how eliminating flying lead igbt driver interconnect improves performance and reliability

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How Eliminating Flying Lead IGBT Driver Interconnect

Improves Performance and Reliability

Renewable Energy Trends

• Solar/PV installations to reach 24 GW, up from 19 GW in 2010. (IMS Research)

• Wind power installations will increase from 236 GW in 2011 to 563 GW in 2017. (Pike Research, 2011)

• 5 million cars manufactured in 2016 will be full HEV, plug-in HEV or EV. (Yole Développement, 2011)

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Renewable Energy Applications Have Increased Performance Requirements For IGBTs

• Decreased $/Watt • Higher current and voltage requirements• Faster switching speeds• Increased heat sensitivity• Higher efficiencies• Reducing switching

losses

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“Tuning” Drivers To IGBTs Help Address These Requirements

• IGBT Driver requirements will vary across IGBT manufacturers and within their product line.

• Optimizing driver design includes adjusting:– Gate resistor values– Desat requirements– Cross over timing– Soft turn off and/or Active HV Clamping

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• Increased requirements to continuously monitor the performance and functionality of the driver and overall system

• IGBT driver designs should account for monitoring the following fault scenarios and conditions:– Separate Hi/Lo fault signals– Desat timing and levels– UVLO– IGBT temperature– Ambient temperature

Increasing Fault Detection Further Enables Safe And Secure Operation

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Plug And Play Improves Manufacturability

• A much more efficient mechanical footprint• Integrating the IGBT module and driver into a

single subassembly – Dramatic increase in producibility and

serviceability• Combined offering allows a more compact and

robust design

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Direct Connection To The IGBT Lowers Inductance And Improves Overall Performance

Measurable benefits include:–Higher frequency operation– Faster driver transitions–Reduced Heat– Improved lifetime reliability

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Plug and Play vs. Flying Lead: Direct

Gate Drive with 1.8 Ohm Resistor - Direct Connection; 1700V/1000A Fuji PrimePack

Note: 1.0 usec turn on after rising edge

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Plug and Play vs. Flying Lead: Flying Lead

Gate Drive with 1.8 Ohm Resistor - 6 inch lead; 1700V/1000A Fuji PrimePACK

Note: 1.1 usec turn on after rising edge

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Plug and Play vs. Flying Lead: Direct

Gate Drive with 1.8 Ohm Resistor - Direct Connection; 1700V/1000A Fuji PrimePack

Note: IGBT turns off 4.15 us after the falling edge.

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Plug and Play vs. Flying Lead: Flying Lead

Gate Drive with 1.8 Ohm Resistor - 6 inch lead; 1700V/1000A Fuji PrimePACK

Note: IGBT turns off 4.3 us after the falling edge.

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Lead Length Correlation to Gate Resistors

The previous slides indicate that flying leads have a real effect on the switching speed of the IGBT.

This slowing is the equivalent of increasing the Gate Resistor from 1.8 Ohms to 3.0 Ohms in a direct connect system using the same gate driver.

How does this affect performance?

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Power Dissipation of the IGBT: Direct Connection

Note: Tj ave is 107.7 C . Inverter loss is 184W and 304W ON/OFF.

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Power Dissipation of the IGBT: Flying Lead

Note Tj ave is 113.4 C. (+6C) Inverter loss is 277W (+93W) and 322W (+18W) ON/OFF (111W total).

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Direct Connect = Increased Efficiency

This indicates that there is additional wattage lost in the slower turn on/off times and reflected in higher junction temperature.This translates to better performance with improved Long Term Life and Reliability.

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• Increased monitoring of the performance and functionality of the driver and IGBT can lead to better reliability.

• Next generation IGBT driver designs should account for monitoring the following fault scenarios and conditions:– Separate Hi/Lo fault signals– Desat timing and levels– UVLO– High Voltage monitoring– IGBT temperature– Ambient temperature

Future: Increasing Fault Detection Further Enables Safe And Secure Operation

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Designing for Plug And Play is Challenging, But Worth It

• The electrical performance and isolation requirements for a gate driver are the same for a plug and play design and a flying lead design.

• However, Plug and play design is more demanding since the ambient temperature of the Driver may be higher due to the close proximity to the IGBT.

• And, additional mechanical requirements and a smaller PCB footprint can make it longer to design and more costly to manufacture.

How to Reach Us

Rob WeberAlbert Charpentier

1650 Arch StreetSuite 1905

Philadelphia, PA 19103info@AgileSwitch.com

484-483-3256

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