Synchronous Generator Slot Configuration Reduces Harmonic Distortion
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Solution Overview
Problem
AC-excited synchronous generators in wind power systems face challenges in reducing the distortion of the armature current waveform due to the influence of higher harmonics, which is not sufficiently suppressed when the number of slots per two poles in the stator minus the number of slots per two poles in the rotor is maintained between +6 and −6, leading to increased weight and complexity.
Innovation Solution
The AC-excited synchronous generator is designed with a rotor and stator having multiple slots, where the number of slots per two poles in the stator minus the number of slots per two poles in the rotor is set to be equal to or greater than +9 or equal to or smaller than −9, optimizing the armature current waveform by reducing higher harmonic components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the air-gap length is reduced to decrease exciting current and reduce generator weight, then the weight of the generator is reduced, but the distortion of the armature current waveform is enhanced due to large spatial change in magnetic resistance
Solution Approach 1:
The patent changes the parameter of slot configuration by setting the number of slots per two poles in the stator minus the number of slots per two poles in the rotor to be equal to or greater than +9 or equal to or smaller than −9. This parameter change modifies the spatial distribution of magnetic resistance in the air gap, thereby suppressing waveform distortion while maintaining the reduced air-gap length for weight reduction.
2Ease of manufacture
If the number of slots per two poles in the stator minus the number of slots per two poles in the rotor is maintained between +6 and −6 as in conventional induction machines, then the design follows conventional practices, but the influence of higher harmonics in the armature current waveform cannot be sufficiently suppressed
Solution Approach 1:
The patent departs from the conventional parameter range of +6 to −6 by establishing a new parameter specification where the difference between the number of slots per two poles in the stator and rotor is equal to or greater than +9 or equal to or smaller than −9. This parameter change effectively suppresses higher harmonics in the armature current waveform while maintaining manufacturability.
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 effectively suppresses the distortion of the armature current waveform, reduces higher harmonic components by more than 30% compared to conventional designs, and allows for a smaller, lighter generator suitable for wind power systems, facilitating easier installation in high-raised positions like windmill nacelles.
Implementation Method 1
a rotor (20) in the plural slots of which the field winding (23) is embedded
Data Source
AI summary
A synchronous generator 1 including a rotor having a field winding placed in the slots thereof and a stator having an armature winding placed in the slots thereof, wherein the value of the number of slots per two poles in stator minus the number of slots per two poles in rotor is equal to or greater than +9, or equal to or smaller than −9.