Rail Vehicle Power Converter Heat Control via Auxiliary Load Shedding
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Solution Overview
Problem
In rail vehicles, the power conversion device is frequently forced to stop due to excessive temperature from engine exhaust air, leading to reduced motor output and potential train delays, as existing control methods decrease torque below desired levels.
Innovation Solution
A power conversion device with temperature sensors and a controller that issues load decrease instructions to auxiliary equipment to manage temperature, preventing emergency stops by reducing engine output and exhaust air temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the power conversion device is provided with a stopping function to prevent failure due to temperature rise, then the reliability of semiconductor elements and control logic unit is improved, but the productivity of train operation deteriorates due to frequent emergency stops
Solution Approach 1:
The controller performs preliminary action by decreasing the output of the motor before the temperature reaches the stopping threshold. When the temperature exceeds a first threshold value, the controller decreases motor output to prevent further temperature rise, thereby avoiding emergency stops and maintaining train operation continuity while still protecting the power conversion device.
Solution Approach 2:
The system implements feedback control by continuously monitoring the temperature of the power conversion device and adjusting the motor output accordingly. The controller receives temperature information from detectors and dynamically adjusts motor output based on the temperature state, creating a closed-loop control system that balances reliability and productivity.
2Temperature
If the output of the motor is decreased to avoid emergency stops, then the temperature of the power conversion device is reduced, but the train operation cannot be maintained as per timetable
Solution Approach 1:
The system applies dynamics by making the motor output adjustable rather than fixed. The controller dynamically changes the motor output based on real-time temperature conditions, allowing the system to adapt between different operating states (full power when cool, reduced power when hot) to maintain both temperature control and timetable adherence.
Solution Approach 2:
The controller changes the operating parameters of the motor based on temperature feedback. When temperature exceeds thresholds, the controller modifies motor output parameters to reduce heat generation in the power conversion device, while carefully managing these parameter changes to maintain acceptable train operation speed and schedule compliance.
3Reliability
If temperature sensors are provided on semiconductor elements and control logic unit, then the reliability of the power conversion device is improved, but the device complexity increases
Solution Approach 1:
The controller serves multiple functions: it not only controls the motor output but also monitors temperature through detectors and makes decisions about when to reduce power. This multi-functionality reduces the need for separate dedicated temperature control hardware, thereby limiting the increase in device complexity while still achieving reliable temperature monitoring and control.
Data Source
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AI summary
The vehicle power conversion device according to one embodiment of the present invention is provided with a converter (4) for converting the AC power generated by a generator to a DC power, said generator generating power by the turning force of all engine; a first inverter (5) for converting the DC power to an AC power supplied to a vehicle drive motor (6); a second inverter (7) for converting the DC power to an AC power supplied to an auxiliary machine (8); a first temperature sensor (102) for measuring the temperature of the first inverter (5); and a control device (9) for limiting the output power of the second inverter (7) when the temperature of the first inverter (5) measured by the first temperature sensor (102) becomes a predetermined temperature or more.