IGBT Drive Circuit with Negative Temperature Diode
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Solution Overview
Problem
Existing drive circuits for power elements like IGBTs suffer from high switching losses and temperature-dependent operation voltage threshold changes, leading to inefficient power conversion and complex control circuit configurations.
Innovation Solution
A drive circuit configuration that eliminates the need for a gate resistor by using a diode with negative temperature characteristics in the second series circuit to adjust the voltage applied to the power element's emitter, ensuring optimal on/off operations and reducing switching losses, while maintaining a constant gate emitter voltage during temperature changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a gate resistor is used in the drive circuit, then the IGBT can be turned on/off, but switching losses increase and power conversion efficiency decreases
Solution Approach 1:
The patent removes the gate resistor from the drive circuit configuration. By extracting this component, the circuit achieves lower switching losses and improved power conversion efficiency while maintaining the essential on/off control functionality through an alternative circuit topology involving series-connected semiconductor switching elements.
Solution Approach 2:
The drive circuit is divided into multiple series-connected semiconductor switching elements (first, second, third, and fourth switching elements) that work in coordination. This segmentation allows the circuit to control the IGBT without requiring a gate resistor, as each switching element performs a specific function in the overall control sequence.
2Device complexity
If the drive circuit uses a simple configuration without temperature compensation, then device complexity is reduced, but the IGBT operation becomes affected by temperature-dependent threshold voltage changes
Solution Approach 1:
The patent introduces a diode as an intermediary component in the second series circuit. This diode provides temperature-dependent voltage compensation that counteracts the IGBT's threshold voltage drift with temperature. The diode acts as a mediator between the power supply and the IGBT emitter, automatically adjusting the emitter voltage to maintain reliable operation across temperature variations.
Solution Approach 2:
The circuit utilizes the temperature-dependent parameters of the diode (forward voltage drop changes with temperature) to compensate for the IGBT's threshold voltage temperature coefficient. By changing the emitter voltage parameter in response to temperature changes, the circuit maintains stable IGBT operation without requiring complex active temperature compensation circuits.
3Device complexity
If the emitter voltage is not adjusted for temperature changes, then the circuit configuration remains simple, but turn-on timing becomes unstable and erroneous on operations may occur
Solution Approach 1:
The diode in the second series circuit serves as a temperature-compensating intermediary that automatically adjusts the emitter voltage based on temperature. This passive compensation mechanism ensures precise and stable IGBT turn-on timing across temperature variations without requiring complex active control circuits or additional sensing components.
Solution Approach 2:
The temperature compensation is achieved through the inherent temperature-dependent characteristics of the diode, which automatically adjusts the emitter voltage as temperature changes. The circuit uses the diode's own temperature characteristics to compensate for IGBT threshold voltage drift, eliminating the need for external temperature sensors or complex control algorithms.
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 allows for efficient power conversion by stabilizing the turn-on timing of the IGBT and reducing switching losses, simplifying the circuit design and reducing manufacturing costs, while preventing erroneous on operations and maintaining power conversion efficiency across temperature variations.
Implementation Method 1
a second series circuit including a third semiconductor switching element and a fourth semiconductor switching element which are connected in series with a semiconductor element, having a negative temperature characteristic, therebetween
Data Source
AI summary
There is provided a drive circuit for turning on/off a power element which controls a main current flow between a first main electrode and a second main electrode in response to a drive signal applied to a control electrode. The drive circuit includes a first semiconductor switching element and a second semiconductor switching element which are connected in series and provided between the power supply terminal and the ground terminal, a third semiconductor switching element and a fourth semiconductor switching element which are connected in series with a semiconductor element, and a control circuit which controls turn-on/off of the power element by turning on/off the first to fourth semiconductor switching elements. The semiconductor element has a negative temperature characteristic.