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DC Machine 1. Content Introduction Elementary DC machine Voltage and Torque Equations Basic Type DC Machines Dynamics characteristics of Magnet Permanent.

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Presentation on theme: "DC Machine 1. Content Introduction Elementary DC machine Voltage and Torque Equations Basic Type DC Machines Dynamics characteristics of Magnet Permanent."— Presentation transcript:

1 DC Machine 1

2 Content Introduction Elementary DC machine Voltage and Torque Equations Basic Type DC Machines Dynamics characteristics of Magnet Permanent and Shunt DC Motor 2

3 Introduction DC machines application not widely used DC generator is replaced by rectifier DC Motor is still used in lower power : – Shunt DC Motor – Permanent Magnet DC Motor Brushless DC motor becomes popular and widely used in electric vehicle. 3

4 Elementary of DC Machine Stator coil as field winding  source of flux Rotor coil as armature 4

5 Voltage Equation Flux linkage : 5 Voltage equation for field winding and rotor coil Mutual inductance winding between field winding and armature as a function of Θr : Θr = 0, π, 2 π, L= Constant

6 Open circuit voltage 6

7 A and a rotor coil DC Machine with paralel winding 7 in out

8 Constant flux is established by magnet permanent Small dc motor with low power control application 8 Comutation of DC Machine with permanent magnet

9 Voltage Equation Voltage field and coil winding 9 is rotor speed is referred as back emf

10 Torque Equation Electromagnetic torque 10 Torque and rotor speed equation : J = inertia of the rotor (kg m 2 or Js 2 ) T L = mechanical load B m = mechanical damping ratio (Nms) T e is positive in direction of θ r and direction of T L opposes of T e

11 Basic Type of DC Machine (1) 11 Separate Winding Shunt DC Machine

12 Shunt Characteristic 12

13 Basic Type of DC Machine (2) 13 Series Winding Application : traction motor for train or bus, hoists and crane High starting torque with mechanical load at normal operation

14 Series Characteristic 14 Torque and speed characteristics

15 Dynamic characteristics of permanent magnet and Shunt DC Machine 15 Two modes of dynamic operation are of interesting : – Starting from stall – Changing in mechanical load Constant voltage source

16 16 Starting characteristics of permanent magnet DC motor Direct on line starting for small power, Current starting limitation in large hp motor

17 17 Dynamic performance during sudden changes in load torque. DC motor 5 hp, 240 V, 127,7 rpm load 1 kg m 2 DC motor 200 hp, 250 V, 600 rpm

18 Time Block Diagram and State Equation Shunt DC motor 18 Solving field voltage equation and armature voltage equation:

19 19 Solving for dω r /dt : State equation in matrix (vector matrix) :

20 Permanent Magnet DC Motor 20

21 21 System Equation : x = state vector u = input vector

22 Example For control Design  to express transfer functions between state and input variables. To derive transfer function between state variables (i a and ω r ) and input variables (i a and T L ). 22 Inertia time constant Second order differential equation in term of ωr: Coefficient of dumping ratio

23 23 Finally,

24 DC shunt Motor Constant Torque 24 Parameter : Vt (rated)= 120 V ; Ia (rated) = 10 A ; n = 1200 rpm ; If = 1,6 A Ra = 0.5 Ω La = 0.01H Rf = 75 Ω Lf = 0.02 H Mechanical Load = 50 N Typical loads include belt conveyors with a fixed loading, extruders, hoists, and mine lifts.

25 25

26 Laplace Transform 26 Parameter dc permanent magnet : 6 V, ra = 7 Ω, LAA = 120 mH kT = 2 oz.in/A, J = 150 µoz.in.s 2. No load rpm = 3350 rpm I no load = 0,15 A

27 27

28 28 Inverse Laplace For step voltage

29 29 Using euler equation : Substituting parameter :

30 PR 1-5 ( Urut ) 6-10 ( Urut 21 – 40) ( Urut 41 – 60) (Urut 61 – 80) 30

31 Electrical Motor Development Basic Priciples of Electrical Machine Analysis DC Machine Reference Frame Theory Induction Machine Synchronous Machine BLDC Machine 31


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