Carrier Waveform Modification for Parallel Switching Systems
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In power electronics systems with multiple semiconductor switches in parallel, simultaneous switching events lead to higher voltage spikes across semiconductor devices, potentially damaging them and necessitating the use of higher voltage-rated devices, which increases cost and volume.
Innovation Solution
A controller adjusts the shape, phase, or properties of carrier waveforms in response to differences in reference waveforms to prevent simultaneous switching of semiconductor devices, either dynamically or through pre-programmed modifications, such as altering waveforms from triangular to sawtooth or phase-shifting, to avoid overlapping turn-on or turn-off events.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If simultaneous switching of semiconductor devices is allowed, then switching speed and productivity are improved, but voltage spikes increase causing device damage and requiring higher voltage-rated components
Solution Approach 1:
The controller detects when reference waveforms indicate potential simultaneous switching events and preemptively modifies the carrier waveform shape or phase to prevent overlapping switching instants. This preliminary intervention avoids the harmful voltage spikes before they occur while maintaining efficient switching operation.
Solution Approach 2:
The system dynamically adjusts carrier waveform properties (shape or phase) in real-time based on the instantaneous difference between reference waveforms. When the difference falls below a threshold indicating potential simultaneous switching, the controller applies dynamic modification to stagger the switching events, resolving the contradiction between switching speed and voltage spike suppression.
2Reliability
If higher voltage-rated semiconductor devices are used, then reliability against voltage spikes is improved, but device volume and cost increase
Solution Approach 1:
The system converts the potential harmful effect of simultaneous switching (voltage spikes) into a controlled parameter by using carrier waveform modification to deliberately stagger switching instants. This approach protects standard-voltage devices from overvoltage damage without requiring higher voltage-rated components, thus avoiding increased device volume and cost.
3Reliability
If carrier waveform modification is applied, then simultaneous switching is prevented improving reliability, but control complexity increases
Solution Approach 1:
The controller modifies existing carrier waveform parameters (shape or phase) rather than introducing entirely new control mechanisms. This approach achieves reliable prevention of simultaneous switching by adjusting waveform characteristics based on reference waveform differences, maintaining relatively simple control logic while effectively resolving switching conflicts.
Data Source
AI summary
A power electronics switching system has a power converter including switching elements respectively disposed in parallel paths. The system also has a controller that outputs switching commands for the switching elements derived from carrier waveforms and reference waveforms corresponding to the switching elements, and generates a shape for one of the carrier waveforms according to a difference in magnitudes between the reference waveforms such that the shape is of a first type responsive to the difference being greater than a first threshold and is of a second type different than the first type responsive to the difference being less than a second threshold.