Drives

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Information about Drives

Published on December 17, 2016

Author: RohtPradhan

Source: slideshare.net

1. To study of electronics control system by using drives in Tata steel

2. Mr. Shankar Banerjee (Sr. Manager Training) UNDER GUIDANCE OF 21th June 2016 TO 11th July 2016 Submitted By :- ROHIT SHRESTHA VT No:- VT20160524

3. CERTIFICATE This is to certify that ROHIT SHRESTHA, VT20160524 have successfully completed the project on, “To study of electronics control system by using drives in Tata steel” as a part of Vocational Training at SNTI, TATA STEEL, Jamshedpur during 21/06/2016 to 11/07/2016 under our guidance. He has successfully completed this project and worked very sincerely to our satisfaction. He has been outstanding throughout his training period. Mr. Shankar Banerjee (Sr. Manager Training)

4. ACKNOWLEDGEMENT First and foremost, I would like to express my heartly thanks and indebtedness to Mr. SHANKAR BANERJEE for his help and encouragement throughout the project. It has been a motivational and excellent learning process in his guidance. It would have been impossible for me to have a clear idea and way of approach without his support. I am also thankful to SNTI department for allowing me for the project.

5. CONTENTo Concept on drives • What is drives ? • How drive does ? • What is torque ? • What is Motor Torque ( Tm )? • What is Motor Speed? o Drive are two types • AC Drive • DC Drive o Pulse Width Modulation o Sinusoidal PWM o Components of ASTAT • What is DTC ? • Direct Torque Control • Control Display Panel • ABB ACS800 DRIVE FOR CRANE

6. Concept on Drives Electrical Energy Electric Motor Mechanical Energy Torque Rotation

7. Electric Supply Starter Motor Machine Conventional Technology Control over Torque & Speed of the motor ? NO ! Requirement of Modern Machines Electric Supply Motor MachineConverter Drive Control over Torque & Speed of the motor ? YES !

8. AC INPUT MOTOR DRIVE GB ROLL ROLL 10 V FIELD GEAR BOX SPEED REFERENCE AC CT T TACHO Operat or Loa d  It is a system which fulfills requirement of both User and Process by adjusting TORQUE and SPEED of the motor. What is drive ?

9. What Drive Does ? Electrical Energy Current carrying conductors Magnetic Field Motor DRIVE Torque Mechanical Energy Rotation

10. What is TORQUE? Twisting Moment of Force about an Axis is called TORQUE R=Radiu s F=Force F=Force R=Radiu s Torque= Force x Radius

11. What is Motor Torque ( Tm )? North Pole South Pole R=Radius F=Force F=Force R=Radiu s + F=Force = Bil = Flux Density x Current x Length Tm = F x R = (Bil)R = Constant x Flux x Current

12. GB What is Motor Speed? Revolution / Unit Time ROLL ROLL Armature Current Field Current • If Tm > TL , Motor Accelerates • If Tm < TL, Motor Decelerates • If Tm = TL, Motor runs at Stable Speed or not run at all Tm = TL + J (dw/dt ) Tm TL

13. Drive are two types Ac Drive Dc Drive

14. AC DRIVE  An AC Drive is a device that is used to control the speed and torque of a motor depending upon the requirement of user or operator.  The electronic product that controls the power to an AC Motor is called AC Drive. AC Drive takes fixed voltage, fixed frequency AC supply (eg. State Electric supply companies) and converts it into a variable frequency and variable voltage AC supply.

15. + - Ns NsN AC motor Current is caused due to Relative Speed (Ns- N) Relative speed and thus Current can be increased by increasing Ns OR Relative speed and thus Current can be increased by decreasing N

16. Power Flow in a AC motor

17. Equivalent Diagram

18. Torque Equation

19. Block diagram of VVVF AC Drive

20. Block diagram of VVVF AC Drive

21. Block diagram of VVVF AC Drive

22. Block diagram of VVVF AC Drive

23. Block diagram of VVVF AC Drive

24. DC DRIVE  Dc drives are Dc motor speed control system . Since the speed of dc motor is directly proportional to armature voltage and inversely proportional to motor flux (which is a function of field current), either armature voltage or field current can be used to control speed.

