Built-in Gate Resistor for Parallel Semiconductor Current Balancing
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Solution Overview
Problem
In three-phase inverters, the parallel connection of semiconductor elements leads to imbalanced gate voltages due to stray inductance and parasitic capacitance, causing non-uniform current distribution and heat concentration issues, making it difficult to control the elements in unison.
Innovation Solution
Incorporating built-in resistors between control terminals and control electrodes in each semiconductor element, allowing for differential resistance values to suppress resonance phenomena and balance current distribution, while enabling both individual and parallel operation modes without external resistive elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If semiconductor elements are connected in parallel and controlled in common, then the elements can be used as a single semiconductor switching element with higher power capacity, but current distribution becomes non-uniform due to resonance in the LC circuit formed by stray inductance and parasitic capacitance
Solution Approach 1:
A built-in resistor is introduced as an intermediary element between the control terminal and control electrode of each semiconductor element. This resistor acts as a mediator to balance the gate voltages across parallel-connected elements by compensating for voltage drops caused by differences in stray inductance and parasitic capacitance, thereby achieving uniform current distribution while maintaining high power capacity
Solution Approach 2:
The electrical resistance value of the built-in resistor is specifically optimized to balance gate voltages. By adjusting this resistance parameter, the system compensates for variations in LC circuit characteristics across parallel-connected elements, suppressing resonance effects and ensuring uniform current sharing without requiring external resistive elements
2Reliability
If external resistive elements are connected to suppress gate voltage resonance, then current distribution uniformity improves, but device complexity and switching losses increase
Solution Approach 1:
The built-in resistor is integrated within the semiconductor element structure itself, merging the resistance function with the existing control electrode connection. This eliminates the need for separate external resistive elements and their associated connection terminals, thereby reducing device complexity while maintaining current distribution uniformity
Solution Approach 2:
The built-in resistor is incorporated directly into the semiconductor element's internal structure, allowing the element to self-regulate its gate voltage without requiring external resistive components. This self-service approach reduces the overall device complexity and eliminates the need for additional external connections
3Reliability
If external resistive elements are used to balance gate voltages, then resonance suppression improves, but switching losses increase
Solution Approach 1:
The built-in resistor is merged with the internal structure of the semiconductor element, allowing for optimized resistance values that minimize switching losses. By integrating the resistor within the element rather than using external components, the resistance can be precisely controlled to provide adequate resonance suppression while minimizing energy dissipation during switching operations
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 effectively balances current across semiconductor elements connected in parallel, reduces switching losses, and enhances operational flexibility by allowing seamless switching between individual and parallel connection modes, thereby preventing heat concentration and improving user convenience.
Implementation Method 1
an LC resonance circuit is formed by a stray inductance and a parasitic capacitance on a path from a drive device to a control electrode (gate) among the plurality of semiconductor elements connected in parallel
Implementation Method 2
an electrical signal for turning on and off the first or second semiconductor element is input to the first control terminal so that a phenomenon of resonance of a gate voltage can be suppressed
Data Source
AI summary
Each of a plurality of semiconductor elements is provided with a first control terminal and a second control terminal. A built-in gate resistor is connected between the semiconductor element and the first control terminal. Individual voltage pulse signals are input to the second control terminals when the plurality of semiconductor elements are individually turned on and off. A common voltage pulse signal is input to some of the first control terminals when a first group of semiconductor elements is turned on and off in common. A common voltage pulse signal is input to others of the first control terminals when a second group of semiconductor elements is turned on and off in common.