Santerno SINUS MV User manual

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MV DRIVE USER MANUAL
SINUS MV
ELETTRONICA SANTERNO SPA

About This User Manual
This book is only used for SINUS MV series standard Medium Voltage Variable Frequency Drive of Santerno
S.P.A
Technical Support
If you encounter any problem about SINUS MV series Medium Voltage Variable Frequency Drive, please
contact with Santerno S.P.A technical service.
ELETTRONICA SANTERNO SPA
Address: Via della Concia 7 – 40023 Castel Guelfo (BO) Italy
Tel. [phone]
Fax [phone]
E-mail: [e-mail]
Technical support: [phone]
More detailed information of products please visit our
website: www.santerno.com.
Santerno reserves all rights to this manual, also in the event of patent issue or registration of any other industrial
property protection right. Misuse, in particular duplication and forwarding to third parties, is not permitted.
This manual has been checked with due care and attention. However, should the user find any errors, these
should be reported to Santerno.
Entries in this manual may differ from the actual product, please refer to user’s manual within the production.
Santerno reserves rights to improve products and explain of this manual.
Santerno S.P.A All Rights Reserved.

CATALOGUE
INDEX
Chapter 1 Safety Issues....................................................................................................01
1.1 Introduction. ................................................................................................................................................01
1.2 Notations Defined in this Manual................................................................................................................01
1.3 Advice. ........................................................................................................................................................01
1.4 Safety Measures. ........................................................................................................................................02
Chapter 2 Introduction of SINUS MV Standard MV VFD....................................................03
2.1 Features. .....................................................................................................................................................03
2.2 Technical Parameters. .................................................................................................................................07
2.3 Model and Selection notation......................................................................................................................08
2.4 Application Industries and Fields.................................................................................................................08
2.5 Execute Standards and Norms....................................................................................................................10
Chapter3 Introduction of SINUS MV Theory and Hardware. ...............................................11
3.1 Theory. ..........................................................................................................................................................11
3.1.1 Main Circuit. .......................................................................................................................................................12
3.1.2 Power Cell. .........................................................................................................................................................13
3.1.3 Control System. ..................................................................................................................................................16
3.2 Hardware. ............................................................................................................................................................................1 8
3.2.1 Transformer Cabinet. ..........................................................................................................................................18
3.2.2 Control/ Power Cell Cabinet. ...............................................................................................................................2 1
3.2.3 Power Cell. .........................................................................................................................................................23
3.2.4 HMI. ....................................................................................................................................................................24
3.2.5 Cabinet Door Buttons. ........................................................................................................................................24
3.2.6 Precharge Box. ..................................................................................................................................................24
3.2.7 Switchgears (optional). ......................................................................................................................................25
3.2.8 Remote Control Box. .........................................................................................................................................27
3.2.9 Optional Components. .......................................................................................................................................27
4.1 Cables Selection. ...............................................................................................................................................................28
4.1.1 Power Cable Selection. ........................................................................................................................................28
Chapter 4 Wiring & Terminal Definition................................................................................28

