Bootstrap Gate Drive Control in Power Converters to Limit Voltage Drop
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Solution Overview
Problem
The bootstrap circuit in existing power converters experiences voltage drops due to the connection of a capacitor and diode in parallel with a gate driver circuit, which can lead to inefficiencies.
Innovation Solution
A power converter design that includes a DC power supply unit, switching circuit, diodes, gate drivers, and a bootstrap circuit, with a control unit controlling the switching elements to minimize voltage drops by alternating the states of the switching elements, ensuring efficient voltage supply to gate drivers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a bootstrap circuit including a capacitor and diode is connected in parallel with the third gate driver circuit, then the third gate driver circuit can be driven, but a voltage drop occurs in the bootstrap circuit
Solution Approach 1:
The patent applies dynamics by making the switching states of the first, second, third, and fourth switching elements variable rather than fixed. The control unit dynamically adjusts which switching elements are ON or OFF based on the desired output voltage level (first through fourth switching states), enabling the bootstrap circuit to be periodically recharged and maintain stable voltage without permanent voltage drop
Solution Approach 2:
The patent implements periodic action through alternating switching states. The control unit periodically transitions between different switching states (first, second, third, fourth control modes), which causes the bootstrap circuit to be periodically recharged through the second switching element and third switching element alternation, preventing cumulative voltage drop while maintaining continuous operation
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 effectively reduces the likelihood of voltage drops in the bootstrap circuit, enhancing the efficiency and performance of the power converter.
Implementation Method 1
a bootstrap circuit including a capacitor and a diode which is connected to the third gate driver circuit in parallel
Implementation Method 2
a bootstrap circuit including a capacitor and a diode which is connected to the third gate driver circuit in parallel
Data Source
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AI summary
The problem is to reduce the chances of causing a voltage drop in a bootstrap circuit. A control unit (60) has a first control mode, a second control mode, and a third control mode. In the first control mode, the control unit (60) controls a first switching element (Q1), a second switching element (Q2), a third switching element (Q3), and a fourth switching element (Q4) so that the first, second, third, and fourth switching elements (Q1, Q2, Q3, Q4) are ON, ON, OFF, and OFF, respectively. In the second control mode, the control unit (60) controls the first, second, third, and fourth switching elements (Q1-Q4) so that the first, second, third, and fourth switching elements (Q1-Q4) are OFF, ON, ON, and OFF, respectively. In the third control mode, the control unit (60) controls the first, second, third, and fourth switching elements (Q1-Q4) so that the first, second, third, and fourth switching elements (Q1-Q4) are OFF, ON, OFF, and ON, respectively When the polarity of a current flowing through an output terminal (41) is positive, the control unit (60) makes a transition to the first control mode via the second control mode immediately after having gone through the third control mode.