NEWS
【Part 2】Why AC Manufacturer Daikin Is Developing Its Own Semiconductors
FEATURE
2024.09.16
Having independently developed core technologies for air conditioners such as motors, pumps, and filters, Daikin Industries has now embarked on developing its own semiconductors for use in inverter circuits. In the previous article, we spoke with the TIC team members responsible for custom microcontroller development, the brain behind these innovations. This time, we interview three members—Yuichi Nagahisa, Shinji Sakai, and Akio Yoshimoto—who are involved in the development of the power semiconductor modules aimed at dramatically improving inverter performance. Here they share their insights on the current development progress, its challenges and joys, and the possibilities for the future.
New Project on Power Semiconductor Modules Begins
――Following the interview with the custom microcontroller development team, this time we focus on the team developing power semiconductor modules. Could you first talk about your professional backgrounds with us?
Yoshimoto: I joined Daikin Industries as a new graduate in 1993 and spent around ten years developing embedded software for semiconductor manufacturing equipment, wafer handling robots, and more. Later, I specialized in heat dissipation and installation techniques for inverters. After transferring to TIC, I was involved in developing a new refrigeration technology called magnetic refrigeration that doesn't use fluorocarbon gas refrigerants. Because of my work in feasibility studies for in-house production of power modules, I was invited to join the current power semiconductor project.
Yoshimoto: I joined Daikin Industries as a new graduate in 1993 and spent around ten years developing embedded software for semiconductor manufacturing equipment, wafer handling robots, and more. Later, I specialized in heat dissipation and installation techniques for inverters. After transferring to TIC, I was involved in developing a new refrigeration technology called magnetic refrigeration that doesn't use fluorocarbon gas refrigerants. Because of my work in feasibility studies for in-house production of power modules, I was invited to join the current power semiconductor project.
Sakai: I joined Daikin mid-career in July 2023 after spending 15 years at a major electronics manufacturer, working primarily in power semiconductor module design. Reflecting upon the future of power module technology and value creation, I felt that new information needed to be input for customer requirements, technological advancements, and current trends. What sold me on Daikin Industries was the chance to break away from the conventional and incorporate new functions and technologies in the design of power modules and electrical components for air conditioner inverters.
Nagahisa: I also joined in April 2023 after working in semiconductor device research since university. In my previous role at a major electronics manufacturer, I was in charge of developing SiC (silicon carbide) semiconductor devices, the presumed next generation power semiconductors. Unfortunately, as these devices entered the mass production stage, a general standardization was set in motion. What interested me was tweaking the performance of the advanced power semiconductors, such as a SiC device, to improve the final product. So, when I learned that Daikin was developing power semiconductors, I knew where I wanted to work.
――Why is Daikin aiming to develop semiconductor devices?
Sakai: At Daikin, we consolidate specialized HVAC technologies, sending them out into the world as final products. Because we are a company that places value on sharing the technologies and ideas that we possess, we are able to work on cutting-edge projects in collation with other departments and leverage these benefits in creating the final product while also maintaining an overall balance in other areas. As TIC acts as a hub connecting business divisions, we welcome individuals who can fuse various technologies and challenge new things.
Sakai: Daikin is advancing the development of microcontrollers and power semiconductors, critical components of inverter circuitry, which is a core technology in air conditioning. Microcontrollers act as the brain, generating control signals for motors and pumps, while power semiconductors drive these devices based on those signals. Recent commercially available power semiconductors are driven largely by demands such as those from the EV sectors and aren't necessarily optimized for air conditioners. That is the reason we decided to pursue in-house development.
Developing Specialized Power Semiconductor Modules to Drive Daikin Air Conditioners
――What are the key points in developing power semiconductors?
Yoshimoto: Our current development aims to increase the carrier frequency of inverters. Higher carrier frequencies reduce the size of major components like capacitors and reactors, allowing cleaner waveform currents (pseudo-sine waves) to flow through motors, improving efficiency and reducing power consumption. However, increasing the carrier frequency also increases switching losses. With conventional Si power semiconductors, there's a limit to how fast you can switch. Therefore, we are developing modules using SiC power semiconductors, which can switch even faster.
We used to mount commercially available power semiconductor modules on the circuits and boards designed in-house. When switching speeds are increased, surges and noise can occur, causing electrical disturbances that may exceed the module's voltage tolerance and lead to failure. In light of this, we have to reevaluate the circuit design and consider a comprehensive design that accommodates both the board and the module, especially for high-frequency compatibility.
Aiming for development to reduce surges by increasing carrier frequency through the use of custom power semiconductor modules and overall design of the board and module.
――Please tell us about the current development status of the power semiconductor modules.
Sakai: We're in the process of defining specifications, prototyping, and refining towards mass production. When embedding the latest global power semiconductor module technologies at Daikin, we aim to develop products that match our unique capacitor-less technology (which reduces electrolytic capacitor capacity on printed circuit boards to save power and cut costs) and high-frequency suppression technology (which suppresses high-frequency components on sine waves). We're considering introducing SiC chips to reduce inverter losses and efficiently cool small-sized SiC chips.
――Have there been any challenges or hurdles in the development of power semiconductor modules so far?
――Could you share your outlook on power semiconductor modules going forward?
Nagahisa: Establishing an environment for producing power semiconductor modules within Daikin was initially challenging. Previously, both Sakai and I had developed semiconductors at workplaces where such environments were already established. However, at Daikin, we had to start from scratch, figuring out what was necessary, deciding which partners to collaborate with, and how to proceed with development. Currently, we've set up the necessary equipment for manufacturing and evaluating semiconductor modules, and our development structure is gradually falling into place.
