Power Converter Auxiliary Winding Switching for Loss Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The power supply circuit for the PFC control circuit in power conversion systems is more lossy than the circuit for the LLC control circuit due to higher conversion efficiency, leading to inefficiencies in DC voltage generation and distribution in image forming apparatuses like multi-function printers.
Innovation Solution
A power converter design with a first circuit converting AC voltage to a first DC voltage and a second circuit using an insulating transformer to convert this DC voltage to a secondary DC voltage, along with separate power supply circuits for each control circuit, optimizing voltage output and reducing losses by switching between auxiliary windings based on activation states of the PFC and LLC circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the first power supply circuit (with inductor) is used to supply DC voltage to the PFC control circuit, then the control circuit can be powered, but the conversion efficiency is lower and power loss is higher
Solution Approach 1:
The system dynamically switches between the first power supply circuit (inductor-based) and the second power supply circuit (transformer-based) depending on the operating state. When the LLC circuit is inactive, the first circuit powers the PFC control circuit. When the LLC circuit is active, the system switches to the second circuit which provides higher efficiency. This dynamic adaptation resolves the contradiction by selecting the appropriate power supply mode based on real-time operational conditions.
Solution Approach 2:
The invention changes the operating parameters of the power supply system by introducing a second power supply circuit with different characteristics (transformer-coupled vs. inductor-based). The system monitors the output voltage of the LLC circuit and switches between power supply modes based on voltage thresholds, thereby changing the operational parameters to optimize efficiency while maintaining reliability.
2Loss of energy
If the second power supply circuit (with transformer) is used to supply DC voltage, then the conversion efficiency is higher, but the circuit can only operate when the LLC circuit is active
Solution Approach 1:
The second power supply circuit is designed to serve multiple functions: it powers the LLC control circuit during LLC operation, and it can also power the PFC control circuit when the LLC circuit is inactive. By making the second circuit universally applicable to both control circuits, the system achieves higher overall efficiency while maintaining adaptability through intelligent switching between power supply modes.
Solution Approach 2:
The system dynamically determines which power supply circuit to use based on the operational state of the LLC circuit. When LLC is active and output voltage exceeds a threshold, the second high-efficiency circuit is used. When LLC is inactive or output voltage is below threshold, the system switches to the first circuit. This dynamic behavior resolves the contradiction between efficiency and adaptability.
3Loss of energy
If separate power supply circuits are used for PFC and LLC control circuits, then each circuit can be optimized independently, but the overall system complexity increases
Solution Approach 1:
The invention merges the two separate power supply circuits into a coordinated system with shared components and unified control logic. The switching between circuits is managed by a single control mechanism that monitors LLC output voltage and determines the appropriate power supply mode. This merging approach maintains the efficiency benefits of separate optimized circuits while reducing overall system complexity through integration and coordination.
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 configuration reduces power loss in the power conversion circuit by ensuring the second power supply circuit with higher efficiency supplies the LLC control circuit when active, and the first power supply circuit is only active when the LLC circuit is not, thereby enhancing overall conversion efficiency.
Implementation Method 1
a first circuit including an inductor and configured to convert an input AC voltage into a first DC voltage
Implementation Method 2
a second circuit including an insulating transformer and configured to convert the first DC voltage input to a primary winding of the insulating transformer to a second DC voltage
Data Source
AI summary
A power converter includes a first circuit including an inductor and configured to convert an input voltage into a first voltage, a second circuit including a transformer and configured to convert the first voltage input to the insulating transformer to a second voltage, a control circuit configured to control the first circuit, a first power supply circuit including a first winding magnetically coupled to the inductor and configured to output a third voltage generated by the first winding to the first control circuit, and a second power supply circuit including a second winding magnetically coupled to the transformer and configured to output a fourth voltage generated by the second winding to the first control circuit. When the second voltage is not output the third voltage is output to the control circuit, and when the second voltage is output the fourth voltage is output to the control circuit.