Adaptive Digital Control for PFC Front-End Harmonic Distortion
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Solution Overview
Problem
Designing control parameters for adaptive digital control in switching mode power supplies is challenging due to non-linearity, requiring time-consuming trial and error methods and potentially destabilizing system identification techniques that can damage the power supply.
Innovation Solution
A method that uses an evaluation model to systematically adjust control loop parameters on the primary side of the power supply to minimize line current total harmonic distortion (THD), optimizing performance and reducing labor and time costs by avoiding the need for system identification and white noise injection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If system identification technique with white noise injection is used to determine control loop parameters, then the system characteristics can be accurately identified, but the stability of the power supply is compromised and damage may occur
Solution Approach 1:
The patent introduces an evaluation model as an intermediary between the power supply system and the control parameter optimization process. This model simulates the system behavior and allows safe determination of control loop parameters without directly injecting noise into the actual power supply, thus preserving system stability while achieving accurate parameter identification
Solution Approach 2:
The patent performs preliminary identification of system characteristics and determination of control loop parameters through simulation and evaluation before implementing them in the actual power supply system. This preliminary action allows optimization to be completed safely offline, avoiding the need for dangerous white noise injection during actual operation
2Reliability
If trial and error method is used to design control loop parameters, then the power supply can be made to operate at steady state and transient state conditions, but the design process becomes extremely time consuming
Solution Approach 1:
The patent implements an adaptive control mechanism that continuously monitors system performance and automatically adjusts control loop parameters based on feedback from the evaluation model. This eliminates the need for manual trial and error by creating a closed-loop optimization process that converges to optimal parameters automatically
Solution Approach 2:
The system performs self-optimization of control loop parameters through the evaluation model and adaptive control algorithm, eliminating the need for external human intervention and lengthy manual tuning processes. The system determines its own optimal parameters automatically based on system characteristics
3Adaptability or versatility
If system identification technique is implemented to adjust control loop parameters dynamically, then the performance can be optimized under changing conditions, but the signal processing burden increases requiring more powerful and expensive hardware
Solution Approach 1:
The evaluation model serves as an intermediary that performs the computationally intensive system identification and parameter optimization tasks offline, allowing the actual power supply controller to remain simple while still achieving adaptive performance through pre-computed parameter sets
Solution Approach 2:
The patent performs system identification and control parameter optimization in advance through the evaluation model, creating lookup tables or pre-computed parameter sets that can be easily retrieved and applied by the simple controller without requiring complex real-time signal processing capabilities
4Ease of manufacture
If conventional small signal modeling is used to design the loop controller, then the control loop parameters can be initially determined, but the process requires extensive trial and error finalization
Solution Approach 1:
The patent uses the evaluation model to provide continuous feedback on control parameter performance, allowing automatic optimization that eliminates the need for lengthy manual trial and error finalization. The feedback mechanism guides the optimization process directly to optimal parameters without human intervention
Solution Approach 2:
The patent replaces the manual mechanical trial-and-error adjustment process with an automated computational optimization system. The evaluation model and adaptive control algorithm automatically determine optimal parameters, substituting human intuition and manual adjustment with systematic computational methods
Data Source
AI summary
A method is directed to providing adaptive digital control for the PFC front-end of a switching mode power supply. The method uses an evaluation model to adjust control loop parameters of a control algorithm used by a controller on the primary side of the power supply. The method performs a series of step adjustments of the control loop parameter values to determine optimized values. In some implementations, the method determines and compares the line current THD corresponding to different control loop parameter values. The method provides simplified digital control loop design, optimizes PFC front-end performance, improves system efficiency by decreasing harmonic ripples, and reduces labor cost and time to market due to shorter research and development phase. System performance optimization is fully adaptive adjusted for changes in operating conditions due to, for example, environmental and temperature variations.