Flyback Converter Dynamic Frequency Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional flyback converter systems face high losses and noise issues due to fixed oscillation frequency, making them unsuitable for large power supplies, and they struggle with soft switching and high-frequency noise generation.
Innovation Solution
A flyback converter system with a trigger-control circuit and timer circuit that adjusts the switching element's on and off periods based on voltage signals from the control coil, using a capacitor to charge differently during on and off periods to control oscillation cycles and reduce losses and noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If PWM control with fixed oscillation frequency is used, then trapezoid current waveform reduces peak and effective values, but discharge noise at specific frequency increases and soft switching becomes difficult
Solution Approach 1:
The patent makes the oscillation frequency dynamic rather than fixed, allowing the system to move away from specific resonant frequencies that cause discharge noise. By varying the frequency, the system可以避免 concentrated noise at specific frequencies while maintaining the low RMS current benefits of trapezoidal waveforms
Solution Approach 2:
The patent uses periodic modulation of the switching frequency superimposed on the base frequency. This periodic variation in frequency prevents the system from settling into a fixed frequency that would generate discharge noise, while maintaining the overall trapezoidal current waveform characteristics for reduced conduction losses
2Loss of energy
If fixed frequency PWM control is used, then trapezoid waveform is achieved, but rapid switching causes high frequency noise and switching loss increases
Solution Approach 1:
The patent applies dynamics by continuously adjusting the switching frequency rather than operating at a fixed frequency. This dynamic frequency adjustment allows the system to optimize the switching timing to reduce rapid transitions, thereby reducing high-frequency noise generation while maintaining the energy-efficient trapezoidal current waveform
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 approach reduces switching losses, noise, and high-frequency noise, enabling efficient large power supply with reduced switching losses and noise, suitable for both low-cost and high-power applications.
Implementation Method 1
a capacitor for timing, which forms the timer circuit, is charged to negative by a negative voltage level which is proportional to the input voltage generated in the on-period of the switching element according to the voltage signal from the control coil, and the capacitor for timing is charged to positive according to positive voltage level proportional to the output voltage generated in the control coil in a off-period
Implementation Method 2
input voltage is applied to a primary coil of a transformer, and switching drive of the input voltage is carried out by a switching element, so that direct-current electric power is outputted from a secondary coil of the transformer
Data Source
AI summary
In a switching power source of a flyback converter system according to the present invention, large electric power can be applied, by reducing loss of a switching element, a coil, and an output smoothing circuit, input voltage is applied to a primary coil of a transformer, and switching drive of the input voltage is carried out by a switching element, so that direct-current electric power is outputted from a secondary coil of the transformer through a rectifier circuit. The power source apparatus includes a trigger-control circuit which detects direct-current output voltage to control an “on” period, detects that current of the secondary coil becomes zero based on a voltage signal from a control coil, and turns on the switching element, and a timer circuit which is operated according to the voltage signal of the control coil, and gives an ON signal to the trigger-control circuit according to a timing signal.