Friday, November 19, 2021
Zhenghai Group and Rohm have inked a joint venture agreement to establish a new power module business. Dubbed “HAIMOSIC”, it will be founded in China in December 2021. Shanghai Zhenghai Semiconductor Technology Co., Ltd. (Zhenghai Semiconductor) of the Zhenghai Group will own 80% and Rohm 20%.
HAIMOSIC will develop, design, manufacture, and sell power modules employing silicon carbide (SiC) power devices, with the aim of creating a power module business suitable for traction inverters and other applications in new energy vehicles.
“The new company will develop, mass-produce, and sell power modules equipped with Rohm’s SiC chips,” said Travis Moench, senior director of sales at Rohm Semiconductor USA, in an interview with Power Electronics News/EE Times Europe. “The company plans to develop power modules optimized for traction inverters with a focus on the new energy vehicle market in China.”
He added, “Rohm has high expectations for sales expansion through the supply of chips, as well as for the adoption and widespread use of SiC power devices. HAIMOSIC’s high-efficiency SiC power modules will play an important role in encouraging the installation of SiC power devices in new energy vehicles, which are gaining momentum in China, as well as in other application research.”
Zhenghai Group and Rohm will work closely with this new company to pursue technological innovation through the development and widespread use of SiC power modules.
The future of silicon carbide
Power devices for high-voltage applications, such as electric vehicles (EVs), power supplies, motor control circuits, and inverters, are made using silicon carbide (SiC), a semiconductor material made up of silicon and carbon. SiC has several benefits over traditional silicon-based power devices like IGBTs and MOSFETs, which have long dominated the industry due to their cost-effectiveness and ease of manufacture.
According to Rohm, there are high expectations for SiC power devices in various markets. “We believe it is important to provide a stable supply of products that meet market and customer needs,” said Moench. “In addition to contributing to energy conservation through the devices, it is important to propose solutions that include peripheral components such as control ICs (gate drivers) to drive the devices and power discrete devices. Rohm is also providing extensive design support for these components. In addition to providing evaluation and simulation tools, we are accelerating the development of joint laboratories (Power Labs) with users.”
The objective is to develop next-generation SiC devices with the best performance-to-cost ratio possible. Cost optimization is still required due to the volume and competitiveness of IGBTs, and it will be critical to optimizing the wafer manufacturing stages to accommodate ever-increasing production volumes. Two of the most significant roadblocks are time and the quality of raw silicon carbide wafers, which often contain crystal structural flaws that reduce yield. This has a direct impact on the cost of the gadgets, and price is always a major factor in the adoption of any new technology.
Moench commented: “Over the past 10-20 years, the main challenges of SiC have shifted significantly from performance (demonstrating clear advantages over Si devices), to reliability (passing industrial and automotive qualification, identifying and mitigating special failure modes), to cost (from serving a niche market to achieving cost-effectiveness for a wide range of applications). At this time, cost is the main remaining barrier for many potential applications that could have adopted SiC to improve system performance and power density. But this is getting better every year, especially after SiC has proven to offer great system value for EV power converters (onboard chargers and traction inverters). As global market demand increases rapidly, SiC device production efficiency is vastly improved through larger wafer diameters and other supply chain advantages. This momentum will eventually enable SiC to overtake Si for 600V+ power devices in a much wider application space, step by step.”
Because they provide a variety of attractive qualities over commonly used silicon, silicon carbide (SiC) devices are rapidly being used in high-voltage power converters with stringent size, weight, and efficiency requirements (Si). On-state resistance and switching losses are significantly reduced, while SiC has nearly three times the thermal conductivity of silicon, allowing components to dissipate heat more quickly. This is significant because, as the size of Si-based devices decreases, it becomes more difficult to extract the heat created by the electrical conversion processes. SiC dissipates the heat more effectively.
SiC offers significant advantages in automotive applications over traditional silicon-based devices, including better power density, higher system efficiency, range extension, cheaper system cost, and long-term dependability.
The efficiency of an electric car’s powertrain and energy management system is directly proportional to the efficiency of its engine and energy management system. Furthermore, critical infrastructures, such as solid-state fast-charging systems capable of hundreds of kilowatts of power, must meet strict size and efficiency limits.
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