Multi-Controller Power Switching for Low-Harmonic AC Waveforms
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Thyristor power controllers generate harmonics that can interfere with other devices and preclude their use due to the harmonics created, and they cannot be switched off once turned on until the current falls to zero.
Innovation Solution
A power controller system comprising multiple power controllers with staggered switch-on and switch-off times within a cycle of a periodic waveform, using switchable power components that can conduct current in both forward and reverse directions, and optimizing switch times based on feedback from the summed output waveform.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If thyristor power controllers are used to control power flow, then precise power control and high current handling are achieved, but harmonics are generated that interfere with other devices
Solution Approach 1:
The patent divides the power control function into multiple independent power controllers (first power controller, second power controller, etc.), each handling a portion of the total load. Each controller generates a segmented waveform that is a partial segment of the complete AC cycle, and these segments are combined to form the complete waveform. This segmentation reduces harmonics generated by each individual controller compared to a single controller handling the full load.
Solution Approach 2:
The patent combines the output waveforms from multiple power controllers to form a complete AC waveform. The first power controller generates a waveform for the first portion of the cycle, the second power controller generates a waveform for the second portion, and their combination produces the complete waveform with reduced harmonics. This merging of multiple controlled waveforms achieves both precise power control and harmonic reduction.
2Speed
If thyristors are used for power control, then fast response and high current handling are achieved, but the devices cannot be switched off until current falls to zero
Solution Approach 1:
The patent employs power controllers with switchable power components that can be dynamically switched on and off at controlled times within each AC cycle. Unlike thyristors that remain conducting until current zero-crossing, these switchable components can be turned off at any point in the cycle, providing dynamic control over the conduction period. This enables flexible timing control for each power controller segment.
Solution Approach 2:
The patent changes the operating parameters of the power controllers by adjusting the switch-on and switch-off times of each controller within the AC cycle. The control circuitry optimizes these timing parameters to ensure that the combined output waveforms reconstruct the complete AC waveform with minimal harmonics. This parameter optimization resolves the contradiction between fast switching and ease of control.
3Object-generated harmful factors
If multiple power controllers are used with staggered switch-on and switch-off times, then harmonics are reduced, but device complexity increases
Solution Approach 1:
The patent segments the AC waveform into multiple portions, with each power controller responsible for generating a specific segment. The first power controller handles the first portion of the cycle, the second power controller handles the second portion, and so on. This segmentation approach reduces harmonics by ensuring each controller operates during optimized time intervals rather than continuously.
Solution Approach 2:
The patent incorporates control circuitry that uses feedback from the summed output waveform to optimize the switch-on and switch-off times of each power controller. The control circuitry monitors the combined output and adjusts the timing parameters to minimize harmonics and ensure accurate waveform reconstruction. This feedback mechanism simplifies the overall system by automatically optimizing the operation of multiple controllers.
Data Source
AI summary
A power controller system comprises multiple power controllers that receive a periodic waveform input and that apply power to multiple loads. A switch-on time and a switch-off time is for each of the power controllers within a cycle of the periodic waveform input. The power controllers generate output waveforms to be applied to the loads that are partial segments of the cycle of the periodic waveform input. Each of the power controllers includes a switchable power component that can be switched on and switched off at any time and that can conduct current in both forward and reverse directions.