As part of the "Super Cluster Program", one of the Industry-Academia Collaborative R&D Programs administered by the Ministry of Education, Culture, Sports, Science and Technology (MEXT) and the Japan Science and Technology Agency (JST), Professor Takashi Hikihara of the Graduate School of Engineering (GSE) and his collaborators have been working since FY2013 on a "three-phase power router" that utilizes a silicon carbide (SiC) power device.
In September 2015, this device was tested in Sakishima, Osaka City, as part of a project aimed at building a regional energy-interchange system that utilizes railway networks and existing heat/power generators that serve as autonomous and distributed sources, under the program operated by the Ministry of the Environment to promote the development and testing of CO2-reduction technologies.
The test objectives were first to evaluate the feasibility and cost-effectiveness of installing private power lines in the wiring spaces of existing public transport tracks and also the possible effects of the noise resulting from switching and other operations related to power routing on the transport system's signal and communication equipment.
The experiment, conducted at midnight after the New Tram's service hours, involved transmission of electricity from distributed sources to multiple loads via the private power lines installed between Cosmosquare and Trade Center-mae Stations, and load-switching using power routers placed at the load side.
Measurements were taken of the effects of the power routing on the signals and communications in the New Tram's test cars and equipment, all of which were connected to the utility grid.
Throughout the session, the load-switching function of the three-phase router worked as intended, demonstrating the viability of a power control system based on a SiC power device.
In addition to being capable of both physical and temporally dynamic switching of source-load connections, the router has been proven through research to function as a transformer, indicating its potential to serve as an on-demand power control device in regional distributed power grids. Further research and development on the SiC power device as a wide-bandgap semiconductor and its applications are required to realize this vision.
Power routing diagram
