PFC Circuit Topology for Longer Holdup Time in Compact AC/DC Converters
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Solution Overview
Problem
Existing power converters, particularly AC/DC converters, suffer from poor power density due to the large volumes of inductors and capacitors used, which affects efficiency and holdup time.
Innovation Solution
A power factor correction circuit is designed with multiple switches, inductance coils, and capacitors, where the first capacitor's volume is reduced by using a boost converter configuration to maintain output voltage during power interruptions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If traditional inductors and capacitors are used in AC/DC converters, then the converter can function properly, but the volume of the converter increases and power density decreases
Solution Approach 1:
The converter is divided into multiple modular units including first and second voltage conversion units, first and second power factor correction units, and associated control units. Each module can be independently designed and optimized, allowing for compact integration while maintaining proper functionality. The segmented architecture enables better space utilization compared to traditional monolithic designs.
Solution Approach 2:
The patent combines multiple functions into integrated units. The first voltage conversion unit and first power factor correction unit share common components and control mechanisms. Similarly, the second voltage conversion unit and second power factor correction unit are merged. This functional integration reduces the overall volume by eliminating redundant components and optimizing component sharing.
2Duration of action of stationary object
If larger capacitors are used to maintain output voltage during power interruptions, then holdup time improves, but the volume of the converter increases and power density decreases
Solution Approach 1:
The power factor correction units perform preliminary energy storage and voltage regulation during normal operation. The capacitors in the PFC units are charged in advance during the AC cycle, storing energy that can be quickly discharged during power interruptions. This preliminary action extends holdup time without requiring oversized capacitors, as the energy is accumulated progressively during normal operation rather than requiring large instantaneous storage capacity.
Solution Approach 2:
The voltage conversion units operate continuously to transfer energy from the input to output, maintaining steady-state operation. The control units continuously adjust the switching of power devices to maintain output voltage within specifications. This continuous energy transfer and regulation ensures that smaller capacitors can maintain holdup time, as the system continuously replenishes energy rather than relying on large capacitive storage alone.
3Productivity
If multiple power factor correction units are used to improve efficiency and holdup time, then converter performance improves, but device complexity increases
Solution Approach 1:
Each power factor correction unit is designed as a universal module that performs multiple functions: power factor correction, energy storage, and voltage regulation. The first and second PFC units use similar circuit topologies and control strategies, allowing for standardized design and reduced development complexity. The modular universal design enables improved performance through parallel operation while keeping individual unit complexity manageable.
Solution Approach 2:
The control units continuously monitor output voltage and adjust the switching of power devices accordingly. Feedback signals from voltage detection circuits are processed by the control units to dynamically adjust the operation of the PFC units and voltage conversion units. This feedback mechanism enables efficient operation and coordinated control of multiple units, managing system complexity through intelligent control rather than complex hardwired logic.
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 increases the holdup time of the output voltage, improves power density, reduces material costs, and provides additional space for enhancing efficiency in power converters.
Implementation Method 1
The first inductance coil includes a fifteenth terminal and a sixteenth terminal. The sixteenth terminal is connected to the second terminal. The second inductance coil includes a seventeenth terminal and an eighteenth terminal.
Implementation Method 2
The first capacitor includes a nineteenth terminal and a twentieth terminal. The nineteenth terminal is connected to the eighth terminal, and the twentieth terminal is connected to the fourth terminal. The second capacitor includes a twenty-first terminal and a twenty-second terminal.
Data Source
AI summary
A power factor correction circuit includes a first switch, a second switch, a third switch, a fourth switch, a fifth switch, a sixth switch, a seventh switch, a first inductance coil, a second inductance coil, a first capacitor, and a second capacitor. The first switch is connected to the second switch, the third switch, and the first inductance coil. The fifth switch is connected to the third switch and the second inductance coil. The sixth switch is connected to the first switch, the fourth switch, and the seventh switch. The seventh switch is further connected to the second switch, the first capacitor, and the second capacitor. The second inductance coil is further connected to the fourth switch and the first capacitor. The second capacitor is connected to the fourth switch, the sixth switch, and the first switch.