Self-Exciting Synchronous Reluctance Generator Stator Design
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Solution Overview
Problem
Conventional synchronous reluctance generators without permanent magnets or windings on the rotor are not self-excited, requiring connection to a power grid for operation, limiting their use in harsh environments and high-temperature applications.
Innovation Solution
A synchronous reluctance generator design featuring a stator with salient poles, DC and AC coils, and permanent magnets that allow for self-excitation through a common lead connection, enabling the generator to initiate electrical power generation without an external excitation source, utilizing a single-phase rectifier and DC coil current regulator for efficient operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a synchronous reluctance generator uses a rotor without permanent magnets or windings, then the generator can operate in harsh environments and at high temperatures, but the generator cannot self-excite and must be connected to a power grid
Solution Approach 1:
The patent introduces an intermediary mechanism (the specific stator winding configuration with DC and AC coils) that enables the reluctance rotor to acquire magnetic field characteristics without permanent magnets. The stator windings create a magnetic field that induces currents in the rotor, allowing self-excitation while maintaining the simplicity and harsh environment tolerance of the reluctance rotor design.
Solution Approach 2:
The patent changes the electrical parameters and configuration of the stator windings (specifically the arrangement of DC and AC coils, and their connection through a common lead) to enable self-excitation. By modifying the winding parameters and connectivity, the system transforms from a grid-dependent configuration to a self-exciting configuration while maintaining the rotor's simple reluctance structure.
2Device complexity
If a reluctance-type rotor is used without permanent magnets or windings, then the generator structure is simplified and can withstand harsh conditions, but an external excitation source is required for operation
Solution Approach 1:
The patent implements self-service by enabling the generator to generate its own excitation current through its stator windings. The specific configuration of DC and AC coils with common lead connections allows the generator to self-excite during operation, eliminating the need for external excitation sources while maintaining the simple rotor structure.
Solution Approach 2:
The stator windings serve multiple functions: they generate the main electrical output and simultaneously provide self-excitation for the reluctance rotor. The DC and AC coils work together to create the necessary magnetic fields that both drive power generation and maintain rotor magnetization, making the system self-sufficient.
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
Enables self-excitation of the generator, allowing it to operate independently as a stand-alone power source in harsh environments and high-temperature conditions, suitable for applications like aircraft electrical systems without the need for an external power source.
Implementation Method 1
The rotation is applied to the generator rotor, which moves a magnetic field created by the generator relative to windings that are fixed relative to the rotor. Movement of the magnetic field induces electrical current in the windings
Implementation Method 2
The magnetic field is typically generated by windings carried by the rotor, permanent magnets affixed to the rotor, or reluctance-type rotors. Reluctance-type rotors become magnetized by flowing a current in proximity to the rotor, typically through an excitation winding located on the stator core
Data Source
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AI summary
A stator (102) for a generator includes a ferromagnetic core (120) with two or more poles (110) arranged about a rotation axis (108), a direct current (DC) field coil (118), permanent magnets and four or more alternating current (AC) coils (114, 116). The DC field coil is wrapped about the pole. A first of the AC coils is wrapped about the pole at a location circumferentially spaced from a second of the AC coils. Generator systems and methods for operating self-exciting synchronous reluctance generators are also described.