Resonant Converter Control Using Dynamic Voltage Thresholds
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Solution Overview
Problem
Resonant converters face challenges in preventing capacitive mode operation, which can lead to unstable behavior and reduced performance.
Innovation Solution
A controller for a resonant converter is configured to set protected power signals based on time delays or integrals of current signals, which are used to set upper and lower voltage threshold values. This configuration ensures that the resonant converter operates within safe boundaries, reducing the likelihood of entering capacitive mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the resonant converter operates at high power levels, then the power delivery capability is improved, but the risk of entering capacitive mode increases
Solution Approach 1:
The controller proactively determines voltage threshold values based on the protected power signal before the converter enters capacitive mode. By calculating thresholds that correspond to protected power levels and comparing actual power levels against these pre-determined thresholds, the system takes preventive action to avoid capacitive mode operation rather than reacting after the problem occurs.
Solution Approach 2:
The controller continuously monitors the actual power level and compares it against the protected power signal to dynamically adjust voltage threshold values. This feedback mechanism ensures that the converter operates within safe boundaries by adjusting thresholds in real-time based on the difference between actual and protected power levels, preventing entry into capacitive mode while maintaining high power delivery capability.
2Stability of the object's composition
If the voltage threshold values are set to prevent capacitive mode, then the stability is improved, but the power delivery range is reduced
Solution Approach 1:
The voltage threshold values are dynamically adjusted based on the protected power signal and actual power level comparisons. Rather than using fixed thresholds, the controller continuously adapts the threshold values to maintain a safe distance from capacitive mode boundaries while maximizing the operational power range. This dynamic adjustment allows the converter to operate stably across a broader power delivery range.
Solution Approach 2:
The controller changes the voltage threshold parameters based on the protected power signal and real-time power level measurements. By adjusting these parameters dynamically, the system maintains operational stability through appropriate threshold setting while preserving maximum power delivery capability. The parameter changes enable the converter to adapt to different operating conditions without entering capacitive mode.
Data Source
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AI summary
A controller for a resonant converter. The controller is configured to: receive a measured current signal that represents current flowing in the resonant tank; receive a measured voltage signal that represents the voltage at a predetermined point in the resonant tank; receive a power setting signal, which defines a requested power level for the load; set a protected power signal based on a time delay between a change in state of one of first and second switches and a subsequent zero-crossing of the measured current signal; set an upper voltage threshold value and a lower threshold value based on the lower of: i) the protected power signal; and ii) the power setting signal; in response to the measured voltage signal exceeding the upper voltage threshold value, open the first switch and close the second switch; and in response to the measured voltage signal dropping below the lower voltage threshold value, open the second switch and close the first switch.