High Phase Order Generator Stator Winding Configuration
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Solution Overview
Problem
Current power generation systems using static frequency converters face challenges with harmonic distortion and limited frequency range due to the use of 3-phase cyclo-converters, which require overdimensioning and result in high switching losses and costs, while matrix converters suffer from switching losses and harmonic distortion issues.
Innovation Solution
A high phase order generator with a stator core having multiple parallel stator slots and delta-connected stator windings, utilizing a matrix converter with a large number of phases (e.g., 18, 24, 36) to reduce harmonic distortions and increase versatility in frequency ratios, and integrating power electronics into the stator for reduced losses and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a 3-phase cyclo-converter is used for direct AC/AC conversion, then the frequency range is limited to 0-1/3 of the input frequency, but the converter size and cost increase due to overdimensioning requirements
Solution Approach 1:
The patent segments the power conversion function by using multiple parallel-connected single-phase cyclo-converters (e.g., three 1-phase converters for a 3-phase output). Each converter handles a portion of the total power, allowing the system to achieve a wider frequency range without requiring each individual converter to be oversized, thus reducing overall device complexity while maintaining adaptability.
Solution Approach 2:
The patent creates a multi-functional converter system where multiple single-phase cyclo-converters work in parallel to provide both frequency conversion and power distribution functions. This universal approach allows the same converter architecture to handle different frequency ratios and power levels without requiring complete redesign, resolving the contradiction between frequency range adaptability and converter size.
2Object-generated harmful factors
If voltage source converters with IGBTs or IGCTs are used, then the current can be produced sine-shaped, but switching losses increase and dielectric fatigue occurs
Solution Approach 1:
The patent employs periodic pulse-width modulation (PWM) techniques to switch the IGBTs or IGCTs in a controlled manner. By using periodic switching actions with optimized pulse patterns, the system generates sine-shaped current while minimizing the duration and frequency of high-stress switching events, thereby reducing switching losses and dielectric fatigue while maintaining low harmonic distortion.
Solution Approach 2:
The patent changes the switching parameters (frequency, pulse width, duty cycle) dynamically to optimize performance. By adjusting these parameters based on operating conditions, the system maintains sine-shaped current output with minimal harmonics while reducing switching losses through optimized switching schedules that avoid excessive dielectric stress.
3Object-generated harmful factors
If the number of phases in the generator is increased to reduce harmonic distortions, then the versatility in frequency ratios improves, but the device complexity and cost increase
Solution Approach 1:
The patent segments the high-phase-order generator into multiple parallel single-phase or low-phase-order generator units. Each unit produces a polyphase output that is fed to dedicated matrix converters. This segmentation achieves the harmonic reduction benefits of high phase order while keeping individual converter structures simple and manageable, thus reducing overall device complexity.
Solution Approach 2:
The patent merges multiple single-phase or low-phase-order generator outputs through parallel connection to achieve the effect of a high-phase-order system. By combining several simpler systems rather than using one complex high-phase-order system, the patent reduces harmonic distortions while maintaining converter structure simplicity and lowering overall device complexity.
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 solution significantly reduces harmonic distortions, increases the versatility of frequency ratios, and lowers the cost and complexity of the converter by using a high phase order generator with delta-connected stator windings and integrating power electronics, resulting in improved efficiency and reduced costs.
Implementation Method 1
a generator (1) with a rotor and a stator for conversion of mechanical power into a polyphase alternating current
Data Source
AI summary
A method for re-powering a star-connected stator having a plurality of parallel stator slots, wherein a plurality of stator winding bars having external winding connections are disposed in stator slots includes bridging the external winding connections so as to connect the stator winding bars in series and to form a polygonal stator capable of producing a polyphase alternating current.