Voltronic Power Axpert MKS-4000 User manual

Axpert MKS-4000/KS-5000 Service manual
1
Axpert MKS Charger/ Inverter
Service manual

Axpert MKS-4000/KS-5000 Service manual
2
Revision
Description
Prepared
by
Approved
by
V00
Initial draft release
Fredricker
2013-11-4

Axpert MKS-4000/KS-5000 Service manual
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Table of contents
1. General information.......................................................................................................................................... 4
1.1 Getting start............................................................................................................................................ 4
1.2 Important safety instructions ............................................................................................................... 4
2. Functional block................................................................................................................................................ 6
3. Working principle of the major functional block............................................................................................ 7
3.1 Switch Power Supply............................................................................................................................ 7
3.2 DC TO DC dual converter (Full bridge converter)............................................................................ 8
3.3 Inverter (Full bridge)............................................................................................................................. 8
3.4 Buck converter....................................................................................................................................... 9
3.5 MPPT solar chager............................................................................................................................... 9
4. Functional explanations for each PCB......................................................................................................... 11
4.1 Main board........................................................................................................................................... 11
4.2 Cntl board............................................................................................................................................. 11
4.3 SCC board ........................................................................................................................................... 11
4.4 COMM board....................................................................................................................................... 12
4.5 LED board............................................................................................................................................ 12
4.6 MPPT board......................................................................................................................................... 12
5. Interface............................................................................................................................................................ 12
5.1 LED Indicator....................................................................................................................................... 12
5.2 LCD Display Icons .............................................................................................................................. 14
6. Troubleshooting............................................................................................................................................... 17
6.1 Fault Reference Code........................................................................................................................ 17
6.2 Warning Indicator................................................................................................................................ 18
6.3 Trouble shooting according to fault indication................................................................................ 18
6.4 Quick start............................................................................................................................................ 20
7. Test Step........................................................................................................................................................... 23
8. Electrical specification.................................................................................................................................... 24
Table 1 Line Mode Specifications .................................................................................................................. 24
Table 2 Invert Mode Specifications............................................................................................................... 25
Table 3 Charge Mode Specifications............................................................................................................. 26
Table 4 General Specifications....................................................................................................................... 26
Charging Controls............................................................................................................................................ 26

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1. General information
1.1 Getting start
This manual is for Axpert MKS 4KVA-5KVA series, it can help service personal perform the basic
maintenance and repair service.
This manual focus on the service, so you should get the basic operation of the Inverter/Charger from the
user manual, and make sure you had read and understood user manual before you use this service
manual.
The manual include 8 sections, as follows
General Information, this section show you the general information of the service manual
Functional Block, this section show you the major functional block of the Inverter/Charger
Working Principle of the major Functional Block, this section show you the major functional block
Function explanations for each PCB, this section show you all the PCBs of the Inverter/Charger
Interface, this section show you the LCD interface, include display and setting
Trouble shooting, this section will give you the way to find the trouble
Test step ,this section tell you how to test the Inverter/Charger after you repair the unit
Electric Specifications, this section show you the basic electric specification of the Inverter/Charger
1.2 Important safety instructions
WARNING: This chapter contains important safety and operating instructions. Read and
keep this manual for future reference.
1. Before using the unit, read all instructions and cautionary markings on the unit, the batteries and
all appropriate sections of this manual.
2. CAUTION --To reduce risk of injury, charge only deep-cycle lead acid type rechargeable batteries.
Other types of batteries may burst, causing personal injury and damage.
3. Do not disassemble the unit. Take it to a qualified service center when service or repair is required.
Incorrect re-assembly may result in a risk of electric shock or fire.
4. To reduce risk of electric shock, disconnect all wirings before attempting any maintenance or
cleaning. Turning off the unit will not reduce this risk.
5. CAUTION –Only qualified personnel can install this device with battery.
6. NEVER charge a frozen battery.
7. For optimum operation of this inverter/charger, please follow required spec to select appropriate
cable size. It’s very important to correctly operate this inverter/charger.
8. Be very cautious when working with metal tools on or around batteries. A potential risk exists to
drop a tool to spark or short circuit batteries or other electrical parts and could cause an explosion.
9. Please strictly follow installation procedure when you want to disconnect AC or DC terminals.

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Please refer to INSTALLATION section of this manual for the details.
10. Fuses (40A, 32VDC *4pcs for 1KVA/2KVA and *6pcs for 3KVA) are provided as over-current
protection for the battery supply.
11. GROUNDING INSTRUCTIONS -This inverter/charger should be connected to a permanent
grounded wiring system. Be sure to comply with local requirements and regulation to install this
inverter.
12. NEVER causeAC output and DC input short circuited. Do NOT connect to the mains when DC
input short circuits.
13. Warning!! Only qualified service persons are able to service this device. If errors still persist after
following troubleshooting table, please send this inverter/charger back to local dealer or service
center for maintenance.

