Doubly-Fed Induction Machine Control for Stable Output Frequency
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Solution Overview
Problem
Existing electric machines for converting energy are large, heavy, and prone to mechanical wear, and they struggle to regulate output power characteristics independently of mechanical input.
Innovation Solution
A doubly-fed induction machine with a rotor and stator having multiple windings, a power conversion unit, a relay unit, and a controller that adjusts the operation based on rotational velocity to regulate output voltage frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional electric machines are used to convert energy, then the system can achieve energy conversion, but the system becomes large, heavy, and prone to mechanical wear
Solution Approach 1:
The patent replaces traditional mechanical regulation systems with electronic control systems. The doubly-fed induction machine uses power electronic converters and control circuits to regulate output characteristics, eliminating the need for heavy mechanical components such as governors, clutches, and mechanical wear-prone parts. This substitution of mechanical systems with electronic systems directly reduces weight while improving reliability by removing mechanical wear sources.
2Power
If traditional electric machines are used to convert energy, then the system can achieve energy conversion, but the system becomes large and heavy
Solution Approach 1:
The patent employs parameter changes through variable frequency control and power electronic conversion. The doubly-fed induction machine uses controllable frequency and voltage parameters to optimize performance, allowing compact design while maintaining high power capability. The electronic control system dynamically adjusts electrical parameters to achieve desired output characteristics without requiring large physical dimensions.
3Adaptability or versatility
If electric machines regulate output power characteristics, then the desired output frequency and amplitude can be achieved, but the system becomes large, heavy, and complex
Solution Approach 1:
The patent implements a doubly-fed induction machine where a single device performs multiple functions: it acts as both motor and generator, provides power conversion, and enables output regulation. The power electronic converters serve dual purposes of controlling rotor excitation and regulating stator output, reducing the need for separate dedicated components and simplifying the overall system architecture while maintaining high adaptability.
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 system effectively regulates output voltage frequency and power characteristics without the need for large, heavy components, reducing mechanical wear and improving efficiency.
Implementation Method 1
a power conversion unit in electrical communication with the plurality of rotor windings, where the power conversion unit is configured to excite the plurality of rotor windings with an alternating current
Implementation Method 2
To convert energy from mechanical to electrical or electrical to mechanical, electric machines (e.g., generators and motors) have been developed
Data Source
AI summary
A system for converting energy includes a doubly-fed induction machine including a rotor having a plurality of rotor windings, and a stator having a plurality of stator windings. The system also includes a power conversion unit in electrical communication with the plurality of rotor windings, where the power conversion unit is configured to excite the plurality of rotor windings with an alternating current. The system also includes a relay unit in electrical communication with the plurality of stator windings, where the relay unit is configured to electrically interconnect a plurality of terminals of the plurality of stator windings. The system also includes a controller in electrical communication with the power conversion unit and the relay unit, where the controller is programmed to adjust an operation of the doubly-fed induction machine using the power conversion unit and the relay unit based on the rotational velocity of the rotor.