Battery Stack AC Output Control for EV Motor Voltage Balance

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Solution Overview

Problem

Existing charge storage devices for electric vehicles face challenges in efficiently managing voltage across multiple battery stacks connected to electric vehicle motors, particularly in producing alternating current (AC) voltage with specific phases and amplitudes to optimize motor performance.

Innovation Solution

The system configures multiple battery stacks to produce AC voltage with controlled phases and amplitudes, ensuring no DC offset by combining AC voltages from multiple stacks, and connects these stacks to electric vehicle motors with precise terminal connections to provide three-phase AC voltage, allowing for efficient energy transfer and motor operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If multiple battery stacks are connected in series to increase voltage output, then the power delivery capability is improved, but the risk of DC offset accumulation increases which can harm motor performance

Engineering Contradiction:
Improvepower delivery capabilityVSAvoidDC offset accumulation
Core Design Contradiction:
PowerVSObject-affected harmful factors

Solution Approach 1:

The battery system is divided into multiple independent battery stacks, each with its own control circuitry. This segmentation allows individual monitoring and control of each stack's voltage output, enabling the system to detect and correct DC offset in individual stacks while maintaining overall high power delivery capability through the series connection architecture.

Inventive Principle:
Principle #1Segmentation

2Productivity

If battery stacks are configured to produce AC voltage with controlled phases, then motor performance is optimized, but the system complexity increases

Engineering Contradiction:
Improvemotor performanceVSAvoidsystem complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

Multiple battery stacks are electrically connected in a configuration that combines their outputs to produce three-phase AC voltage. The control system merges the voltage outputs from individual stacks, synchronizing their phases to directly generate balanced three-phase power for the motor, thereby achieving optimized motor performance while managing system complexity through integrated control.

Inventive Principle:
Principle #5Merging (Combining)

3Loss of energy

If voltage distribution across battery stacks is optimized for efficient energy transfer, then energy efficiency is improved, but the control difficulty increases

Engineering Contradiction:
Improveenergy transfer efficiencyVSAvoidcontrol difficulty
Core Design Contradiction:
Loss of energyVSDifficulty of detecting and measuring

Solution Approach 1:

The system incorporates voltage sensing and control circuitry that continuously monitors the voltage output of each battery stack. This feedback mechanism enables the control system to detect voltage imbalances and adjust the operation of individual stacks to optimize voltage distribution, thereby improving energy transfer efficiency while managing control difficulty through automated feedback-based regulation.

Inventive Principle:
Principle #23Feedback

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 configuration enhances the efficiency of energy transfer to electric vehicle motors by eliminating DC offset, optimizing voltage distribution, and improving motor performance through synchronized AC voltage production.

Implementation Method 1

The string voltage may be configured to be multiple integers of the cell voltage, determined by the number of cells serially connected in the string

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP4292863A1Charge storage device
Publication Date: 2023.12.20 SOLAREDGE TECH LTD
  • EP4292863A1 patent drawingFigure 1A
  • EP4292863A1 patent drawingFigure 1B
  • EP4292863A1 patent drawingFigure 1C

AI summary

Systems, apparatuses, and methods are described for charge storage devices with a plurality of battery cells. The plurality of battery cells may be connected to each other in one or more battery stacks. The plurality of battery cells may be connected to one or more coils of a motor of an electric vehicle.