Could Toshiba’s Triple-gate IGBT Lead the Way for a Carbon Neutral Future?

When it comes to power management, every watt counts. The process of considering where power losses occur in a system sometimes results in identifying a common culprit: switching loss.

 

Switching power loss for an IGBT. Image used courtesy of Avci and Ucar

 

Today, Toshiba teased the results of their triple-gate insulated gate bipolar transistor (IGBT) prototype, which promises to reduce the amount of power lost through switching loss. 

 

Switching Loss and IGBTs

Designers often come across two main issues regarding power loss in IGBTs: conduction and switching on and off. It can be difficult to reduce this power loss because conduction losses often increase switching losses. 

 

Switching waveforms of Toshiba’s IGBT prototype. Image used courtesy of Toshiba

 

With this issue in mind, Toshiba hopes that, by integrating triple-gate IGBTs with gate control technology, switching loss could be reduced by 50% (turn-on) and 28% (turn-off). Comparing this prototype with conventional IGBTs, Toshiba claims that it could reduce the overall power loss of switching up to 40.5%. 

If this prototype can provide the specs that Toshiba claims, this IGBT could reduce power loss in power converters significantly.

 

Toshiba’s IGBT Prototype

Toshiba’s triple-gate IGBT prototype includes the main gate (MG), a primary control gate (CGp), and a secondary control gate (CGs).

 

Toshiba’s prototype triple-gate IGBT. Image used courtesy of Toshiba

 

Each gate is driven independently. By delaying the secondary control gates and turning on the main gates and primary control gates, large electron and hole flows become simultaneous from all three gate electrodes. They then accumulate in the IGBT at a higher speed, thus creating a faster switch time and lower turn-on loss.

When Toshiba's prototype switches off, the electrons and holes are reduced by turning the primary control gate off before turning off the main gate (while leaving the secondary control gates off). The turn-off loss decreases when the main gate is switched off because, when the IGBT turns off completely, the electrons and holes quickly disappear.

With this proposed advancement, the development of future, more power-efficient IGBTs can make their way into eco-friendly electrical systems.

 

Moving Towards Carbon Neutral Future

Carbon neutrality is an increasingly common goal for individual devices and systems, all the way up to mission statements for corporations. While innovations towards this goal span engineering disciplines, IGBTs could play a prominent role in designing more efficient power systems.

Companies like STMicroelectronics hope to be carbon neutral by 2027, while Infineon aims for 2030. Though companies play a large role in carbon emissions, this initiative has reached a global scale, with over 110 countries pledging to be carbon neutral by 2050. 

With many countries and companies pushing towards becoming more environmentally friendly by lowering their carbon footprint, this advancement from Toshiba seems like a promising achievement in the right direction. This technological improvement could be one of many that we will see in the not-so-far future.