Mitsubishi Electric Y Series Manual page 163

PWM control
Y-Series EP R2-Series EP WY-Series
Y-Series P R2-Series P WR2-Series
PWM control is used to control the number of motor revolutions
according to operational load. It varies the inverter pulse width
(electric signal wave occurring over a short period) to control the
output.
Optimal control of electrical current is required according to
operation.
• For low loads
Does not require a high target output current.
Output voltage
0 A
AC
0 V
• For high loads
Requires a high output current.
0 A
AC
0 V
Pulse-on width increases
Flat-tube heat exchanger
Y-Series EP R2-Series EP
The flat-tube heat exchanger delivers high heat exchange efficiency. The use of flat tubes increases the number of piping
stages while maintaining the same size of heat exchanger. The inside of the tube is divided into thin compartments to
increase the area of contact between the refrigerant and air, and thereby increase heat exchange effectiveness and
significantly improve energy-saving performance. The flat-tube heat exchanger improves heat exchange effectiveness by
approximately 30% compared to round-tube heat exchangers.
• Round-tube heat exchanger
Air Air
Air Air
Air Air
Round-tube shape
Target output current
Output
current
Time
Pulse width is adjusted
Output current
is increased
Time
• Flat-tube heat exchanger
Air Air
Air Air
Air Air
Air Air
Flat-tube shape
TECHNOLOGY INTRODUCTION
Control HIC*
*Hybrid Integrated Circuit
To achieve the target output current, the intervals
at which the "pulse" signal is turned on are
controlled to adjust the output current.
At low load time, the pulse-on width is minimized
to save energy.
The increased pulse-on width increases both the
duration that the voltage is applied and the amount
of electrical current compared to the low load time,
and accelerates the rotation speed of the
compressor from 60 rps to 140 rps.*
*The number of compressor rotations differs depending on the usage
condition.
The ability to adjust the pulse range and output
current to suit a given load increases the
operating range of the unit.
Approximately 30% increase
in heat-exchange efficiency
(compared to the round-tube)
220% increase in surface
area
(compared to the round-tube)
(Illustration)
163