Multi-Wire Gate Choke for Common-Mode Immunity in Paralleled Semiconductors
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Solution Overview
Problem
Power conversion modules in vehicles face challenges with common mode and differential mode high frequency transient voltages and currents, which threaten the integrity of gate driver control circuitry due to high switching speeds and parasitic capacitances, leading to electromagnetic interference (EMI) and potential damage from circulating currents.
Innovation Solution
A multi-wire choke is implemented in the gate driver circuit to present impedances, specifically a first wire between the gate and source/emitter terminals and a third wire between the drain/collector terminal, magnetically coupled to prevent common and differential mode transient signals from feeding back into the gate driver control device, thereby reducing unwanted circulating currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high switching speeds are used in power transistors, then productivity and power conversion efficiency are improved, but common mode and differential mode transient voltages and currents increase, threatening gate driver circuitry integrity
Solution Approach 1:
The patent introduces a multi-wire choke as an intermediary component between the power transistor and gate driver circuitry. This choke presents high impedance to common mode and differential mode transient signals, blocking their propagation to the gate driver while allowing normal power switching operation to continue, thus resolving the contradiction between high switching speeds and transient signal suppression
Solution Approach 2:
The patent converts the harmful high-frequency transient signals into a beneficial filtering action by utilizing the choke's inductive properties. The transient signals that would normally damage the gate driver are instead used to demonstrate the choke's filtering capability, where the same high-frequency signals that cause harm are blocked by the choke's impedance, transforming the problem into a solution
2Reliability
If filters are added to reduce transient signals, then reliability of gate driver circuitry is improved, but device complexity increases
Solution Approach 1:
The patent merges multiple filtering functions into a single multi-wire choke component. Instead of adding separate common mode chokes and differential mode filters, the invention combines both filtering capabilities in one integrated component, thus improving reliability while minimizing the increase in device complexity
Solution Approach 2:
The multi-wire choke serves multiple functions simultaneously: it acts as a common mode filter, a differential mode filter, and a circulating current suppressor. This multi-functionality allows a single component to address multiple reliability concerns without proportionally increasing circuit complexity
3Power
If paralleled power semiconductors are used, then power handling capability is improved, but circulating current increases due to mismatched inductances and gate thresholds
Solution Approach 1:
The patent introduces the multi-wire choke as an intermediary component in the gate drive loop of paralleled power semiconductors. The choke presents high impedance to circulating currents caused by mismatches in source/emitter inductances and gate thresholds, thereby suppressing these harmful currents while allowing the paralleled configuration to maintain its enhanced power handling capability
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 multi-wire choke effectively reduces common mode and differential mode transients, enhancing the immunity of the gate driver circuitry to high frequency signals and preventing false overload activations, thus improving the reliability and performance of power switching transistors.
Implementation Method 1
a multi-wire choke effectively reducing common mode and differential mode transients... the first wire and second wire providing an impedance preventing common mode transient signals... the third wire providing a further impedance preventing differential mode transient signals
Implementation Method 2
magnetically coupled to prevent common and differential mode transient signals from feeding back into the gate driver control device
Data Source
AI summary
A multi-wire choke filter is implemented in an inverter module of a modular power control system for a vehicle. Such an inverter module includes gate driver circuits to control switching power transistors used to power loads in a vehicle. The switching power transistors and gate drivers are configurable to support both a three-phase and a single phase current drive driver circuit topology in which switching power transistors are connected in parallel to share driving currents and dynamic switching losses. In any configured topology, the multi-wire choke is connected in series between gate driver circuit components and switching power transistors to mitigate any EMI threat to the gate driver circuitry by presenting an impedance to reduce circuit susceptibility to any differential and common mode noise currents that can flow through the gate driver circuit that can overwhelm gate driver circuitry and negatively effect power transistor switching performance at any time.