Battery Pack Voltage-Switching Control for Electric Drive Motors
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Solution Overview
Problem
Current hybrid and electric vehicles face challenges in securely and reliably managing multiple traction battery packs during powertrain operation, particularly in maintaining constant voltage and isolating battery packs from the inverter and drive system to prevent energy exchange and ensure efficient operation.
Innovation Solution
The implementation of battery pack voltage-switching (V-switch) systems with control logic and algorithms that allow for dynamic voltage switching between battery packs, including pack-to-pack voltage-switching control algorithms, DC bus voltage balancing protocols, and fault-tolerant switch control strategies to manage voltage and isolate battery packs during operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple battery packs are used to provide higher voltage delivery and greater system capacity, then power and energy capacity are improved, but system complexity and control difficulty increase
Solution Approach 1:
The battery system is divided into multiple independently-operable battery packs, each with its own control module. This segmentation allows the system to achieve higher power delivery through parallel or series configurations while managing complexity through modular architecture, where each pack can be controlled and monitored independently.
Solution Approach 2:
The system implements dynamic voltage switching capability that allows real-time reconfiguration between series and parallel battery pack connections. This dynamic reconfiguration enables the system to adapt power delivery characteristics based on operational requirements, resolving the contradiction by providing high power when needed while maintaining manageable system complexity through flexible control.
2Stability of the object's composition
If battery packs are switched during operation to maintain constant voltage, then voltage stability is improved, but switching reliability and safety risks worsen
Solution Approach 1:
The control module pre-assesses switching conditions before executing battery pack voltage switching operations. By evaluating system state, load requirements, and pack readiness in advance, the system ensures voltage stability is maintained while minimizing switching risks through proactive preparation and condition verification.
Solution Approach 2:
The system continuously monitors battery pack voltage, current, and operational parameters, using this feedback to make real-time switching decisions. This closed-loop control ensures voltage stability is maintained during transitions while improving switching reliability through data-driven decision-making and adaptive control strategies.
3Loss of energy
If battery packs are isolated from the inverter during operation, then energy exchange control is improved, but system response time and efficiency may worsen
Solution Approach 1:
The system selectively isolates individual battery packs from the inverter when energy exchange control is required, extracting only the necessary packs from active operation. This partial isolation approach improves energy exchange control by preventing unwanted energy flow while maintaining system response time by keeping other packs connected and ready for immediate operation.
Data Source
AI summary
Presented are battery pack voltage-switching (“V-switch”) systems, methods for making/operating such systems, and multi-pack, electric-drive motor vehicles with battery pack V-switch capabilities. A method for controlling operation of a vehicle includes a vehicle controller receiving a voltage switch signal to change a voltage output of the vehicle's battery system. The vehicle controller determines if a speed of a traction motor is less than a calibrated base speed; if so, the controller transmits a pack isolation signal to a power inverter to electrically disconnect the traction battery packs from the traction motor. The vehicle controller determines if a bus current of a DC bus is less than a calibrated bus current threshold; if so, the controller transmits an open signal to open one or more pack contactor switches and a close signal to close one or more pack contactor switches thereby causing the vehicle battery system to output the second voltage.