IGBT Gate Drive Circuit With Fast Turn-Off and Resonance Suppression
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Solution Overview
Problem
Conventional gate drive apparatuses for large-current-capacity IGBTs face challenges in suppressing resonance and reducing loss due to the influence of resonance suppression resistors, which limit the ability to quickly turn off small-current-capacity IGBTs when the resistance of the off-drive resistor is set lower than that of the resonance suppression resistors.
Innovation Solution
An electronic apparatus that includes a plurality of switching elements with common input and output terminals, resonance suppression resistors, an on-drive circuit with an on-drive resistor, and an off-drive circuit with an off-drive resistor, where the off-drive resistor's resistance is set lower than the resonance suppression resistors, allowing electric charge to be released from the switching elements without going through the resonance suppression resistors, thereby controlling the switching elements independently of these resistors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the resistance of the off-drive resistor is set lower than that of the resonance suppression resistors, then the turn-off time of switching elements is reduced and loss is decreased, but the resonance suppression resistors still influence the charge release path
Solution Approach 1:
The patent divides the charge release path into two separate paths: one through the resonance suppression resistor and another through the off-drive resistor. By providing a dedicated off-drive circuit with a lower resistance path, the charge can be released more quickly without being constrained by the higher resistance of the resonance suppression resistor, thus reducing both turn-off time and energy loss.
Solution Approach 2:
The off-drive circuit acts as an intermediary component that provides an alternative charge release path. This intermediary path with lower resistance allows the control terminal to discharge quickly to the potential of the common terminal, bypassing the limitation imposed by the resonance suppression resistor while still maintaining the resonance suppression function through the original path.
2Stability of the object's composition
If resonance suppression resistors are used to suppress resonance between parallelly-connected small-current-capacity IGBTs, then resonance is suppressed, but the ability to quickly turn off the IGBTs is limited
Solution Approach 1:
The patent segments the circuit functions by providing separate resistors for resonance suppression and for charge release. The resonance suppression resistor maintains stability by damping oscillations, while the off-drive resistor with lower resistance enables fast turn-off by providing a dedicated low-impedance discharge path for the control terminal capacitance.
Solution Approach 2:
The patent implements multi-functionality by having the off-drive circuit serve dual purposes: it provides a low-resistance charge release path for fast turn-off, and it works in conjunction with the resonance suppression resistor to maintain stable operation. The system achieves both resonance suppression and fast switching through the coordinated action of these components.
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 configuration enables efficient control of switching elements by allowing faster turn-off times and reduced loss in large-current-capacity IGBTs, as the off-drive circuit can release electric charge without being influenced by the resonance suppression resistors, thereby improving the overall performance of the motor control apparatus.
Implementation Method 1
an off-drive circuit which allows release of electric charge from the control terminals of the switching elements to turn off the switching elements
Implementation Method 2
an on-drive circuit which applies electric charge to the control terminals of the switching elements to turn on the switching elements
Implementation Method 3
In order to suppress the resonance in the conventional art, resonance suppression resistors are arranged between the constant-voltage-pulse gate drive circuit and the gates of the small-current-capacity IGBTs. Thus, the current passing through the closed circuit can be suppressed. As a result, resonance can be suppressed.
Data Source
AI summary
An electronic apparatus is provided which includes switching elements, resonance suppression resistors which have first ends connected to control terminals of the switching elements and second ends having a common connection, an on-drive circuit which has an on-drive resistor and is connected to a drive power circuit, and which is supplied with voltage from the drive power circuit and applies electric charge to the control terminals of the switching elements via the on-drive resistor to turn on the switching elements, and an off-drive circuit which has an off-drive resistor and releases electric charge from the control terminals of the switching elements via the off-drive resistor to turn off the switching elements. A resistance of the off-drive resistor is set to be smaller than a resistance of the resonance suppression resistors. The off-drive circuit releases electric charge from the control terminals of the switching elements not via the resonance suppression resistors.