Rail Vehicle Drive System Motor Merging for Energy Loss Reduction
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Solution Overview
Problem
Existing rail vehicle drive systems, particularly those using permanent-magnet traction motors, face inefficiencies in energy consumption due to ongoing losses during partial load operations, while asynchronous machines incur rotor losses, leading to suboptimal energy balance during phases like coasting and braking.
Innovation Solution
A rail vehicle drive system comprising a combination of permanent-magnet motors and asynchronous or reluctance motors, where the number of wheel sets driven by permanent-magnet motors is twice or equal to those driven by asynchronous or reluctance motors, allowing for efficient power distribution and switching off lossy motors during partial load operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If asynchronous motors are switched off during partial load operations to eliminate losses, then energy efficiency is improved, but the system cannot maintain high tractive force during acceleration phases
Solution Approach 1:
The patent merges multiple motor types with different characteristics into a single drive system. Asynchronous motors provide high starting torque and robust performance during acceleration phases, while permanent-magnet motors provide superior efficiency during partial load operations. The combination allows the system to leverage the strengths of each motor type in appropriate operational phases.
Solution Approach 2:
The control system dynamically adjusts which motors are active based on the operational phase. During acceleration phases requiring high tractive force, asynchronous motors are activated alongside permanent-magnet motors. During partial load or coasting phases, asynchronous motors are switched off to eliminate losses, while permanent-magnet motors continue to provide necessary propulsion.
2Power
If a higher number of drive motors are installed to provide high tractive force during acceleration, then tractive force is improved, but the number of lossy motors operating during partial load phases increases
Solution Approach 1:
The patent segments the drive system into different motor types with different operational characteristics. By dividing the total drive capacity across permanent-magnet motors and asynchronous motors, the system can selectively activate only the necessary motors during each operational phase, reducing total losses during partial load while maintaining adequate tractive force capability.
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 combination enables high efficiency in both partial load operations and peak traction phases, reducing energy consumption and maintaining simplicity in maintenance and operation by using shared components and control systems.
Implementation Method 1
permanent-magnet traction motors (PM motors)... rotor losses in PM traction motors are almost completely eliminated
Implementation Method 2
asynchronous machines... rotor losses contribute around 25 to 30 percentage points to the total losses
Implementation Method 3
the rotating permanent magnet flux continues to cause eddy current and hysteresis losses in the iron core
Implementation Method 4
the rotating permanent magnet flux continues to cause eddy current and hysteresis losses in the iron core
Data Source
Figure 1~2
Figure 3~4
AI summary
A propulsion system (6) for a rail vehicle (1) is proposed, comprising a plurality of propulsion motors (7a, 7b, 7c, 7d, 11a, 11b, 11c, 11d, 11e, 11f, 12a, 12b, 12c, 12d, 15a, 15b, 15c, 15d). The drive system (6) is characterized in that it comprises at least one permanent magnet excited motor (7c, 7d, 11a, 11b, 11c, 11d, 12a, 12b, 15c, 15d) and at least one asynchronous motor and/or at least one reluctance motor (7a, 7b, 11e, 11f, 12c, 12d, 15a, 15b) as drive motors (7a, 7b, 7c, 7d, 11a, 11b, 11c, 11d, 11e, 11f, 12a, 12b, 12c, 12d, 15a, 15b, 15c, 15d).