Primary Side Regulator Auxiliary Winding Ripple Filtering
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Solution Overview
Problem
Primary side regulators face challenges in accurately estimating output voltage and current due to large voltage and current ripples caused by the ripple of the line input voltage, leading to low power factor and kick-in/kick-out phenomena.
Innovation Solution
A primary side regulator is designed with a power switch, insulated secondary and auxiliary windings, a diode, and filtering and amplification circuits to improve estimation accuracy by filtering and amplifying signals related to output voltage and current, using peak detectors, sample and hold units, and error amplifiers to control the switching operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If the primary side regulator uses the ripple of the line input voltage to generate output voltage and current estimation signals, then the regulator can operate without secondary side feedback, but the large voltage and current ripples cause low power factor and kick-in/kick-out phenomena
Solution Approach 1:
The patent introduces an auxiliary winding as an intermediary element between the primary and secondary windings. This auxiliary winding generates an auxiliary voltage that is proportional to the output voltage, serving as a mediator to provide accurate output voltage estimation without direct secondary side feedback. The auxiliary winding's voltage signal is used to generate the estimation voltage signal, resolving the contradiction by providing a reliable intermediary measurement path.
Solution Approach 2:
The patent implements a feedback mechanism where the auxiliary voltage from the auxiliary winding is fed back to the control circuit. This feedback loop allows the regulator to continuously monitor and adjust the output based on the auxiliary voltage signal, which is proportional to the actual output voltage. The feedback enables the regulator to maintain stable operation and improve power factor by using the auxiliary voltage as a reference for control decisions.
2Device complexity
If the regulator estimates output current using the square of the line input voltage, then the regulation can be simplified, but large current ripples occur in the estimation result
Solution Approach 1:
The patent uses the auxiliary winding as an intermediary to obtain a more accurate current estimation. Instead of directly using the square of the line input voltage, the system uses the auxiliary voltage (which is proportional to output voltage) combined with power factor information to derive a more precise output current estimation. This intermediary approach reduces the ripple in the estimation signal while maintaining estimation capability.
Solution Approach 2:
The patent changes the parameter used for current estimation from directly using the square of line input voltage to using a combination of auxiliary voltage and power factor. By changing the estimation parameter from a purely voltage-based calculation to a hybrid approach involving auxiliary winding voltage and power factor correction, the system achieves more accurate current estimation with reduced ripple.
3Device complexity
If the regulator uses the ripple of line input voltage for output estimation, then the regulation mechanism is simplified, but the output voltage estimation contains large voltage ripple
Solution Approach 1:
The patent introduces the auxiliary winding as an intermediary measurement device that provides a voltage signal proportional to the output voltage. This auxiliary voltage serves as a mediator between the input voltage ripple and the output voltage estimation, filtering out the harmful ripple while maintaining the proportional relationship. The control circuit uses this intermediary auxiliary voltage to generate a clean estimation voltage signal for feedback control.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enhances the accuracy of output voltage and current estimation, reducing voltage and current ripples, thereby improving the power factor and preventing kick-in/kick-out phenomena.
Implementation Method 1
an auxiliary winding coupled to the primary winding, and insulated and coupled to the secondary winding
Implementation Method 2
a voltage obtained by filtering at least one of an estimation voltage signal corresponding to an output voltage of the output terminal and an estimation current signal corresponding to an output current
Data Source
AI summary
A primary side regulator according to an embodiment includes a power switch connected to a primary winding, a secondary winding configured to be insulated and coupled to the primary winding, a diode connected between the secondary winding and an output terminal, and an auxiliary winding coupled to the primary winding, and insulated and coupled to the secondary winding. The primary side regulator controls a switching operation of the power switch using a voltage obtained by filtering at least one of an estimation voltage signal corresponding to an output voltage of the output terminal and an estimation current signal corresponding to an output current flowing through the diode.