4.1.2 Selection of Control, Signal and Communication Cables................................................................................29
4.2 Primary Wiring.................................................................................................................................................29
4.3 Secondary Circuit Wiring..................................................................................................................................31
4.3.1 Terminal Row Above Interface Board..........................................................................................................31
4.3.2 Terminal Row Below Interface Board..........................................................................................................34
Chapter 5 HMI.......................................................................................................................38
5.1 Touch Screen Interface....................................................................................................................................38
5.2 Touch Screen Display Instructions...................................................................................................................38
5.2.1 Monitoring Interface.................................................................................................................................39
5.2.2 Trend Curve............................................................................................................................................36
5.2.3 Function Parameter and System Parameter................................................................................................42
5.2.4 Restore to Default....................................................................................................................................44
5.2.5 Parameter Download and Upload..............................................................................................................44
5.2.6 Fault Record...........................................................................................................................................45
5.2.7 Other Settings.........................................................................................................................................46
5.2.8 Power Cell Status....................................................................................................................................50
5.3 Important Parameter Description.....................................................................................................................52
5.3.1 Run Mode...............................................................................................................................................52
5.3.2 Stop Mode..............................................................................................................................................52
5.3.3 Control Mode..........................................................................................................................................52
5.3.4 Set Mode................................................................................................................................................52
5.3.5 Start Mode..............................................................................................................................................53
5.3.6 Reverse Rotation Running........................................................................................................................53
5.3.7 Motor Rated Frequency and Voltage..........................................................................................................54
5.3.8 Start Frequency and Minimum Frequency...................................................................................................55
5.3.9 Acceleration & Deceleration Time...............................................................................................................55
5.3.10 Cell Bypass...........................................................................................................................................56
5.3.11 Skip Frequency......................................................................................................................................56
5.4 Appendix.........................................................................................................................................................57
Chapter 6 Function Application..............................................................................................68
6.1 The combination of control mode and set mode..............................................................................................69
6.2 Closed Loop Operation................................................................................................ ...................................69
6.3 Synchronous Transfer Switch...........................................................................................................................70
6.4 Rotating Speed Start........................................................................................................................................71
6.5 MV Loss Solution..............................................................................................................................................71
6.6 Instantaneous Power Stop Function.................................................................................................................73
6.7 Torque Lifting....................................................................................................................................................73
6.8 System Bypass Function (recommended)........................................................................................................74
6.9 Master slave control.........................................................................................................................................74

6.10 Low Frequency Oscillation Restrain................................................................................................................75
6.11 Motor overload protection Function.................................................................................................................75
6.12 VFD Speed Loss Prevention Function............................................................................................................76
6.13 Automatic Adjustment Output Voltage (AVR)...................................................................................................77
6.14 Power Cell Bypass and Neutral Point Drift......................................................................................................77
Chapter 7 Transportation, Storage and Installation..................................................................79
7.1 Requirements of Transportation and Storage...................................................................................................79
7.2 Acceptance Inspection......................................................................................................................................79
7.3 Handling............................................................................................................................................................80
7.4 Installation.........................................................................................................................................................81
Chapter 8 Troubleshooting and Maintenance...........................................................................84
8.1 Light Fault Items and Alarm..............................................................................................................................84
8.2 Heavy Fault Items and Alarm............................................................................................................................84
8.3 Normal Problems processing............................................................................................................................85
8.3.1 VFD trip analysis......................................................................................................................................85
8.3.2 VFD normal faults and solutions.................................................................................................................86
8.4 Power Cell Replacement...................................................................................................................................91
8.5 Maintenance..........................................................................................................................................................91
8.5.1 Routine maintenance and inspection..........................................................................................................91
8.5.2 Regular maintenance...............................................................................................................................92
8.5.3 Spare cell maintenance............................................................................................................................92
Appendix A：Emperature Controller of Dry-type Transformer Setting Instruction...........93
Appendix B：MODBUS Communications Protocol...................................................................99

Thanks for using SINUS MV Standard MV VFD manufactured by Santerno!
SINUS MV Standard MV VFD is a kind of MV electrical equipment, personal safety has been fully considered during
the design process. But it is as dangerous as other MV devices. There exists potentially lethal voltage in the
cabinets, and many other internal high power electric elements are all thermally hot to touch, improper operation
will cause personal injury, equipment damage and property loss.
To avoid personal injury and property losses, before starting work on the SINUS MV Standard MV VFD, standard
safety regulations must be read and followed strictly.
Beginning any installation, commission, starting-up and maintenance work under the instructions in this manual,
the SINUS MV Standard MV VFD is safe.
The safety notations dened in this manual are listed as following. The meanings of these notations keep the
same throughout the document:
We will give technical training about installation, commission, operation and maintenance to the related
personnel, and guarantee that everyone understands the safety instructions in this manual deeply. Besides the
safety instructions presented in this manual, the standard safety regulations of electric power industry must be
abided by.
Santerno will not be responsible for the personal injury or property losses caused by the ignoring of safety
instructions.
01
Safety Issues
Chapter 1
Static electricity!—Static electricity protection to avoid damage to electrical components
and equipment.
Caution!—Warnings that notice the operation to prevent signicant damage to the VFD or to
cause personal injury or death to the related personnel.
Comment:—Key information to help study Santerno products.
1.1 Introduction
1.2 Notations Dened in this Manual
1.3 Advice
Danger!—Operations without following instructions can cause personal injury or death.

