EV & HEV Drive System Technology Expo 2012
Nidec displays permanent magnet-less SR motor, capacitors for regenerative systems by Nippon Chemi-C
The 3rd EV & HEV Drive System Technology Expo (The 3rd EV Japan) was held from January 18 to 20, 2012, at the Tokyo Big Sight. Some of the exhibited items are reported below along with certain displays from the co-exhibited Car-Ele Japan (International Automotive Electronics Technology Expo). There will be a separate report on the Automotive Weight Reduction Expo that was also held simultaneously.
Motor technologies exhibited at the 3rd EV Japan included the permanent magnet-less SR (switched reluctance) motor by Nidec, and the motor drive system QMET-II by Yaskawa Electric using a switchable winding wire motor. Displays of particular appeal regarding the EV and HEV technologies included the electrically-driven intelligent brake system coordinated with regenerative braking exhibited by Hitachi Automotive Systems.
Exhibited at the Car-Ele Japan included the electric double-layer capacitors being supplied by Nippon Chemi-Con Corporation for Mazda's deceleration energy regenerating system.
Motors: Permanent magnet-less SR motors by Nidec, motor drive system QMET-II by Yaskawa Electric
Nidec exhibited the SR motor that uses permanent magnet-less rotor, scheduled for commercial production starting around 2013. Yaskawa Electric exhibited the motor drive system, QMET-II, based on a switchable winding wire motor of a broader efficiency range.
Meidensha, a supplier of motors and inverters for Mitsubishi, exhibited motors and inverters currently in the process of development. Shicoh and Mitsuba exhibited their in-wheel motors.
SR motor by Nidec
Panel showing the SR motor specs (enlarge)
Nidec: Permanent magnet-less SR motor
|SR motor||A permanent magnet-less switched reluctance (SR) motor allowing volume production at low costs (see Notes). The steel-made rotor is lightweight and highly responsive. It has maximum output of 44 kW and maximum torque of 86N･m. Volume production is scheduled to start around 2013 after the company finds ways to keep high efficiency not only in high ranges near 10,000 rpm but also in lower ranges below 5,000 rpm.|
|(Notes) 1.||The SR motor uses reluctance. A stator made of an electromagnet continuously pulls on the rotor made of steel to generate a rotary motion. This principle has been in existence since the 19th century but the use of SR motors is limited because of the torque ripple and resulting noise.|
|2.||In September 2010, Nidec acquired motors and controls business of Emerson Electric Company, a US corporation that is said to have half the titles of international patents about SR motors.|
Yaskawa Electric: Motor drive system QMET-II
|QMET-II is the second-generation of Yaskawa's motor drive system, announced in January 2012 that uses a switchable winding wire motor. Low-speed motors are often characterized by high torque available in low ranges but not in high ranges. Likewise, high-speed motors are known for high-speed revolutions and unavailable high torque in low ranges. By introducing a winding wire switching mechanism, the motor combines the characteristics of low- and high-speed motors offering high torque in low ranges and high-speed revolutions with an extended efficiency range.|
|Weight reduction||QMET-II is smaller and lighter (23% less volume, 43% less mass) than the first generation.|
|Non-rare earth||Volume production of rare earth-free, permanent-magnet synchronous motors is planned (sample shipment to start in November 2012).|
|Platforming||Standardization of core motor drive technologies, shared parts and modularization result in a broader lineup. This allows the user to have customized motor design and interface of the best combination of maximum torque and maximum speed of revolution.|
(Note) The first-generation QMET was announced in June 2009. The switchable winding wire motor technology was developed for machine tools that form Yaskawa's main business.
QMET-II motor by Yaskawa Electric
QMET-II inverter by Yaskawa Electric
|Capacity||Product||Type of vehicle||Sample shipment||Volume production|
|120 kW class||QMET-II||Sedan (1.6L-), bus, truck||July 2012||After spring of 2013|
|80 kW class||QMET-II||Compact car (1-1.5L class)||April 2012-|
|50 kW class||QMET-II, YMEV||Minivehicle||June 2012-|
|30 kW class||YMEV||June 2012-|
(Note) YMEV is a small capacity drive motor system without the switchable winding wire announced in January 2011 by Yaskawa Electric.
