latest power electronics based drive technology used in Overhead electrical crane and many other traction system.

1. M A H E S H K U M A R
S M S 2 E L E C T R I C A L
B S M 0 5 6 6
ACTIVE FRONT END
DRIVE OF
KONECRANE

2. VARIABLE VOLTAGE VARIABLE
FREQUENCY DRIVE (VVVF)
• VVVF drive is a power electronics based device which
converts a basic fixed frequency, fixed voltage sine wave
power (line power) to a variable frequency, variable
output voltage which is used to control speed of
induction motor.
• It regulates the speed of a three phase induction motor
by controlling the frequency and voltage of the power
supplied to the motor.
Ns = 120*f
P
• Since the number of pole is constant the speed Ns can
be varied by continuously changing frequency.

3. • Any reduction in the supply frequency without a change in the
terminal voltage causes an increase in the air gap flux which
will cause magnetic saturation of motor. Also the torque
capability of motor is decreased.
• Hence while controlling a motor with the help of VVVF Drive
we always keep the V/f ratio constant.

4. • The mains AC supply voltage is converted into a DC voltage
and current through a rectifier. The DC voltage and current
are filtered to smooth out the peaks before being fed into an
inverter, where they are converted into a variable AC voltage
and frequency.
• The output voltage is controlled so that the ratio
between voltage and frequency remains constant to
avoid over-fluxing the motor.
AC DRIVE SYSTEM

5. PULSE WIDTH MODULATION:
• Pulse-width modulation (PWM) is a modulation technique used to
vary the width of the pulse.
• PWM signals are pulse trains with fixed frequency and magnitude
and variable pulse width.
• Continuous change of the pulse width results in a continuous
change of the average value of the voltage.

6. ACTIVE FRONT END DRIVE
The diode rectifier does not allow power flow from the DC link to the supply side ,so
diode rectifier is replaced with an IGBT rectifier.
The 6-pulse PWM bridge converter with IGBTs is shown in figure and is electrically
similar to a normal PWM inverter.
As with the PWM inverter, it can transfer electrical energy in either direction,
depending on the switching sequence of the IGBTs.

7. ELECTRIC MOTOR – SPEED / TORQUE
Quadrant I -- Driving or motoring,
forward accelerating quadrant with
positive speed and torque
Quadrant II -- Generating or braking,
forward braking- decelerating quadrant
with positive speed and negative
torque
Quadrant III - Driving or motoring,
reverse accelerating quadrant with
negative speed and torque
Quadrant IV - Generating or braking,
reverse braking decelerating quadrant
with negative speed and positive
torque.

8. POWER CIRCUIT DIAGRAM

9. MOTOR ARRANGEMENT IN CRANE

10. MOTOR & DRIVE DETAIL

11. OVERVIEW
• The DynA Vector II family is a
complete control system for
every crane motion providing
dynamic and safe crane
operation.
• The family includes DynAC
Vector II (D2C) for travelling,
• DynAHoist Vector II (D2H) for
hoisting and DynAReg Vector
II (D2R) for regenerative
network braking.
• Their robust construction
ensures excellent tolerance to
extreme ambient conditions.

12. • The three phase utility interface of variable speed D2C and D2H AC-drives can be
improved effectively by applying the D2R PWM-rectifier. The PWM-rectifier costs
more than a simple diode rectifier, but it provides numerous benefits.
Bidirectional Power Flow
• The regenerative network braking enables very efficient energy optimization. The
crane operation requires frequent starting and stopping. During each braking
period as well as during load lowering, the generated energy must be either
wasted by resistor braking or, specially in process duty with high power ratings,
fed back to the supply line with the D2R.
Low Line Current Distortion
• The line current distortion of a six pulse diode rectifier is seldom below 40 %.
Distortion levels exceeding 100 % are not unusual. By included LCL line filter the
total harmonic distortion of D2R can be typically decreased by a factor of 10.
• Unity Power Factor
• Basically, the displacement factor of a diode rectifier is good, but due to the line
current harmonics the actual ratio of active and apparent power is not good. The
D2R can be controlled to unity power factor with sinusoidal line currents, thus
reducing the supply fuse sizes.

13. • Insensitivity To Line Voltage Variations
• Due to the closed loop DC-voltage control, the dc-link becomes insensitive to line
voltage variations. Voltage dips, for example, do not affect the operation provided
that the maximum current is not exceeded. With the D2R the need to oversize
the equipment is minimal - even for weak networks
• Controllable DC-voltage
• The DC-link voltage is controlled by the D2R, resulting to a constant voltage with
a level higher than with a diode rectifier. The actual voltage level can be chosen
almost independently from the line voltage - typically the level is adjusted 10 ...
25 % above that achieved with a diode rectifier.
• Latest Technology
• The D2R PWM-rectifier is of a state-of-the-art design with IGBT-switches. The
space vector based control strategy provides extremely fast response and
excellent accuracy.
• Spare Parts
• As the D2R belongs to the same family with D2C and D2H, a great number of
common components minimize the spare part inventory and simplify the
maintenance procedures.

14. TECHNICAL DATA

15. TYPE MARK CODING

16. PRE CHARGING CIRCUIT
• The Active Front End unit requires an external pre-charging circuit. The
purpose of the pre charging unit is to charge the voltage in the
intermediate circuit to a level sufficient for connecting the Active Front
End unit to the mains.
• The Active Front End unit must not be connected to mains without pre-
charging.

17. CONTROL UNIT
The control unit of Vacon NX Active Front End consists of the control board and
option boards (see Figure 49 and Figure 50) connected to the five slot
connectors (A to E) on the control board.

18. CONNECTIONS ON CONTROL BOARD
• Basic I/O board (Slot A) It has two board levels, one for electronics
level signals (terminals 1-10) and one for control voltage signals (42-
240 Vac).
• Relay / Thermistor board (Slot B)
• SSU Speed Supervision board (Slot C)
• I/O Extension board (Slot D)
• Relay Extension board (Slot E)
• Profibus board (Slot E) The board has the 9-pin female D-connector
for the Profibus cable.

19. INVERTER
• Inverter includes Power supply unit (PSU) and Control unit (CSU),
which are separate parts , connected through fiber optic cable.
• PSU includes supply, brake resistor and motor connections. IGBTs
are placed to PSU. Microprocessors and ASIC are placed to CSU.
Same CSU can be used in every power class.

20. CLOSED LOOP VECTOR CONTROL

21. ACTIVE FRONT END UNIT BLOCK DIAGRAM

22. Thank you!