Machine Tool Braking Energy Feedback With Series Battery Voltage Control

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Solution Overview

Problem

Existing machine tools with multiple energy supply devices face challenges in efficiently recycling braking energy, as uneven voltage distribution can lead to overload and potential damage to energy supply devices.

Innovation Solution

A braking process for battery-driven machine tools that connects multiple energy supply devices in series, actively regulates intermediate circuit voltage, and uses an unbalanced factor to ensure voltage limits are not exceeded, allowing for efficient energy recuperation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If multiple power supply devices are connected in series to increase system voltage and power capacity, then the power supply capability and operating range are improved, but uneven voltage distribution during braking energy feedback can cause overload and damage to individual power supply devices

Engineering Contradiction:
Improvepower supply capabilityVSAvoidpower supply device safety
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The control unit continuously monitors the voltage of each power supply device during braking energy feedback and dynamically adjusts the feedback strategy. This feedback mechanism ensures that voltage limits are respected while maximizing energy recuperation, preventing overload conditions that would compromise reliability

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system transitions from a static voltage distribution approach to a dynamic one where the voltage allocation to each power supply device is continuously adjusted based on real-time conditions. The control unit modifies the feedback parameters adaptively, allowing the system to maintain optimal power capability while preventing any single device from exceeding its voltage limits

Inventive Principle:
Principle #15Dynamics

2Loss of energy

If braking energy is fed back into power supply devices, then energy efficiency is improved, but voltage limits may be exceeded causing overload and potential damage

Engineering Contradiction:
Improvebraking energy recoveryVSAvoidoverload and voltage limit violations
Core Design Contradiction:
Loss of energyVSObject-affected harmful factors

Solution Approach 1:

The system changes the voltage parameters dynamically during energy feedback. The control unit adjusts the voltage allocation to each power supply device based on their current state and limits, ensuring that the total braking energy is recovered while no individual device exceeds its voltage parameters

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The control unit acts as an intermediary between the braking energy source and the power supply devices. It manages the energy feedback process, distributing the recovered energy appropriately among the power supply devices while preventing any harmful voltage spikes or overload conditions

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of operation

If the machine tool is braked rapidly to prevent coasting and ensure safety, then user safety is improved, but the braking process may generate excessive voltage that exceeds power supply device limits

Engineering Contradiction:
Improveuser safetyVSAvoidpower supply device integrity
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The system prepares for the voltage surge that will occur during rapid braking by having a pre-configured control strategy in place. The control unit is designed to immediately manage the feedback voltage distribution when braking begins, preventing voltage limits from being exceeded while still achieving rapid deceleration for user safety

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

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 enables efficient energy recuperation, minimizes braking time, and ensures the safety and longevity of machine tools by preventing overload and maintaining voltage limits across all energy supply devices.

Implementation Method 1

The electrical energy released during braking of the machine tool is fed back into the first power supply device and/or the second power supply device

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP4535642A1Method for braking a machine tool with at least two energy supply devices and machine tool
Publication Date: 2025.04.09 HILTI AG
  • EP4535642A1 patent drawingFigure 1
  • EP4535642A1 patent drawingFigure 2
  • EP4535642A1 patent drawing

AI summary

The present invention relates to a method for braking a machine tool, wherein the machine tool is a battery-powered machine tool and can be connected to at least one first power supply device and a second power supply device to be supplied with electrical energy. The electrical energy released during braking of the machine tool is fed back into the first power supply device and/or the second power supply device of the machine tool. The power supply devices are connected in series, and the method can include active control of an intermediate circuit voltage, where a limit value of the intermediate circuit voltage U_intermediate_circuit, limit is less than the sum of the limit values ​​of the voltages U_battery_pack, limit of the power supply devices. In a second aspect, the invention relates to a machine tool for carrying out the braking method.