Teaching Utility Applications of Power Electronics in a First Course on Power Systems.ppt
- 1. Ned Mohan, Amit Jain, Philip Jose University of Minnesota and Raja Ayyanar Arizona State University Teaching Utility Applications of Power Electronics in a First Course on Power Systems
- 2. 2 Outline Importance of teaching power electronics in a power systems course Description of proposed approach consisting of four segments Functional aspects of power electronics Power device capabilities and Power Electronic Structures Role of power electronics in utility applications Details of the power electronics structures
- 3. 3 Control Center Micro-Turbine Hospital Commercial Building Fuel Cell Smart House Performance Building Combined Heat and Power Plant (CHP) Factory Commercial Building House Apartment Building Wind Power Plants Village Commercial Building Central Power Station Solar Power Plants CHP House Importance Increasing applications of Power Electronic Equipment in Power Systems Availability of high power semiconductor devices Decentralized renewable energy generation sources Increased power transfer with existing transmission system Effective control of power flow needed in a deregulated environment Norms for Power quality Future Power System
- 4. 4 Approach Top Down approach consisting of four segments Function of power electronics as an interface, and the listing of utility applications requiring power electronics interface (1 lecture) Power device capabilities and the resulting structures of power electronic interfaces to exploit them (1 lecture) Importance and the role of power electronic interfaces in various applications (2 lectures) Discussion of power electronics interface in appropriate detail (3 lectures)
- 5. 5 Segment 1: Function of Power Electronics in Utility Applications Enabling technology providing interface between two (ac/dc) electrical systems E.g. Interconnection of two asynchronous ac systems dc to ac conversion is required to connect fuel cells or photovoltaics to the utility grid Converter Controller Source Load
- 6. 6 Segment 1: Listing of Power Electronic Applications Distributed generation (DG) Renewable resources (wind and photovoltaic) Fuel cells and micro-turbines Storage: batteries, super-conducting magnetic energy storage, flywheels Power electronics loads: Adjustable speed drives Power quality solutions Dual feeders Uninterruptible power supplies Dynamic voltage restorers Transmission and distribution (T&D) High voltage dc (HVDC) and medium voltage dc Flexible AC Transmission Systems (FACTS): Shunt and Series compensation, and the unified power flow controller
- 7. 7 Segment 2: Power Device Capabilities & Resulting Power Electronic Structures Power Semiconductor Devices and their Capabilities Polarity of voltage blocked and direction of current conduction Switching speeds and power ratings IGBT MOSFET Thyristor IGCT 101 102 103 104 102 104 106 108 Thyristor IGBT MOSFET Power (VA) Switching Frequency (Hz) IGCT
- 8. 8 Segment 2: Structure of Power Electronic Systems Voltage-Link Systems Transistors and diodes that can block voltage of only one polarity Current-Link Systems higher power bipolar voltage- blocking capabilities of thyristors Solid State Switches bidirectional voltage blocking and current conduction AC1 AC2 AC1 AC2
- 9. 9 Segment 3: Role of Power Electronics in Important Utility Applications Distributed Generation (DG) Applications Power electronic interface depends on the source characteristics AC DC DC AC Wound rotor Induction Generator Generator-side Converter Grid-side Converter Wind Turbine Isolated DC-DC Converter PWM Converter Max. Power- point Tracker Utility 1f Wind Power Generation with Doubly Fed Induction Motors Photo-voltaics Interface
- 10. 10 Segment 3: Role of Power Electronics in Important Utility Applications Power Electronic Loads: Adjustable Speed Drives Controller Motor Utility Rectifier Switch-mode Converter
- 11. 11 Segment 3: Role of Power Electronics in Important Utility Applications Power Quality Solutions for voltage distortion unbalances voltage sags and swells power outages Load Feeder 1 Feeder 2 Dual Feeders Power Electronic Interface Load Dynamic Voltage Restorers (DVR) Uninterruptible Power Supplies Rectifier Inverter Filter Critical Load Energy Storage
- 12. 12 Segment 3: Role of Power Electronics in Important Utility Applications Transmission and Distribution: DC Transmission most flexible solution for connection of two ac systems AC1 AC2 HVDC AC1 AC2 MVDC
- 13. 13 Segment 3: Role of Power Electronics in Important Utility Applications Transmission and Distribution: Flexible AC Transmission Systems (FACTS) 1 2 sin E E P X 1 E 2 E 3 E + - 3 E 1 E 2 E S h u n t c o n v e r t e r S e r i e s c o n v e r t e r I Shunt and Series Compensation Series Compensation Shunt Compensation Utility STATCOM jX
- 14. 14 Segment 4: Discussion of Power Electronics Interface Fundamental concepts for understanding the operation of the power electronic structures voltage-link systems current link systems solid state switches
- 15. 15 Voltage-Link Systems Unifying approach: Power-Pole Building Block building block of all voltage-link systems AC1 AC2 dA i A v A i d V control v 1 or 0 A q A s d T + - + - PWM Voltage port Current port
- 16. 16 Voltage-Link Systems Power conversion using Pulse Width Modulation (PWM) Power reversal with reversal of current direction Averaged conversion dA i A v A i d V control v 1 or 0 A q A s d T + - + - PWM Voltage port Current port A v t d V A v A s d T s T on A d A d s T v V d V T
- 17. 17 Voltage-Link Systems Averaged Representation of Power Pole Average quantities are of main interest dA i A v A i d V control v A s d T + - + - PWM 1: A d dA i A v A i d V control v 1 or 0 A q A s d T + - + - PWM Voltag e port Current port ( ) ( ) A A d v t d t V ( ) ( ) ( ) dA A A i t d t i t
- 18. 18 Voltage-Link Systems Synthesis of AC voltages voltage to be synthesized duty ratio needed dc side current A i t 0 v d V d V 2 0 t A v I ( ) sin 2 d AN V v t V t 1 sin 2 A d d t 1 ( ) sin ( ) 2 1 ˆ sin sin( ) 2 1 ˆ cos sin( ) cos(2 ) 2 dA a i t d t i t d t I t I d t d t
- 19. 19 Voltage-Link Systems Implementation of bi-positional switch A i d V + - A q A q 1 A A q q dA i A v A i d V 1 or 0 A q A s d T + - + -
- 20. 20 Current-Link Systems Exclusively thyristor based One of (T1, T2, T3) and (T2, T4, T6) conduct at a time Average dc voltage controlled by ‘firing angle’ Power flow reversed by reversing voltage polarity AC1 AC2 3 2 3 cos d LL c d V V L I a i b i c i d v + - d I 1 T 3 T 5 T 4 T 6 T 2 T c L b L a L
- 21. 21 Solid State Switch Can conduct current in both directions Turn-on or off in an ac circuit in one-half of a line- frequency cycle
- 22. 22 Conclusion Teaching utility applications of power electronics in a power systems course is very important A top down approach, starting with functional aspects and going to implementation details is suggested Topics outlined in the four segment proposed structure will introduce students to future practices and technologies in power engineering The proposed structure may be adapted based on individual preferences