Work Machine Drive Braking Using Regenerated Power Transfer
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Solution Overview
Problem
Existing electric drive systems for work machines require additional costly components like braking resistors and friction brakes to achieve sufficient braking power, as they can only produce sufficient braking power when the energy store is not fully charged, leading to increased costs and maintenance needs.
Innovation Solution
A method where a first electric motor associated with the travel drive operates in generator mode to produce braking power, with excess power either stored or supplied to a second electric motor for the work drive, eliminating the need for a separate braking resistor and reducing the reliance on friction brakes by utilizing the second electric motor to consume excess power, thus maximizing braking power utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If electric motors are operated in generator mode for braking, then braking power is produced and energy is recuperated, but sufficient braking power can only be achieved when the energy store is not fully charged
Solution Approach 1:
The patent introduces a friction brake as an intermediary component to work in combination with the electric motor's generator mode. The friction brake provides additional braking force when the energy store is fully charged, ensuring sufficient total braking power is available at all times while maintaining energy recuperation capability when possible.
Solution Approach 2:
The electric motor is designed to serve multiple functions: it acts as a drive motor during normal operation and as a generator during braking to recuperate energy. The system universally handles both energy recovery and safety braking requirements through coordinated control of the motor and friction brake.
2Reliability
If a friction brake is provided to ensure maximum braking power, then safety is improved, but costs and maintenance needs increase
Solution Approach 1:
The patent merges the friction brake system with the electric motor braking system into a coordinated hybrid braking system. The friction brake and electric motor work together in a unified control scheme, allowing the friction brake to be smaller and less expensive since it only needs to supplement braking power when necessary rather than providing full braking capability alone.
Solution Approach 2:
The control system continuously monitors the energy store charge state and dynamically adjusts the braking force distribution between the electric motor and friction brake. When the energy store is not full, the electric motor provides primary braking; when full, the friction brake supplements or replaces electric braking, optimizing cost-effectiveness while maintaining safety.
3Power
If a braking resistor is added to handle excess power, then braking capability is improved, but device complexity and costs increase
Solution Approach 1:
The patent extracts or removes the braking resistor component from the system entirely. Instead of using a braking resistor to dissipate excess power, the system relies on the coordinated action of the electric motor in generator mode and the friction brake to provide sufficient braking power without requiring energy dissipation through resistive heating.
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 approach reduces wear and costs associated with friction brakes, eliminates the need for a separate braking resistor, and ensures maximum braking power is maintained without additional costs, enhancing operational efficiency and safety.
Implementation Method 1
operating the first electric motor in generator mode to produce braking power of the travel drive, electric power being produced in the generator mode
Data Source
AI summary
A method for operating a drive system for a work machine is described. A first electric motor is associated with a travel drive of the drive system and a second electric motor is associated with a work drive of the drive system. An electric energy store for operating the first and the second electric motors is associated with the travel drive and the work drive. The method includes operating the first electric motor in generator mode to produce braking power of the travel drive, electric power being produced in the generator mode. The method further includes supplying, completely or partly to the energy store and/or to the second electric motor depending on a state of the energy store, the electric power.