Traction Motor Inverter Rectifier Mode Power Supply
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Solution Overview
Problem
Existing power supply methods for traction motors, particularly those with permanent magnet motors, are not adaptable to all scenarios, as they require inverter control based on train position or speed, and often necessitate a dedicated external inverter for power supply when the train is not connected to a catenary.
Innovation Solution
A method where the electronic power supply control device alternately triggers the supply of traction motors between a first and second mode, disconnecting the second motor from its inverter and operating it as a rectifier, using the rectified voltage to power the first inverter and motor, eliminating the need for a dedicated external inverter and allowing on-board inverters to reuse the power supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dedicated external inverter is used to power traction motors when the train is not connected to a catenary, then the power supply reliability is improved, but the device complexity and cost increase
Solution Approach 1:
The inverter is designed to perform multiple functions: it can operate as a standard inverter when powered by the catenary, and switch to rectifier mode when powered by external AC sources. This multi-functionality eliminates the need for dedicated external inverters while maintaining power supply reliability.
Solution Approach 2:
The inverter serves itself by switching between different operating modes (inverter mode and rectifier mode) depending on the power source available. This self-service capability reduces the need for additional external equipment while ensuring continuous operation.
2Adaptability or versatility
If the inverter operates in rectifier mode using external AC power supply, then the adaptability to different power sources is improved, but the control complexity increases
Solution Approach 1:
The inverter's operating mode is dynamically switched between inverter mode and rectifier mode based on the available power source. This dynamic adaptability allows the system to work with different power sources (catenary DC or external AC) without requiring separate dedicated equipment for each mode.
Solution Approach 2:
The inverter changes its operational parameters (switching between inverter and rectifier modes) to adapt to different input power conditions. This parameter change enables the system to handle both DC catenary power and AC external power sources using the same hardware.
3Device complexity
If the second inverter operates as a rectifier to power the first inverter, then the need for dedicated external inverters is eliminated, but the energy conversion losses increase
Solution Approach 1:
The patent merges the functions of multiple inverters into a single coordinated system where one inverter (operating as rectifier) powers another inverter. This consolidation eliminates the need for separate dedicated external inverters while accepting some energy conversion losses as a trade-off for reduced system complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution provides a flexible and efficient power supply for traction motors, including permanent magnet motors, enabling the train to move to a depot without a dedicated external inverter, and maintaining motor speed control within a limited range.
Implementation Method 1
control the second inverter so that it operates as a rectifier; said second inverter operating as a rectifier being supplied by a second supply voltage
Data Source
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AI summary
Method of supplying a set (10) of traction motors comprising a first and a second traction motor (11, 12) and a first and a second inverter (21, 22), comprising the following steps: - in a first mode, a first DC supply voltage being supplied to the input of said first and second inverters, supplying the first motor with the signal from the first inverter and supplying the second motor with the signal from the second inverter; - in the second supply mode, electrically disconnecting the second motor from the second inverter, commanding the second inverter to operate as a rectifier; said second inverter being supplied with a second supply voltage; - supplying the first inverter with the rectified voltage supplied by said second inverter operating as a rectifier and supplying the first motor with the AC signal delivered by the first inverter.