Development of High Speed Motor and Inverter for Electric Supercharger 2013-01-0931
In recent years, the fuel consumption improvement of automobiles
is indispensable due to the global move to reduce CO₂ emissions.
Downsizing of engines by turbocharger obtains the output equal to a
large engine, and improves the fuel consumption. However,
turbocharger has the response delay called turbo lag. In order to
improve a transient response, we developed a high-speed motor. The
electric supercharger consists of high-speed motor and compressor,
and drives compressor by high-speed motor instead of an exhaust gas
turbine. By combining conventional turbocharger and electric
supercharger, we developed two-stage turbocharger system.
In this paper, we explained development of high-speed motor and
inverter. And, as application example, we explained electric
two-stage turbocharger system. The high-speed motor and inverter
are connected without harness, and assembled in one single unit.
The motor is driven at high efficiency by vector control. The
performance test shows a high speed response of 0.7 sec
acceleration time from zero to maximum speed 90,000 rpm. Electric
two-stage turbocharger, applying high-speed motor, is evaluated by
engine simulation tool (GT-Power) and engine bench test. As a
result of engine test using a 1.5-liter gasoline engine, the
electric two-stage turbocharger demonstrated the 43% improvement in
a response time at 1500 rpm, compared with normal two-stage
turbocharger. This experiment shows that electric supercharger is
effective to improve transient response. It is expected to
contribute ever tightening CO₂ reduction with automobile engines
from now on.