Application of Sine Wave DC Inverter
Technology in Air Conditioner
Headquarter of Haier Air Conditioner Co., Ltd
1
Content
•
Key energy-saving technology of air conditioner
•
Comparison of 120°square wave and 180°sine wave in
control part
•
Technical feature of Haier 180 °sine wave
•
Test results
2
Energy consumption of air con
89% of the energy is consumed by compressor.
compressor 89%
outdoor fan 5%
indoor part 5%
Others 1%
Rating running
0
100
200
300
400
500
Power input [W]
outdoor fan 11%
indoor part 10%
compressor 76%
compressor
Others 3%
Lowing loading running
0
100
200
300
400
500
Power input [W]
motor
Energy
Energy saving
saving of
of compressor
compressor is
is the
the key
key issue
issue for
for the
the energy
energy saving
saving of
of aircon
aircon
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The key technology of energy-saving air conditioner 1
Temp control wave for DC inverter and on/off machines
ON/OFF Type
It needs more time to reach
the setting temperature
Inverter Type
Increasing speed of
compressor so as to reach
the setting temperature
in a shorter time.
To decrease speed of compressor
to maintain a certain temperature
Feature of inverter
Providing a comfortable room space
DC machines can adjust the room temp at very small range, so it can assure the small temp
changing.
Energy-saving
DC machines can adjust the compressor running speed, when just starting, running at high speed,
fast cooling, when nearly to setting temp, reducing running speed, so that reducing compressor
power, so it can save energy.
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Comparison of 120°square wave and 180°sine wave in control part
(1)
●Coil have some period with no
current,
●Torque is disturbed largely, has
large electromagnetism noise
●Harmonic wave part is large
●Compressor has low efficiency
●All period have current, with high
efficiency,
●Torque is smooth, electromagnetism
noise is small
●Harmonic wave is small
●Compressor has high efficiency,
expecially in mid-high speed
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Comparison of 120°square wave and 180°sine wave in control part
(2)
Efficiency comparability of 120°square wave and 180 °sine wave
Motor run speed
Efficiency improvement of sine wave
30Hz
+0.9
50Hz
+2.3
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Detection method for Current DC motor
Sup
Svp
Sun
Svn
Svp
Swp
Sun
Svn
Swn
Swp
Power
supply
VDC
Sup
PM
Swn
Iu
power
supply
PM
IDC
Iw
Iu
(a) CT method
Iv
Iw
(b) 3-shunt method
Sup
Svp
Swp
Sun
Svn
Swn
power
supply
PM
RDC
IDC
(c) 1-shunt method
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Feature 1; High Reliability
Feature 2; High-efficiency control (for Saving Energy)
(1) Demagnetizing Protection Double Over Current Protection
(2)High Efficiency PFC
Motor Voltage
(4) Maximum Torque/Current
Ratio Control
Motor Current Minimum
kE
kE2
−
+ Iq2
Id = −
2
2 Ld − Lq
4 Ld − Lq
(
(6)Special
Start
Sequence
)
(
(5)Torque Control
(for reducing
compressor
vibration)
)
(3)Weakening magnet Control
( Improve the efficiency running
range)
k
1
Id = − E +
Ld Ld
V0m 2
ω12
(
- Lq I q
)2
Heating
Cooing
Starting
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Motor Speed
(1)Current protection of compressor demagnetization
Advantage: Double current protection, can efficiently protect
compressor not to be demagnetized, extending compressor life
The rotor of DC compressor is permanent magnet, if the
compressor current exceed one point, even if the short current
strike can cause demagnetization, decreasing the compressor life
or breaking compressor.
Normal overcurrent protection for DC aircon only protects the
virtual value of current, could not check the peak value of the
current and protect it, so could not avoid the demagnetization
efficiently.
Haier 180°sine wave DC inverter have not only the n ormal
compressor overcurrent protection, but also have special
demagnetization protecting circuit, can check the compressor peak
value current quickly, and protect compressor before reaching
demagnetizing current, so that can avoid compressor
demagnetizing efficiently.
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(2) High Efficiency PFC
Advantage: reducing Harmonic wave of the current, increasing power factor
new-active PFC. Value of current can decide the on and off of the PFC, can reducing
power consumption efficiently at same time, reducing EMI.
Current wave when PFC is off:
Current sudden change is serious, di/dt is
large, so there is a lot of harmonic wave,
high order harmonic wave is serious.
Current wave when PFC is on:
Current sudden change is small, di/dt is
small, so the current harmonic wave is
small and high order harmonic wave is
weak.
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(3) Weakening magnet Control
Advantage: do weak magnet control when the voltage reaches
saturation, can expend running speed range of compressor
,
Id
D
D :
kE
1
Id = −
+
Ld Ld
V0m=Vam−r ⋅ Iam
Vam , I:am
,
V0m 2
ω12
(
- LqI q
)2
Iq
Vmax
Formula of Min
Current
∆Id1
+
+
+
Id instruction
V instruction
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(4) Maximum Torque/Current Ratio Control
Advantage: Control Maximum torque/current in steady condition.
When in same torque, current is Min, so it can reducing power
and improving efficiency
When in certain moment and speed, the relationship of motor
current lm and exciting current ld is as following chart. When Im is
in min, the relationship of Id and Iq is in following:
I‚ Ť
kE
kE2
−
+ Iq2
Id = −
2 Ld − Lq
4 Ld − Lq 2
(
) (
)
Min Im
Id
Relationship of exciting current Id
and motor current Im
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(5)Low Frequency Torque Control
Advantage: reducing vibration of single rotary inverter compressor at
low frequency, increasing the range of running frequency.
.
,
,
,
.
,
,
,
.
Low frequency Moment control wave of single rotary compressor:
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(6)Special Start Sequence
Advantage: special compressor start technology, can reduce the
possibility of failure compressor start.
60
-120
120
180
-60
0
Point
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(7)High reliability of IPM Module
Advantage: adding temp protecting function, can
protect IPM not to be broken due to overheating .
Haier IPM of DC inverter adopts the fourth smart
IPM from Mitsubishi. Besides of short circuit
protecting, under-voltage protecting for normal
IPM, Haier IPM adds inside temp protecting. When
the inside temp of IPM is on abnormity, units will
be protected and stopped. Solved the
phenomenon when reactor and IPM is connected
not so well, temp of reactor is not high, but IPM
temp is so high, so that the IPM will be broken.
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Development of Haier DC inverter
1. In 1993, Haier made the first set of inverter aircon in China. In1998,
Haier made the first DC inverter aircon in China. From 2005, Haier
began to adopt 180 sine wave technology to DC inverter machines.
Now in 2008, Haier has adopted this 180 sine wave technology to all
DC inverter machines. In these 15 years development and update,
technology of Haier DC inverter is nearly maturity and perfect. Haier
Invests world-class air conditioner specialists and spends 5 years to
develop this special technology, now Haier DC inverter machines are
sold to all of Europe, it belongs to the advanced project of International
DC inverter technology, has reached Japanese top-ranking DC inverter
level.
2. Haier has full series of DC inverter machines. From split type,
cabinet type, split 1 by 2, split 1 by 3, cabinet and split mixed 1 by 2.
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Test results
Start waves
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TEST RESULT 30Hz
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TEST RESULT 40Hz
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TEST RESULT 60Hz
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TEST RESULT 70Hz
21
TEST RESULT 90Hz
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TEST RESULT 100Hz
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Thank You!
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