TOKYO -- Japan's electronics makers are set to ramp up production of a key semiconductor device used in electric cars.

Toshiba plans to spend 30 billion yen ($270 million) adding 50% more capacity for power semiconductor devices, which improve energy conservation in electric cars. Mitsubishi Electric and Fuji Electric also have plans to expand production lines.

Japanese companies maintain a relatively strong presence in the global market for power semiconductor devices, which require a high degree of manufacturing expertise, though they are playing catch-up with market leaders in Germany and the U.S.

The devices are used to convert between direct and alternating currents and adjust voltage. They make their way into home appliances, industrial machinery and solar power equipment. The electric vehicle market, growing as environmental regulations tighten around the world, is expected to become the main demand center for the devices, which can help reduce the size of power equipment and efficiently control electric motors.

Unlike memory devices, whose market is led by South Korean and Chinese companies, power devices are typically made in small quantities for a range of applications. This requires sophisticated technological know-how and creates a high barrier to entry.

South Korean and Chinese companies have been unable to increase their presence in the market, which has not experienced rapid price declines.

Toshiba intends to increase its capacity to build power devices by 50% in the year through March 2021 from the level for the year through this past March.

Lines at Kaga Toshiba Electronics, a subsidiary in Ishikawa Prefecture, are operating at full capacity, and other production facilities will be expanded. Toshiba also plans to bolster assembling processes at two other plants, one in the western Japanese city of Himeji and the other in Thailand.

The company plans to invest 30 billion yen over the next three years to ramp up production at these bases.

Toshiba's production focus is on the so-called discrete, or nonintegrated, type of power devices, which typically allow for profit margins of around 10%. The company aims to expand these products' sales by 25% to 200 billion yen by the end of fiscal 2020.

Toshiba regards the power semiconductor business as a key candidate to drive revenue now that it has sold its flash memory business, which had generated over 400 billion yen in revenue each year.

The fast-growing electric vehicle industry is becoming hungrier for these components. The International Energy Agency forecasts global electric vehicle sales by the end of 2030 to be at 21.5 million units, up fifteenfold from last year. By 2030, the power device market will be worth 4.68 trillion yen, up 70% from 2017, according to Tokyo market research company Fuji Keizai.

There could be even more demand for the devices if electric vehicles are introduced at a faster pace, Fuji Keizai believes.

According to U.S. research company IC Insights, Japan in 1990 was the biggest seller of semiconductors, accounting for 49% of the global market. In 2017, that figure had plummeted to 7%.

Power semiconductor devices represent only about 5% of the global semiconductor market, where Mitsubishi Electric is the No. 3 seller and Toshiba No. 4.