전세계적으로 요구되는 에너지 효율 표준이 계속해서 기준이 높아지는 가운데 실리콘카바이드(이하 SiC)가 효율 향상에 큰 역할을 한다는 전문가의 의견이 제시됐다.
SiC MOSFETs and diodes, up to 2.16% efficiency improvement
SiC, 4kW Air Conditioning Unit System and Power Usage Costs ↓
As energy efficiency standards required worldwide continue to rise, experts have suggested that silicon carbide (SiC) plays a major role in improving efficiency.
Wolfspeed’s Lee Tae-hoon and Ham Jeong-ho, vice presidents, presented ‘Wolfspeed SiC’s Heat Pump and Air Conditioning Solutions’ at the e4ds webinar on the 1st.
Mr. Ham Jeong-ho said that SiC can contribute to the efficiency of heat pumps and air conditioning systems of 4kW or more.
The main requirements in the industry are to meet global efficiency regulations, achieve higher efficiency, and reduce noise that can occur when driving motors at low frequencies.
The reason SiC is attracting attention in these two fields is that energy efficiency standards such as SCOP required in the US and Europe are continuously being raised, and SiC has advantages in terms of improving system costs and power usage costs.
“SiC can get some help with changes to the switching elements and achieve ultimate efficiency improvements through external thermal management elements,” said Ham. “SiC MOSFETs and diodes can increase system efficiency by up to 2.16%, so it is clear that SiC is headed in the right direction for increasing efficiency regulations.” He said.
Even in the electric vehicle sector, the trend toward adopting SiC heat pumps is increasing as the vehicle approaches high-end.
A report was also published that said applying a heat pump increased winter driving range by approximately 19%.
This is a credit to the Heat Pump system itself, but it can also be said that the use of SiC MOSFETs contributed to improving efficiency.
Additionally, SiC has shown an efficiency improvement of approximately 5% under light load conditions within the system compared to IGBTs.
The reason SiC is required in EV heat pumps and air conditioning is because the system can achieve high efficiency, low temperature due to excellent thermal performance, and smaller size due to high frequency usage.
The reason for emphasizing global energy efficiency regulations is that efficiency regulations in each region of the world, such as the United States, Europe, and China, which pursue high efficiency, are acting as a major factor in the application of SiC.
In Canada, a ban on oil-based heating is coming into effect for new buildings, and the UK has begun the transition to heat pumps by banning the sale of gas boilers after 2035.
Director Ham divided the system conditions used as an example into two stages and explained them.

▲ Wolfspeed December 1st e4ds webinar presentation materials
The first is PFC. It changes the silicon pin diode to a SiC Schottky diode. This is the easiest way to upgrade the AC/DC section and it has resulted in a 1.5% efficiency improvement.
A power reduction of 60W is achieved for a 4KW system.
The second step is to upgrade the inverter part.
Replacing six IGBTs with SiC MOSFETs improved efficiency by 0.66% and reduced power by 26 W.
Combining the first two parts resulted in an 86W loss reduction and a 2.16% efficiency improvement.
Although the reduction may seem small, when calculating the power bill, you will see that after a certain period of time, the system constructed with SiC is superior in terms of power bill and reliability.
Additionally, Vice President Ham Jeong-ho explained the difference in power loss through actual simulation results using IGBT and SiC.
▲ Wolfspeed December 1st e4ds webinar presentation materials
The test conditions were 4KW power level, 50% operation duty cycle.
Switching frequencies of 5KHz and 16KHz were applied respectively and simulations were conducted on the status.
The SiC MOSFETs used here were 650 V, 60 mΩ, and 120 mΩ, and the IGBTs were 650 V, 30 A, and 40 A to compare the switching loss.
37A in the lower left bar graph is 60mΩ, 22A is 120m&OmIt can be interpreted as ega.
It shows the switching loss when driven at 5kHz. The switching loss of the IGBT is smaller than the conduction loss, but it exists and is larger than that of SiC.
The graph on the right shows the test results at a switching frequency increased to 16 kHz.
In the case of IGBT, the switching loss increases by more than three times, while SiC has an overall increase in switching loss of about twice, but the amount of loss is relatively very small, and the overall loss shows only a 10% increase, which is a big difference from IGBT.
What the inverter market demands from manufacturers is high efficiency, small size, and light weight.
As standards are strengthened, difficulties arise when trying to increase efficiency with existing IGBTs.
To make it smaller and lighter, the switching speed must be increased, but it is difficult to maintain system efficiency as switching loss increases.
SiC is the most effective power semiconductor to replace IGBT, but drop-in replacement increases the cost.
“It will take 195 days to recover the cost of replacing SiC,” said Vice President Ham. “Wolfspeed calculated the electricity bill by focusing on the amount of power saved due to improved efficiency.”
Assuming 6 hours of use per day for 15 years based on a 2.16% efficiency improvement when changing to SiC, a total of 2,838 kWh can be saved.
Assuming SiC's efficiency is 2.16% higher, and at a German electricity price of 0.64 euros per kWh, users can recover the added initial cost of SiC after 195 days of use.
Meanwhile, Wolfspeed will launch the Speedval KIT in January 2023.
Revolution of discrete devicesIt is a platform type development tool for God. It is configured to support virtually any discrete product using a single test platform.
You can choose from a number of gate drivers from manufacturers that have strategic partnerships with Wolfspeed to provide you with a choice of gate drivers.
There is a degree of freedom in topology, and power device cards, etc. can be inserted in slot form, allowing for a variety of highly flexible configurations.
This allows us to implement experimental prototype models.
Wolfspeed also introduced its technology support platform, Power Application Forum.
Power Application Forum, one of Wolfspeed's design support tools, was launched in January 2022.
You can ask questions about SiC and Wolfspeed engineers will answer them.
Customers can interact with Wolfspeed's SiC power experts and participate by answering questions directly.
Vice President Lee Tae-hoon talked about Wolfspeed, saying that the company is the world's number one producer of SiC substrates and accounts for more than 60% of the global SiC supply.
▲ Wolfspeed December 1st e4ds webinar presentation materials
Wolfspeed said that more than 90% of SiC produced to date has been produced and that it achieved sales of $525 million in 2021, with sales of $243.1 million in the last quarter alone.
Wolfspeed also established the world's first 200mm wafer mass production plant, giving it a raw materials production capacity of $1.3 billion.
In April 2022, Wolfspeed opened the Mohawk Valley Wafer Fab (MVF).
MVF is a lights out factory with fully automated systems throughout the entire process and has also received IATF certification.
MVF is the first fab to adopt an overhead transport system and automatic loading port in its 200mm wafer SiC wafer manufacturing process.
As a manufacturing system that supports a big data environment, MVF is fully automated.
It reduces production processes from 10,000 to 0, minimizing yield loss and operating 24/7 even in bad weather.
Automation is a key element of improved quality control, higher reliability and lower costs.
MVF uses world-class automated processes with fully enclosed wafer transport to improve quality and reduce risks associated with manual operations.
The recently announced 1.8km2 Siler City Factory advanced SiC wafer facility is focused on producing 200mm wafers and is expected to increase Wolfspeed’s raw material production by a factor of ten.