Staggered Multi-Controller Power Switching for Harmonic Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Thyristor power controllers generate harmonics that interfere with other devices and limit their use due to their inability to switch off until current falls to zero, despite providing precise power control.
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 like BJTs or MOSFETs, and control circuitry that optimizes these times to minimize harmonics and match the input waveform.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If thyristor power controllers are used to provide precise power control, then power control precision is improved, but harmonic distortion increases and interferes with other devices
Solution Approach 1:
The patent divides the power control function into multiple independent power controllers (first, second, third controllers) that each handle a portion of the total power. By segmenting the control across multiple devices with staggered timing, the harmonic distortion from each individual controller is reduced, and their effects partially cancel out when combined.
Solution Approach 2:
The patent employs periodic switching of power controllers within each AC cycle, where controllers are turned on and off at different phases. This periodic action with varying phase angles creates a more sinusoidal combined waveform, reducing harmonic content while maintaining precise power control capability.
2Ease of operation
If thyristors are used to control power flow, then power control capability is improved, but the ability to switch off current is lost
Solution Approach 1:
The patent segments the power control into multiple controllers where at least one controller can be fully turned off when its current becomes negligible. This segmentation allows the system to maintain power control capability while enabling complete switch-off of individual controller currents, addressing the thyristor limitation.
Solution Approach 2:
The patent changes the operational parameters of the power controllers by using different switching strategies for different controllers. Some controllers operate in phase-angle control mode while others can be completely switched off, changing the operational state from continuous conduction to discontinuous conduction to enable current interruption.
3Object-generated harmful factors
If multiple power controllers are used to reduce harmonics, then harmonic distortion is reduced, but device complexity increases
Solution Approach 1:
The patent uses segmentation by dividing the power control into multiple controllers, which reduces harmonics through phase distribution. The complexity is managed by coordinating these segmented controllers with staggered timing to achieve harmonic cancellation.
Solution Approach 2:
The patent merges the outputs of multiple power controllers into a single combined power delivery system. By combining the controlled outputs of multiple controllers with different switching phases, the system achieves reduced harmonic distortion while delivering the required power.
Data Source
Figure 1
Figure 2A~2B
Figure 2C~2D
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.