|Conventional industrial 11 kW induction motor (left) and Hitachi’s new 11kW motor (right). Source: Hitachi. Click to enlarge.|
Hitachi has developed a high-efficiency 11 kW permanent magnet synchronous motor without using rare earth (neodymium, dysprosium) materials; the work follows on its 2008 announcement of a prototype 150 W motor that used cores made of amorphous metal coupled with ferrite magnet rotors. (Earlier post.)
Hitachi says the new 11 kW motor has an efficiency of about 93%, and delivers IE4 performance (the highest of the International Efficiency classes—Super Premium Efficiency—defined by IEC 60034-30) from a size smaller than that of a comparable conventional motor. The company is targeting commercialization for industrial applications in 2014.
The earlier 150 W prototype motor showed an efficiency of 86%.
|Arrow points to the amorphous iron core. Source: Hitachi. Click to enlarge.||Laminated structure of the amorphous core. Source: Hitachi. Click to enlarge.|
The new 11 kW double-rotor, axial-gap motor uses a laminated stator core based on a low-loss amorphous iron material. Hitachi says that the losses from its laminated material are about 10% of those of conventional electromagnetic steel laminations.
Amorphous metal has a disordered atomic structure in contrast to the crystalline structure of conventional metals, and features a high tensile strength and extremely low magnetic losses. As such, it has been a target of interest for motor development for decades. Its adoption, however, has been hampered by the cost of manufacturing—an issue which Hitachi says it is addressing.
To optimize the efficiency of the laminated design, Hitachi used 3D magnetic field analysis software to analyze the various characteristics of the core laminations.
Hitachi developed the technology with support from Japan’s New Energy and Industrial Technology Development Organization (NEDO).