Vehicle Drive Unit Regulating Level Control for AC-Supply Stability
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Solution Overview
Problem
The operation of multiple vehicles connected to the same AC-supply line leads to instability and power oscillations, limiting the number of vehicles that can operate without causing detrimental effects on connected components.
Innovation Solution
Implementing a control method for the drive unit that switches between high and low regulating levels based on the vehicle's operational mode, adjusting the accuracy of power conversion and the number of active sub-functions to minimize contributions to power oscillations, allowing more vehicles to operate without causing instability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple vehicles operate on the same AC-supply line with high regulating level, then power conversion accuracy is improved, but power oscillations and instability increase
Solution Approach 1:
The patent applies dynamics by making the regulating level adjustable rather than fixed. The control system dynamically switches between high and low regulating levels based on operational mode, allowing the system to adapt its power conversion accuracy and stability characteristics to different operating conditions. This resolves the contradiction by enabling high accuracy when needed while accepting lower accuracy when stability is prioritized.
Solution Approach 2:
The patent changes the regulating level parameter based on operational mode. When in non-operational mode, the system switches to low regulating level, which reduces power oscillations and maintains AC-supply line stability. When in operational mode, the system uses high regulating level for accurate power conversion. This parameter change strategy directly resolves the contradiction between accuracy and stability.
2Productivity
If the number of vehicles operating in the same area is increased, then productivity is improved, but power oscillations and instability increase
Solution Approach 1:
By implementing adjustable regulating levels, the patent enables more vehicles to operate simultaneously. Each vehicle can switch to low regulating level when in non-operational mode, reducing its individual contribution to power oscillations. This allows the AC-supply line to support a higher total number of vehicles without exceeding stability thresholds, thereby resolving the contradiction between productivity and stability.
3Stability of the object's composition
If low regulating level is used to reduce power oscillations, then AC-supply line stability is improved, but power conversion accuracy decreases
Solution Approach 1:
The patent makes the regulating level dynamic rather than fixed. The system automatically switches between low and high regulating levels based on whether the vehicle is in non-operational or operational mode. This dynamic adjustment ensures that power conversion accuracy is maintained when needed while minimizing power oscillations when the vehicle is idle, resolving the contradiction between stability and accuracy.
Solution Approach 2:
The regulating level is periodically adjusted based on operational mode changes. The control system monitors the operational state and switches between regulating levels accordingly, ensuring that low regulating level (for stability) is used during non-operational periods while high regulating level (for accuracy) is used during operational periods. This periodic switching resolves the contradiction by applying the appropriate regulating level at the appropriate time.
Data Source
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AI summary
A method for controlling a drive unit (1, 1a, 1 b) and a drive unit of a vehicle connected to an AC-supply line (3). The drive unit comprises an AC/DC-converter (7) adapted to convert electric power to a target value and a control unit (15) comprising a regulating function comprising a high regulating level converting electric power to the target value with a first accuracy and a low regulating level converting electric power to the target value with a second accuracy. The control unit is adapted to receive information on whether the vehicle is in is in an operational or a non-operational mode, and in dependency of the information switch the regulating function between the high and low regulating level so that the regulating function is set to the high regulating level when the vehicle is the operational mode and to the low regulating level when the vehicle is in the non-operational mode.