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2. Functional block
Axpert MKS 4KVA-5KVA series production employ a double conversion topology, comprise following
functional blocks, as shown in figure 2.1.
MPPT Solar Charge
Controller
DC/AC Inverter
AC/DC Rectifier
DC/DC Converter
Charger
DC Fuse
Input Breaker
Thermal Switch Protection
to
NTC Sensor
to
NTC Sensor
Reverse Polarity Protection
Safety Relay
Load Detection
PV+
PV-
LI/P
NI/P
LO/P
NO/P
Battery +
Battery -
Inverter Relay Output Relay
Isolation
to
NTC Sensor
Figure 2.1 function block diagram

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3. Working principle of the major functional block
3.1 Switch Power Supply
The switch power supply (SPS) supplies DC power for Inverter/Charger operation. The input voltage of
the SPS is the battery orAC Charger output voltage.
Figure 3.1 basic circuit of power supply
This is the fly-back DC-DC converter, fly-back operation can be easily recognized from the position of the
dots on the transformer primary and secondary(these dots show starts of the winds). When Q36 is ON,
the dot ends of all winds are negative with respect to their no-dot ends. Output rectifier diodes D54, D57,
D67 and D70 are reverse-biased and all the output load currents are supplied from storage filter
capacitors C78, C75, C79 and C116.The primary coil of the transformer acts as an inductor and stored
energy.
When Q36 is OFF, the stored energy in the primary coil is delivered to secondary filter capacitors C78,
C75, C79 and C116.
As shown in figure 3.1, this circuit may generate several output voltage, such as +12V,-12V, +15V, +5V,
HFPW+.

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3.2 DC TO DC dual converter (Full bridge converter)
The full bridge topology is a transformer isolated forward-mode regulator. Unlike the
Fly-back transformer, the push-pull transformer does not store any energy and output current is drawn
when either power switches (S1-S4 or S2-S3) is conducting. P1 is the battery, P2 is the BUS
This is dual converter, it means that battery can feed power to BUS and also BUS can charge the battery.
And it is an open loop control: the transformer N1:N2 is 1:8, when the battery voltage is transformed
through the converter to more than the BUS voltage, the battery discharge power to the BUS, or the BUS
can charge the battery.
Figure 3.2 DC TO DC dual converter
3.3 Inverter (Full bridge)
The Inverter circuit (Figure 3.3) and PWM control are can both active under battery mode and line mode.
In line mode, the inverter can convert power from gird to BUS for charging .The Inverter circuit of Axpert
series is based on a full-bridge circuitry and its output is driven by photo-couplers. The photo-couplers are
capable to drive high energy and high speed power of MOSFET and IGBT with independent high and low
referenced output channels.
To construct a high frequency PWM inverter, the drivers receive switching signals from PWM generation
circuit through a pair of photo-couplers to trigger the upper IGBT and the lower IGBT alternately. The
output of IGBT's is filtered by an LC circuit to reduce the o/p voltage harmonics distortion.

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L
N
VBUS
+
-
Q1Q2
Q3Q4
L1
L2
Figure 3.3 Full-bridge topology
3.4 Buck converter
The Buck circuit (Figure 3.3) is active only when the line charging the battery. When the battery is
discharging, S12 is ON, and S10 is OFF, D10 is reversed cut off, L15 is used as a filter inductor.
Figure 3.4 Buck topology
3.5 MPPT solar chager
It employed an interleave buck converter, comprise following functional blocks, as shown in figure as
below.

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Figure 3.5 MPPT topology

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4. Functional explanations for each PCB
Item
Series name
PCB name
PCB serial number
Quantity
Remark
1
KS4000
Main
71-500264-XXG
1
2
SCC
71-500244-XXG
1
3
COMM
71-500245-XXG
1
4
LED
71-500238-XXG
1
5
CNTL
71-500251-XXG
1
6
MPPT
71-500362-XXG
1
1
KS5000
Main
71-500352-XXG
1
2
SCC
71-500244-XXG
1
3
COMM
71-500245-XXG
1
4
LED
71-500238-XXG
1
5
CNTL
71-500XXX-XXG
1
6
MPPT
71-500362-XXG
1
Note: “XX” in the serial number is the version of the PCB.
4.1 Main board
The main board consists of SPS, DC-DC converter, inverter. Many semiconductors and easy-failure
components on the board, so it should be play more attention when the system is abnormal.
4.2 Cntl board
The cntl board consists of AD sample, MCU control and communication module. It control the other module work
orderly.
4.3 SCC board
The solar current control (SCC) board based on a PW control mode .When the solar source is presented,
battery charged from solar source; MAX charge current is 50A if solar panel with enough energy.