02
SANTERNO USER MANUAL
The designs and safety instruments of SINUS MV Standard medium voltage VFD is safe with proper installation,
commission, operation and maintenance. To avoid the man-made accidents, the following safety regulations must
be abided by:
1.4 Safety Measures
Caution!
Only qualified individuals/personnel shall install, operate, troubleshoot, and maintain the drive. A
qualied individual is one who passes the strict training and is familiar with the construction and
operation of the equipment and the regulations of electric power industry.
Always working with another person present when testing operating and maintaining of the drive.
Always wearing insulated shoes when commissioning, operating and maintaining.
Preparing MV test pencil, grounding wire, protective rail and caution board before examining or
maintaining the SINUS MV Standard medium voltage VFD.
When connecting the external wires, the related regulations and standards of electric power industry
should be abided by.
To avoid personal injury and property losses, before any operation the safety regulations in this
manual must be read carefully.
SINUS MV Standard MV VFD must be placed at proper environment, and be at a maintainable state.
Only professional individuals are allowed to install, connect or set the parameters of the drive. If
modify parameters, must contact with Santerno to conrm.
In case of VFD failure causing an accident or damage, the user and its designer must consider the
complete safety solutions during the selection of VFD and corollary equipment.
Only restart the drive and switch on the main input power to the equipment after inspection and
maintenance procedures when VFD trip.
There are heating elements in VFD cabinet. Before maintenance, never touch anything within the
cabinets until verify it is neither thermally hot nor electrically alive after turning off the VFD.
●
●
●
●
●
●
●
●
●
●
●

03
Caution!
●
●
●
●
●
●
Static electricity!
Electric devices are sensitive to static electricity. When installing, maintaining, closing or touching
with the elements in VFD cabinet, the related personnel must put on electrostatic-proof bracelet.
Nonprofessionals are not allowed to touch the electric elements.
During the transportation and storage of the electric elements or circuit boards, electrostatic-proof
package must be used.
When installing or touching the circuit boards, hold the rim of the circuit board, avoid touching the
electric elements in the circuit board.
Hazardous voltage may still exist within the cabinets even when the supply power is shut off.
Isolate the VFD reliably (contactor cannot be used as isolator), the inputs and outputs of VFD are
connected with ground, do not touch the components of the main power circuit until conrming
that the charging light is off.
Always work with one hand, wear insulated shoes and gloves.
Never run the drive with cabinet doors open, except for the secondary cabinet.

04
SANTERNO USER MANUAL
Introduction of SINUS MV Standard MV VFD Chapter 2
2.1 Features
SINUS MV Standard MV VFD is manufactured by Santerno. It is equipment for use with medium voltage (synchronous
or asynchronous) AC motor speed adjusting and driving. It has the following functions and features:
●SVPWM control technology has advantages of high control accuracy, fast response, and more than
98% VFD efciency;
● Modular design of power cell, convenient to maintain;
● Wide input voltage range meets the demand of grid;
●Power cells connecting in series topology and wave stacking method, well developed technique and
reliable devices;
●Output voltage has AVR (automatic voltage regulating) voltage stabilizing function of to prevent
damage to motor insulation from over-voltage and reduce the motor wear and tear;
● Torque boost function, raise output voltage & output torque during low frequency running;
● Rotating speed (ying-start) start function, realize the motor restart during rotating, meet the
continuous production requirement;
●Instantaneous power outage function, inverse charging to ensure normal running when the network
loss power in a very short time;
● Auto-start on MV trip, suitable for working conditions like dual power switch and grip voltage loss;
●Synchronous transfer switch function (optional), realize “no disturb” motor switch between grid and
VFD, reduce the impact to equipment and grid;
● Power cell by-pass function (optional), automatically bypass the failure cell without inuence the VFD
running;
●English HMI easy for operation, (eight languages are optional).
●Synchronous motor, synchronous/asynchronous start
●Master-slave function to make multiple VFD control
●Compact design and proper arrangement( possible to do special design according to customer
requirements)
Besides above advantages, SINUS MV Standard MV VFD has the following functions and features:
●Motor over-load protection
●Over-current protection
●Input Phase loss protection

