PFC Circuit Dynamic Compensation for Inrush Current Control
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Solution Overview
Problem
Conventional power factor correction (PFC) circuits face challenges in controlling high pulse load current and inrush current, particularly in applications like mobile radiographic X-ray machines, due to high storage device requirements and significant losses at lower loads, leading to inefficient operation and potential damage from inrush current surges.
Innovation Solution
A PFC circuit utilizing a buck-boost module and a controller that employs Integral Gain Compensation (IGC) or Integral Value Compensation (IVC) techniques, receiving input, output, and current feedback to manage high pulse load current and inrush current, dynamically switching between boost, buck-boost, and buck modes to optimize operation and reduce storage device size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional PFC circuits use boost converter with voltage control loop compensation, then inrush current control is achieved, but storage device requirements increase and response speed decreases
Solution Approach 1:
The patent implements dynamic compensation by detecting the operating state of the PFC circuit and dynamically adjusting the compensation coefficient of the proportional controller. The compensation coefficient is adjusted based on the ratio of actual output voltage to reference voltage, allowing the system to adapt to different operating conditions (light load, heavy load, inrush current) and achieve fast response without increasing storage device capacity.
Solution Approach 2:
The patent changes the control parameters by using state-based compensation coefficients. Different compensation coefficients (Kp1, Kp2, Kp3) are applied depending on the detected state, transforming the fixed-parameter control into a variable-parameter control system that optimizes performance across different operating conditions while maintaining compact storage device requirements.
2Stability of the object's composition
If conventional PFC circuits use slow output voltage control to maintain PFC, then power factor correction is achieved, but response speed to pulse load decreases
Solution Approach 1:
The patent employs state detection feedback by continuously monitoring the ratio of actual output voltage to reference voltage. Based on this feedback, the system determines the current operating state and selects appropriate compensation coefficients, creating a closed-loop control system that maintains PFC stability while enabling fast response to pulse load changes through adaptive parameter adjustment.
Solution Approach 2:
The system transitions from static voltage control to dynamic state-based control. By detecting the operating state and dynamically adjusting the proportional gain based on the voltage ratio, the system achieves both stability (through maintained PFC) and speed (through adaptive compensation) without the trade-off inherent in conventional slow control methods.
3Stability of the object's composition
If DC-DC converter operates with high DC bus voltage at lower load, then voltage regulation is maintained, but converter losses increase
Solution Approach 1:
The patent implements dynamic voltage regulation by adjusting the DC bus voltage according to the load state. During inrush current or pulse load conditions, the system maintains high voltage for stability. During normal lower-load operation, the system reduces the DC bus voltage to minimize converter losses, achieving both voltage regulation and energy efficiency through adaptive voltage control.
Solution Approach 2:
The system changes the DC bus voltage parameter based on operating conditions. By detecting the load state and adjusting the voltage level accordingly (high voltage during inrush/pulse, lower voltage during normal operation), the system optimizes the trade-off between voltage regulation stability and converter loss minimization.
4Stability of the object's composition
If compensation is done at slower rate due to low frequency ripple, then boost converter stability is maintained, but inrush current control precision decreases
Solution Approach 1:
The patent implements dynamic compensation rate adjustment based on the detected operating state. During inrush current conditions, the system applies higher compensation coefficients for precise and rapid control. During normal operation with low frequency ripple, the system uses standard compensation rates to maintain stability, achieving both precision and stability through adaptive compensation.
Solution Approach 2:
The system applies different compensation qualities to different operating conditions. By detecting the state and applying appropriate compensation coefficients locally (higher precision during inrush, standard during normal operation), the system optimizes control precision where needed while maintaining overall system stability across all operating conditions.
Data Source
AI summary
A power circuit for protecting against high pulse load current and inrush current is disclosed. The power circuit comprises a buck-boost module and a PFC controller operatively coupled with the buck-boost module. The PFC controller is configured to receive an input voltage feedback, an output voltage feedback, and a current feedback, and is configured to utilize one of an Integral Gain Compensation (IGC) and an Integral Value Compensation (IVC) to control the high pulse load current and inrush current in the power circuit.