Flyback Converter Switching Modes for Variable Load Efficiency
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Solution Overview
Problem
Existing power converters, particularly those employing flyback converters, face challenges in efficiently accommodating varying input voltage and loading conditions, leading to inefficiencies in power usage.
Innovation Solution
A power converter system with a transformer and synchronously-operated transistor switches, controlled by a controller that generates drive signals to manage the high side and low side switches, allowing for multiple modes of operation based on input voltage and load power consumption, including frequency control and current control modes, to optimize efficiency across different operating conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a flyback converter employs a single switching mode, then the circuit structure is simple, but the efficiency deteriorates under varying input voltage and load conditions
Solution Approach 1:
The patent implements multiple switching modes (first mode with single pulse, second mode with multiple pulses, third mode with continuous switching) that are dynamically selected based on operating conditions such as input voltage level and load power consumption. The controller transitions between these modes to optimize efficiency across different operating scenarios, resolving the contradiction between structural simplicity and operational efficiency.
2Loss of energy
If the high side switch is operated in multiple modes, then the efficiency under varying conditions is improved, but the control complexity increases
Solution Approach 1:
The controller changes operational parameters (number of pulses, switching frequency, duty cycle) based on detected operating conditions. The system monitors input voltage and load power consumption, then adjusts the switching mode accordingly - using single pulse mode for light loads, multiple pulse modes for medium loads, and continuous mode for heavy loads - thereby improving efficiency while managing control complexity through parameter adaptation.
3Productivity
If the switching frequency is increased, then the power transfer speed is improved, but the power loss increases
Solution Approach 1:
The patent employs periodic switching action with variable frequency and pulse count based on operating conditions. During light load conditions, the system uses intermittent periodic switching (single or multiple pulses per cycle) rather than continuous high-frequency switching, thereby maintaining power transfer capability when needed while reducing average power loss. The periodic nature allows the system to adapt frequency and pulse duration to balance speed and 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 achieves improved efficiency by dynamically adjusting switch operations to match varying input voltage and load conditions, ensuring efficient power transfer and minimizing power usage across different operating scenarios.
Implementation Method 1
A flyback converter employs a transformer that transfers energy from the input of the flyback converter to its output and provides electrical isolation between the input and output of the flyback converter
Implementation Method 2
An input voltage, such as the rectified output voltage of a PFC stage or rectifier, is applied across the transformer primary winding by closing a switch; as a result, a primary winding current flows and magnetic flux in the transformer increases, thereby storing energy in the transformer
Data Source
AI summary
A power supply comprises a controller configured to control a power converter by generating drive signals that control the opening and closing of a high side switch and a low side switch. The controller is configured to selectively control the high side switch according to various modes of operation depending on operating conditions such as input voltage and load power consumption. The modes of operation can include, for example, a mode in which the high side switch is closed and then opened once during each of the series of switching cycles and a mode of operation in which the high side switch is closed and then opened two times during each of the series of switching cycles.