Japanese Firm Unveils 'World's Smallest' PHEV/EV Charger

Jan 20, 2012
Tsuneyuki Miyake, Tech-On!
The exhibited prototype of the small-size charger
The exhibited prototype of the small-size charger
[Click to enlarge image]

Power Assist Technology Ltd and Shimane University developed what they claim is the world's smallest charger for plug-in hybrid electric vehicles (PHEVs) and electric vehicles (EVs).

They exhibited the charger at the 2nd Automotive Weight Reduction Expo, which runs from Jan 18 to 20, 2012, in Tokyo.

The exhibited prototype of the charger measures 116 x 279 x 225mm, and the volume of the charger has already been further reduced by about 1/3. The small size was realized by improving efficiency by 92% or more (when input, output and electric power are AC200V, DC400V and 3.3kW, respectively), compared with existing chargers, to reduce the size of the part used for heat radiation.

To improve efficiency, Power Assist Technology and the university used an interleaving technology, which divides the inverter circuit of AC-DC converter into two. Because current dealt with by each circuit decreases, loss can be reduced. In addition, they employed a soft switching technology. Because switching takes place when the current and voltage are zero, switching loss can be reduced.

The new technology was employed for a kit that changes a normal vehicle into an electric one. And Power Assist Technology and the university are currently encouraging Japanese automakers to employ the technology, which is ready to be used for production vehicles.