Switchable Battery Pack Configuration for EV Voltage Transition Control
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Solution Overview
Problem
Electric vehicles face inefficiencies in power management due to fixed battery voltage configurations, which limit performance and efficiency during varying operating conditions such as motoring and regeneration.
Innovation Solution
A power control system that dynamically reconfigures N battery packs between parallel and series connections using contactors and power inverters, with a controller determining transitions based on torque and speed to generate torque transients, allowing operation at multiple voltage levels and optimizing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If battery packs are connected in fixed configuration, then system complexity is reduced, but adaptability to different operating conditions deteriorates
Solution Approach 1:
The battery system dynamically reconfigures between series and parallel connections based on operating conditions (motoring vs. regeneration). The contactor arrangement allows the battery packs to switch configurations during operation, enabling the system to adapt voltage output to match varying torque and speed requirements of the electric machine.
Solution Approach 2:
The same battery packs serve multiple functions by being reconfigurable between series connection (for high voltage during motoring) and parallel connection (for low voltage during regeneration). This multi-functionality allows a single battery system to handle both motoring and regeneration operations effectively without requiring separate battery systems.
2Loss of energy
If battery voltage is changed during operation, then efficiency is improved, but risk of short circuits and capacitor in-rush currents increases
Solution Approach 1:
The controller prepares for voltage transitions by monitoring operating conditions and initiating reconfiguration sequences in advance. The contactors are switched at predetermined times based on the operating state, ensuring that transitions occur when the electric machine is in appropriate states (e.g., during regeneration when voltage needs to decrease), thereby preventing harmful in-rush currents.
Solution Approach 2:
The contactor arrangement acts as an intermediary mechanism that safely mediates the transition between voltage configurations. By using controlled contactor switching sequences, the system intermediate between the two voltage states, preventing direct abrupt transitions that would cause short circuits or capacitor in-rush currents.
3Productivity
If battery packs are reconfigured during driving, then performance is optimized, but device complexity increases
Solution Approach 1:
The power control system implements dynamic reconfiguration of battery packs during vehicle operation. The controller monitors torque and speed signals and automatically switches between series and parallel connections to optimize power delivery, enabling the system to maintain high performance across varying driving conditions without manual intervention.
Solution Approach 2:
The system performs self-service by automatically managing its own configuration based on operating conditions. The controller uses feedback from torque and speed sensors to autonomously determine when reconfiguration is needed and executes the switching sequence without external input, optimizing performance while reducing the need for complex external control mechanisms.
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 system enhances electric vehicle efficiency by selecting the most suitable voltage level for operating conditions, improving performance and reducing stress on components during transitions, while preventing short circuits and capacitor in-rush currents.
Implementation Method 1
causing one of a positive torque transient and a negative torque transient to be generated by at least one of the M electric machines
Data Source
AI summary
A power control system comprises a battery system including N battery packs. A plurality of contactors selectively connects N battery packs of a battery system in a first configuration supplying a first voltage level, a second configuration supplying a second voltage level, and a disconnected configuration. M power inverters connect the battery system to M electric machines, respectively. A controller is configured to determine when to transition between the first configuration and the second configuration. The controller is configured to transition between the first configuration and the second configuration by causing one of a positive torque transient and a negative torque transient to be generated by at least one of the M electric machines, transitioning the battery system from one of the first configuration and the second configuration to the disconnected configuration, and transitioning from the disconnected configuration to the other one of the first configuration and the second configuration.