05
●Over-voltage protection
●Over-heat protection
●Current limit function
●Control power fault protection
●Two-path redundancy of control power
● Power cell communicate with controller through optic ber, completely electric isolated
● System running in closed-loop, able to use the expected value of eld controlled volume (such as pressure,
temperature etc.) set by the users to adjust the motor rotating speed automatically. For instance: constant
pressure water supply system can realize pressure constant control
●Multiple communication methods with host computer, isolated RS485 interface, standard MODBUS RTU
communication protocol, PROFIBUS DP (optional), industrial Ethernet communication protocol (optional)
●Accurate fault records, able to search information and locate the faults
●Cabinet door opening alarm function
The power supply input and output of SINUS MV Standard MV VFD meet the most stringent IEEE STD 519-1992
and GB/T14549-1993, no need for a separate input lter, the cost for harmonic elimination is saved for customers.
Because of the high power factor of the system, the compensation device for power factor is not needed, thus the
reactive input and the input capacity are reduced, and the cost for capacity increasing of power grid is minimized.
Using an isolated transformer, the input of SINUS MV Standard MV VFD could be isolated to grid. By phase shifting
of the secondary winding and multi-pulse diode rectier, isolated power can be acquired and supplied for power
cells.（30/36 pulses for 6kV, 54 pulses for 10kV（By using the technique of multi-pulse rectifier, the harmonic
current caused by individual power cell could be eliminated greatly.
Figure 2.1 30 pulse input waveform (CH1 voltage, CH3 current)

The technique of power cell series connecting (namely multiple power cell structure) applied in SINUS MV Standard
MV VFD greatly eliminates the output harmonic content. The output waveform is almost a perfect sine waveform
(see Figure 2-2 and 2-3). Compared with other MV and high power VFDs, it has the following advantages:
● No need of extra output ltering device
●Directly driving the medium voltage AC motor
●No need of motor derating operation
●No dv/dt damage to insulation of motor and cable
●No torque ripple induced by harmonics, and the service life of motors and mechanism devices can be extended
●No cable length requirement when cable voltage drop is in the allowable range
06
SANTERNO USER MANUAL
Fig. 2-2 Line-Voltage Output Waveform Fig.2-3 Current Output Waveform

07
VFD rated power 210~28000kVA ※
For motor power 150~20000kW※
Rated voltage 3.3~11kV（-20%～+5%）※
Rated frequency 50Hz/60Hz（-10%～10%）※
Modulation technique SVPWM
Control power 380VAC，≤30kVA（depend on power level）
Input power factor >0.96
Efciency >95%，for variable frequency part >98%
Output frequency range 0Hz～80Hz ※
Frequency resolution 0.01Hz/ 0.002Hz
Instantaneous over-current
protection 150% protect immediately (customized )
Overload capability 120% ,125s
Current limited protection 10%-150% (1000ms~3s inverse time protection)
Analoginput Three ways 4～20mA/2～10V
(excitation feedback 4～20mA/2～10V included)
Analog output Four ways 4～20mA (two ways xed, two ways optional)
Host communication Isolated RS485 interface, ModBus RTU,
Probus DP(optional), Industry Ethernet Protocol (optional)
Acceleration and
deceleration time 5s～1600s( related to load)
DI 14 inputs/22 outputs
Environment temperature -5～＋45℃※
Storage/transportation
temperature -40～＋70℃※
Cooling forced air cooling
Humidity <95%, no condensation ※
Altitude ≤1500m ，when altitude is higher than 1500m，each 100 meter increasing needs
1% derating of VFD
Dust Non-conductive, no causticity，＜6.5mg/ｄｍ３ ※
Protection level IP30 ※
Cabinet colors RAL 7032(customized)
Table 2-1 Technical parameters of the SINUS MV Standard MV VFD
We have following SINUS MV Standard MV VFD products with 3.3kV~11kV class standard. The customer-design
products with given voltage and power grade can also be provided.
2.2 Technical Parameters
※Please consult with Santerno for the information beyond the below table.
※The dimensions are subject to change without notice, take the technique protocol for correct dimensions.

