Flying Capacitor Inverter for Mixed-Chemistry Battery Power Balancing
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Solution Overview
Problem
Existing systems struggle to effectively transfer and balance power between battery packs of different chemistries, as passive balancing techniques are inadequate for mixed chemistry battery systems, leading to inefficient power distribution.
Innovation Solution
A vehicle system utilizing a flying capacitor multi-level inverter with a controller to operate as a DC-DC converter, enabling power transfer and balancing between battery packs of distinct types by controlling transistors via pulse width modulation and phase shifting, utilizing the motor's internal inductance for power flow without rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If passive power balancing techniques are used, then identical battery cells can be balanced, but power transfer between different chemistry battery packs is not effective
Solution Approach 1:
The patent introduces a DC-DC converter as an intermediary device between battery packs of different chemistries. This converter acts as a mediator that can handle the different electrical characteristics and operating parameters of distinct battery chemistries, enabling effective power transfer and balancing that passive techniques cannot achieve directly between incompatible battery types
Solution Approach 2:
The patent employs active power balancing that can dynamically adjust electrical parameters such as voltage, current, and power flow between battery packs. This parameter control capability allows the system to adapt to different chemistry characteristics and optimize power transfer efficiency across mixed chemistry configurations
2Adaptability or versatility
If distinct battery pack types are utilized, then different vehicle operational modes can take advantage of different battery characteristics, but power transfer between battery packs becomes difficult
Solution Approach 1:
The DC-DC converter is designed with multi-functionality to handle various battery chemistry combinations and operational modes. It can perform power transfer, power balancing, and voltage matching across different battery types, reducing the need for separate dedicated systems for each battery pair and thereby managing complexity while maintaining versatility
3Adaptability or versatility
If active power balancing system is implemented, then power transfer between mixed chemistry battery packs is enabled, but system complexity increases
Solution Approach 1:
The active power balancing system incorporates control mechanisms that automatically monitor battery states and adjust power flow without manual intervention. The system self-regulates to maintain optimal operation across mixed chemistry packs, reducing the operational complexity burden despite the increased hardware capability
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 efficient power transfer and balancing between mixed chemistry battery packs, optimizing charging processes and providing fault protection, while maintaining system stability and safety.
Implementation Method 1
A multi-level inverter converts direct current (DC) power from the battery pack into an alternating current (AC) power form that is provided to a motor and drives the motor to rotate
Implementation Method 2
utilizing the motor's internal inductance for power flow without rotation
Data Source
AI summary
A vehicle system includes a first battery pack connected to a second battery pack via a flying capacitor multi-level inverter. The fling capacitor inverter has multiple inverter legs, with each inverter leg being arranged in a flying capacitor topology. A three phase motor is connected to the inverter. A controller connected to the motor and the inverter. The controller includes a memory storing instructions configured to cause the controller to control the inverter as a direct current (DC)-DC converter such that a circulating current passes through the motor, the first battery pack and the second battery pack.