to a system with any number of battery packs, does not require any additional hardware, and is an inexpensive technique to protect an expensive component of the electric vehicle.