08
SANTERNO USER MANUAL
2.3 Model and Selection Notation
SINUS MV Standard MV VFD model selection depends on the motor type, load features, and motor current, voltage
In the case of the special load or special motor or special working environment, besides refer to rated power and
rated current of the motor, should abide by the following advices:
1. If load torque ripple such as compressor, vibrating machine and kneader is large, the practical process and the
working condition should be found out rstly, and that the rated current of the selected SINUS MV medium voltage
VFD is larger than the maximum current under the industrial frequency must be ensured.
2. Motor rated current used in submersible pump or submerged oil pump is usually greater than the rated current
of the motor; the rated current of SINUS MV Standard MV VFD should be larger than motor rated current.
3. The rated current of the selected SINUS MV Standard MV VFD which is used in the special fans, such as roots
fan, should be increased in proportion.
4. When one SINUS MV Standard MV VFD drives multiple motors at one time, the VFD which has the larger current
should be selected according to the total current of the motors.
5. For impacting load, such as oil pump, a proper enlarge of the capacity should be taken into account during
selection of SINUS MV Standard MV VFD.
6. When used in the extreme environments, such as high temperature or high altitude (>1500m), SINUS MV
Standard MV VFD should be derating, and one level higher VFD should be selected.
2.4 Application Industries and Fields
SINUS MV Standard medium voltage VFD series is widely used in various fields in national economy, exported
to Europe, Middle East, Southeast Asia etc., and has a good reputation. Perfect solutions for soft start, speed
adjusting, energy saving and intelligent control of medium voltage AC motors (including synchronous and
asynchronous motors) could be supplied to customers.
Typical application industries are:
●The above advice do not cover all of the cases of special loads and motors. Please contact with
Santerno to conrm the model selection of SINUS MV Standard MV VFD.
●If the working condition demands of explosion-proof, SINUS MV Standard MV VFD should be
placed at safety site because that it has no explosion-proof design.
Comment:

09
Metallurgy
● Induced draft fan
● Force draft fan
● Secondary de-dusting fan
● Compressing blower
● B la s t fu r na ce bl ow e r
● Blast de-dusting fan
● Converter de-dusting fan
● Electric furnace de-dusting fan
● Sulfur dioxide blower
● S l a g -  u s h i n g p u m p
● Feeding pump
● Water-delivery pump
● Phosphorus removal pump
● Mud pump
● De-scaling pump
● K neadin g machi n e
● Oxygen compressor
● Gas compression pump
Petrochemical
● Booster fan
● Induced draft fan
● Pipeline transportation pump
● Water injection pump
● Feed water pump
● Submerged pump
● Oil transfer pump
● Brine pump
● Circulating water pump
● Compressor
Electricity
● Powder exhaust fan
● Booster fan
● Force draft fan
● Induced draft fan
● Condensation pump
● Slurry pump
● Water pumping energy storage pump
● Circulating water pump
● Boiler (feed) pump
● Compressor
Cement
● Kiln draft fan
● Kiln gas blower
● Separator fan
● Kiln head fan
● High temperature fan
● Cement mill fan
● Dust removal fan
● Circulating fan
● Grate cooler
● Raw material mill fan
● Raw material mill
● Coal mill
● Kiln tail fan
● Rotating kiln transmission
● Compressive force draft fan
Municipal projects
● Aeration fan
● Induced draft fan
● F orce draft fan
● Force pump
● Medium water pump
● Sewage pump
● Hot water circulating pump
● Lifting pump
● Cleaning water pump
● Water supply pump
Light industry
● Gas blower
● Force pump
● Cleaning pump
● Axial ow pump
● Soft water pump
● Water-delivery pump
● Compressor
● Beating engine
● Shredding machine
Coal mines & minerals
● BFDS
● De-dusting fan
● Main fan
● Axial ow fan
● De-scaling pump
● Mud pump
● Slurry pump
● Clean water pump
● Feeding pump
● Stirring pump
● Agitating pump
● Drainage pump
● Medium pump
● Band conveyor
● Kiln drive
Others
● Pump test stand
● Inverter power supply test stand
● Motor test stand
● Wind tunnel test

