Battery Charger Heating Mode Using Stacked Half-Bridge Converters
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Solution Overview
Problem
Battery charging systems in cold climates face inefficiencies and require additional heating elements to maintain optimal temperatures, which increases complexity and cost.
Innovation Solution
A battery charger with an AC side stacked half bridge converter and a DC side stacked half bridge converter, controlled by circuitry to operate in a heating mode that generates heat without delivering or drawing current from the battery, using alternating switching states and frequency control to regulate heat production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If additional heating elements are added to battery charging systems for cold climate operation, then the battery system can maintain optimal temperature, but the device complexity and cost increase
Solution Approach 1:
The battery charger is designed to perform multiple functions: it can charge the battery during warm conditions and function as a heater during cold conditions. The same charger circuitry, including the full-bridge converter and control system, is used for both charging and heating operations, eliminating the need for separate heating elements and reducing overall system complexity
Solution Approach 2:
The battery charging system provides its own heating capability through the charger's inherent circuitry. The charger generates heat as a byproduct of its operation and can deliberately operate in a heating mode to warm the battery when needed, making the system self-sufficient and eliminating external heating requirements
2Temperature
If additional heating elements are added to battery charging systems for cold climate operation, then the battery system can maintain optimal temperature, but the cost increases
Solution Approach 1:
The battery charger is designed to perform multiple functions: it can charge the battery during warm conditions and function as a heater during cold conditions. The same charger circuitry, including the full-bridge converter and control system, is used for both charging and heating operations, eliminating the need for separate heating elements and reducing overall system complexity
Solution Approach 2:
The heating function is merged with the charging function in a single integrated system. The charger's power conversion circuitry serves dual purposes: transferring electrical energy to the battery during charging and converting electrical energy to thermal energy during heating mode, consolidating components and reducing manufacturing costs
3Temperature
If the charger operates in heating mode without delivering charging current, then heat can be provided to regulate battery temperature, but the energy efficiency decreases
Solution Approach 1:
The charger operates in periodic alternating cycles, switching between charging mode and heating mode. During charging mode, electrical energy is transferred to the battery; during heating mode, the same circuitry converts electrical energy to thermal energy. This periodic operation allows the system to provide heating when needed while maintaining overall energy efficiency through controlled cycling
Solution Approach 2:
The control system adjusts operating parameters to optimize performance in different modes. By modifying switching frequencies, duty cycles, and load configurations, the charger can efficiently transition between charging and heating operations, minimizing energy losses and adapting to varying temperature requirements
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 heat generation within the charger itself, eliminating the need for additional heating elements and improving battery system operation in cold conditions by controlling temperature through closed-loop feedback.
Implementation Method 1
The control signals can operate the battery charger in a heating mode that does not deliver charging current to or draw discharging current from the battery by: closing one switch of the second upper half bridge and one switch of the second lower half bridge to provide a current path through the secondary winding of the transformer
Data Source
AI summary
Operating a battery charger having an AC side stacked half bridge configuration coupled to a primary winding of a transformer and a DC side stacked half bridge configuration coupled to a secondary winding of the transformer to provide heating can include either operating the AC side stacked half bridges to provide a current path through the primary winding that does not include an AC source or operating the DC side stacked half bridges to provide a current path through the secondary winding that does not include a battery. In the former case, operation can include operating the DC side stacked half bridges to alternate between switching states that selectively couple a battery to the secondary winding of the transformer. In the latter case, operation can include operating the AC side stacked half bridges to alternate between switching states that selectively couple the AC source to the primary winding.