TM4 ReflexTM advantage

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Inverter optimization


Inverters are a key component in electric and hybrid electric vehicles:

  • Their primary function is to provide regulated AC current to the powertrain’s electric motor
  • They usually use IGBT modules when the battery voltage is above 250 Vdc
  • A good inverter design should balance losses between inverter and motor


Typical inverters are designed to use the highest operating voltage and output current from IGBTs. Here are some limitations of the IGBT semiconductor:

  • When switching, the overvoltage across the IGBTs limits its maximum operating voltage
  • IGBT temperature (losses) limits the output current


This leads to the objective of designing for faster switching transitions to decrease IGBT losses. The downside is that faster switch time leads to greater switching overvoltage. TM4 has overcome this challenge using ReflexTM technology


TM4 REFLEX™ advantage

TM4’s unique new feature is an active mechanism that uses the stray inductance of the IGBT to control the current during the turn-off process, without slowing down the rate of voltage change. Used in the TM4 CO150 inverter and TM4’s multiphase inverters, It is only active when necessary, and it has virtually no negative effect on efficiency and temperature. The TM4 Reflex™ gate driver technology results in:

  • Higher current: Availability of up to 65% more current at high operating frequency
  • Higher efficiency: Faster switching time
  • Higher reliability: Closed loop limitation of overvoltage
  • Higher operating voltage: Limited overshoots
  • Lower operating temperature: Faster switching time
  • True short-circuit protection

Effect of Reflex - 20KHz

Combining many hardware and software innovations, TM4’s inverter platform uses Reflex™ gate driver technology to anticipate a voltage peak on the IGBT, and it ensures that it never reaches the voltage limit. TM4 uses INFINEON® HybridPACK™2 but designs and manufactures its own gate drivers. Most companies using the same module limit the current to 450 Amps, while TM4 manages to extend the current limit to 650 Amps.


This technology is also licensed for inclusions in third-party products. Contact us for more information.