10
SANTERNO USER MANUAL
2.5 Execute Standards and Norms
GB 156-2007 Standard voltages
GB/T 1980-2005 Standard frequencies
GB/T 1980-2005 Standard frequencies
GB/T 2423.10 Electric and electronic products--Basic environmental test regulations for electricians--Guidelines
for vibration (sine)
GB/T 2681 Colors of insulated conductors used in electrical assembly devices
GB 2682 Colors of indicator lights and push-buttons used in electrical assembly devices
GB/T 4588.1-1996 Specication for single and double sided printed boards with plain holes
GB/T 4588.2-1996 Sectional specication: Single and double sided printed boards with plated-through holes
GB 7678-87 Semiconductor self-commutated converters
GB 10233-88 Basic test method for electric-driving control gear assemblies
GB 12668-90 Standard specication for speed control assembly with semiconductor adjustable frequency for A.C.
motor
GB/T 15139-94 Standard technical standard for electrical equipment structure
GB/ 13422-92 Power semiconductor converters--Electrical test methods
GB/T 14549-93 Quality of electric energy supply harmonics in public supply network
IEEE std 519-1992 Practices and requirements for harmonic control in electrical power systems
GB/T 12668.4-2006 Adjustable speed electrical power drives systems. Part 4: Standardrequirements. Rating
specications for A.C. power drive systems above 1000V A.C. and not exceeding 35kV
GB 3797-2005 Electric-driving control gear--Part 2: Electric-driving control gear incorporating electronic devices
GB/T 2900.18-2008 Electrotechnical terminology--Low voltage apparatus (eqvIEC60050-441:1984)
GB/T 3859.1-1993 Semiconductor converters. Specication of basic requirements (eqv IEC60146-1-1:1991)
GB/T 3859.2-1993 Semiconductor converters. Application guide (eqv IEC60146-1-2:1991)
GB/T 3859.3-1993 Semiconductor converters. Transformers and reactors (eqv IEC 60146-1-3,1991)
GB 4208-2008 Degrees of protection provided by enclosures (IP Code) (eqv IEC 60529:1989)
GB/T 16935.1-2008 Insulation coordination for equipment within low-voltage systems - Part 1: Principles, requirements
and tests(idt IEC 60664-1：1992)
IEC 60038:1983 IEC Standard voltages
IEC 60050-151:2001 International electrotechnical vocabulary, chapter 151: electrical and magnetic devices.
IEC 60050-551:1999 International Electrotechnical Vocabulary. Chapter 551: Power electronics.
IEC 60076 Electric power transformer
IEC 60721-3-1:1997 Classication of environmental conditions Part 3: Classication of groups of environmental
parameters and their severities, storage.
IEC 60721-3-2:1997 Classication of environmental conditions Part 3. Classication of groups of environmental
parameters and their severities.
IEC 60721-3-3:2008 Classication of environmental conditions Part 3. Classication of groups of environmental
parameters and their severities. Stationary use at weather protected locations.

