C h a p t e r 2
With the growing emphasis on
sustainability, regulatory compliance, and
extended operational lifetimes, power
efficiency has become a top concern
for motor control systems. For example,
regulatory standards such as ENERGY
STAR
®
mandate high efficiency levels
and have compelled manufacturers
to optimize motor control systems for
minimal energy waste. Meanwhile, battery-
powered systems face the additional
constraint of limited energy reserves,
requiring every component to contribute
to extending battery life.
Power efficiency in motor control involves
two primary aspects: the efficiency of the
motor and the efficiency of the power
inverter stage.
Motors inherently incur losses because
of resistance in the winding and other
conversion inefficiencies. As motors
convert electrical energy into mechanical
energy, a portion of that energy is
inevitably lost as heat.
Within the power stage, the efficiency
of components such as metal-oxide-
semiconductor field-effect transistors
(MOSFETs) comprising the inverters is
notable. Factors like switching losses,
conduction losses, deadtime losses, and
gate driver losses significantly impact
overall performance. For instance,
MOSFETs' drain-source on-resistance
(R
DS(on)
) determines conduction losses,
which become a substantial factor in
high-current applications. Similarly, a
MOSFET's total gate charge determines
POWER EFFICIENCY
Lei Han
Principal Systems Engineer, Qorvo
High temperatures increase
resistive losses in motor
windings and degrade efficiency.
Effective thermal management is
key to maintaining performance
in these scenarios."
11
10 Experts Discuss the Fundamentals of Motor Control
