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Little Has been Said about OMRON’s Power Electronics Technology “OMRON’s Best Kept Attraction” as Told by Development Leaders

Power Electronics Technology: behind OMRON’s Businesses

Nagaoka:Power electronics is a technology widely used for a variety of products that OMRON Group’s business domains have to offer. For example, in the factory automation business, we are looking at power supplies for control equipment; in the social systems, solutions and service business, power conditioners and uninterruptible power supplies (UPSs) that control solar power generation; and in the device & module solutions business, power supplies for gaming gear and wireless power transfer (WPT) applications for shared electric bikes, which have become increasingly popular in recent years.

In the factory automation business, power supplies are embedded into control panels at factories.The control panel is the brain of the equipment that integrates the factory's production facilities for efficient operation, and the power supply is the heart of the control panel. The power supply converts 100 VAC(commercial power source) to 24 V/48 VDC(widely used for production equipment), and is indispensable for factory automation.Control panels are required to function in an increasingly sophisticated manner. Due to limited foot space, however, components to be housed must also be compact.

In response to this downsizing requirement, in 2016, OMRON released S8VK-S(1), the world’s smallest class power supply. This power supply uses "resonant circuit technology to improve conversion efficiency" to suppress heat loss itself, and "thermal control technology" to achieve this by arranging components with high heat dissipation.

The resonant circuit technology developed then has since found a new application to WPT(2)

(1) Switching power supply catalogue
CSM_S8VK-S_S8FS-G_SGTC-066_7_4 (omron.co.jp)

(2) Link to a video on WPT
https://www.youtube.com/watch?v=Q_aLA9bE-_Y

Some of the applications with high demand for WPT include battery-assisted bicycles, electric kickboards, electric wheelchairs, and autonomous mobile robots (AMRs), all of which require easier power feeding. The conventional contact method requires electrodes to withstand wearing, be easy to clean, and have a shock prevention mechanism.

In addition, the current WPT requires strict positioning. Therefore, OMRON is developing a technology that allows for power supply even if there is some misalignment. The key technology here is our proprietary resonant circuit technology, which is also used for power supplies.

OMRON’s Power Electronics Technology Playing an Integral Role in Solar Power Generation

Okada：OMRON’s power conditioners for solar power generation and storage systems for housing are both quite popular and enjoy the largest market share in Japan. We have reached the top all because of anti-islanding control technology (AICOT(3)). Actually, this technology may not have been that important when solar power generation was still in its infancy. With the proliferation of solar power generation, however, this technology is indispensable. When we started, we imagined a future where solar power generation was the norm and worked on technology that we thought would be necessary. AICOT prevents malfunctioning of the solar power system caused by mutual interference among a large number of power conditioners. We had set eyes on this social issue quite early on and kept improving its technology until it became a de facto standard.

We then branched out into the storage battery business, which has since evolved into power conditioners for Vehicle to Home (V2H), which transfer the energy stored in the battery of an electric vehicle (EV) to the home for use as a power source.

Because conventional V2H power conditioners are rather bulky and need foundation work for installation, people believed that it would take time for them to become widely adopted in Japan. So, we devised an idea to build them small enough to be hung on the wall, which we did, and put them on the market. Several technologies made this happen. To give you one example, it was the adoption of GaN devices(4) for popularly-priced systems for the first time. Compared to conventional Si devices, GaN devices have the advantage of faster switching speeds, but are liable to produce noise, making them rather difficult to handle. So, we developed a drive circuit and a filter circuit that suppress the noise, allowing us to tap into GaN devices’ full potential and realize one of the industry’s most compact and lightweight power conditioners.

(3) AICOT: Smoothly prevents “islanding,” an unsafe condition in which a solar photovoltaic system continues to supply power to the grid when the electric grid is down, when several systems are installed close together. Without having to check actual systems for interference for the first time in the industry, it also reduces expenditures for purchasing safety devices for systems and significantly increases the quantity of solar power system installations.
https://www.omron.com/global/en/technology/information/brand/aicot/

(4) GaN device: Next-generation semiconductor power device formed on gallium nitride crystals Capable of handling a larger amount of electricity with a smaller loss than silicon power devices
e.g. https://www.jsap.or.jp/columns/gx/e2-6-2

Attempting to Develop New Power Electronics Technology

Uematsu：In the past, electric power generation used a centralized system to transmit power from power plants. More recently, however, a small-scale dispersed energy system is taking its place. While we continue catering to the ongoing demand for higher efficiency and greater downsizing of power supplies and V2H, we believe it will be necessary to have a function that simulates the inertia(5) current systems possess in order to resolve an emerging problem of systems becoming unstable as DC power transmission has become a norm and dispersed power sources increase in number.

In other words, we will be required to have information management technology for controlling the supply-demand balance of energy, in addition to power electronics technology.

(5) Inertia: Motors are used to generate power. When they rotate, inertia is produced to keep them rotating. With conventional power generation systems, inertia keeps the motors going even in the event of a problem. Dispersed power sources using solar power, on the other hand, stop supplying power once a problem occurs, and no inertia is at play. For grid power, it is crucial to keep generating power even in the presence of a problem.
e.g. https://www.tdgc.jp/information/docs/5bc445f2c046a78e881ec2d4dd13a619fb1285fe.pdf in Japanese only

It has been published that dispersed power sources are becoming commonplace(6), but some are concerned that there’s no way to control them if their diffusion rate exceeds 70%.

When it comes to fluctuations in power supply at a rather slow frequency, which gives us a relative abundance of leeway in time, we do have some known adjustment techniques that generate inertial force, such as governor-free operation(7), and load frequency control(8), . However, with the adjustment of fluctuations one second or shorter, we are increasingly required to offer technology that enables power conditioners to respond by themselves, and we are hoping to implement such technology into our power conditioners.

If you want to hone your power electronics technology to bring about innovation, just join us on our adventurous journey!

(6) Handout No. 3, the 55th Committee Meeting on Adjustment and Supply-Demand Balance Evaluation, Etc., Organization for Cross-regional Coordination of Transmission Operators, Japan (OCCTO)

(7) Governor-free operation (in Japanese)
e.g. https://www.iee.jp/pes/termb_081/

(8) Load frequency control (in Japanese)
e.g. https://www.power-academy.jp/learn/glossary/id/1417

In conclusion

We were lucky to have the three engineers who are leading OMRON’s power electronics technology development speak on its appeals. They reminded us that the very source of power to develop one-of-a-kind products is the joy of implementing new technologies into products and the mindset of continually refining sensitivity to predict the future through technical development.