Nonlinear DC-DC Converter Control for Mode Transients
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Solution Overview
Problem
Existing DC-DC converters face inefficiencies due to high switching energy consumption and transients when changing operational modes or dealing with line or load variations, particularly requiring multiple switch configurations and causing output voltage transients.
Innovation Solution
A nonlinear DC-DC converter with a controller that generates a PWM signal based on feedback variables like output voltage and coil current, allowing operation in buck, boost, or buck/boost modes using only two phases and a single controller strategy, eliminating the need for hysteresis bands and reducing switching energy by selecting modes on the fly during switching periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple switch configurations are used for mode changes, then operational flexibility is improved, but switching energy consumption increases
Solution Approach 1:
The patent employs a single switch configuration that can operate in multiple modes (buck, boost, and buck-boost) by controlling the switching signals differently. This universal approach eliminates the need for multiple dedicated switch configurations for each mode, thereby reducing switching energy consumption while maintaining operational flexibility across all converter modes
2Speed
If mode changes are implemented quickly, then response speed is improved, but output voltage transients increase
Solution Approach 1:
The patent implements dynamic mode selection where the converter can transition between buck, boost, and buck-boost modes on-the-fly during operation based on real-time conditions. This dynamic approach allows quick response to load or line variations while maintaining output voltage stability by seamlessly switching between modes without causing harmful transients
Solution Approach 2:
The patent uses feedback control mechanisms that continuously monitor output voltage and adjust the switching signals accordingly. This feedback ensures that mode changes are executed in a controlled manner, maintaining response speed while preventing output voltage transients by making real-time adjustments to compensate for any disturbances during mode transitions
3Stability of the object's composition
If hysteresis bands are used for mode selection, then stability is improved, but switching frequency increases
Solution Approach 1:
The patent extracts and eliminates the hysteresis band mechanism from the mode selection process. Instead of using hysteresis to prevent oscillations between modes, the patent employs a different control strategy that determines mode based on instantaneous voltage and current relationships, thereby maintaining mode selection stability without the need for hysteresis bands that would increase switching frequency
4Measurement precision
If separate controllers are used for different modes, then control precision is improved, but device complexity increases
Solution Approach 1:
The patent employs a single universal controller that can precisely control the converter in all modes (buck, boost, and buck-boost). This unified controller uses a systematic control method that adapts to different modes based on real-time conditions, maintaining control precision across all operations while significantly reducing device complexity by eliminating the need for multiple separate controllers
Data Source
AI summary
A nonlinear converter, such as a DC-DC converter, includes a nonlinear controller configured to receive an output voltage and a current, and configured to generate a PWM signal. The PWM signal is generated based on setting the converter to a first phase associated with both buck and boost modes when a clock signal is asserted, and selecting a second phase associated with the buck mode of the converter, if a sliding function signal achieves a first predetermined relationship with respect to a buck threshold before a next clock signal is asserted, or selecting a third phase associated with the boost mode of the converter, if the sliding function signal achieves a second predetermined relationship with respect to a boost threshold before a next clock signal is asserted. The nonlinear converter may include a power stage configured to provide the output voltage and a coil current to the nonlinear controller.