25. ACCTACCT Field Converter Armature Converter Armature Tacho Generator Field Winding VfVa N Ia If Very Basic Concept Of DC Drive 3 Phase Input 3 Phase Input To control Speed Drive adjusts “ Va “ and “Vf” (Based on Desired Speed, Actual Speed, Armature Current and Field Current) DRIVE Desired Speed (N*)

26. ACCTACCT Tacho Generator Field Winding VfV a Ia If Very Basic Concept Of DC Drive DRIVE Controlle r Firing Angle (α) Desired Speed (N*) Actual Speed (N) • Firing Angle (α) depends upon Error ( N* - N ) • Va depends upon α • N and Tm depends upon Va

27. ACCTACCT Tacho Generator Field Winding VfV a Ia If Very Basic Concept Of DC Drive DRIVE Controlle r α N* Firing Circuit N V* • V* depends upon Error ( N* - N) • Firing Angle (α ) depends upon V* • Va depends upon α • N and Tm depends upon Va

28. Field PAFPG Open Loop Control of Thyristorised DC Drive

29. Field PAFPG Speed MU Manual Closed Loop Control of Thyristorised DC Drive

30. Field PASC CC FPGe e TMU ACCTMU Closed Loop Control of Thyristorised DC DriveClosed Loop Control of Thyristorised DC Drive with Current Limiting

31. Field PASC CC FPGe e TMU ACCTMU Closed Loop Control of Thyristorised DC Drive with I and Firing Angle Limiting  Min = 30 0  Max = 150 0

32. Field PARG SC CC FPGe e TMU ACCTMU Closed Loop Control of Thyristorised DC Drive with Ramp Generator Ramp Up Time Set Ramp Dn Time Set

33. Field PARG SC CC FPGLogic e e TMU ACCTMU Closed Loop Control of Thyristorised DC Drive with Logic circuit

34. Field Arm PARG SC CC FPGLogic e e MU ACCTMU Unidirectional Armature Voltage Controlled Thyristorised DC Drive

35. Field Arm PARG SC CC FPGLogic e e MU ACCTMU Unidirectional Armature Voltage Controlled Thyristorised DC Drive

36. Unidirectional Armature Voltage Controlled Thyristorised DC Drive Field Arm PARG SC CC FPGLogic e e TMU ACCTMU DCVT- IR VDC E b Speed F/B

37. 1 2 7654 18 13 16 14 12 159 11 10 0 17 Unidirectional Armature Voltage Controlled Thyristorised DC Drive

38. Unidirectional Armature Voltage Controlled Thyristorised DC Drive PE Microprocessor Memory ( EPROM, EEPROM, FLASHPROM, RAM ) Counter Programmable Interrupt Controller (PIC) Programmable Peripheral Interface (PPI) Bridge Interface Board A/O A/I D/O D/I ADC DAC Optos Relays PA FPB FPB System Interface Board Power Supply 115 V AC Frequency Input RS232/ RS485 Serial Link E- Stop E- Stop Reset E- Stop OK E -Stop OK Fault Drive OK MC Close 24 V 24 V 10 V 10 V 24 V 0 V 0 V 24 V

39. Unidirectional Armature Voltage Controlled Thyristorised DC Drive PE Microprocessor Memory ( EPROM, EEPROM, FLASHPROM, RAM ) Counter Programmable Interrupt Controller (PIC) Programmable Peripheral Interface (PPI) Bridge Interface Board A/O A/I D/O D/I ADC DAC Optos Relays PA FPB FPB System Interface Board Power Supply 115 V AC Frequency Input RS232/ RS485 Serial Link E- Stop E- Stop Reset E- Stop OK E -Stop OK Fault Drive OK MC Close 24 V 24 V 10 V 10 V 24 V 0 V 0 V 24 V

40. Unidirectional Armature Voltage Controlled Thyristorised DC Drive PE Microprocessor Memory ( EPROM, EEPROM, FLASHPROM, RAM ) Counter Programmable Interrupt Controller (PIC) Programmable Peripheral Interface (PPI) Bridge Interface Board A/O A/I D/O D/I ADC DAC Optos Relays PA FPB FPB System Interface Board Power Supply 115 V AC Frequency Input RS232/ RS485 Serial Link E- Stop E- Stop Reset E- Stop OK E -Stop OK Fault Drive OK MC Close 24 V 24 V 10 V 10 V 24 V 0 V 0 V 24 V

41. Field ACCTMU Reversible Armature Voltage Controlled Thyristorised DC Drive RG SCLogic e CC FPGePRA RL PA PA MU I I I

42. Field ACCTMU Reversible Armature Voltage Controlled Thyristorised DC Drive RG SCLogic e CC FPGe RL PA PA MU

43. Field ACCTMU Reversible Armature Voltage Controlled Thyristorised DC Drive RG SCLogic e CC FPGe RL PA PA MU

44. Field ACCTMU Reversible Armature Voltage Controlled Thyristorised DC Drive RG SCLogic e CC FPGePRA RL PA PA MU

45. Field ACCTMU Reversible Armature Voltage Controlled Thyristorised DC Drive RG SCLogic e CC FPGePRA RL PA PA MU

46. Field ACCTMU Reversible Armature Voltage Controlled Thyristorised DC Drive RG SCLogic e CC FPGePRA RL PA PA MU

47. Field ACCTMU Reversible Armature Voltage Controlled Thyristorised DC Drive RG SCLogic e CC FPGePRA RL PA PA MU

48. Field ACCTMU Reversible Armature Voltage Controlled Thyristorised DC Drive RG SCLogic e CC FPGePRA RL PA PA MU P16=R.U P17=R.D

