Hybrid Flyback Circuit Control for ZVS and Magnetizing Current
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Solution Overview
Problem
Conventional hybrid flyback circuits face inefficiencies in dynamically adjusting the negative peak value of the magnetizing current, especially under varying output currents, leading to performance degradation and efficiency issues.
Innovation Solution
A hybrid flyback circuit with a control unit that includes an output voltage feedback unit, peak current comparison unit, dead time delay units, and conduction control units, allowing for feedback-controlled adjustment of switch conduction durations to maintain the negative peak current close to the ideal value, enhancing response speed and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the negative peak value of the magnetizing current is increased to achieve ZVS of the upper switch, then the zero voltage switching is realized, but additional losses increase and efficiency decreases
Solution Approach 1:
The patent implements a feedback control mechanism where the controller detects the actual negative peak value of the magnetizing current and adjusts the conduction time of the lower switch dynamically. This closed-loop feedback ensures the negative peak current is maintained at the optimal value needed for ZVS while preventing excessive current that would cause additional losses, thus resolving the contradiction between achieving reliable ZVS and minimizing energy losses.
Solution Approach 2:
The patent makes the conduction time of the lower switch dynamically adjustable based on the detected negative peak current value. Instead of using a fixed conduction time, the system adapts the timing parameters in real-time to match the actual operating conditions, allowing the circuit to achieve ZVS efficiently without generating excessive losses under varying load conditions.
2Reliability
If the negative peak value of the magnetizing current is excessively high, then ZVS function is achieved, but the efficiency of the hybrid flyback circuit is reduced
Solution Approach 1:
The controller continuously monitors the negative peak value of the magnetizing current through sampling circuits and uses this feedback information to adjust the conduction time of the lower switch. This ensures the negative peak current is maintained at the precise level needed for ZVS operation, preventing both insufficient current (which would fail to achieve ZVS) and excessive current (which would reduce efficiency).
Solution Approach 2:
The patent changes the conduction time parameter of the lower switch dynamically based on the detected negative peak current value. By adjusting this timing parameter in response to actual circuit conditions, the system optimizes the balance between achieving ZVS function and maintaining high efficiency, avoiding the fixed parameter limitations of conventional designs.
3Device complexity
If conventional control methods are used, then the circuit structure is simple, but the response speed to dynamic output changes is slow
Solution Approach 1:
The patent incorporates real-time feedback sampling of the negative peak current value and uses this information to dynamically adjust the lower switch conduction time. This feedback mechanism enables the controller to respond quickly to dynamic output changes by continuously adapting the switching parameters, significantly improving response speed while maintaining a relatively simple overall circuit structure through efficient use of control 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 feedback control mechanism ensures the negative peak value of the magnetizing current is accurately maintained, improving the hybrid flyback circuit's efficiency and responsiveness to dynamic output changes.
Implementation Method 1
The transformer has a primary winding and a secondary winding magnetically coupled to each other
Implementation Method 2
The resonant circuit is electrically connected in series to the primary winding of the transformer
Implementation Method 3
the primary side switch of the hybrid flyback circuit is turned on with zero voltage (ZVS)
Implementation Method 4
The rectifier circuit is electrically connected to the secondary winding of the transformer
Data Source
AI summary
A hybrid flyback circuit is provided and includes an upper switch, a lower switch, a transformer, a resonant circuit, a current sampling circuit and a control unit. The control unit includes an output voltage feedback unit, a peak current comparison unit controlling the upper switch to turn off when a sampling voltage corresponding to the current sampling signal is equal to the first voltage feedback signal, a first dead time delay unit controlling the lower switch to turn on after a first dead time starting from the turn-off time of the upper switch, a negative peak current feedback unit for generating a second voltage feedback signal, a conduction control unit controlling the lower switch to turn off, and a second dead time delay unit controlling the upper switch to turn on after a second dead time starting from the turn-off time of the lower switch.