11
Introduction of SINUS MV Theory and Hardware
Chapter 3
Figure 3-1 SINUS MV Standard MV VFD system diagram (take 10kV for example）
IEC 61000-2-4:2002 Electromagnetic compatibility (EMC) Part 2- Environment chapter 4- Compatibility levels in
industrial equipments for low-frequency conducted disturbances.
IEC 61000-4-7:2002
Electromagnetic compatibility (EMC) Part 4: Testing and measurement techniques chapter 7.
Standard guide on harmonics and inter-harmonics measurements and instrumentation, for power
supply systems and equipment connected.
IEC 61800-3:2004 Adjustable speed electrical power dive systems Part 3:product standard including specic test
methods.
IEC 60757-1983 Identication of insulated and bare conductors by colors.
IEC guideline 106:1989 Environment condition guides for specifying performance rating of equipments.
DL/T 994-2006 Power station fan and water pump medium voltage VFD
3.1 Theory
SINUS MV MV VFD is composed of transformer, power cells and control system.
CellA1
CellB1
CellC1
CellA2
CellB2
CellC2
CellA8
CellB8
CellC8
CellA9
CellB9
CellC9
10 kV
Motor
Test of
Output
Voltage
HIMI
I/O
Board
Test of
Input
Voltage
Input Power
Isolated
Transformer
Test of Output Current
Power Cell
I/O SIGNAL
I/O SIGNAL
RS485, MODBUS COMMUNICATION PROTOCOL
Controller
RJ45
Test of Input Current
380V Assistant Winding
Remote control Host control
RS485
H

12
SANTERNO USER MANUAL
Rated Voltage (kV) Cells Per Phase Input Voltage Per
Cell (V) Phase Voltage (V) Line Voltage (kV) Levels of Voltage
3.3 3 640 1900 3.3 7
4.16 4 600 2400 4.16 9
6 5 690 3460 6 11
6 6 640 3460 6 13
6.6 6 640 3810 6.6 13
10 9 640 5770 10 19
11 9 700 6350 11 19
3.1.1 Main Circuit
Figure 3-2 SINUS MV 6kV topology diagram
The isolated transformer is dry-type transformer and forced air cooling. The primary loop is Y-connection, directly
connects with MV cables. The secondary windings use extended delta connection. There is a certain degree of
phase difference between secondary windings.
Phase-shift angle = , n = number of cells in each phase
The secondary windings supply power for power cells, the phase difference between windings is determined by
the number of power cells and the voltage level of the VFD (see Table 3-1).
Table 3-1: The Power Cell Conguration
60°
n

13
The SINUS MV Standard MV VFD with 6kV voltage grade has 15 /18 power cells, and 10kV has 24/27 power cells.
By using power cells connected in series, voltage wave stacking, connecting the output of three phases in Y type
and keeping the neutral point grounded by resistor, a three phase medium voltage VFD is built. See the diagrams
in Figure 3-3 and 3-4.
Fig. 3-3 Voltage Stacking Diagram of 6kV VFD Fig. 3-4 Voltage Stacking Diagram of 10kV VFD
Take the 6kV series VFD with 5 power cells as an example, 11 levels output voltage can be gotten (-5~0~+5).
With the increase of voltage levels, the value of each voltage level decreases; it can reduce the dv/dt pressure
and THD of output voltage. Figure 3-5 shows the voltage waveforms of 5 cells and phase voltage waveform at 5
cells connecting in series.
Fig. 3-5 Voltage Waveforms of 5 Cells and Phase Voltage Waveform
3.1.2 Power Cell
Fig. 3-6 Power Cell