Meidensha: Motors and inverters for Mitsubishi Motors and those being developed
|Motors and inverters for MINICAB-MiEV||Meidensha exhibited its motors and inverters alongside a cutaway-model of MINICAB-MiEV, a commercial minivehicle released for sale by Mitsubishi Motors in December 2011. The motors and inverters are used on the MINICAB-MiEV. The motor has a maximum power of 30kW/2,500-6,000rpm and maximum torque of 196N･m/0-300rpm.|
|Motors and inverters being developed||Meidensha's motors and inverters being developed for EV/PHV/HV were also exhibited. Their specs (see below) are there for reference only and will be tuned to OEM's needs. Samples will be available in 2013 at the earliest.|
Meidensha's motor for next EV model
Meidensha's inverter for next EV model
Specs of motors and inverters being developed (reference only)
|Mass||Max. rating||Max. rpm||Volume|
|Minivehicle class (30-40kW)||25kg||30kW-75Nm-3,820rpm||12,000rpm||3.5L|
|Small car class (50-60kW)||35kg||60kW-150Nm-3,820rpm||12,000rpm||4.6L|
|Mid-size car class (80-90kW)||40kg||80kW-200Nm-3,820rpm||12,000rpm||6.5L|
Shicoh: In-wheel motor with a hollow rotor
|Shicoh develops and sells compact coreless motors and compact generators. It exhibited an in-wheel motor (see Note), based on a coreless motor for compact generators, developed primarily for minivehicles. The motor has 5kW power and features a hollow rotor to accommodate the brake or other components inside.|
|The coreless motor on which the in-wheel motor is based has a stator made of copper sheet in the place of the conventional copper-wire winding. The result is a motor characterized by 1) light weight and high density, power and rigidity, 2) outstanding heat dissipation and 3) extremely smooth rotation.|
(Note) Shicoh calls it "wheel-in motor."
Shicoh's in-wheel motor with a hollow rotor
Mitsuba: Motors for microcommuter EV
|Mitsuba, a manufacturer of automotive electric components, exhibited in-wheel motors used in the microcommuter i-TT2 of Gunma Micro EV Association. The outer rotor type 3-phase brushless motor has a maximum revolution of 9,400rpm, rated output of 0.3kW and mass of 3kg.|
Mitsuba's motor for microcommuter EV
EV and HEV-related systems: Electrically-driven intelligent brake system coordinated with regenerative braking exhibited by Hitachi Automotive Systems, on-board chargers exhibited by Nichicon
Hitachi Automotive Systems exhibited a hybrid system and an electrically-driven intelligent brake system coordinated with regenerative braking that combined hydraulic brake. Nichicon exhibited an on-board charger. Nidec Tosok exhibited an electrically-driven oil pump designed for cooling motors.
Motor generator for the Chevrolet Volt
Inverter for the Chevrolet Volt
Hitachi Automotive Systems: Hybrid system
|Hybrid system||Hitachi Automotive Systems exhibited a motor generator, an inverter and lithium-ion batteries to demonstrate its capability to supply all key components of a hybrid system.|
|Motor generator||The motor generator supplied for GM's Chevrolet Volt (see Note). High power output from a compact design results from high-density concentrated winding and compact connection structure.|
|Inverter||The inverter supplied for GM's Chevrolet Volt. The car uses a driving inverter and a built-in inverter for auxiliary systems as well that increases the overall downsizing. The improved cooling system has increased heat dissipation to cope with higher-output hybrid systems.|
|Li-ion battery||Lithium-ion battery module, designed for GM's mild hybrid system e-Assist, has 32 cells of LIB-III lithium-ion battery in it.|
(Note) The GM Chevrolet Volt uses two motors and both are supplied by Hitachi Automotive Systems. The product on display is the motor that doubles as a generator.
