10-03-2016 | | By Paul Whytock
Solar power systems by their very design have inefficiency problems when it comes to power loss.
This occurs when the DC current generated by solar panels is changed to AC current. This process is enabled by passing the current through an inverter circuit.
A critical element and a major contributor to power loss happens in the power devices employed in the solar system. Consequently cutting power loss that occurs in Insulated Gate Bipolar Transistors (IGBTs) enhances the power generation performance of solar systems.
And it's not only those systems that can benefit. It can also have a notable effect for UPS systems in server rooms and data centres because power here must constantly pass through a power converter circuit to monitor if the power supply has been interrupted.
Supplier of IGBT components Renesas has addressed some of these power loss situations in its six new products in the 8th generation G8H Series of IGBTs which it says can reduce conversion losses in power conditioners for solar power generation systems and also UPS systems. In addition to developing the new IGBTs the company also claims to have achieved the industry’s first TO-247 plus package for a 1,250V IGBT with built-in diode.
The design advantage of this package is the underside of the TO-247 is metal which means heat generated by IGBT power loss can be transferred to the package exterior. Consequently, the new devices can deal with temperatures up to 175°C.
A further operational advantage of the new IGBTs focuses on how the company used a trench gate configuration in the process structure.
Renesas says this process is exclusive to them and it means the new IGBTs can achieve a combination of fast switching performance and low saturation voltage (Vce (sat)) features. This results in a performance index that is increased by up to 30%. In addition, Renesas analysed the elements contributing to power loss in inverter circuits and designed the new devices to minimise conduction and switching loss.
In IGBTs there is a recognised tradeoff between noise characteristics and switching speed. Renesas believes these 8th-generation IGBTs generate less gate noise during switching, enabling system manufacturers to eliminate the gate resistors previously needed to reduce noise.
Six versions are available rated at 650 V/40 A, 50 A, and 75 A, and at 1,250 V/25 A, 40 A, and 75 A, and production is scheduled to begin in September 2016 and is expected to reach a volume of 600,000 units per month by March 2017.