Doubly Fed Induction Machine Power System With Segmented Converters
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Solution Overview
Problem
Conventional power systems in locomotives are inefficient due to bulky power converters rated for full power output, leading to compromised efficiency and higher power ratings, which are not optimized for partial power handling.
Innovation Solution
A power system utilizing a plurality of doubly fed induction machines and power converters with a speed regulation unit, where at least one stator or rotor winding terminal is coupled to power converters, allowing for efficient power transfer and regulation, reducing the power rating of converters and enhancing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If power converters are rated to withstand full power output from the alternator, then reliability is improved, but device complexity and bulkiness increase
Solution Approach 1:
The power converter is divided into multiple modular units (first power converter, second power converter, third power converter) that can be independently configured and scaled. Each module handles a portion of the total power, allowing the system to achieve full power capability without requiring a single oversized converter, thus reducing complexity and bulkiness while maintaining reliability through distributed architecture
Solution Approach 2:
The patent employs power converters with ratings that are partially sufficient for full power output (e.g., 300kW converters for a 1MW alternator). By using multiple such converters in parallel and intelligently controlling their operation, the system achieves reliable full power capability without the complexity and bulk of a single converter rated for the complete 1MW output
2Power
If power converters are rated for full power output, then power handling capability is improved, but efficiency is compromised
Solution Approach 1:
The system dynamically controls the operation of multiple power converter modules based on real-time power demands. Converters are activated or deactivated, and their power ratings are adjusted dynamically to match actual load requirements, ensuring that converters operate at optimal efficiency points rather than being constantly overloaded or underutilized, thus improving overall energy efficiency while maintaining full power handling capability
Solution Approach 2:
The patent changes the operational parameters of power converters by using multiple units with different power ratings (e.g., 300kW, 350kW, 400kW converters) that can be selectively activated. This allows the system to optimize converter operating points and maintain high efficiency across varying power demands while still achieving full power output capability when all converters operate simultaneously
3Power
If switches in power converters have higher power rating, then power handling is improved, but device complexity and size increase
Solution Approach 1:
The switching function is segmented across multiple power converter modules, each with switches rated for lower power levels. Instead of using a single complex switch or switch bank rated for full power, the system distributes switching operations across multiple simpler, lower-rated switches in parallel, reducing individual component complexity while maintaining overall power handling capability
Solution Approach 2:
The patent uses switches with power ratings that are partially sufficient for the total system power (e.g., switches rated for 300-400kW in a 1MW system). By deploying multiple such switches in parallel and controlling them selectively, the system achieves full power handling capability without requiring excessively high-rated individual switches, thus reducing device complexity and size
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
The proposed power system achieves efficient power transfer during both motoring and braking operations with lower-rated power converters, improving efficiency and reducing bulkiness, enabling efficient power management in mobile assets like locomotives.
Implementation Method 1
a power system utilizing a plurality of doubly fed induction machines and power converters with a speed regulation unit, where at least one stator or rotor winding terminal is coupled to power converters, allowing for efficient power transfer and regulation
Data Source
AI summary
A power system including at least one electrical machine, plurality of doubly fed induction machines (DFIMs), a plurality of first power converters, and a speed regulation unit is presented. The electrical machine includes a mechanical input end and at least one of a first stator winding terminal and a first rotor winding terminal. Each DFIM includes a second stator winding terminal, a second rotor winding terminal, and a mechanical output end. At least one of the first stator winding terminal and the first rotor winding terminal is coupled to one of first power converters and the second rotor winding terminal of each DFIM is coupled to one of the first power converters. The speed regulation unit is coupled to at least one of the mechanical input end and the mechanical output end.