1. TECHNICAL TRAINING
2008

2. Inverter Mini Chiller
System and Control

3. Content
1. Introduction
2. Basic Inverter Technology
3. Components
4. Control Algorithm
5. Protection

4. Introduction

5. Introduction
5ACV100/135/210 CR
5ACV55/75 CR
5ACV30 CR

6. Introduction Model Capacity (kW) Cooling Heating 5ACV030CR 7.94 9.66
14.65
16.12
5ACV075CR
20.52
21.99
5ACV100CR
27.80
29.30
5ACV135CR
38.54
41.47
5ACV210CR
58.62
61.55

7. Introduction New Technology BPHE- True Dual Circuits
Conventional Back to Back Circuits BPHE
Secondary Circuit
Primary Circuit 1
Primary Circuit 2
5ACV True Dual Circuits BPHE
Primary Circuit 1
Primary Circuit 2

8. Introduction
Inverter Compressor
Conventional System
Inverter System

9. Introduction Elimination of Water Tank Modular Installation
Inverter system provide constant Water Temperature band, or much lesser water temperature fluctuation. With this, water tank of mini chiller system can be eliminated
Modular Installation
A network up to 50 chillers in a system is possible. Control on the operation of chillers will be done through the microprocessor controller. The external water piping connection can be made either from the left or right side of the unit.
Safety Protection
High & Low Pressure Switches
Anti Freeze Protection Sensor
Discharge Temperature Sensor
Over Pressure Relief Valve
Water Pressure Differential Switch
Anti Freeze Heater on BPHE
Compressor, Water Pump Overload Protector

10. Basic Inverter Technology

11. Basic Inverter Technology
The system:-
Power supply
Input frequency
50Hz
Inverter t1 u
AC/DC
Rectifier
DC/AC
Inverter t t
50 Hz
15 Hz
100 Hz
(compressor motor input)
PWM

12. Basic Inverter Technology
Three-phase inverter
PWM control
Power supply unit
Compressor
(Waveform formation)
AC Inverter Unit
Three-phase induction motor AC DC
Temperature detection signal
Operating frequency signal

13. Basic Inverter Technology
Inverter Basic Structure
Inversion
PLC Control
Rectification AC
DC Link Converter
PWM Signal
SMPS M

14. Basic Inverter Technology
Rectification Circuit
EMI filter to minimize emission effect (EMC) and raise immunity level (EMS)
PTC to cushion start-up current to capacitor
Diode bridge inverts AC to DC
EMI Filter
Rectifier Bridge
PTC Starter
Relay

15. Basic Inverter Technology
DC Stage
PFC capacitor acts to curb PF losses caused by DC voltage fluctuation in order to drive the asynchronous motor
PFC Capacitor
Reactor
Stabilizing Capacitor
Diode

16. Basic Inverter Technology
Inversion Circuit
Consists of 6 IGBT (Insulated Gate Bipolar Transistor)
Controlling the ON/OF linkages, different frequency and voltage of 3-phase AC can be generated
IPM (Intelligent power module) encased the inversion circuitry together with error detection and protection features

17. Soft-start. No current surge Yes, operates at high freq.
Basic Inverter Technology
Advantages of Inverter Air Conditioners
Item
Fixed Speed AC
Inverter AC
Energy Saving No
Yes, by 30% - 40%
Temp. Fluctuation
± 2°C
± 0.5°C
Adjust to Load
Yes
Start-up
Current surge of 7-11x
Soft-start. No current surge
Full Load Op.
Yes, operates at high freq.
Speed of Cool/Heat
Slow
Fast
Defrosting
Less efficient
Accurate and fast
Protection Features
Basic
Complete
Auto-Mode Features

18. Components

19. Components Fan guards Coil guards fan motors
Heat exchangers with gold fin as standard
Expansion tank ( 8L)
True dual circuits BPHE (Brazed plate heat exchanger)
Control box assembly
Water pump

20. Components High pressure switch (NC) 600 psi – open, 480psi – close.
Low pressure switch
(NC) 18 psi – open, 28 psi – close.
Pump OLP (overload protector)
Differential pressure switch
Over pressure relief valve
Anti freeze heater on BPHE
Compressor OLP (overload protector)
Chiller panel controller
Fixed speed scroll compressor (R410A)
Variable drive system compartment
Fixed drive system compartment
Variable speed scroll compressor (R410A)

