Axpert 3KVA-110V User manual

SERVICE MANUAL
3KVA-110V/120V
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Table of contents
1. General information.............................................................................................................................................. 3
1.1 Getting start................................................................................................................................................. 3
1.2 Basic topology introduction....................................................................................................................... 3
1.3 Inverter family.............................................................................................................................................. 4
1.4 Overview the inverter................................................................................................................................. 4
1.5 PCB overview.............................................................................................................................................. 5
2. Troubleshooting.................................................................................................................................................... 7
2.1 How to do..................................................................................................................................................... 7
2.2 Check the fault information....................................................................................................................... 7
2.3 Fault condition............................................................................................................................................. 7
2.4 Test step....................................................................................................................................................... 8
3. Checking and measuring guide.......................................................................................................................... 9
3.1 Check the battery side components........................................................................................................ 9
3.2 Check the bus side components............................................................................................................ 16
3.3 Check the buck circuit.............................................................................................................................. 18
3.4 Check the INV full bridge ........................................................................................................................ 20
3.5 Check the PWM SCC board................................................................................................................... 22
3.6 Check the MPPT SCC board.................................................................................................................. 23
4. Disassembling guide.......................................................................................................................................... 24
4.1 Open the case........................................................................................................................................... 24
4.2 Remove the control board....................................................................................................................... 25
4.3 Remove the fans...................................................................................................................................... 26
4.4 Remove the MPPT board........................................................................................................................ 28
4.5 Remove the main board.......................................................................................................................... 29
5. Cables connection.............................................................................................................................................. 31

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1. General information
1.1 Getting start
This manual is used as a checking and repairing guide for 3KVA-110V/120V model. Before read this
manual, it’s better to have some electrical or electronic background knowledge. With this guide, you can
fix the inverter by yourself firstly.
There are five main parts of this guide:
General information: This part is the basic information of the inverter; you can start to know the inverter
from this chapter.
Troubleshooting: This part will tell you how to do when you face a problem.
Checking and measuring guide: This part will teach you how to check or repair the inverter by
measuring the critical components.
Assembling guide: This part teaches you how to take the board outside and fix the new one.
Cables connection: This part is a reference for cable connection.
1.2 Basic topology introduction
The topology of the inverter shows as below:
Solar charger
Battery
Load
Utility
Solar Inverter
Converter
Control
SCC board Main board
CNTL board
Parallel
PAR board
(Option)
Compare with UPS or normal inverter, INVERTER combines a solar charger inside. Solar charger can be
a supplement for battery when there is not grid or for saving energy purpose. And with the solar charger,
the inverter can have more working modes than UPS. For detail information please refer to our user
manual.

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1.3 Inverter family
This service manual includes different models of the inverter, the table as below contains some important
parameters with different models.
These models names are only neutral names; please match the real model name of your inverter to the model
name in the table by comparing the typical characteristics.
Model name
Power rating
Solar charger
type
Solar charger
number
Off-grid/Hybrid
Inverter with PWM 3KVA
3KVA/2.4KW
PWM
1
OFF-grid
Inverter with MPPT 3KVA
3KVA/2.4KW
MPPT
1
OFF-grid
1.4 Overview the inverter
MPPT board
Control board
Main board
LCD LED
PWM 3KVA
is without
MPPT board

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1.5 PCB overview
Main board (MPPT):
Control board terminal
Power
supply
BUS soft start
power supply
Grid
connection
To MPPT board
Solar
connection
ISO TX
ISO TX
Load
connection
Battery
connection
Main board (PWM):
Control board terminal
Power
supply
BUS soft start
power supply
Grid
connection
PWM SCC
block
Solar
connection
ISO TX
ISO TX
Load
connection
Battery
connection

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Control board:
CPU
To LCD
To LED
To Parallel To Comm
To SCC
MPPT SCC board:
Solar connection
Battery connction

