Electric Motor Speed Synchronization Thermal Management
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Solution Overview
Problem
Electrically driven working machines face challenges in speed synchronization during shifting operations due to the higher moment of inertia and greater speed spectrum of electric motors compared to combustion engines, leading to increased thermal loading and wear on clutch elements.
Innovation Solution
The method involves using two electric motors, where speed synchronization during shifting is achieved through energization of the second electric motor, reducing the need for friction-based clutch engagement, and implementing measures to manage thermal loading, such as temperature detection and cooling, to prevent damage and prolong motor life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If speed synchronization is carried out by friction work between clutch elements during shifting operations, then the shifting operation can be performed, but the clutch elements experience high thermal loading and wear
Solution Approach 1:
The patent replaces the mechanical friction-based speed synchronization system with an electrical control system. The control device detects the thermal state of the second electric motor and controls its speed synchronization during shifting operations, substituting the mechanical clutch friction process with an electronically controlled motor speed regulation process, thereby eliminating thermal loading and wear on clutch elements
Solution Approach 2:
The control device acts as an intermediary between the shifting operation requirements and the second electric motor. It detects thermal states and mediates the speed synchronization process by controlling the motor's speed based on thermal conditions, preventing direct thermal contact and wear that would occur in traditional friction-based systems
2Power
If the moment of inertia of the electric motor is increased, then the motor can provide greater power, but speed synchronization during shifting becomes more difficult
Solution Approach 1:
The control device implements a feedback mechanism by continuously detecting the thermal state of the second electric motor and using this information to adjust speed synchronization control during shifting operations. This feedback loop enables the system to manage the high moment of inertia motors effectively, coordinating speed changes while preventing thermal overload
Solution Approach 2:
The system dynamically adjusts the speed synchronization process based on real-time thermal detection. The control device modifies the speed control strategy during shifting operations according to the detected thermal state, enabling flexible adaptation to the high moment of inertia characteristics while maintaining effective speed synchronization
3Adaptability or versatility
If the speed spectrum of the electric motor is expanded, then the motor can operate across a wider range of speeds, but greater speed differences must be synchronized during shifting
Solution Approach 1:
The control device performs preliminary detection of the thermal state before initiating speed synchronization during shifting operations. Based on this preliminary thermal assessment, it pre-adjusts the speed control strategy to account for the broader speed spectrum differences, preventing thermal overload before it occurs by preparing the synchronization process in advance
Solution Approach 2:
The system changes operational parameters dynamically during speed synchronization. The control device adjusts speed control parameters based on detected thermal states, modifying the synchronization profile to accommodate the expanded speed spectrum while maintaining thermal safety margins throughout the shifting operation
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 allows for more compact and less powerful clutch designs, reducing costs and weight while minimizing thermal stress on electric motors, thereby enhancing their durability and operational efficiency.
Implementation Method 1
speed synchronization is carried out by energization of the second electric motor
Implementation Method 2
a temperature of the second electric motor is detected
Data Source
AI summary
The disclosure relates to a method for operating a drive train for a working machine, in which a working drive of the working machine is driven by a first electric motor via a first gear arrangement, a travel drive of the working machine is driven by a second electric motor via a second gear arrangement and, in a shifting procedure of the second gear arrangement, the rotational speed of the second electric motor is synchronised and the temperature of said second electric motor is recorded. In the disclosed method, the rotational speed is synchronised by supplying current to the second electric motor, and in the event of a threshold temperature being exceeded, at least one measure is carried out to relieve the thermal load of the second electric motor. The disclosure further relates to a corresponding drive train and to a working machine.