Resonant Converter Phase Control for Voltage Stability
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Solution Overview
Problem
Resonant mode power converter circuits face challenges in maintaining stable output voltage due to the inability to quickly respond to changes in input voltage and output load impedance, as existing controllers rely solely on monitoring output voltage and lack the capability to adjust switching frequency based on phase relations between resonant current and control signals.
Innovation Solution
A controller device for resonant mode power converter circuits that determines the phase relation between resonant current and control signals for two driving periods, allowing it to adjust the switching frequency based on differences in these phase relations, thereby anticipating and responding to changes in output voltage more effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the controller relies solely on monitoring output voltage to adjust switching frequency, then the control method is simple, but the response speed to changes in input voltage and output load impedance is slow
Solution Approach 1:
The controller performs preliminary action by detecting the phase relation between resonant current and control signals before output voltage changes occur. By monitoring phase differences between the resonant current waveform and the control signal waveform, the controller anticipates upcoming voltage changes and adjusts the switching frequency in advance, rather than waiting for output voltage deviations to trigger correction.
Solution Approach 2:
The controller implements feedback by continuously monitoring the phase relation between resonant current and control signals. The phase difference information is fed back to the switching frequency adjustment mechanism, creating a closed-loop control system that dynamically adapts the switching frequency based on real-time phase relationship measurements, thereby improving response speed without excessive complexity.
2Reliability
If the controller adjusts switching frequency based on phase relation differences, then the control loop gain and responsiveness improve, but the device complexity increases
Solution Approach 1:
The controller uses feedback by continuously measuring the phase relation between resonant current and control signals, then adjusting the switching frequency based on detected phase differences. This closed-loop approach maintains output voltage stability by dynamically compensating for changes in input voltage and load impedance through phase-based feedback control.
Solution Approach 2:
The controller replaces traditional voltage-based mechanical/electrical measurement systems with a phase detection mechanism. By substituting direct voltage monitoring with phase relation analysis between current and control signals, the system achieves higher reliability and responsiveness while managing complexity through signal processing rather than additional hardware components.
3Reliability
If the controller quickly responds to changes by adjusting switching frequency, then output voltage stability is maintained, but the requirement for output capacitor size may increase
Solution Approach 1:
The controller performs preliminary action by detecting phase relation changes before they manifest as output voltage deviations. By adjusting the switching frequency in advance based on phase differences between resonant current and control signals, the controller prevents voltage fluctuations rather than correcting them, thereby maintaining output voltage stability while potentially reducing the required output capacitor size.
Solution Approach 2:
The feedback mechanism monitors phase relations and adjusts switching frequency proactively, creating a stabilizing effect that reduces the need for large output capacitors. The continuous phase-based feedback control compensates for voltage variations dynamically, allowing for smaller energy storage components while maintaining reliability.
Data Source
AI summary
In some examples, a method of controlling a first switch and a second switch of a resonant mode power converter circuit, the method comprising delivering control signals to the first switch and the second switch at a switching frequency. The method also comprises determining, for a first driving period, a first phase relation between a phase of a resonant current in the resonant mode power converter circuit and a phase of the control signals. The method further comprises determining, for a second driving period, a second phase relation between a phase of the resonant current and a phase of the control signals, and controlling the switching frequency based on a difference of the first phase relation and the second phase relation.