Yoshimoto: We want to incorporate the unique features that only Daikin can offer into the power semiconductor modules. Currently, we design separate printed circuit boards and modules, but we expect to integrate these into a unified design as we absorb various technologies.
Nagahisa: Most of Japan's current power semiconductor modules are focused on EVs. Redirecting this focus toward our products is also crucial.
A Workplace Where You Can Speak Freely and Get Ideas through Collaboration
――Let's ask the veteran members about the TIC workplace environment. Have you noticed anything since joining?
Sakai: I've been involved in electrical and electronic fields for a long time, but Daikin's focus on air conditioning makes it easier to reach a consensus during discussions, even with developers from different fields. While there are pros and cons, the atmosphere allows you to express your thoughts freely, incorporating the various perspectives of other employees to create new things in a positive environment.
Nagahisa: Daikin has a close relationship with top management, and decision-making is quick. In my previous job, communication between divisions within the business unit was often limited due to vertical power sharing. At Daikin, I feel there is a culture of making decisions by gathering all necessary individuals for discussions.
Sakai: I've been involved in electrical and electronic fields for a long time, but Daikin's focus on air conditioning makes it easier to reach a consensus during discussions, even with developers from different fields. While there are pros and cons, the atmosphere allows you to express your thoughts freely, incorporating the various perspectives of other employees to create new things in a positive environment.
Nagahisa: Daikin has a close relationship with top management, and decision-making is quick. In my previous job, communication between divisions within the business unit was often limited due to vertical power sharing. At Daikin, I feel there is a culture of making decisions by gathering all necessary individuals for discussions.
――Could you comment on the TIC atmosphere from a long-term regular employee perspective, Mr. Yoshimoto?
Yoshimoto: I've been with Daikin for a long time, so I can't compare it with other companies. Originally, TIC was launched as an organization combining staff from multiple research institutes and technical engineers from the business divisions. Since then, the focus has shifted towards co-creation and developing research and development that leads to viable business opportunities in the future. This project is a perfect example. We strive to conduct development that meets this philosophy and generates profit.
Yoshimoto: I've been with Daikin for a long time, so I can't compare it with other companies. Originally, TIC was launched as an organization combining staff from multiple research institutes and technical engineers from the business divisions. Since then, the focus has shifted towards co-creation and developing research and development that leads to viable business opportunities in the future. This project is a perfect example. We strive to conduct development that meets this philosophy and generates profit.
Appeal of Semiconductor Development at AC Manufacturer Daikin
――Finally, as an engineer, what is the appeal of developing semiconductors at Daikin?
Yoshimoto: Since Daikin has very few semiconductor developers, joining now means you can make a big impact (laughs). Being able to design power semiconductor modules that are actually used in the company is an opportunity that other companies do not provide. With the dramatic changes approaching in inverter technology, those who want to fully utilize their capabilities should definitely join us!
Nagahisa: Yes, if you're looking to do something cutting-edge, this workplace is incredibly exciting. Development of general-purpose products tends to result in rounded-off variations. If you're interested in creating something unique, this workplace offers high job satisfaction for engineers. During this period of significant change in development, maximizing your potential will be an invaluable experience, contributing to personal growth.
Nagahisa: Yes, if you're looking to do something cutting-edge, this workplace is incredibly exciting. Development of general-purpose products tends to result in rounded-off variations. If you're interested in creating something unique, this workplace offers high job satisfaction for engineers. During this period of significant change in development, maximizing your potential will be an invaluable experience, contributing to personal growth.
※The information and profiles are based on the time of the interview.
Yuichi Nagahisa
Senior Engineer, Technology and Innovation Center (TIC), Daikin Industries.
Joined in April 2023. Originally from Kanagawa Prefecture. Responsible for power module element technology development, exploration of advanced power semiconductors .
"I aim to incorporate user perspectives and challenge myself in developing technologies that maximize the performance of new power semiconductors."
Senior Engineer, Technology and Innovation Center (TIC), Daikin Industries.
Joined in April 2023. Originally from Kanagawa Prefecture. Responsible for power module element technology development, exploration of advanced power semiconductors .
"I aim to incorporate user perspectives and challenge myself in developing technologies that maximize the performance of new power semiconductors."
Shinji Sakai
Senior Engineer, Technology and Innovation Center (TIC), Daikin Industries.
Joined in July 2023. Originally from Saitama Prefecture. Responsible for power module design, integration of new core technologies .
"I am committed to advancing semiconductor and inverter technologies. By incorporating new innovations, I strive to continuously enhance semiconductor capabilities."
Senior Engineer, Technology and Innovation Center (TIC), Daikin Industries.
Joined in July 2023. Originally from Saitama Prefecture. Responsible for power module design, integration of new core technologies .
"I am committed to advancing semiconductor and inverter technologies. By incorporating new innovations, I strive to continuously enhance semiconductor capabilities."
Akio Yoshimoto
Technology and Innovation Center (TIC), Daikin Industries.
Joined in April 1993. Originally from Hyogo Prefecture. Responsible for power module package technology, magnetic heat pump technology.
"I want to bring new, unrealized technologies to life and introduce them to the world."
Technology and Innovation Center (TIC), Daikin Industries.
Joined in April 1993. Originally from Hyogo Prefecture. Responsible for power module package technology, magnetic heat pump technology.
"I want to bring new, unrealized technologies to life and introduce them to the world."
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