This document discusses motor converter control for a 6000 HP IGBT-based locomotive. It includes a block diagram of the motor control system and describes functions like torque reference generation, motor torque control, weight transfer between bogies, axle force correction, line current control, and induction motor torque control using vector control. Wheel slip slide detection uses the rate of change of motor speeds and difference between motor and vehicle speeds. Wheel slip control reduces torque after detection, and a limiter prevents excess speed difference. Start stop jerk is limited for individual inverters. SPWM modulation generates pulse patterns from reference and carrier waves.

1. MOTOR CONVERTER CONTROL IN 6000 HP
IGBT BASED LOCOMOTIVE
BY
V.MURALI KRISHNA

2. PLAN
Introduction
Functional blocks
Torque reference
generation and processing
Motor torque control

3. BLOCK DIAGRAM OF MOTOR CONTROL
MAIN TRANSFORMER
DCU
DCU
DCU
4 QUADRANT
CONVERTER
3-Ф INVERTER
3-Ф
IM
3-Ф INVERTER
3-Ф
IM
3-Ф INVERTER
3-Ф
IM

4. BASIC STRUCTURE

5. SOFTWARE FUNCTIONS

6. MOTOR CONVERTER

7. MOTOR CONVERTER ENABLE
 To enable the motor converter the following pre conditions have to
be satisfied
 Protective disconnection inverter disable should be low(from fault handling)
 Direction ok high
 Cooling ok high
 fqc charged high

8. WEIGHT TRANSFER FUNCTION
The leading bogie gets 95% of the demanded force while the trailing bogie
gets 105% of the demanded force.
This function is implemented in VCU depending on driving direction

9. AXLE FORCE CORRECTION
 The force on each axle of a bogie is further corrected
 The leading axle of the bogie gets 97% of the demanded force on
the bogie while the trailing axle gets 103% of the demanded force.

10. FORCE REFERENCE CREATOR
 The force input coming from the VCU is multiplied with axle
correction factor and generates the force reference to the motor

11. LINE CURRENT CONTROL AND LINE BREAK CONTROL
Line current control reduces the force reference
Line break control limits the force reference in order to maintain Dc link
voltage at reference value

12. GENERATION OF TORQUE REFERENCE
 From the force reference on each motor the torque reference
is created by multiplying with wheel diameter
 This torque reference along with the axle speed calculated
from the speed sensor output is given to the speed torque
curves to limit the maximum torque for the speed

13. WHEEL SLIP SLIDE CONTROL
 The torque obtained from motor torque curves is processed
through wheel slip slide control block which does the following
functions
 Wheel slip slide detection
 Wheel slip slide control(ler)
 Wheel slip slide limiter
 Wheel slip slide indication

14. Wheel slip slide detection
 The rate of change of the speed of the motors (filtered value of dn/dt)
is greater than maximum allowable change
 The speed difference between the motor speeds and the vehicle
speed.
 The wheel slip limiter is active
 The locomotive speed is calculated as
 The minimum (during traction) / maximum (during braking) speed of the
motor axles of the locomotive

15. MATLAB IMPLEMENTATION OF WHEEL SLIP DETECTION

16. WHEEL SLIP CONTROLLER
The wheel slip slide controller reduces the torque after slip / slide detection
.
when difference between loco and axle speed is within the limits and no
slip/slide is high the controller increases the torque again to original value

17. WHEEL SLIP LIMITER
The wheel slip limiter becomes active when the difference between axle
and loco speed exceeds the predefined curve settings.
This limiter is a fast controller which prevents the system for speeding up
further the axle speed.
It acts more or less as a fast clipping on a pre-defined value of allowed
speed difference.
The advantage of this system is that the controller doesn’t has to act that
fast.

18. START STOP JERK LIMITER
 In the case that a drive system consists of multiple inverters,
each inverter must be able to stop and start individually
 TCstate enables SSJL depending on TCM state whether the
drive has to be stopped or started depending on the inputs
received from fault handling.
 The rate of increase or decrease of torque is limited by SSJL

19. SSJL IMPLEMENTATION

20. INDUCTION MOTOR TORQUE CONTROL
 The production of torque in an induction motor is a function of the
position or vector relationship in space of the air-gap magnetic flux to
the rotor current
 But in case of induction motor both these quantities are dependent on
each other.
 Hence these quantities are decoupled and controlled.
 The object of vector control, sometimes referred to as “field orientation
control”, is to separately control the magnitude of the two components
Id and Iq, such that
 Flux controlling component(Id )
 Torque controlling component(Iq)

21. CONTROL SCHEME
 The approach of a vector control means that the 3 motor currents are
transformed into a 2 dimensional vector. At first, the current vector in
the stationary frame is calculated: [I_alpha, I_beta].
 Based on an assumed position of the momentary rotor flux, this
vector is decomposed into a flux generating component Id and a
torque generating component Iq (Park d-q reference frame)
 The required voltage to the stator of the motor can be expressed in
the same reference frame by means of the 2 dimensions of the
vector: Usd and Usq.
 These vector is first transformed into the stator voltages U_alpha and
U_beta and then into the 3 phase voltages Ur, Us and Ut.
 These voltages are the basis for a switching pattern to control the
power electronics.

22. ID-IQ GENERATION

23. IDREF AND IQREF CALCULATIONS

24. TACT CALCULATION

25. MODULATION INDEX

26. PULSE PATTERN GENERATION

27. PPG

28. SPWM
 The pulses are generated by comparison of a sine
wave(reference wave) with a triangular wave(carrier wave)
 The comparator gives a high output whenever the reference
wave is greater than the carrier wave.
 The ratio of amplitude of reference wave to the carrier wave is
modulation index.
 By varying the frequency of reference the fundamental output
frequency can be varied
 The frequency of the carrier wave gives the switching
frequency.
 The three phases of a inverter are generated by identical
reference waves with 120 degrees phase displacement

29. SPWM
Fc-frequency of carrier wave
Fr-frequency of reference wave

30. SPWM
 Fc and Fr must be kept in synchronization otherwise adjacent
cycles of inverter output will differ from one another and
generate sub-harmonic components in the output
 At low reference frequencies below 10Hz asynchronous PWM
is used
 As the frequency Fr increases the modulation index also has
to be increased to keep v/f constant.
 As the reference frequency is increased the pulse pattern
should get transformed.
 PPG consists of a stored set of patterns .
 The PPG defines which pattern should be used depending on
the modulation index and frequency.

31. THANK YOU ALL

32. QUERIES???