14
SANTERNO USER MANUAL
The power cell sees in the Figure 3-6. The input power terminal R,S,T are connect with three-phase low voltage
output of transformer secondary winding. The three-phase diode full wave rectication charge for DC capacitor,
the voltage from capacitor is provided to the single phase H bridge style inverter circuit composed of IGBTs. The
power cell receives the signals through the optic ber, and adopts the SVPWM mode to control the conduction and
break of IGBT (Q1~Q4), output single phase PWM waveform. Each cell only has three possible output voltage
statuses, see in the Figure 3-6. When Q1 conducts with Q4, the output voltage status of L1 and L2 is 1; when Q2
conducts with Q3, the output voltage status of L1 and L2 is -1; when Q1 conducts with Q2 or Q3 conducts with
Q4, the status of L1 and L2 is 0.
The cell bypass is an optional function of power cell (standard Sinus MV MV VFDs don’t include this function). When
a cell can not continue to work due to phase loss, overheating or IGBT fault, this cell and the corresponding two
cells in other two phases are automatically bypassed, at this time Q1～Q4 locked the output, the bypass switch K
is conducted to ensure the VFD work continuously, and the bypass warning is sent out in the same time.
Each cell has an independent control board and a driving board: the control board is connected to the controller
by optic bers. See the power cell principle in Figure 3-7. The cell drive boards are mainly used to drive IGBT, see
Figure 3-8. Because the bers are the only way to connect with power cell and main controller, so it completely
achieves the electrical isolation between power cells and the main controller.
The control board receives the signals sent from the controller through the optic ber (XS4). After decoded by
the decoder, the signals are used to control the IGBT and the SCR used for cell bypass. There are many fault
detecting circuits on the control board, such as overheating, phase loss, DC-link over-voltage, optic ber fault and
driving fault. After encoded by the fault logical encoding circuit, the fault signals are sent to controller through the
optic ber (XS3) to execute the fault protecting (the I/O board outputs fault protection power off and fault alarm
warning) and fault recording (the fault reason, time and location are displayed in HMI).
The control board power is directly obtained from the DC-link of the power module unit (through XS1), the power
is isolated and converted by the switch power, therefore, when medium voltage power is off, the control power will
not disappear immediately, the indicating lamp will be off after a few minutes. This kind of power supply method
can ensure the realization of “momentary power-off function”, see 7.6 .
Figure 3-7 Power Cell Control Board Principle Diagram

15
Figure 3-8 Cell Drive Board Principle Diagram
The drive board is used to generate 4 IGBT drive signals, and sends the IGBT fault signals to cell control board.
The terminal XS5 of drive board connects the terminal XS6 of control board:
●”L”controls the two IGBTs Q1 and Q3 on the left bridge leg, and ”R” controls the two IGBT Q2 and Q4 on the
right bridge leg. Q1, Q3 and Q2, Q4 are interlocked by phase inverter.
●”/INHB” is the forbidding signal of IGBT, ”/DR” is the fault signal of IGBT, these signals are fed back to the
control board for cell protection.
●The control board supplies power to the drive board, +15V power are converted to 4 isolated power branches
which are used to drive 4 IGBTs.
XS5
GND
VCC
+15V
R
L
/IHNB
/DR
16
15
14
13
12
11
10
1
2
3
4
5
6
7
8
9
1
2
5
XS1
DCT
DRG
DGND
/ER
DRC
L+V+
L+V-
V+
DRCM
DRIVING
CONTROL
MODULE-1
V-
1
2
5
XS2
DCT
DRG
DGND
/ER
DRC
L-V+
L-V-
V+
DRCM
DRIVING
CONTROL
MODULE-2
V-
1
2
5
XS3
DCT
DRG
DGND
/ER
DRC
R+V+
R+V-
V+
DRCM
DRIVING
CONTROL
MODULE-3
V-
1
2
5
XS4
DCT
DRG
DGND
/ER
DRC
R-V+
R-V-
V+
DRCM
DRIVING
CONTROL
MODULE-4
V-
L+G
L-G
R+G
R-G
L+V+
L+G
L+V-
ISOLATED
POWER-1
R-V+
R-G
R-V-
ISOLATED
POWER-4
L-V+
L-G
L-V-
ISOLATED
POWER-3
R+V+
R+G
R+V-
ISOLATED
POWER-2
GND
+15V