Flyback Converter Hold-Time Circuit for Post-Power-Off Operation
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Solution Overview
Problem
Existing single-stage flyback converters stop operating immediately after AC power is off, leading to malfunctions in IT power products.
Innovation Solution
A power converter and conversion system incorporating a hold time circuit with energy storage units and switching units that extend operation after power is off by connecting energy storage units in series or parallel configurations to discharge to the conversion circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single-stage flyback converter is used to reduce size and cost, then device complexity is reduced, but the converter stops operating immediately after AC power is off, causing malfunctions
Solution Approach 1:
The hold time circuit stores energy in advance during AC power operation through the energy storage inductor and capacitors. When AC power is turned off, this pre-stored energy is released to maintain output voltage, ensuring continuous operation without requiring complex multi-stage architecture.
Solution Approach 2:
The hold time circuit acts as an intermediary between the flyback converter and the load. It includes an energy storage inductor, capacitors, and switching elements that transfer and regulate energy during the transition from AC power to hold time mode, maintaining stable output voltage throughout.
2Stability of the object's composition
If full-bridge rectifier is used for stable voltage, then voltage stability is improved, but power loss increases due to diodes conducting during both half cycles
Solution Approach 1:
The patent extracts the rectification function from the traditional full-bridge rectifier structure and integrates it into the hold time circuit. By using the energy storage inductor and controlled switching elements, the system achieves voltage stabilization without the continuous diode conduction losses inherent in full-bridge rectifiers.
3Loss of energy
If bridgeless architecture is used to reduce power loss, then energy efficiency is improved, but it is difficult to achieve both power factor correction and flyback conversion
Solution Approach 1:
The hold time circuit is designed to perform multiple functions: it acts as a power factor correction circuit during AC power operation, stores energy in the energy storage inductor, and transitions to a flyback converter mode when AC power is turned off. This multi-functional design eliminates the need for separate PFC and flyback stages while maintaining energy efficiency.
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 system effectively extends the holding time, allowing load elements to continue operating by storing and releasing energy post-power-off, enhancing stability and functionality.
Implementation Method 1
a first energy storage unit, a second energy storage unit, a first charging unit, a second charging unit and a first switching unit, wherein the first energy storage unit, the second energy storage unit, the first charging unit and the second charging unit are connected in series
Implementation Method 2
the first energy storage unit and the second energy storage unit are connected in series and discharge to the conversion circuit
Data Source
AI summary
A power converter and a power conversion system are provided. The power converter includes a hold time circuit and a conversion circuit. The hold time circuit includes a first energy storage, a second energy storage, a first charging unit, a second charging unit and a first switching unit, wherein the first energy storage, the second energy storage, a first charging unit and the second charging unit are sequentially formed in cascaded connection, wherein the first switching unit being in parallel with the series path formed by the first charging unit and the second charging unit. The conversion circuit and the hold time circuit are electrically connected. When the first switching unit of the hold time circuit is turned on, the first energy storage unit of the hold time circuit and the second energy storage unit of the hold time circuit are connected in series and discharged to the conversion circuit.