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4.4 COMM board
This inverter/charger is equipped with a communication port to communicate with a PC with
corresponding software. Please use supplied communication cable to connect to communication port of
this inverter and RS-232 port of the PC.
4.5 LED board
The LED display panel includes there indicators and four functional keys.
4.6 MPPT board
The MPPT board consists of SPS, BUCK converter, MCU control. It integrated the MOSFET driver board
and SPS driver board on it. Many semiconductors and easy-failure components on the board, so it should
be play more attention when the system is abnormal.
5. Interface
The operation and display panel, shown in below chart, is on the front panel of the inverter. It includes
three indicators, four function keys and a LCD display, indicating the operating status and input/output
power information.
5.1 LED Indicator
LED Indicator
Messages
LCD display
LED indicators
Function keys

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Green
Solid On
Output is available in bypass mode
Flashing
Output is powered by battery in inverter mode
Green
Solid On
Battery is fully charged
Flashing
Battery is charging.
Red
Solid On
Fault mode
Flashing
Warning mode

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Function Keys
Function Key
Description
ESC
Exit setting mode
UP
To previous selection
DOWN
To next selection
ENTER
To confirm the selection in setting mode or enter setting mode
5.2 LCD Display Icons
Icon
Function description
Input Source Information
Indicates the AC input.
Indicates the PV input
Indicate input voltage, input frequency, PV voltage, battery voltage and
charger current.
Configuration Program and Fault Information
Indicates the setting programs.
Indicates the warning and fault codes.
Warning: flashing with warning code.
Fault: lighting with fault code
Output Information

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Indicate output voltage, output frequency, load percent, load in VA and
load in Watt.
Battery Information
Indicates battery level by 0-24%, 25-49%, 50-74% and 75-100% in battery
mode and charging status in line mode.
In AC mode, it will present battery charging status.
Status
Battery voltage
LCD Display
Constant
Current mode
/ Constant
Voltage mode
<2V/cell
4 bars will flash in turns.
2 ~ 2.083V/cell
Bottom bar will be on and the other three
bars will flash in turns.
2.083 ~ 2.167V/cell
Bottom two bars will be on and the other
two bars will flash in turns.
> 2.167 V/cell
Bottom three bars will be on and the top
bar will flash.
Floating mode. Batteries are fully charged.
4 bars will be on.
In battery mode, it will present battery capacity.
Load Percentage
Battery Voltage
LCD Display
Load >50%
< 1.717V/cell
1.717V/cell ~ 1.8V/cell
1.8 ~ 1.883V/cell
> 1.883 V/cell
50%> Load > 20%
< 1.817V/cell
1.817V/cell ~ 1.9V/cell
1.9 ~ 1.983V/cell
> 1.983
Load < 20%
< 1.867V/cell
1.867V/cell ~ 1.95V/cell
1.95 ~ 2.033V/cell
> 2.033

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Load Information
Indicates overload.
Indicates the load level by 0-24%, 25-50%, 50-74% and 75-100%.
0%~25%
25%~50%
50%~75%
75%~100%
Mode Operation Information
Indicates unit connects to the mains.
Indicates unit connects to the PV panel.
Indicates load is supplied by utility power.
Indicates the utility charger circuit is working.
Indicates the DC/AC inverter circuit is working.
Mute Operation
Indicates unit alarm is disabled.

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6. Troubleshooting
This section describes how to find the trouble when the system is abnormal. We suggest you can follow
the service procedure:
a. Check the system status by LED and LCD display, the sounds of buzzer.
b. Observe the failure board, static checking.
c. Replace the failure components.
d. Static checking.
e. Power up checking.
f. Test after repair.
Following section will help service person to solve most of problem.
6.1 Fault Reference Code
Fault Code
Fault Event
Icon on
01
Fan is locked
02
Over temperature
03
Battery voltage is too high
04
Battery voltage is too low
05
Output short circuited or Over temperature
06
Output voltage is abnormal
07
Over load time out
08
Bus voltage is too high
09
Bus soft start failed
11
Main relay failed
51
Over current inverter
52
Bus soft start failed
53
Inverter soft start failed
54
Self-test failed