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2. Troubleshooting
2.1 How to do
When the inverter was faulty, normally there are two main symptoms:
No display at all;
Fault code or warning code on the LCD;
When the fault occurred, please help to record the fault information and follow “How to check” of part 2.3
to check the inverter, then feedback the checking result to the service center. It will be very helpful for
solving the problem as soon as possible.
2.2 Check the fault information
Please follow the steps as below to find the issues!
Make sure that you can finish all the steps and feedback us the results. Or we may not be able to
give you the right solution.
Step 1: Test the battery working mode.
Before turning on the inverter, only connect the battery with the inverter which means no solar input and
grid input. Turn on the switch, the LCD will light up and wait for the battery connecting to load.
If the connection is failed, please record the fault code.
Step 2: Test the grid charging mode.
Before turning on the inverter, only connect the utility and battery with the inverter. Without press any
buttons, the LCD will light up.And wait for the utility connecting to battery.
If the connection is failed, please record the fault code.
Step 3: Test the solar charging mode.
Before turning on the inverter, only connect the solar and battery with the inverter. Without press any
buttons, the LCD will light up.And wait for the solar connecting to battery.
If the connection is failed, please record the fault code.
2.3 Fault condition
Note:
When open the top cover, please have a look first, are there any obviously damaged parts?
When take the main board out, please have a look around, are there any obviously damaged
parts?
2.2.1. Not working at all/ No display
Description
The inverter couldn’t startup completely.
Possible reason
1. SPS module damaged.
How to check
1. Firstly, please measure the resistor between BAT+ and BAT-. If it is not shorted,
only connect the inverter with battery, and press “ON” button, could the inverter
startup? If not, please check the fan.
2. If the LCD couldn’t light up and fan doesn’t work, please disconnect all the wires
and open the top cover, and then take the main board outside by following part 4.

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How to solve
Replace the main board.
2.2.2. 09 fault
Description
Bus soft start fails.
Possible reason
DC-DC module was damaged.
How to check
Check the main board by following “3.1~3.4”;
How to solve
Repair the main board or replace it directly.
2.2.3. 56 fault
Description
Battery couldn’t be detected.
Possible reason
Wire connection or fuse was burnt.
How to check
1. Check the wire connection, the priority of the battery cable;
2. Check the main board by following “3.1”.
How to solve
Repair the main board or replace it directly.
2.4 Test step
After replacing all defected components, testing steps can be used to confirm the repair result and the
reliability of the Inverter.
Set up the testing system as below:

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3. Checking and measuring guide
3.1 Check the battery side components
Fuse and capacitors
F3
Parts
Attribute
Reference values
Failure status
F3
Resistor
0 ohm
Open
C18/C13/C8
If the capacitors explode as below, they need to be replaced.

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Power devices
DC/DC MOSFET: Q11/Q17/Q20/Q24 & Q38/Q21/Q22/Q12 & Q13/Q18/Q23/Q19 & Q40/Q26/Q25/Q14
Parts
Attribute
Reference values
Failure status
All:
Resistor1
GS: 11.7k
GD: 250k
DS: OL
Short or explosion
Diode
SD: 0.43V
DS: OL
Note1: When you use the multimeter to measure the resistor of the transistor, because of the capacitor in
the circuit, it will cause the changing of the values when you measure the DS and GD. So we recommend
you measure the diode forward voltage of SD, and the resistor of GS. These two values can reflect the
situation of the transistor more correctly.
Note: If one or more of them were damaged, please replace all of them.

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3.1.1. Drivers (This part is only used for repair checking)
Note: Drivers usually need to be checked when users want to repair the boards. Because when power
devices were damaged, the high voltage will rush to driver circuit through the gates of power devices.
The reference of the resistors list as below:
R41/R59/R70/R76/R80/R78/R75/R42/R52/R62/R81/R64/R93/R92/R87/R53
Use multimeter to measure each resistor, find the burnt resistors and replace them; don’t need to replace
them all.
Parts
Attribute
Reference values
Failure status
All: 22ohm
Resistor
22 ohm
Open or other values
If the resistors need to be replaced, please also check the driver transistors and control IC.

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The Q46and Q48 are 11-300012-00G (TR 2A50V NPN TO-92)
The Q47and Q49 are 11-300005-00G (TR 2A50V PNP TO-92NL)
The Q41and Q43 are 11-300012-00G (TR 2A50V NPN TO-92)
The Q15and Q16 are 11-300005-00G (TR 2A50V PNP TO-92NL)
Parts
Attribute
Reference values
Failure status
Q46/Q48/Q41/Q43
Resistor
BE: 420k
BC: 420k
CE: 30k
Short or explosion
Diode
BE: 0.6V
BC: 0.6V
CE: 2.3V
Q47/Q49/Q15/Q16
Resistor
BE: 420k
BC: 420k
CE: 1.2k
Short or explosion
Diode
BE: 0.6V
BC: 2.6V
CE: 0.2V

