Mobile Working Machine Voltage Control via Dynamic Filter Bandwidth
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Solution Overview
Problem
Existing methods for controlling electromechanical power transmission chains in mobile working machines fail to effectively reduce peak power taken from the energy source, particularly when load variations are unpredictable, as they assume predictable temporal load changes.
Innovation Solution
A mobile working machine system with a storage circuit, first and second electronic power converter stages, and a control system that adjusts signal processing properties based on stored electrical energy, using a controllable filter with increased bandwidth when energy deviates from a reference value, allowing slower control responses within desired limits and faster responses outside these limits to manage peak power needs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the control system responds quickly to power fluctuations, then peak power can be reduced, but the electrical energy storage may deviate from desired limits causing instability
Solution Approach 1:
The control system dynamically adjusts the bandwidth of the controllable filter based on the deviation of electrical energy from reference values. When electrical energy deviates significantly from reference values, the bandwidth is increased for faster response. When electrical energy is within acceptable ranges, the bandwidth is reduced for smoother control, thus resolving the contradiction between quick peak power response and electrical energy stability
Solution Approach 2:
The system changes the signal processing parameters (bandwidth) of the controllable filter based on the state of electrical energy storage. This parameter adaptation allows the system to optimize its response characteristics dynamically, enabling fast response when needed while maintaining stability under normal conditions
2Device complexity
If the control system uses fixed bandwidth filtering, then the system is simpler to implement, but it cannot effectively handle unpredictable load variations
Solution Approach 1:
The control system transitions from a static fixed bandwidth filter to a dynamic controllable filter whose bandwidth can be adjusted in real-time based on system conditions. This dynamic adaptation enables the system to handle unpredictable load variations effectively while maintaining reasonable complexity through structured control logic
3Power
If the control system allows electrical energy to vary freely, then peak power demands can be met, but the electrical energy may deviate too much from reference values
Solution Approach 1:
The control system continuously monitors the electrical energy storage and compares it against reference values. Based on this feedback, the system adjusts the bandwidth of the controllable filter to maintain electrical energy within acceptable deviation limits while still allowing sufficient variation to meet peak power demands. The feedback mechanism ensures that electrical energy remains controlled and does not deviate excessively
Data Source
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AI summary
A mobile working machine comprises an energy source (101), a storage circuit (103) for storing electrical energy, a first electronic power converter stage (104) between the storage circuit and the energy source, an electrical machine (106) for driving actuators, a second electronic power converter stage (107) between the storage circuit and the electrical machine, and a control system (108) for controlling the first electronic power converter stage responsive to the power taken by the second electronic power converter stage from the storage circuit, the control system providing a control signal path from the storage circuit to the first electronic power converter stage. The signal processing properties of the control signal path are dependent on the electrical energy stored by the storage circuit in order to allow the electrical energy to vary, but within desired limits, so as to reduce the peak power taken from the energy source.