21. Components Control box assembly 3 phase rectifier bridge diode
IPM board
(Intelligent power module)
Main board
Magnetic
contactors
EMI filter
Capacitor board
PFC capacitor
(Power factor correction)
Uni-directional bridge diode
3 phase rectifier bridge diode
Fan capacitors
Power board
EMI filter - EMI filter is a device placed between the power source and control device circuit.
Prevents external electromagnetic interference from getting into the controller. Prevents internally
generated electromagnetic emission from polluting the supply grid.
EMI filter verification - Resistance between A-A’, B-B’, C-C’ & N-N’ should be 0 ohm.
Resistance between A-B, A-C, B-C should be about 1360kohm. Resistance between A-N, B-N,
C-N should be about 680kohm. Resistance between A, B, C, N and casing should be infinity.
3 phase rectifier - To convert AC to DC current.
Uni-Directional bridge
PFC capacitor - To raise power factor to about 0.9. Testing - use dial type multimeter to measure
the circuit, the resistance should gradually increase from zero to rated resistance.
Capacitor board - Supply to power board.
IPM - Invert DC to AC current, drive variable compressor.
Electronic starter (PTC Thermistor) - PTC electronic starter and relay combination acts to
cushion the excessive charge current because of high capacitor charge current during start up.
Testing - Use multimeter to check the resistance of electronic starter on sheet metal at ambient
temperature is 40+/-20%ohm. Resistance of electronic starter on PCB is 47+/-20%ohm. When
current exceeds 10A rated level, the temperature of PTC resistor will rise and increase the
resistance to restrict current increase.

22. Components EMI Filter Function
EMI Filter is a device placed between the power source and control device circuit.
Prevents external electromagnetic interference from getting into the controller.
Prevents internal electromagnetic emission from polluting the supply grid.
EMI filter - EMI filter is a device placed between the power source and control device circuit.
Prevents external electromagnetic interference from getting into the controller. Prevents internally
generated electromagnetic emission from polluting the supply grid.
EMI filter verification - Resistance between A-A’, B-B’, C-C’ & N-N’ should be 0 ohm.
Resistance between A-B, A-C, B-C should be about 1360kohm. Resistance between A-N, B-N,
C-N should be about 680kohm. Resistance between A, B, C, N and casing should be infinity.
3 phase rectifier - To convert AC to DC current.
Uni-Directional bridge
PFC capacitor - To raise power factor to about 0.9. Testing - use dial type multimeter to measure
the circuit, the resistance should gradually increase from zero to rated resistance.
Capacitor board - Supply to power board.
IPM - Invert DC to AC current, drive variable compressor.
Electronic starter (PTC Thermistor) - PTC electronic starter and relay combination acts to
cushion the excessive charge current because of high capacitor charge current during start up.
Testing - Use multimeter to check the resistance of electronic starter on sheet metal at ambient
temperature is 40+/-20%ohm. Resistance of electronic starter on PCB is 47+/-20%ohm. When
current exceeds 10A rated level, the temperature of PTC resistor will rise and increase the
resistance to restrict current increase.

23. Components
Main Board
For Model 55, 75, 100 & 135
For Model 30

24. Components Power Board
To convert rectified DC current +590VDC to respective desired voltages
12VDC relay
MCU +5VDC
IPM +15VDC
Ensure stability of above voltages within power supply voltage fluctuation range ( VAC)
Over voltage feedback
Output short circuit protection

25. Components
Capacitor Board

26. Components IPM Function Invert DC to AC current
Drive variable compressor
In-Built Protection
Low voltage lock-out
Over-heating, over-current and short-circuit protection.

27. Components Schematic Diagram
1. Variable drive discharge temperature sensor (Disch temp 1)
variable compressor discharge temperature protection and system superheat correction sampling input.
2. Coil in temperature sensor (Cond In Temp 1)
sampling input not applicable during cooling . Only for heating.
3. Coil out temperature sensor (Cond Out Temp 1)
normally common sampling point for defrosting. Sampling input for over-temperature protection during cooling, and sampling input for superheat and defrost control.
4. BPHE In temperature sensor (BPHE In Temp)
sampling input not applicable during cooling. During heating, inputs for superheat control and high pressure protection control.
5. BPHE Out temperature sensor (BPHE Out Temp)
sampling input for low temperature evaporation point protection and sampling input for superheat control during heating.
6. Suction temperature sensor (Suct Temp)
sampling input for superheat/subcool control during heating/cooling.
7. High/low pressure switch (HP1, LP1)
sampling input for high/low load pressure for variable drive system. Similar for fixed drive system.
8. Fixed drive discharge pressure sensor (Disch Temp2)
overheating protection for fixed drive.
9. Coil temperature sensor
sampling input for high chilled temperature protection during cooling and defrosting during heating.
10.High/low pressure switch (HP2, LP2)
sampling point for high/low load pressure for fixed drive system.

