Technical.ppt
- 1. POWER ELECTRONICS AND APPLICATIONS Rakan Khalil Antar Department of Power Electrical Engineering Technical College / Mosul
- 2. What is power electronics Branch of electrical engineering devoted to conversion and control of electric power using electronic converter based on semiconductor power switches
- 3. Input DC AC Output DC AC Choppers Cycloconverters or controllers Types of power conversion and the corresponding power converters
- 4. Power Electronics Applications Any load with special voltage/frequency demand for example: • Variable speed motor drives. • Power supply circuits. • Electric/solar/hybrid Vehicles Propulsion • High voltage dc transmission • Process control and factory automation
- 5. Power Electronics Approach The main objective of the power electronics is to produce Efficient and Controllable systems that process electric power...
- 6. Semiconductor Switching Devices •ideal switching devices •Non-controlled devices (Power Diode) • Semi-controlled devices (SCR, Triac) •Fully controlled devices (GTO, BJT, Power MOSFET, IGBT, MCT)
- 7. Fully Controllable Switches GTO (Gate turn-off thyristor) BJT (Bipolar Junction Transistor) Power MOSFET (Metal-Oxide Semiconductor Field Effect Transistor) IGBT (Isolated-Gate BJT) MCT (MOSFET-Controlled Thyristor)
- 8. Ideal Switch Characteristics •Conduction (ON-state) resistance = 0 •Blocking (OFF-state) resistance = •Instantaneous Switching, or zero switching time. •Fully Controlled.
- 10. Thyristor Family Thyristors Uncontrollable Half-controllable Fully-controllable Diode Reverse-Blocking Triode Thyristor SCR Bidirectional Triode Thyristor Triac Gate-Turn Off Thyristor GTO MOSFET- Controlled Thyristor MCT
- 11. Silicon Controlled Rectifier, SCR K V A G I IG0 IG1 IG2 IG3 IG4 IG4 < IG3 <IG2<IG1<IG0=0 ITH VTH VRB IL IH I V VFB
- 12. How the SCR can be turned ON? 2. Through the Gate: If the Anode current (IT) increased to higher than the device latching current (IL), while the gate pulse is being applied. 1. If the forward voltage (VAK) acceded the forward blocking voltage of the device (VFB)
- 13. How the SCR can be turned OFF? SCR can be turned-off ,when the forward conduction current be reduced to a value below the holding current (Ih ) of the devices for sufficient time. In AC circuits SCR turns OFF as the currents tends to change its polarity (natural commutation) In DC circuits, to turn OFF the SCR an additional auxiliary circuit is applied to bring the SCR to zero (forced commutation)
- 14. AC-to-DC Converters Uncontrolled and controlled Rectifiers 1. Three-pulse rectifier 2. Six pulse rectifier
- 16. 0 p/6 5p/6 3p/2 Van Vbn Vcn DA DB DC
- 18. Six Pulse Diode Rectifier VAN VBN VCN DA DB DC DA- DB- DC- Io N Vo P N
- 19. van vbn vcn DA DB DC DA- DB- DC- DB- 0° 30° 90° 150° 210° 270° 330° 390°
- 20. Controlled Rectifier VAN VBN VCN N Vo TA TB TC TA' TB' TC' a a+p/3 a+2p/3 a+p a+4p/3 a+5p/3 I o p n
- 21. 0 20 40 60 80 100 120 140 160 180 -1 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1 Vout,dc verses Alpha alpha(degree) Vout,dc/Vll,p Vo,dc is negative for a >90°
- 22. io vo VAN VBN VCN N Vo I o VAN VBN VCN N Vo TA TB TC TA' TB' TC' a a+p/3 a+2p/ 3 a+p a+4p/3 a+5p/3 I o 1 2 3 4
- 23. Common Applications AC-to-DC converter applications: •DC motor supply. •High voltage DC transmission. •Supply DC-fed converters (such as inverters). •Battery chargers. •Electric Welding.