Machine Tool Braking With Regenerative Feedback and Brake Chopper
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Solution Overview
Problem
Existing machine tool braking methods, such as short-circuit braking, brake choppers, and recuperation, face issues of limited control over braking torque and time, hardware complexity, increased weight and cost, and potential damage to electronics due to exceeding power supply device limits during regenerative braking.
Innovation Solution
A method for braking a machine tool that involves regenerative braking, feeding back electrical energy into the power supply device or intermediate circuit, and using a brake chopper to absorb excess energy only when necessary, controlled by voltage and current regulators to prevent exceeding power supply limits, allowing efficient energy recovery and compact design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If regenerative braking is used to feed back electrical energy into the power supply device, then energy recovery efficiency is improved, but the power supply device may exceed its voltage or current limits causing damage
Solution Approach 1:
The patent introduces a brake chopper as an intermediary component between the motor and the power supply device. The brake chopper acts as a mediator that diverts excess braking energy away from the power supply device when voltage or current limits are approached, preventing damage while allowing regenerative braking to operate efficiently under normal conditions
Solution Approach 2:
The control unit continuously monitors the voltage and current levels of the power supply device during braking. When the monitored parameters approach predetermined limit values, the control unit activates the brake chopper to divert excess energy. This feedback mechanism ensures the power supply device operates within safe parameters while maximizing energy recovery
2Reliability
If a brake chopper is installed to absorb excess braking energy, then power supply device protection is improved, but the machine tool's weight and volume increase
Solution Approach 1:
The brake chopper is designed to perform multiple functions: it serves as a protection mechanism for the power supply device during regenerative braking, and simultaneously acts as a safety brake for the machine tool. This multi-functionality reduces the need for separate components, thereby minimizing weight and volume increases
Solution Approach 2:
The brake chopper's resistance value is specifically optimized to match the machine tool's braking energy characteristics. By adjusting the resistance parameter, the brake chopper can effectively absorb the required amount of energy with minimal material, reducing its weight and volume while maintaining protection capability
3Power
If brake chopper components are installed for high pulse power handling, then braking capability is improved, but manufacturing complexity and installation space increase
Solution Approach 1:
The brake chopper components are merged with the machine tool's existing braking system architecture. The brake chopper shares mounting space and control infrastructure with other braking components, reducing the need for separate installation space and simplifying manufacturing and assembly processes
Solution Approach 2:
The brake chopper uses readily available, standardized high-power electronic components that can be easily replaced if needed. This approach simplifies manufacturing by using off-the-shelf parts rather than custom-designed components, reducing both manufacturing complexity and installation space requirements
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 method provides effective protection against injury with exceptionally short braking times, ensures efficient energy recovery, and maintains a compact, portable machine tool design by optimizing power loss and avoiding electronic damage.
Implementation Method 1
During braking, the machine tool motor can be braked in a controlled manner, thus becoming a generator. The energy released can be fed back into the DC link and from there transferred to the power supply devices.
Implementation Method 2
absorbing part of the electrical energy by the brake chopper if the electrical energy released during braking exceeds at least one limit value of the power supply device or the DC link voltage
Data Source
Figure 1
Figure 2a
Figure 2b
AI summary
The present invention relates to a method for braking a machine tool (10), wherein the machine tool (10) is a battery-powered or mains-powered machine tool and has a brake chopper, and electrical energy released when braking the machine tool (10) is fed back at least partially into a power supply device (14) or an intermediate circuit of the machine tool (10).