Variable Frequency Switched Tank Converter Light Load Efficiency
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Solution Overview
Problem
Conventional switched tank converters (STCs) experience low efficiency at light load magnitudes due to unchanged switching losses, leading to poor performance as load magnitude decreases.
Innovation Solution
Implementing a variable switching frequency STC, where the switching frequency decreases with load magnitude, reducing switching losses and maintaining high efficiency at light loads by adjusting the frequency based on load conditions, and incorporating a controller to manage switching signals and resonant tank circuit current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional STC operates with fixed switching frequency, then the converter achieves stable voltage conversion ratio, but switching losses remain unchanged leading to low efficiency at light load magnitudes
Solution Approach 1:
The patent applies dynamics by transitioning from fixed switching frequency to variable switching frequency that adapts to load conditions. The controller dynamically adjusts the switching frequency based on detected load magnitude, allowing the system to optimize efficiency across different operating conditions while maintaining stable voltage conversion through compensating the duty cycle.
Solution Approach 2:
The patent changes the switching frequency parameter from constant to variable based on load magnitude. By detecting load changes and adjusting the switching frequency accordingly, the system reduces switching losses at light loads while maintaining adequate frequency at full load for proper resonant operation, thereby improving overall efficiency.
2Loss of energy
If the switching frequency is reduced to lower switching losses, then efficiency at light load improves, but transient response may be degraded
Solution Approach 1:
The system dynamically adjusts switching frequency based on real-time load detection. During transient conditions, the controller detects the load change and adjusts frequency accordingly, ensuring fast response when needed while maintaining low losses during steady-state light load operation.
Solution Approach 2:
The patent implements feedback by detecting the magnitude of the load and using this information to adjust the switching frequency. This closed-loop control ensures that the switching frequency is optimized for both efficiency and transient response based on actual operating conditions.
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 variable switching frequency STC maintains high efficiency across varying load magnitudes, reduces switching losses, and enhances transient response by maintaining peak resonant tank circuit current, thereby minimizing output voltage undershoot during load changes.
Implementation Method 1
a first resonant tank circuit... driving the first resonant tank circuit at a first frequency... driving the first resonant tank circuit at a second frequency
Data Source
AI summary
A method for controlling a switched tank converter (STC) includes (a) driving a first resonant tank circuit of the STC at a first frequency and with a first fixed on-time, to obtain a first fixed ratio of output voltage of the STC to input voltage of the STC, while the STC is powering a load having a first magnitude and (b) driving the first resonant tank circuit of the STC at a second frequency and with the first fixed on-time, to obtain the first fixed ratio of output voltage of the STC to input voltage of the STC while the STC is powering a load having a second magnitude. The second frequency is smaller than the first frequency, and the second magnitude is smaller than the first magnitude.