Resonant Converter Switching Control with Feedback Delay Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Resonant converters face challenges in accurately controlling switch states due to delays in feedback paths, leading to overshoot and instability in output power.
Innovation Solution
A controller for a resonant converter that determines voltage-correction-signalling based on measured current signals, integrates this with measured voltage signals to provide corrected-voltage-signalling, and adjusts switch states based on threshold crossings, thereby compensating for delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If voltage feedback control is used to control switch states, then switching timing can be controlled, but delays in the feedback path cause timing errors leading to overshoot and instability
Solution Approach 1:
The controller determines voltage-correction-signalling based on measured current signals before the voltage threshold crossing event occurs. By calculating the correction term in advance using current measurements and compensation factors, the controller compensates for feedback delays proactively, ensuring accurate switch state timing without waiting for delayed voltage feedback.
Solution Approach 2:
The patent introduces voltage-correction-signalling as an intermediary element that bridges the gap between measured voltage signals and the actual switching decision. This correction signal, derived from current measurements and compensation factors, mediates the timing error caused by feedback delays, allowing the controller to make accurate switching decisions despite the delayed voltage feedback path.
2Measurement precision
If delay compensation is implemented using measured current signals and compensation factors, then switching timing accuracy is improved, but controller complexity increases
Solution Approach 1:
The controller uses the measured current signal for multiple purposes: it serves as both the primary control parameter for determining voltage-correction-signalling and as a timing reference for detecting threshold crossings. This multi-functional use of the current signal reduces the need for additional sensors or complex processing circuits, thereby limiting the increase in controller complexity while maintaining high switching timing accuracy.
3Stability of the object's composition
If voltage-correction-signalling is applied to compensate for feedback delays, then overshoot is reduced and stability is improved, but the control algorithm becomes more complex
Solution Approach 1:
The patent changes the control parameter from raw voltage feedback to corrected voltage signalling that incorporates compensation factors. By multiplying the measured current signal by a compensation factor (determined based on expected delay characteristics), the controller transforms the control parameter to account for delays, thereby improving stability. This parameter transformation approach is more straightforward than implementing complex predictive control algorithms.
Data Source
AI summary
A controller for a resonant converter. The resonant converter comprising: a first switch and a second switch connected in series with each other between the supply source and a reference terminal; and a resonant tank that is electrically connected to the first and second switches, wherein the resonant tank comprises a resonant capacitor. The controller is configured to: receive a measured voltage signal that represents the voltage at a predetermined point in the resonant tank; determine voltage-correction-signalling based on a measured current signal, which represents the current flowing in the resonant tank; and in response to the measured voltage signal crossing a voltage threshold value, after the application of the voltage-correction-signalling to either the measured voltage signal or the voltage threshold value as an offset, change the state of the first switch and the second switch.