One-sided Parallel LLC Converter Resonant Switching
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Solution Overview
Problem
Conventional switch-mode power converters for high-voltage applications in data centers face challenges such as short on-duty time, reliability issues due to high-voltage stress, and low efficiency, particularly when performing 48V to 1V power conversions, which are complex and inefficient.
Innovation Solution
A power converter design featuring a primary circuit with parallel LC tanks, a transformer, and a low-pass filter, operated at resonance frequency with zero-voltage switching, eliminating the need for high-side switches and enabling the use of high-efficiency GaN transistors, thus achieving high step-down ratios with improved reliability and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional switch-mode power converters are used for 48V to 1V power conversion, then voltage conversion capability is achieved, but efficiency deteriorates and power loss increases
Solution Approach 1:
The patent applies resonant oscillation at the LC tank's natural frequency to enable zero-voltage switching. By operating at resonance, the inductor and capacitor naturally oscillate, creating conditions where switching occurs when voltage across the switch is zero, eliminating switching losses and dramatically improving conversion efficiency.
Solution Approach 2:
The patent changes the operating parameter from fixed-frequency switching to resonance-frequency switching. By dynamically adjusting the switching frequency to match the LC tank's resonant frequency, the system achieves optimal efficiency and zero-voltage switching conditions, resolving the efficiency deterioration problem.
2Reliability
If conventional switch-mode power converters operate at high voltage, then voltage conversion capability is maintained, but reliability deteriorates due to high-voltage stress
Solution Approach 1:
Resonant oscillation creates zero-voltage switching conditions where switches turn on and off when voltage across them is naturally zero. This eliminates voltage stress during switching transitions, preventing breakdown and improving reliability in high-voltage applications.
Solution Approach 2:
The LC tank acts as an intermediary that naturally oscillates and mediates the voltage transitions. By using the resonant tank as the switching medium rather than direct semiconductor switching, the system achieves high-voltage conversion with reduced stress on switching devices.
3Device complexity
If conventional switch-mode power converters are designed for high-voltage operation, then voltage conversion capability is achieved, but device complexity increases due to level-shifting requirements
Solution Approach 1:
The patent uses asymmetric half-bridge topology where one switch handles the high-voltage side and the other handles the low-voltage side. This asymmetric arrangement eliminates the need for complex level-shifting circuits, as each switch operates in its appropriate voltage domain, simplifying the overall design.
Solution Approach 2:
The circuit is segmented into distinct high-voltage and low-voltage domains with dedicated switches for each. This segmentation allows independent optimization of each switching stage and eliminates the need for complex high-side driver level-shifting circuits, reducing overall design complexity.
4Duration of action of moving object
If conventional switch-mode power converters are used, then basic power conversion is achieved, but on-duty time becomes extremely short limiting practical application
Solution Approach 1:
The patent utilizes periodic resonant oscillation where energy is transferred in complete cycles rather than brief pulses. The resonant tank naturally oscillates for extended periods, allowing sustained energy transfer and practical duty cycles, unlike conventional converters that require extremely short on-times.
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
The design achieves high efficiency and reliability in high-voltage to low-voltage conversions, reducing power loss and operational complexity, making it suitable for data center applications.
Implementation Method 1
a secondary inductor electromagnetically coupled to the primary inductor to form a transformer
Implementation Method 2
the first and second primary LC circuits having the same or about the same primary LC resonance frequency; operate the first and second primary circuit switches at about the primary LC resonance frequency
Data Source
AI summary
A power converter includes a primary circuit and a secondary circuit. The primary circuit includes two primary LC circuits that are in parallel electrically with each other. A first node of each primary LC circuit is electrically coupled to a high-voltage input. A second node of each primary LC circuit is coupled to a respective terminal of a primary inductor that forms a transformer with a secondary inductor in the secondary circuit. Each primary LC circuit is electrically coupled to a primary switch that operates at approximately the resonance frequency of the primary LC circuits to output an alternating current that passes through the primary inductor. The terminals of the secondary inductor are coupled to respective secondary switches. The switches operate at the resonance frequency of the primary LC circuit to rectify the power. A low-pass filter outputs the mean of the received voltage.