Power Controller Frequency Adjustment for Overload Protection
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Solution Overview
Problem
Conventional switched-mode power supplies face challenges in effectively managing overload conditions, particularly in preventing transformer saturation and efficiently adjusting to varying loading states without increasing circuit complexity.
Innovation Solution
The solution involves a controller system that detects inductive current and adjusts the operating frequency based on loading states, maintaining a constant peak current magnitude under normal conditions and increasing frequency during overloads, with a tolerable duration independent of frequency variations, utilizing a clock generator, current limiter, and overloading limiter to prevent excessive current flow and transformer saturation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the operating frequency is increased during overloaded state, then the power output can be temporarily increased, but the circuit complexity increases due to frequency adjustment mechanisms
Solution Approach 1:
The patent implements dynamic frequency adjustment by switching between a first operating frequency under normal loading conditions and a second operating frequency under overloaded conditions. The controller dynamically changes the switching frequency of the switch based on the detected loading state, allowing the power supply to temporarily increase power output during overloads by operating at the higher second frequency while maintaining simplicity through automated frequency switching.
2Reliability
If conventional overload protection is implemented by limiting output current or inductive current, then power output can be prevented from exceeding a certain level, but the circuit complexity increases
Solution Approach 1:
The patent changes the operating parameter (switching frequency) in response to overload conditions rather than simply limiting current. By detecting the loading state and switching between two operating frequencies, the system provides overload protection through parameter adjustment rather than through complex current limiting circuits, thereby maintaining reliability while reducing circuit complexity.
3Ease of operation
If the tolerable duration is made dependent on clock oscillator frequency, then timing control is simplified, but the tolerable duration varies with frequency adjustments
Solution Approach 1:
The patent introduces an intermediary mechanism (separate timing circuit or frequency-independent timing reference) that determines the tolerable duration independently of the main clock oscillator frequency. This allows the timing control to remain simple while ensuring that the tolerable duration remains stable and consistent regardless of whether the system is operating at the first or second frequency, thus resolving the contradiction between ease of operation and stability.
Data Source
AI summary
A power supply has an inductor and determines loading state of the power supply according to a compensation signal. When the loading state is determined to be a light loading state or a no-loading state, a switch is operated at a low operating frequency. When the loading state is determined to be a heavy loading state, the switch is operated at a high operating frequency. If the compensation signal exceeds a critical value, it is determined that the loading state is an overloaded state. When the overloaded state continues past a tolerable duration, the switch is turned off. The tolerable duration is determined by an external capacitor and is independent of the operating frequency.