Power Converter Dynamic Gate Drive for EMI and Conduction Loss
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Solution Overview
Problem
High-voltage power converters face challenges in balancing efficiency and electromagnetic interference (EMI) due to rapid switching transistor conduction, which leads to significant power losses and EMI generation.
Innovation Solution
A power converter system that dynamically adjusts the driving current of the switching transistor based on a target voltage representing the input terminal voltage change, switching to a higher current after entering the Miller plateau stage to reduce EMI and conduction loss, while using an auxiliary winding to detect voltage changes and avoid high-voltage measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If rapid conduction of the switching transistor is used to improve efficiency, then conduction loss is reduced, but electromagnetic interference (EMI) increases
Solution Approach 1:
The patent applies dynamics by transitioning from fixed driving current to dynamic multi-stage driving current adjustment. The control circuit dynamically changes the driving current magnitude based on the real-time switching state of the transistor, using a first driving current during voltage drop phase and a second driving current during Miller plateau phase, thereby optimizing both EMI and conduction loss at different time points
Solution Approach 2:
The patent segments the switching process into distinct phases (voltage drop phase and Miller plateau phase) with different driving current characteristics. By dividing the conduction process and applying different driving currents to different phases, the system can reduce EMI during voltage transitions while maintaining rapid conduction during the plateau phase, thus resolving the contradiction between EMI reduction and efficiency improvement
2Measurement precision
If direct measurement of input terminal voltage is used to achieve accurate control, then control precision is improved, but device complexity and safety risks increase
Solution Approach 1:
The patent uses the auxiliary winding as an intermediary to indirectly obtain the input terminal voltage information. Instead of directly measuring the high-voltage input terminal, the control circuit measures the voltage induced in the auxiliary winding, which is electrically isolated and operates at lower voltage levels, thus avoiding the complexity and safety risks of direct high-voltage measurement while maintaining control accuracy
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
Effectively reduces EMI and conduction loss by dynamically adjusting the driving current strength, improving the overall efficiency and reliability of the power converter system.
Implementation Method 1
The transformer transmits the generated high-frequency square wave signal to a secondary winding by magnetic induction
Data Source
AI summary
A power converter includes: a switching transistor, a transformer, a control circuit; the control circuit is configured to determine a target voltage in a process that the switching transistor is driven to conduct; the target voltage can represent a voltage change of an input terminal of the switching transistor; when the target voltage starts to drop but is higher than a reference voltage, drive a control terminal of the switching transistor with a first driving current; when the target voltage decreases to be lower than the reference voltage, drive the switching transistor with a second driving current; the second driving current is higher than the first driving current; the switching transistor is driven by the first driving current for part or all of the time before entering the Miller plateau stage, and is driven by the second driving current after starting to enter the Miller plateau stage.