Variable-Gauge Train Inverter Control During Gauge Conversion
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Solution Overview
Problem
In variable-gauge trains employing a collective control method, reducing torque for racing wheels within a gauge converter leads to a decrease in driving force for wheels outside the converter, affecting the entire train's propulsive force, and this issue persists even when the inverter is stopped.
Innovation Solution
A variable-gauge train control apparatus that uses a voltage control unit to adjust the output voltage of a single inverter, treating the average or smallest rotational frequencies of wheels outside the gauge converter as a reference frequency, and adding a slip frequency command to prevent over-rotation and maintain driving force for wheels in contact with rails.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If torque of all main motors is reduced by racing/sliding control when one motor races, then racing wheels are prevented from over-rotation, but driving force of wheels in contact with rails outside the gauge converter is also reduced
Solution Approach 1:
The control system segments the axles into two groups: those inside the gauge conversion section and those outside. The voltage control unit independently manages the reference frequency for each group, allowing selective torque control only for racing axles while maintaining full driving force for non-racing axles. This segmentation resolves the contradiction by preventing unnecessary torque reduction for axles that are not racing.
Solution Approach 2:
The control system applies different control strategies to different locations. For axles outside the gauge converter, the system uses the average rotational frequency as reference to maintain normal driving force. For axles inside the gauge converter, the system detects racing conditions and applies torque reduction only to those specific axles. This local differentiation resolves the contradiction by applying torque control only where necessary.
2Device complexity
If a single inverter collectively controls multiple main motors, then device complexity is reduced, but independent torque control of individual motors becomes difficult
Solution Approach 1:
The voltage control unit changes the reference frequency parameter based on the position and status of each axle. By dynamically adjusting the reference frequency for each motor based on its rotational frequency and position relative to the gauge converter, the system achieves independent torque control through a single inverter. This parameter-based control resolves the contradiction by enabling differentiated control without requiring separate inverters.
Data Source
AI summary
A variable-gauge train control apparatus includes an inverter that collectively controls the torque of main motors; and a voltage control unit that controls an output voltage of the inverter. When at least one of axles to be driven by the main motors is within the gauge conversion section and at least one of the axles is located outside the gauge conversion section, the voltage control unit treats, as a reference frequency, a value obtained by conversion of an average value of rotational frequencies of the axles located outside the gauge conversion section into the electric angular frequencies of the main motors, and adds up a slip frequency command and the reference frequency to provide the frequency of the output voltage of the inverter.