Electric Drivetrain Control for Working Machine Efficiency
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Solution Overview
Problem
Existing electrically driven working machines do not effectively utilize the decoupling between the travel drive and work drive, leading to inefficient operation of the hydraulic work system.
Innovation Solution
The method involves operating the work drive independently of the travel drive, taking into account the efficiency of the work motor and work device to supply the demanded power, considering factors like moment of inertia and hydraulic power steering assistance, and using environment sensors for situation detection to optimize power changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the work drive is operated independently of the travel drive with optimized efficiency control, then energy efficiency and operating time are improved, but the control system complexity increases
Solution Approach 1:
The control system is segmented into separate control modules for the work drive and travel drive, allowing independent optimization of each drive's efficiency without requiring complex integrated control. The work motor controller and hydraulic pump controller operate independently with their own efficiency maps and control algorithms.
Solution Approach 2:
The system pre-calculates and stores efficiency maps for the work motor and hydraulic pump before operation. During operation, the controller references these pre-computed efficiency maps to determine optimal operating points, avoiding the need for complex real-time calculations and simplifying the control algorithm execution.
2Power
If the hydraulic pump is controlled as a variable displacement pump with adjusted swivel angle, then the hydraulic pressure and volume flow are improved, but the mechanical complexity of the pump system increases
Solution Approach 1:
The hydraulic pump is designed as a variable displacement pump with an adjustable swivel angle that can be dynamically changed during operation. This allows the pump to adapt its displacement and output characteristics to match the actual hydraulic demands of the work device, optimizing power delivery while maintaining mechanical feasibility through a well-established variable displacement mechanism.
Data Source
AI summary
A method for operating an electric drivetrain of a working machine is provided wherein, the drivetrain includes a work drive with a hydraulic work device and an electric work motor, and a travel drive with an electric travel motor. The method includes operating the work drive independently of the travel drive, and supplying a power demanded by the work drive taking into account an efficiency of the work motor and an efficiency of the work device.