Hitachi Automotive Systems: Electrically-driven intelligent brake system coordinated with regenerative braking
|Electrically-driven intelligent brake system coordinated with regenerative braking||The brake system provides a coordinated control of the regenerative brake driven by a drive motor and an ordinary hydraulic brake and is used on Nissan's LEAF EV and Fuga HV. The system comprises an electrically-controlled brake actuator (e-ACT), ESC, stroke sensors, and calipers with electrically-driven parking brake function.|
|The brake pedal effort is converted into an electric signal by a magnet type contactless stroke sensor. The on-board computer uses the signal and calculates the necessary amounts of braking on the regenerative brake and the hydraulic brake.|
|The required hydraulic pressure is generated when the ball screw of the e-ACT is driven by a motor. The ball screw and the brake pedal are ordinarily not connected directly.|
Electrically-driven intelligent brake system coordinated with regenerative braking
Nichicon: On-board chargers for Nissan LEAF and Mitsubishi i-MiEV
|On-board chargers for EV||The on-board charger, used on the Nissan LEAF, is connectable to all types of electric grids all over the world (input voltage of 100VAC to 264VAC) and has maximum charging efficiency of 90%, output of 3.3kW and output voltage of 200V to 410V. The water-cooling system is integrated with the charger.|
|DC-DC converter integrated with on-board charger for EV||The DC-DC converter integrated with on-board charger, used on the Mitsubishi i-MiEV, has the same basic performance as the charger for the LEAF above. The DC-DC converter has an input voltage of 200 to 410V, output voltage of 14V and output current of 80 to 120A. Cooling water runs between the charger and the converter.|
Nichicon's on-board charger for the Nissan LEAF
Nichicon's DC-DC converter integrated with on-board charger for the Mitsubishi i-MiEV
Nidec Tosok: Electric oil pump
|Electric oil pump||The electric oil pump being developed by Nidec Tosok features a pump housing made of iron rather than the conventionally used aluminum to reduce friction torque (to be protected by patents). The company also manufactures inverters that go with the pump. The compact electric oil pump is integrated with the inverter.|
(Note) The electric oil pump is used to cool the driving motor or to maintain necessary hydraulic pressure in the transmission when the start-stop system operated.
Nidec's electric oil pump
Capacitors: Low-resistance electric double-layer capacitor exhibited by Nippon Chemi-Con, lithium-ion capacitors exhibited by Shin-Kobe Electric Machinery
Nippon Chemi-Con Corporation exhibited electric double-layer capacitors developed for Mazda's deceleration energy regeneration system. The company plans to develop general-use capacitors for roll-out to other automakers. Shin-Kobe Electric Machinery exhibited lithium-ion capacitors slated for volume production to start in the spring of 2012.
Electric double-layer capacity module supplied by Nippon Chemi-Con for Mazda
DXE series of third-generation electric double-layer capacitors by Nippon Chemi-Con
|Nippon Chemi-Con||Electric double-layer capacitor DLCAP for Mazda||Capacitors supplied for Mazda's deceleration energy regeneration system i-ELOOP (see Note) were exhibited (modules are also assembled by Nippon Chemi-Con). The capacitors feature one third of the internal resistance compared to the previous type to increase high-current charge/discharge capability. Heat resistance too has been raised from 60 to 70 degrees Celsius to allow mounting in the engine room.|
|DXE series||The capacitors, developed for Mazda vehicles, will be tuned as general-purpose components (third-generation DXE series) for automotive, solar power generation and other applications for volume production starting in FY2012. The company will also develop capacitors with heat resistance raised to 85 degrees Celsius.|
|Shin-Kobe Electric Machinery||Lithium-ion capacitor||Lithium-ion capacitors feature higher input/output, longer life and higher heat resistance (80 - 90 degrees Celsius) than the electric double-layer capacitors. Volume production will start in the spring of 2012 for industrial application in the order of several tens of thousands of cells. Those for automotive use will be combined with lead batteries to increase durability of the start-stop systems and contribute to increasing fuel efficiency.|
|Lithium-ion capacitors cost 3 to 4 times more today compared to electric double-layer capacitors. Some of the parts of the lithium-ion capacitors can be shared with the company's lithium-ion batteries and the company thinks cost reduction is possible once full production starts for the lithium-ion capacitors.|
|Nichicon||Electric double-layer capacitor||The (screw terminal type) electric double-layer capacitors used primarily by energy industries were on display. Nichicon highlighted ultra-low resistance modules and high-power density capacitors. The capacitors are not supplied for automotive application at present.|
(Note) Mazda's concept car, Takeri, with i-ELOOP debuted at Tokyo Motor Show in December 2011. The car is scheduled for market launch in 2012.
Lithium-ion capacitors by Shin-Kobe Electric Machinery
Electric double-layer capacitors by Nichicon
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