Converter Control for Electric Vehicle Charging Efficiency
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Solution Overview
Problem
Existing power supply systems for electric vehicles with multiple power storage devices and converters arranged in parallel face inefficiencies in charging from external power sources, particularly due to converter switching losses during prolonged charging periods.
Innovation Solution
A power supply system with a control device that selectively turns on and off power semiconductor switching elements in converters to prevent switching losses, allowing only a part of the converters to switch and maintaining others in a holding state to reduce energy loss during external charging, ensuring efficient charging of power storage devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If all converters operate in parallel to charge multiple power storage devices, then charging capacity is improved, but converter power loss increases due to switching operations
Solution Approach 1:
The patent divides the charging system into multiple independent converter channels, each capable of operating independently. During external charging, only one converter is activated at a time to charge a specific power storage device, while other converters remain inactive. This segmentation allows the system to maintain high charging capacity through multiple devices while reducing total power loss by avoiding simultaneous switching operations across all converters.
Solution Approach 2:
The patent implements periodic switching between multiple converters during the charging process. Instead of all converters operating simultaneously, they are activated in sequence or in periodic intervals. This periodic action reduces the cumulative switching losses while ensuring that all power storage devices eventually receive charge, thereby maintaining overall charging capacity without the continuous energy loss of simultaneous operation.
2Stability of the object's composition
If converters continuously switch to balance charge across power storage devices, then charge distribution is improved, but energy loss from switching increases
Solution Approach 1:
The patent enables power storage devices to self-regulate their charging status through the converter selection mechanism. The control system monitors charge levels and automatically selects which converter to activate based on current charge distribution, allowing the system to self-balance without requiring continuous active switching of all converters. This reduces switching losses while maintaining charge distribution stability.
Solution Approach 2:
The patent changes the operational parameters of converters dynamically based on charge distribution needs. Instead of maintaining all converters in a constant switching state, the system adjusts which converters are active based on real-time charge levels. This parameter change approach allows the system to achieve charge balancing only when necessary, thereby reducing unnecessary switching losses while maintaining stable charge distribution.
3Speed
If multiple converters operate simultaneously during external charging, then charging speed is improved, but overall charge efficiency decreases due to cumulative losses
Solution Approach 1:
The patent implements preliminary selection of which power storage device to charge first based on charge level monitoring. Before initiating charging, the system identifies the target device and activates only the corresponding converter. This preliminary action prevents unnecessary simultaneous operation of multiple converters, reducing cumulative switching losses while maintaining efficient charging speed by focusing power on the most needs device first.
Solution Approach 2:
The patent makes the converter operation dynamic rather than static. Converters are activated and deactivated based on real-time charging progress and charge distribution needs. This dynamic approach allows the system to maintain high charging speed by adapting to changing conditions, while avoiding the fixed inefficiency of continuous simultaneous converter operation. The system transitions between different converter states optimally throughout the charging process.
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 approach significantly reduces converter power loss and enhances charge efficiency by minimizing switching operations during prolonged external charging, allowing for more effective charging of power storage devices in electric vehicles.
Implementation Method 1
Each converter is configured to include a plurality of power semiconductor switching elements to convert electric power between an associated power storage device of the plurality of power storage devices and the electric power line bidirectionally
Data Source
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AI summary
Converters (8-1, 8-2) are configured to operate in a normal operation to convert the electric power that is input/output to/from secondary batteries (6-1, 6-2) bidirectionally to direct current voltage. In a predetermined mode allowing the secondary batteries (6-1, 6-2) to be charged, at least one of the converters (8-1, 8-2) does not perform a switching operation and holds on an upper arm element (Q1B, Q2B) to avoid a switching loss in charging the secondary batteries (6-1, 6-2). An electric power loss caused at the converters in charging the secondary batteries can be reduced, and charging efficiency can be enhanced.