Predictive Pulse Power Factor Correction Without Current Sensing
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Solution Overview
Problem
Conventional power factor correction methods face challenges in maintaining a constant phase angle between current and voltage, leading to reduced power quality and efficiency, especially with complex alternating current loads, and often require current sensing or multipliers.
Innovation Solution
A method using a generated predictive pulse with a varying duty ratio to charge and discharge a power factor correction inductor, ensuring the inductor current is in phase with the AC voltage without current sensing or multipliers, by adjusting the ON and OFF times of the pulse to match the voltage phase and load demand.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional power factor correction methods are used, then the power factor is improved, but the device complexity increases due to requirement of current sensing or multipliers
Solution Approach 1:
The patent extracts and eliminates the current sensing and multiplier components from the conventional PFC circuit. Instead of using these complex components, the invention uses a simplified voltage-based control method where the PWM duty cycle is directly controlled by the voltage error amplifier output, achieving PFC without current sensing or multiplication operations.
Solution Approach 2:
The voltage error amplifier serves multiple functions: it provides both the voltage regulation function and the PFC control function. The same amplifier that regulates the output voltage also generates the PWM duty cycle signal that achieves power factor correction, eliminating the need for separate current sensing and control circuitry.
2Loss of energy
If conventional power factor correction methods are used, then the power factor is improved, but the manufacturing complexity increases
Solution Approach 1:
The patent removes the need for current sensing circuits and multiplier components, significantly simplifying the manufacturing process. The invention uses only standard operational amplifiers and passive components that are easier to manufacture and assemble, reducing both manufacturing complexity and cost.
3Power
If complex alternating current loads are used, then the power supply capability increases, but the phase displacement between current and voltage increases
Solution Approach 1:
The patent employs voltage feedback through the voltage error amplifier that continuously monitors the output voltage and adjusts the PWM duty cycle accordingly. This feedback mechanism ensures that the input current remains in phase with the input voltage even when handling complex alternating current loads, maintaining stable phase relationship while providing adequate power supply capability.
Data Source
AI summary
A method of power factor correction without using current sensing or a multiplier is disclosed. A generated predictive pulse is used to charge and discharge a power factor correction (PFC) inductor so that the current in the PFC inductor has a similar phase angle as the input AC voltage. Each ON portion of the pulse is used for charging while each OFF portion is used for discharging. As the input voltage increases in phase, the predictive pulse gradually increases in ON time duty and the PFC inductor is charged in increasing amount and discharged in decreasing amount per pulse. When peak is reached the duty ratio is reduced each pulse and the PFC inductor current is reduced along with the input AC voltage source until phase angle reaches 180 degrees and the ON time becomes zero.