49. Field ACCTMU Reversible Armature Voltage Controlled Thyristorised DC Drive RG SCLogic e CC FPGePRA RL PA PA MU P31=Kp P32= Ki

50. Field ACCTMU Reversible Armature Voltage Controlled Thyristorised DC Drive RG SCLogic e CC FPGePRA RL PA PA MU P39=+ I LIM P40= - I LIM

51. Field ACCTMU Reversible Armature Voltage Controlled Thyristorised DC Drive RG SCLogic e CC FPGePRA RL PA PA MU P64= Kp P65= Ki

52. Field ACCTMU Reversible Armature Voltage Controlled Thyristorised DC Drive RG SCLogic e CC FPGePRA RL PA PA MU P94=  g P95=  W

53. 1 2 7654 18 13 16 14 12 159 11 10 0 17 Unidirectional Armature Voltage Controlled Thyristorised DC Drive

54. 1 2 7654 18 13 16 14 12 159 10 0 17 Spillover Controlled Thyristorised DC Drive 22212019 2318 11 24

55. Pulse Width Modulation  The PWM stands for “Pulse Width Modulation". The average voltage delivered to the load is controlled by ratio of total on time and off time of voltage in half cycle. By varying this ratio we can vary the voltage from zero to maximum.  The PWM voltage output is the preferred voltage output waveform. In this the positive and negative halves of square wave output are "chopped". By chopping we do not get a sinusoidal voltage at the output but we can make the current flowing through the motor winding to take sinusoidal path.

56.  It should be noted here that the motor winding is an inductive load. The current being sinusoidal now reduces the harmonics level and thereby improving the quality of line supply

57. Sinusoidal PWM  In this method of modulation a comparison is made between a triangular wave (carrier) and a sinusoidal signal or modulating wave (reference).  The frequency of the triangular signal is much higher than that of sine wave. The resulting pulse train which is the outcome of comparison then controls the power switching devices in the inverter.

58.  The frequency of the sinusoidal voltage determines the output frequency and thus the speed of the motor.  The magnitude of the output voltage is determined by the magnitude of sinusoidal voltage as it determines the on and off time of the pulse in each half cycle.  This method -sinusoidal modulation -is preferred as it provides maximum on time at 90 degrees and the same gradually reduces as we approach 0 degree and 180 degrees.

59.  One can expect a very close to sinusoidal current in the motor winding using this method. The frequency of modulating triangular wave is referred as carrier frequency or switching frequency

60.  Signal for switches are generated by comparing sinusoidal reference signal with triangular carrier signal  Pulse width of all the pulses in a half cycle are not uniform  Width of pulses is proportional to amplitude of sine wave at the center of the Pulse  No. of Pulse / Half Cycle is determined by the frequency of triangular carrier

61.  Sinusoidal PWM technique can eliminate lower order harmonics  Lowest Order Harmonic ( LOH) present in Inverter O/P : LOH = (2P-1) Where, P= No. of Pulse/Half Cycle  Larger the carrier/switching frequency, more is the elimination of lower order harmonics (typical switching frequency = 2 KHz range: 1-16 KHz)

62.  Use of higher carrier frequency asks for higher switching frequency of semiconductor devices used in power circuit of inverter and also increases switching losses and hence temperature of switches.

63. Case Study-1  A)Digital ASTAT Drive ASTAT is a highly developed, well proven system for speed control of heavy duty motors in cranes and other heavy industrial machinery.  ASTAT main components are the control system module that controls the motion and the thyristor module that controls the torque of the slip ring induction motor.

64.  For control of motor ASTAT uses two variables A) Stator Voltage Control B) Rotor Resistance Control To supply desired stator voltage a set of thyristors are included in the staor circuits which are turned on at appropriate firing angles. To optimize motor torque either resistances are introduced in the rotor circuit or withdrawn from the rotor circuit through a set of contactors.

65.  ASTAT is a close loop speed control system which employs both stator voltage and rotor resistance control.  ASTAT receives fixed voltage AC Supply at constant frequency. Keeping frequency unchanged ASTAT supplies variable AC voltage to stator winding. A set of SCRs are put in one leg. Six SCRs form a bridge.  According to desired stator voltage firing angle for SCRs are adjusted by a digital controller.

