Power Converter Feedback Control for Output Power Regulation
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Solution Overview
Problem
Conventional switched mode power converters face instability in control loops due to rapid changes in output voltage, leading to constant adjustments in output current and instability in regulating output power.
Innovation Solution
Implementing a digital measurement of output current and subsequent calculation of output voltage to provide controlled output power, using a controller that receives current sense signals, filters them, and adjusts parameters of the power switch to stabilize the output voltage and achieve desired output power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If output voltage is measured and parameters of power switch are varied to regulate output power, then output power regulation is achieved, but control loop instability occurs due to rapid changes in output voltage
Solution Approach 1:
The patent implements a feedback control mechanism where the controller measures output voltage and current, calculates output power, and adjusts power switch parameters accordingly. The feedback signal is adjusted based on the relationship between output power and power switch parameters, creating a closed-loop control system that stabilizes the control loop while maintaining accurate output power regulation.
Solution Approach 2:
The patent changes the control parameter from directly varying power switch parameters based on output voltage measurement to varying parameters based on calculated output power. By using the relationship between output power and power switch parameters, the control system achieves stable regulation without the instability caused by rapid output voltage changes.
2Power
If conventional output power regulation is implemented by measuring output voltage and varying power switch parameters, then output power control is achieved, but constant adjustments in output current occur leading to instability
Solution Approach 1:
The system uses a feedback mechanism where the controller continuously monitors output voltage and current, calculates output power, and adjusts the feedback signal based on the relationship between output power and power switch parameters. This closed-loop control eliminates constant adjustments in output current by providing stable feedback that maintains reliable output power control.
Solution Approach 2:
The patent replaces the conventional mechanical/electrical control approach (direct voltage measurement and parameter variation) with a digital signal processing approach. The controller digitally measures output voltage and current, calculates output power, and processes the feedback signal to determine optimal power switch parameters, eliminating the instability inherent in conventional analog control methods.
Data Source
AI summary
A controller for use in a power converter comprising a feedback reference circuit coupled to receive a feedback signal representative of an output voltage of the power converter. A feedback reference circuit generates a drive signal in response to the feedback signal and the drive signal is used to control switching of a power switch of the power converter to regulate the output voltage. The controller further comprises an output power control circuit coupled to receive a current sense signal representative of an output current of the power converter and a power signal representative of a desired value of an output power of the power converter. The output power control circuit generates an adjust signal to adjust the feedback signal such that the controller modifies the output voltage to regulate to the desired value of the output power.