28. Control Algorithm

29. Clash between current & selected mode of operation?
Control Algorithm
General Control Flow Chart
Start No
Stop Inverter Comp
Yes
Stop pump
60s
Clash between current & selected mode of operation?
Cooling mode
Heating?
Heating mode
System On?
Cooling?
10s
Stop Fixed Comp

30. Control Algorithm Variable Drive Compressor Control Cooling mode
Start up condition :
Pump runs normally for 3 minutes *
For example :
Return water temp.= 14 to 16 °C
Set temp = 12°C
D T = 2 to 4°C
2°C £ T water return – T set £ 4°C
No irreversible errors in variable drive and the systems
Satisfy a delay of 3 minutes before restart #
Note : If fixed drive system starts first, the variable drive system should trail after 30 sec.
* Depends on Parameter P2 (flow switch alarm delay at pump start. Min 0s, max 199s, default 180s )
# Depends on Parameter C2 (compressor min stop time. Min 0s, max 1990s, default 180s)

31. Control Algorithm Variable Drive Compressor Control Cooling mode
Cooling mode selected  water pump starts  Outdoor fan starts  variable drive compressor starts
Rated Freq.
55Hz
5Hz t
3 min
5 sec
1 min ON
OFF
Variable drive comp
Outdoor fan
Increase to rated frequency with the rate of 1Hz/s
5ACV100CR=75Hz
5ACV135CR=95Hz
Inverter compressor will start from 5Hz to 55Hz and maintain this frequency for 1 min.
Outdoor fan will start 5 sec before compressor start

32. Control Algorithm Variable Drive Compressor Control Cooling mode
Shut down condition :
Cooling mode terminates, OR
Variable drive system error occurs, OR
T water return – T set £ -2°C
For example :
Return water temp.= 10°C
Set temp = 12°C
D T = -2°C

33. Fixed drive starts first followed by variable drive
Control Algorithm
Fixed Drive Compressor Control
Cooling mode
Start up condition :
Pump runs normally for 3 minutes *
For example :
Water return temp = 16°C
Set temp = 12°C
DT = 4°C
T water return – T set > 4°C
Fixed drive starts first followed by variable drive
No irreversible errors in fixed drive and the systems
Satisfy a delay of 3 minutes before restart #
Note : If variable drive system starts first, the fixed drive system will only start after the frequency of variable drive drops to 50Hz.
* Depends on Parameter P2 (flow switch alarm delay at pump start. Min 0s, max 199s, default 180s )
# Depends on Parameter C2 (compressor min stop time. Min 0s, max 1990s, default 180s)

34. Control Algorithm Fixed Drive Compressor Control Cooling mode
Cooling mode selected  water pump starts  Outdoor fan starts  compressor starts
Fixed drive compressor starts
Fixed drive comp
Outdoor fan
1 min
3 min
5 sec ON
OFF
Outdoor fan will start 5 sec before compressor start
Outdoor fan will stop after compressor has stopped for 1 min

35. Control Algorithm Fixed Drive Compressor Control Cooling mode
Shut down condition :
Cooling mode terminates, OR
Fixed drive system error occurs, OR
T set - T water return > 2°C and variable frequency drops pass 20Hz
For example :
Set temp = 12°C
Water return temp = 10°C
DT = 2°C

36. Control Algorithm Variable Drive Compressor Control Heating mode
Start up condition :
Pump runs normally for 3 minutes *
For example :
Set temp = 40°C
Return water temp.= 36 to 38 °C
D T = 2 to 4°C
2°C £ T set - T water return £ 4°C
No irreversible errors in variable drive and the systems
Satisfy a delay of 3 minutes before restart #
Note : If fixed drive system starts first, the variable drive system should trail after 30 sec.
* Depends on Parameter P2 (flow switch alarm delay at pump start. Min 0s, max 199s, default 180s )
# Depends on Parameter C2 (compressor min stop time. Min 0s, max 1990s, default 180s)

37. Control Algorithm Variable Drive Compressor Control Heating mode
Heating mode selected  water pump starts  Variable drive 4WV engages  Outdoor fan starts  compressor starts
Increase to rated frequency with the rate of 1Hz/s
Rated Freq.
45Hz
5Hz t
3 min
10 sec
1 min ON
OFF
Variable drive comp
Outdoor fan
Variable 4WV
5 sec
5ACV100CR=65Hz
5ACV135CR=90Hz
Inverter compressor will start from 5Hz to 45Hz and maintain this frequency for 1 min.
Variable drive 4WV start 10 sec before compressor start
Outdoor fan will start 5 sec before compressor start

38. Control Algorithm Variable Drive Compressor Control Heating mode
Shut down condition :
Heating mode terminates, OR
Variable drive system error occurs, OR
T set - T water return £ -2°C
For example :
Set temp = 40°C
Water return temp = 42°C
DT = -2°C

39. Control Algorithm Fixed Drive Compressor Control Heating mode
Start up condition :
Pump runs normally for 3 minutes *
For example :
Set temp = 40°C
Water return temp = 36°C
DT = 4°C
T set - T water return > 4°C
No irreversible errors in fixed drive and the systems
Satisfy a delay of 3 minutes before restart #
Note : If variable drive system starts first, the fixed drive system will start after the variable drive frequency drops to 50Hz.
* Depends on Parameter P2 (flow switch alarm delay at pump start. Min 0s, max 199s, default 180s )
# Depends on Parameter C2 (compressor min stop time. Min 0s, max 1990s, default 180s)

