DC/DC Converter Controller Reducing Turn-On Losses
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Solution Overview
Problem
DC/DC converters experience significant switching losses due to turn-on and turn-off losses in switching transistors, which hinder energy efficiency improvements in power conversion processes.
Innovation Solution
A controller system for a DC/DC converter that utilizes two switching transistors and a transformer with an excitation inductor and leakage inductor, controlling the transistors to minimize turn-on losses by optimizing switching cycles and energy transfer, including zero-voltage and zero-current switching techniques to reduce parasitic capacitance resonance and electromagnetic interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a switching transistor is used to convert input direct current voltage into specified direct current voltage, then voltage conversion function is achieved, but switching loss increases due to overlapping voltage and current during turn-on and turn-off processes
Solution Approach 1:
The controller controls the first switching transistor to turn on before the second switching transistor turns off, proactively preparing the circuit for the next switching phase. This preliminary action allows the first capacitor to form a closed circuit with the excitation inductor and leakage inductor, enabling the current to increase in a negative direction and reduce the voltage across the second switching transistor before it turns off, thereby minimizing turn-on loss.
Solution Approach 2:
The patent changes the timing parameters of the switching transistors, specifically controlling the first switching transistor to turn on at a predetermined time before the second switching transistor turns off. This parameter change in switching timing creates a non-overlapping switching sequence that eliminates the traditional turn-on loss by ensuring the first transistor is already conducting when the second transistor turns off.
2Productivity
If switching frequency is increased to improve power conversion efficiency, then productivity increases, but switching loss and electromagnetic interference increase
Solution Approach 1:
The patent implements a periodic switching sequence where the first and second switching transistors alternately conduct in a controlled manner. By establishing a regular periodic pattern where the first transistor turns on before the second turns off, and maintaining this sequence cyclically, the system achieves stable power conversion with reduced electromagnetic interference and optimized 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 solution significantly reduces turn-on losses and enhances energy utilization efficiency by optimizing switching cycles and energy transfer, thereby improving the overall performance of the DC/DC converter.
Implementation Method 1
The first capacitor forms a first closed circuit with the excitation inductor and the transformer leakage inductor by using the first switching transistor. A current in the excitation inductor increases in a first direction.
Implementation Method 2
controlling the transistors to minimize turn-on losses by optimizing switching cycles and energy transfer, including zero-voltage and zero-current switching techniques to reduce parasitic capacitance resonance
Implementation Method 3
A primary side of the transformer is connected in parallel to two ends of the first switching transistor by using the first capacitor, and a secondary side of the transformer is coupled to a direct current load.
Data Source
Figure 1~2
Figure 3~5
Figure 6~7B
AI summary
This application provides a controller and control system for a DC/DC converter. The DC/DC converter includes a first switching transistor, a second switching transistor, a first capacitor, and a transformer. The transformer includes an excitation inductor and a transformer leakage inductor. The controller controls the first switching transistor to turn on to form a first closed circuit, where a current in the excitation inductor increases in a first direction; when a preset time period expires, the controller controls the first switching transistor to turn off, so that a voltage at two ends of the second switching transistor decreases; and when the voltage at the two ends of the second switching transistor is a first preset voltage threshold, the controller controls the second switching transistor to turn on to form a second closed circuit, where in this case, the DC/DC converter enters a first state, the current in the excitation inductor increases in a second direction, and the second direction is opposite to the first direction. When embodiments of this application are implemented, a turn-on loss in the DC/DC converter can be reduced.