Auxiliary Winding Internal Power Generation for PFC Stability
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Solution Overview
Problem
Existing power supply apparatuses face challenges in stably supplying internal power over a wide range from minimum input voltage to the steady state of a boost stage, particularly due to limitations in input range and efficiency, and often require additional stages or increased size and cost to achieve this stability.
Innovation Solution
A power supply apparatus utilizing an auxiliary winding connected to the output terminal of a PFC unit and a DC/DC conversion unit, which includes a Vcc power circuit, Vcc_DC/DC connection unit, and Vcc voltage change unit to generate and supply internal power, using resistors and an NMOS switch device to manage voltage levels and reduce losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an additional standby stage is used to generate internal power, then stable internal power supply is achieved, but device complexity and space requirements increase
Solution Approach 1:
The auxiliary winding on the DC/DC converter transformer is made to serve dual purposes: providing internal power for the PFC unit and supporting the main DC/DC conversion function. This eliminates the need for a separate standby stage while maintaining reliable internal power supply across the full input voltage range.
Solution Approach 2:
The function of generating internal power is merged with the main DC/DC conversion function by using the auxiliary winding of the DC/DC converter transformer. The auxiliary winding is connected to the output terminal of the PFC unit, combining the internal power generation path with the main power conversion path into a single integrated system.
2Reliability
If a voltage regulator is used to generate internal power from PFC output, then internal power is supplied across wide voltage range, but cost and apparatus size increase
Solution Approach 1:
The internal power generation function is extracted from the main DC/DC converter by adding an auxiliary winding to its transformer. This auxiliary winding is specifically dedicated to generating internal power for the PFC unit, separating the internal power generation function from the main power conversion function while utilizing the same transformer structure.
Solution Approach 2:
The auxiliary winding serves multiple functions: it provides internal power for the PFC unit, utilizes the magnetic flux already present in the DC/DC converter transformer, and operates effectively across the full input voltage range without requiring additional voltage regulation components.
3Loss of energy
If LLC resonant converter is used for DC-DC conversion, then efficiency is improved, but input voltage range for internal power generation is limited
Solution Approach 1:
The auxiliary winding is designed to generate internal power at the output terminal of the PFC unit before the DC/DC conversion stage. This preliminary action ensures that internal power is available across the full input voltage range, including minimum input voltage conditions, without being constrained by the narrow input range of the LLC resonant converter.
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
This solution enables stable internal power supply over a wide range from minimum input voltage to the steady state of the boost stage, reducing device count and operational losses, thus improving efficiency and space utilization.
Implementation Method 1
an auxiliary winding connected to a primary side winding of a transformer of the DC/DC conversion unit and generating the DC voltage having a predetermined magnitude
Implementation Method 2
a power factor correction unit correcting a power factor of the DC voltage
Data Source
AI summary
Embodiments of the invention provide a power supply apparatus, including an AC/DC rectifying unit converting an AC voltage into a DC voltage, a power factor correction unit correcting a power factor of the DC voltage, and a DC/DC conversion unit converting the DC voltage having the corrected power factor into a DC voltage having a different magnitude therefrom. According to various embodiments, the power supply apparatus further includes an auxiliary winding connected to a primary side winding of a transformer of the DC/DC conversion unit and generating the DC voltage having a predetermined magnitude, and an internal power generation unit connected to an output terminal of the power factor correction unit and the auxiliary winding and using a voltage of the output terminal of the power factor correction unit and a voltage generated by the auxiliary winding to generate temporary Vcc power and supply the generated temporary Vcc power as internal power of the power factor correction unit.