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55
Over DC voltage on output of inverter
56
Battery connection is open
57
Current sensor failed
6.2 Warning Indicator
Warning
Code
Warning Event
Audible Alarm
Icon flashing
01
Fan is locked
Beep three times every
second
03
Battery is over charged
Beep once every
1second
04
Low battery
Beep once every 1
second
07
Overload
Beep once every 0.5
second
10
Power limitation
Beep twice every 3
seconds
6.3 Trouble shooting according to fault indication
Problem
LCD/LED/Buzzer
Explanation / Possible cause
What to do
Unit shuts down
automatically
during startup
process.
LCD/LEDs and
buzzer will be active
for 3 seconds and
then complete off.
The battery voltage is too low
(<1.91V/Cell)
1. Re-charge battery.
2. Replace battery.
No response after
power on.
No indication.
1. The battery voltage is far too
low. (<1.4V/Cell)
2. Battery polarity is connected
reversed.
1. Check if batteries and the
wiring are connected well.
2. Re-charge battery.
3. Replace battery.
Mains exist but the
unit works in
battery mode.
Input voltage is
displayed as 0 on
the LCD and green
LED is flashing.
Input protector is tripped
Check if AC breaker is
tripped and AC wiring is
connected well.
Green LED is
flashing.
Insufficient quality of AC power
(Shore or Generator)
1. Check if AC wires are too
thin and/or too long.
2. Check if generator (if
applied) is working well, or
check if input voltage range

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setting is correct
(UPSAppliance)
Green LED is
flashing.
Set Solar power as the priority of
output source
Change output source
priority to Utility first.
When the unit is
turned on, internal
relay is switched
on and off
repeatedly.
LCD display and
LEDs are flashing.
Battery is disconnected.
Check if battery wires are
connected well.
Buzzer beeps
continuously and
red LED is on.
Fault code 07.
Overload error. The inverter is
loaded with more than 110%
load and time is up
Reduce the connected load
by switching off some
equipment.
Fault code 05.
Output short circuited.
Check if wiring is connected
well and remove abnormal
load.
Temperature of internal
converter component is over
120°C.
Check whether the air flow
of the unit is blocked or
whether the ambient
temperature is too high.
Fault code 02.
Internal Inverter component over
100°C
Fault code 03.
Battery is over charged.
Return to repair center.
The battery voltage is too high.
Check if spec and quantity
of batteries are meet
requirements.
Fault code 01.
Fan fault
Replace the fan.
Fault code 06.
Output abnormal (Inverter
voltage below than 190Vac or is
higher than 260Vac)
1. Reduce the connected
load.
2. Return to repair center
Fault code 08.
Internal components may be
failed.
1. Restart the inverter
again.
2. If the problem still exists,
please return to repair
center.
Fault code 09.
Fault code 11
Fault code 51
Fault code 52
Fault code 53
Fault code 54
Fault code 55
Fault code 56
Battery is disconnected.
Check if battery wires are
connected well.
Fault code 57
Internal components may be
failed.
1. Restart the inverter
again.
2. If the problem still exists,
please return to repair
center.

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6.4 Quick start
Before any detail check of the system, please check the components listed as follow table.
NOTE: It is important to check the capacitor’s voltage on the board lower than the safety voltage before
any check action.
Functional
block
Checked components
Instruction
function
Reference value
Failed status
DC-DC Converter
Fuse
F1/F2/F3/F4/F5
Resistance
0.14 ohm
short or open
MOSFET(IRFB3307)
Q13/Q18/Q23/Q19
Q11/Q17/Q20/Q24
Q38/Q21/Q22/Q12
Q40/Q26/Q25/Q14
Resistance
>490k DS
short or open
271k GD
short or open
11.74k GS
short or open
Diode(30DQ60BG)
D13
Resistance
>24K
short or open
Driver NPN /PNP
Q51/Q52/Q54/Q56
Resistance
11.9K PIN1-2
short or open
Q50/Q53/Q55/Q57
11.9K PIN1-3
short or open
BUCK MOS
Q32/Q31
Resistance
>280K DS
short or open
39K GD
short or open
17K GS
short or open
Driver IC
UC3525
Resistance
>400K
PIN14-PIN13/12
PIN12-PIN13/11
short or open
IGBT(IRGP4063)
Q27/Q28/Q29/Q30
Resistance
>340K CE
short or open
184K GC
short or open
22.5 ohm GE
short or open
Resistance
R52/R62/R81/R64
R41/R59/R70/R76
R80/R78/R75/R42
R93/R92/R87/R533
R91/R96/R102/R101
Resistance
22 ohm
short or open
R55/R60/R79/R63
R45/R58/R68/R69
R77/R73/R74/R46
R86/R85/R88/R56
R95/R89/R100/R101
Resistance
47K
short or open
R1/R4/R47/R20
R51/R49/R61/R54
Resistance
10 ohm
short or open
R17/R44/R50/R57
Resistance
200 ohm
short or open