Train Drive Mode Control Using OBESS SoC Thresholds
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Solution Overview
Problem
Conventional hybrid trains require continuous operation of on-board generator units (GUs) for motive power, leading to greenhouse gas emissions and noise pollution, and the state of charge (SoC) of on-board energy storage systems (OBESSs) can reduce excessively, affecting their lifetime.
Innovation Solution
A control system determines available drive modes based on OBESS SoC, prioritizing OBESS use to maintain SoC levels, adapting modes to external influences, and preventing excessive depletion or overcharging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the train operates in hybrid mode or battery-only mode to reduce emissions, then greenhouse gas emissions and noise pollution decrease, but the state of charge of OBESSs reduces excessively, shortening their lifetime
Solution Approach 1:
The control system continuously monitors the state of charge (SoC) of the OBESSs and uses this feedback to dynamically determine which drive modes are available. When SoC falls below a threshold, the system automatically restricts operation to generator mode, preventing excessive discharge and protecting OBESS lifetime while still allowing emission reduction when SoC is sufficient.
Solution Approach 2:
The system dynamically adjusts the available drive modes based on real-time SoC conditions rather than operating in fixed modes. The control system adapts the operational characteristics by enabling or disabling specific drive modes (generator mode, hybrid mode, battery-only mode) according to the current energy state, optimizing both emission reduction and OBESS protection.
2Object-generated harmful factors
If the driver requests battery-only drive mode in low emission zones, then emissions are reduced, but the SoC of OBESSs may deplete below safe levels
Solution Approach 1:
The control system monitors SoC levels and uses this feedback to override driver requests when necessary. When the driver requests battery-only mode but SoC is below the threshold, the system responds by not enabling that mode, thereby protecting OBESS lifetime while still allowing emission reduction when conditions permit.
Solution Approach 2:
The system preemptively prevents SoC depletion by determining drive mode availability before the driver can execute a request that would harm OBESS lifetime. By evaluating SoC conditions first and restricting available modes accordingly, the system avoids the need for corrective action after excessive discharge occurs.
3Object-generated harmful factors
If the train maximizes OBESS usage to reduce emissions, then environmental impact decreases, but the control system complexity increases
Solution Approach 1:
The control system uses a simple parameter threshold (SoC level) to determine drive mode availability. When SoC exceeds the threshold, battery-only and hybrid modes are available; when below, only generator mode is available. This parameter-based approach enables emission reduction through intelligent mode selection while keeping the control logic relatively simple and manageable.
Data Source
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AI summary
There is provided a method and a control system for operating a drive system of a train in a plurality of driving modes. The plurality of driving modes include: a generator mode in which power is drawn from an on-board generator, a hybrid mode in which power is drawn from the on-board generator assisted by one or more on-board electrical storage systems, and a battery-only mode where power is drawn only from the one or more on-board electrical storage systems. The control system is configured to: receive a detected state of charge, SoC, from the one or more on-board electrical storage systems, determine an availability of one or more of the driving modes based on the detected SoC, and allow the drive system to operate in one of the available driving modes.