66. Components of ASTAT  ASTAT Drive comprises of the following: A. Control system module DARA1001 B. Thyristor Module DASD 101 C. Rotor adoption module DADT100 D. Cabin I/O Module DAPM100 E. Overvoltage Protection Module

67.  Control System module comprises of following: 1. DAPC100 Processor Board 2. DATX110 Process I/O Board 3. DAPU100 Communication interface 4. DATX132 Torque Estimation Board 5. DASA110 and DASA100 power supply unit 6. DAPU100 Communication board

68.  Thyristor Module comprises of following: 1. SCRs 2. Snubber circuits 3. ACCTs(AC Current Transformer) 4. DATX100 System I/O Board

69. Case Study-2  ABB ACS800 DRIVE FOR CRANE  ACS800 crane drive from M/S ABB is a drive which is used for electric overhead crane operation.  It can control speed and torque of heavy duty squirrel cage induction motor with multi-quadrant operations.

70.  Direct Torque Control (DTC) developed by ABB has improved motor control accuracy without the requirement of speed feedback device. Accurate speed and torque control of the manufacturing process optimizes the quality of the end product.  Many applications no longer require additional speed feedback when the ACS800 with DTC is used.

71. What is DTC ? Direct Torque Control (DTC) is an optimised AC drives control principle where inverter switching directly controls the motor variables: flux and torque. The measured input values to the DTC control are motor current and voltage. The voltage is defined from the DC-bus voltage and inverter switch positions. The voltage and current signals are inputs to an accurate motor model which produces an exact actual value of stator flux and torque every 25 microseconds. Motor torque and flux two-level comparators compare the actual values to the reference values produced by torque and flux reference controllers.

72. The outputs from these two-level controllers are updated every 25 microseconds and they indicate whether the torque or flux has to be varied. Depending on the outputs from the two-level controllers, the switching logic directly determines the optimum inverter switch positions. Therefore every single voltage pulse is determined separately at "atomic level". The inverter switch positions again determine the motor voltage and current, which in turn influence the motor torque and flux and the control loop is closed.

73. Direct Torque Control  Let Ws and Wr be known stator flux and rotor flux respectively. Initially both the vectors rotate at synchronous speed, in the same direction.  Rotor Flux vector lags behind the stator flux vector by delta angle. This angle depends upon load torque.  If load torque increases then the angle also increases. Rotor flux moves under the pull of stator flux vector.

74.  But if speed of stator flux vector is suddenly increased then because of inertia of rotor and its connected load, the rotor flux vector cannot respond to sudden change in the speed of stator flux vector.  As a result it falls further behind the stator flux vector. The load angle i.e. the angle between stator flux vector and rotor flux vector thus gets increased.  Motor torque thus increases for the time being. We can similarly reduce the torque angle by sudden decrease in the speed of stator flux vector.

75.  The magnitude of desired Stator flux and actual stator flux as well as the magnitude of motor torque and actual motor torque are also compared through different comparator.  Stator flux and rotor flux vectors are assumed to rotate 360 degrees for every rotation.  One complete rotation can be subdivided into in six parts or sectors. Each sector will thus cover 60 degrees

76. Direct Torque Controlled AC Digital Drive

77.  The outputs of these two comparators and sector position of stator flux vector are used to decide an appropriate voltage vector.  The selected voltage vector is used to decide the set of IGBTs which are required to be triggered for meeting with torque and flux requirement.  The desired values are set by controllers and actual values are calculated by an intelligent motor model. This motor model contains a set of programs and it can calculate actual motor torque and stator flux very precisely every 25 us.

78. Control Display Panel

79. ABB ACS800 DRIVE FOR CRANE

80. CONCLUSION Under the guidance of Mr. Shankar Banerjee we made the following conclusions, • Drive is system which fulfills requirement of both User and Process by adjusting TORQUE and SPEED of the motor. • Drives are two types A. AC Drive B. DC Drive • AC Drive is a device that is used to control the speed and torque of a motor depending upon the requirement of user or operator. • Dc drives are Dc motor speed control system . Since the speed of dc motor is directly proportional to armature voltage and inversely proportional to motor flux (which is a function of field current), either armature voltage or field current can be used to control speed. • ASTAT is a highly developed, well proven system for speed control of heavy duty motors in cranes and other heavy industrial machinery • Direct Torque Control (DTC) developed by ABB has improved motor control accuracy without the requirement of speed feedback device. At last I would like to thanks all those who have helped me in improving these very important knowledge which in future I know will be very helpful to me.

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