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The Q54and Q56 are 11-400011-00G (TR 2A 50V SOT-89)
The Q55and Q57 are 11-400010-00G (TR 3A50V SOT-89)
The Q51and Q52 are 11-400011-00G (TR 2A 50V NPN SOT-89)
The Q50and Q53 are 11-400010-00G (TR 3A50V PNP SOT-89)
Parts
Attribute
Reference values
Failure status
Q54/Q56/Q51/Q52
Resistor
BE: 12k
BC: 260k
CE: OL
Short or explosion
Diode
BE: 0.6V
BC: 0.6V
CE: OL
Q55/Q57/Q50/Q53
Resistor
BE: 12k
BC: OL
CE: 277k
Short or explosion
Diode
BE: 0.6V
BC: OL
CE: 1.09V

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The Q60 and Q61 are 11-420007-00G (MOSFET 5.8A 30V SOT-23)
Parts
Attribute
Reference values
Failure status
Q60/Q61
Resistor
GS: 5.637k
GD: 12k
DS: 35k
Short or explosion
Diode
SD: 0.184V
DS: 1.2V

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Parts
Attribute
Reference values
Failure status
U9
Resistor
PIN13 TO PIN12: 22k
PIN11 TO PIN12: 432k
PIN14 TO PIN12: 432k
Short or explosion
Note: If you are not sure about these components, we recommend you replacing them all.

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3.2 Check the bus side components
Power devices
DC/DC IGBT: Q27/Q28/Q29/Q30
Parts
Attribute
Reference values
Failure status
Q27/Q28/Q29/Q30
Resistor1
GE: 22 ohm
GC: 181k
CE: 1 Meg
Short or explosion
Diode
EC: 0.37V
CE: OL
Note1: When you use the multimeter to measure the resistor of the transistor, because of the capacitor in
the circuit, it will cause the changing of the values when you measure the CE and GE. So we recommend
you measure the diode forward voltage of EC, and the resistor of GE. These two values can reflect the
situation of the transistor more correctly.
Note: If one or more of them were damaged, please replace all of them.

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Drivers (This part is only used for repair checking)
Meanwhile, we also need to check the driver tubes of these power tubes.
Parts
Attribute
Reference values
Failure status
R91/R102/R96/R101
Resistor
22 ohm
Open or other values
R90/R99/R94/R97
Resistor
0 ohm
D32/D35/D33/D342
Resistor
+ to -: 240k
- to +: OL
Short or explosion
Diode
+ to -: 0.6V
- to +: OL
Note2: When test the diode; please remove the R90/R99/R94/R97 from the board, or the test result is not
right.

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3.3 Check the buck circuit
Power devices
BUCK MOSFET and Diode: Q32/D13
Parts
Attribute
Reference values
Failure status
Q32
Resistor
GS or GE: 23.5k
GD or GC: 273k
DS or CE: 800k
Short or explosion
Diode
SD or CE: 0.44V
DS or EC: OL
D13
Resistor
+ to -: 168k
- to +: OL
Diode
+ to -: 0.36V
- to +: OL

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Drivers (This part is only used for repair checking)
Parts
Attribute
Reference values
Failure status
R125
Resistor
47 ohm
Open or other values
R124
Resistor
10 ohm
D38
Resistor
+ to -: 240k
- to +: OL
Short or explosion
Diode
+ to -: 0.6V
- to +: OL
Note: When test the diode; please remove the R124 from the board, ortherwise the test result is not right.

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3.4 Check the INV full bridge
Power devices
INV IGBT: QA1/QC1/QB2/QD2
Parts
Attribute
Reference values
Failure status
QA1/QC1/QB2/QD2
Resistor
GE: 23k
GC: 235k
CE: 900k
Short or explosion
Diode
EC: 0.4V
CE: OL
Note1: If one or more of them were damaged, please replace all of them.

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Drivers
Parts
Attribute
Reference values
Failure status
R48/R144/R140/R137
R139/R145/R150/R152
Resistor
47 ohm
Open or other values
D5/D6/D12/D161
Resistor
+ to -: 240k
- to +: OL
Short or explosion
Diode
+ to -: 0.6V
- to +: OL
Optocoupler: U1/U2/U3/U4/U12