Compound Motor-Generator for Super-Synchronous Energy Storage
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Solution Overview
Problem
Existing motor-generators face inefficiencies and complexity in energy storage and power conversion, particularly in achieving super-synchronous speeds without the use of power electronics, which limits their cost-effectiveness and maintenance requirements.
Innovation Solution
A super-synchronous motor-generator system comprising two or more machines connected end-to-end or concentrically, with each machine having a rotor and stator, operating at multiples of AC system frequency, where the second rotor is driven by the first rotor to achieve rotational speeds twice that of the synchronous speed, reducing the need for power electronics and enhancing energy storage capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If power electronics are used to achieve super-synchronous speeds, then speed control is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts and removes power electronics from the system by using a mechanical gearless connection between the first rotor and second rotor. The first rotor directly drives the second rotor through magnetic coupling, eliminating the need for complex power electronic converters while achieving super-synchronous speeds.
Solution Approach 2:
The patent replaces the electrical control system (power electronics) with a direct magnetic coupling mechanism. The first rotor's magnetic field directly induces rotation in the second rotor, substituting electronic control with a purely electromagnetic mechanical-like system that achieves speed multiplication naturally.
2Ease of operation
If power electronics are used for speed control, then operational flexibility is improved, but maintenance requirements increase
Solution Approach 1:
The patent removes power electronic components that require maintenance by using direct magnetic coupling between rotors. This eliminates semiconductors, capacitors, and other electronic parts that need periodic replacement and maintenance, resulting in a system with minimal moving parts and no electronic maintenance requirements.
3Quantity of substance
If synchronous speed operation is used, then system simplicity is maintained, but energy storage capacity is limited
Solution Approach 1:
The patent creates a dynamic speed multiplication system where the second rotor rotates at super-synchronous speeds (multiples of AC frequency) driven by the first rotor. This dynamic speed increase directly translates to increased energy storage capacity in the rotating mass without requiring additional physical space or materials.
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 configuration improves system cost and efficiency, increases energy storage capacity, and simplifies maintenance by achieving super-synchronous speeds without power electronics, enabling efficient energy storage and power conversion while maintaining power quality.
Implementation Method 1
The stator is supplied with electrical current from an AC system, and generates a rotating magnetic flux wave that rotates at synchronous speed with respect to the stator. The rotor is magnetically coupled to the stator, and rotates at synchronous speed in response to the rotating magnetic flux wave.
Implementation Method 2
The rotational second stator rotates around a common axis with the second rotor. The rotational second stator flux wave rotates at a speed that is the combination of the second rotor flux wave and the second rotor mechanical rotation speed. Thus, the rotational second stator rotates at double the synchronous speed.
Data Source
AI summary
A compound motor-generator system including a first motor-generator and a second motor-generator. The first motor generator includes a stator having a set of three-phase field windings and a first rotor disposed inside and coaxial with the stator and configured to rotate relative to the stator. The second motor-generator includes a rotational stator and a second rotor coupled to a common shaft with the rotor of the first motor-generator and disposed inside and coaxial to the rotational stator. The rotational stator is configured to rotate relative to the second rotor and at a higher rotational speed than the second rotor.