Resonant Converter Control Using Current-Based Voltage Correction
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Solution Overview
Problem
Resonant converters face challenges due to delays in the feedback path, leading to overshoot and instability, which affect the accuracy of power measurement and the stability of operating modes.
Innovation Solution
A controller for a resonant converter that determines voltage-correction-signalling based on a measured current signal, combines it with a measured voltage signal, and adjusts the switch states accordingly, thereby compensating for delays and improving power measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If voltage feedback control is used in resonant converters, then power measurement capability is provided, but delays in the feedback path cause overshoot and instability
Solution Approach 1:
The controller determines voltage-correction-signalling based on the measured current signal before the voltage signal is used for switching decisions. This preliminary action compensates for feedback delays by proactively adjusting the voltage threshold or signal, preventing overshoot and instability while maintaining accurate power measurement capability.
2Device complexity
If the measured voltage signal is used directly for switching control, then the control is simple, but overshoot occurs due to feedback delays
Solution Approach 1:
The patent introduces voltage-correction-signalling as an intermediary element between the measured voltage signal and the switching control. This correction signal, derived from the measured current, mediates the control process by adjusting the voltage threshold or signal to compensate for delays, reducing overshoot while adding minimal complexity to the control circuit.
3Stability of the object's composition
If compensation for feedback delays is implemented, then stability and overshoot reduction are achieved, but additional control complexity is introduced
Solution Approach 1:
The patent compensates for feedback delays by changing the voltage threshold parameter or voltage signal parameter based on the measured current. This parameter adjustment approach achieves stability and overshoot reduction through dynamic parameter modification rather than complex additional circuitry, balancing performance improvement with acceptable control complexity.
Data Source
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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.