40. Control Algorithm Fixed Drive Compressor Control Heating mode
Heating mode selected  water pump starts  Fixed drive 4WV engages  Outdoor fan starts  compressor starts
Fixed drive compressor starts
3 min
10 sec
1 min ON
OFF
Fixed drive comp
Outdoor fan
Variable 4WV
5 sec
Fixed drive 4WV start 10 sec before compressor start
Outdoor fan and 4WV will stop after compressor has stopped for 1 min
Outdoor fan will start 5 sec before compressor start

41. Control Algorithm Fixed Drive Compressor Control Heating mode
Shut down condition :
Heating mode terminates, OR
Fixed drive system error occurs, OR
T water return - T set > 2°C
For example :
Water return temp = 42°C
Set temp = 40°C
DT = 2°C

42. Control Algorithm Pump Control Pump start up Pump shut down
When starting the system, pump will run for 3 minutes * before proceeding to next step.
* Depends on Parameter P2 (flow switch alarm delay at pump start. Min = 0s, Max = 199s, default = 120s)
Pump shut down
After both compressors shut down for 1 minute, pump shuts down.

43. Protection

44. Compressor Over-Current Protection
Variable drive compressor
When variable drive compressor current reaches the Ib, over-current
protection triggers and the compressor frequency will reduce.
When the compressor current drops into Ic to Ib, frequency will not increase.
When the compressor current drops below the Id, frequency variation resumes.
When compressor current increase rapidly and reaches the Ia, the
system will be determined as compressor overload and stop the compressor.
Comp amp
(A)
Variable compressor stops Ia
Frequency step down Ib
Maintain frequency Ic Id
Normal Operation

45. Protection Compressor Over-Current Protection
Variable drive compressor
Inv Comp Current
M5ACV030
M5ACV055
M5ACV075
M5ACV100
M5ACV135
M5ACV210 Ia 29
20.5 Ib 27 18 Ic 25 17 Id 16

46. Protection Compressor Over-Current Protection Fix drive compressor
When fixed compressor current > Ie. The compressor will stops and resumes after 3 minutes
Note: When either drive overload protection occurs more than 3 times within 30 minutes, system triggers irreversible error protection.
Comp amp
(A)
Fixed compressor stops Ie

47. Protection High Discharge Temperature Protection Variable drive system
When variable drive discharge temperature reaches 110°C, system stops.
When variable drive discharge temp. between 100°C and 110°C, frequency drops.
When variable drive discharge temperature is less than 97°C and more than 100°C,
frequency increased restricted.
When discharge temperature falls below 94°C, normal operation resumes.
System shuts down
Frequency step down
Maintain frequency
Normal operation
Compressor
discharge
temperature
110°C
100°C
97°C
94°C

48. Protection High Discharge Temperature Protection Fixed drive system
When fixed drive discharge temperature reaches 110°C, system stops.
When discharge temperature falls below 94°C for 3 minutes, system resumes.
Td = Compressor discharge temperature Td
110°C
Comp Cut
94°C
Comp start
3 min

49. Protection Outdoor Coil High Temperature Protection
Variable drive system
During cooling, when Tcoil1 > 60 °C, frequency drops.
During cooling, when Tcoil1 < 55 °C, system resumes.
Fixed drive system
During cooling, when Tcoil2 > 64°C, compressor stops.
During cooling, when Tcoil2 < 51°C, system resumes.

50. Protection Low Pressure Switch Protection
Alarm delayed at compressor startup : 30 sec depends on Parameter P3*.
No protection during defrosting.
If variable drive or fixed drive low pressure switch is activated for 5 seconds, alarm will be triggered.
* Parameter P3 (Low pressure alarm delay at compressor start up. Min=0s, max=199s, default=30s)
Note : If low pressure alarm occur more than 3 times within 30 minutes, system shuts down to irreversible error.

51. Protection High Pressure Switch Protection
If fixed drive high pressure switch is activated for 30 sec, alarm will be triggered.
If variable drive high pressure switch is activated, frequency of variable drive compressor will decrease at 1Hz/s. If it is re-activated for 30 sec, alarm will be triggered.
Note : If high pressure alarm occur more than 3 times within 30 minutes, system shuts down to irreversible error.

52. Protection 3 Phase AC Phase Sequence Protection
If 3 phase AC phase sequence is incorrectly connected, system will not start and controller will indicate error. System will resume after rectification. (except M5ACV030CR)
3 Phase AC Phase Missing Protection
If phase missing happens, system will not operate. Controller will indicate error. System will resume after rectification.

53. Thank You