Resonant Converter Ring Mode for Low Power Modulation
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Solution Overview
Problem
Resonant converters face challenges in efficiently operating at very low power levels, requiring high frequencies that lead to increased switching losses and difficult control, making it hard to modulate low powers effectively.
Innovation Solution
The resonant converter employs a 'ring' mode operation where switches are held in a specific state for extended periods, allowing zero net-energy transfer initially, followed by controlled energy transfer to achieve desired output power, reducing the need for high switching frequencies and minimizing losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If frequency modulation is used to modulate very low powers in resonant converters, then the converter can operate at high frequency to achieve low power modulation, but switching losses increase and control becomes more difficult
Solution Approach 1:
The patent applies periodic action by using burst mode operation where the resonant converter operates in intermittent cycles rather than continuous high-frequency switching. The converter performs multiple switching cycles in bursts to transfer the required energy, then remains idle, thereby reducing overall switching losses while maintaining low power modulation capability
Solution Approach 2:
The patent changes the operating parameters by adjusting the switching frequency and duty cycle dynamically. At low power levels, the converter operates at lower frequencies with higher duty cycles, avoiding the high-frequency regime that causes excessive switching losses. This parameter adaptation allows efficient operation across different power levels
2Power
If frequency modulation is used to modulate very low powers in resonant converters, then the converter can operate at high frequency to achieve low power modulation, but control difficulty increases
Solution Approach 1:
By using burst mode operation with periodic on-off cycles, the control system simplifies low power modulation by converting continuous high-frequency control into intermittent lower-frequency bursts, making the control waveform generation more manageable and less prone to instability
Solution Approach 2:
The patent employs dynamic adjustment of operating parameters including switching frequency, duty cycle, and burst duration based on the required output power level. This dynamic adaptation allows the converter to maintain optimal control characteristics across different power levels, avoiding the fixed high-frequency operation that causes control difficulties
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables easier control and reduced switching losses when operating at very low output powers, allowing efficient power conversion without the need for high-frequency operation, thus improving the efficiency and control of resonant converters.
Implementation Method 1
a resonant circuit comprising a capacitor and an inductor
Data Source
AI summary
Method and apparatus for power conversion. In one embodiment, the method comprises operating a resonant converter in a ring mode comprising (i) holding a plurality of switches of the resonant converter in a first switching state throughout a pre-determined number of resonant periods; and (ii) maintaining the plurality of switches in the first switching state for a fraction of a subsequent resonant period until an amount of energy has been transferred through the resonant converter to achieve a pre-determined output power from the resonant converter.