Stacked Half-Bridge Battery Charging With Integrated Cell Balancing
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Solution Overview
Problem
Conventional battery charging systems for high voltage batteries require additional power converters for boosting and balancing, leading to increased cost, complexity, and space usage.
Innovation Solution
A battery charging system that uses a stacked half bridge rectifier with a blocking capacitor as a flying capacitor, operated by control circuitry to selectively switch between different modes for charging and discharging, eliminating the need for a dedicated balancer or booster converter by utilizing the transformer's leakage inductance for soft switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If additional power converters (booster and balancer) are used to charge high voltage batteries, then charging capability is improved, but system complexity and cost increase
Solution Approach 1:
The patent combines the booster converter and balancer converter into a single integrated power converter unit. This single converter performs both voltage boosting (to match battery voltage) and battery balancing (equalizing charge across multiple batteries) functions, eliminating the need for separate dedicated converters and reducing overall system complexity
Solution Approach 2:
The power converter is designed with multi-functionality to serve multiple purposes: it acts as a booster converter to step up voltage from lower voltage sources, operates as a balancer converter to distribute charge evenly across series-connected batteries, and can function in different operating modes (single battery charging, dual battery charging with balancing) based on system requirements
2Adaptability or versatility
If additional power converters are added for boosting and balancing, then charging functionality is improved, but space consumption increases
Solution Approach 1:
The patent merges the booster and balancer converters into one physical unit, significantly reducing the space required in the charging system. Instead of having two separate converter assemblies each with their own components (switches, capacitors, inductors, control circuits), a single integrated converter shares these components and performs both functions sequentially or simultaneously based on operational needs
3Adaptability or versatility
If additional power converters are used, then charging capability is improved, but manufacturing cost increases
Solution Approach 1:
The integration of booster and balancer converters into a single unit reduces the total component count, assembly steps, and testing requirements, thereby lowering manufacturing costs. The shared components (such as the power switch bridge, capacitors, and control circuitry) can be produced as a standardized module, achieving economies of scale
4Reliability
If conventional boost converter and dedicated balancer are used, then voltage matching and battery balancing are achieved, but system mass increases
Solution Approach 1:
The patent integrates the booster and balancer converters into a single power converter unit, reducing the total mass of the charging system. The shared components (power switches, capacitors, inductors, control circuits) are common to both functions, eliminating duplicate mass from having separate converter assemblies while maintaining both voltage boosting and battery balancing capabilities
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 allows for efficient charging of high voltage batteries from lower voltage sources without additional converters, reducing system complexity and cost while maintaining high efficiency through soft switching techniques.
Implementation Method 1
one or more contactors and switching devices of a stacked half bridge rectifier as a switched capacitor booster using the blocking capacitor as a flying capacitor
Implementation Method 2
The inductance can include a leakage inductance of the transformer
Implementation Method 3
A frequency of alternating between the first switching state and the second switching state can be controlled to achieve soft switching using energy stored in an inductance that resonates with the flying capacitor
Data Source
AI summary
A battery charging system can include a stacked half bridge rectifier (“SHBR”) having an upper half bridge (“UHB”) and a lower half bridge (“LHB”); a blocking capacitor and a winding coupled between a midpoint of the UHB and a midpoint of the LHB; a battery coupled across the SHBR; and control circuitry that can selectively operate the SHBR as a switched capacitor converter (“SCC”) using the blocking capacitor as a flying capacitor by alternating between: a first switching state in which lower switches of the UHB and LHB are closed while upper switches of the UHB and LHB are opened; and a second switching state in which upper switches of the UHB and LHB are closed. The battery can further include first and second series-connected batteries having a midpoint coupled to a midpoint of the SHBR, and the SCC can operate as a balancer to equalize charge between the batteries.