Cycle-Skipping Control System Phase Angle Shift Harmonic Reduction
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Solution Overview
Problem
Cycle-skipping motor speed control systems experience high amplitude harmonic components when multiple cycle skippers are connected to a common source, leading to undesirable effects like vibration and noise due to temporally aligned firing patterns.
Innovation Solution
Implementing a phase angle shift in the firing patterns of multiple cycle skippers to distribute current flow more evenly, reducing harmonic components by configuring the firing signals to be non-concurrent, thereby minimizing noise and heating effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple cycle skippers are connected to a common source with temporally aligned firing patterns, then the system can drive multiple loads efficiently, but high amplitude harmonic components are generated causing vibration and noise
Solution Approach 1:
The patent divides the firing cycle into multiple segments by implementing phase angle shifting for different cycle skippers. Each skipper operates in a different phase segment, so that their firing patterns are distributed throughout the cycle rather than concentrated at the same time. This segmentation of the firing timeline reduces the simultaneous generation of harmonic components while maintaining the ability to drive multiple loads.
2Ease of operation
If cycle skippers operate with concurrent firing patterns, then control simplicity is maintained, but current flow is not distributed evenly leading to increased harmonics
Solution Approach 1:
The patent introduces dynamic phase angle shifting where the firing patterns of multiple cycle skippers are shifted by different phase angles relative to the source voltage. This dynamic distribution of firing times throughout the cycle ensures even current flow distribution while maintaining relatively simple control logic. The controller simply needs to implement phase shifts rather than complex real-time adjustments.
Data Source
AI summary
A method, computer-readable code, and controller are provided for configuring a cycle-skipping control system having two or more cycle skippers connected to a common multi-phase AC (alternating current) power source to drive a variable frequency load. One or more circuit architectures (modified relative to a baseline circuit architecture) are provided. The modified circuit architectures enable at least some interconnections not enabled by the baseline circuit architecture when connected between the phases of the power source and the load phases. A respective firing sequence is generated to be applied to a plurality of power switches to the two or more cycle skippers with a modified circuit architecture for implementing a desired mode of operation.