HIGH-SPEED GENERATOR - CONVERTER SET FOR AUXILIARY POWER UNITS

Transcription

1 30 th DASC 2011 October 16-20, 2011, Seattle HIGH-SPEED GENERATOR - CONVERTER SET FOR AUXILIARY POWER UNITS by Jan Leuchter 1, Pavol Bauer 2 1 University of Defence, Faculty of Military Technology the Czech Republic 2 Delft University of Technology, Faculty Electrical Engineering, Mathematics and Computer Science the Netherlands 1

2 Outline Significant features of power source for auxiliary power unit with variable high-speed generatorconverter set Basic concepts of power electronics for power conversion systems with high-speed generator Main feature of these high-speed generators The efficiency of the overall system and an optimal topology 2 2

3 Introduction (1/9) In generally, AC generators are used as the typical power source in almost all transport and military aircrafts. The AC system supplies nearly all the electric power systems and if DC is needed, rectifiers are used. For emergency situations AC generators driven by auxiliary power units (APU) or Ram Air Turbines (RAT) are often used. 3 3

4 Introduction (2/9) The nominal power of electric systems for aircraft increase every years e.g. B787 includes 2x 250 kva per engine and 2x 225 kva on APU or A380 includes 4x 150 kva and 2x 120 kva on APU. 4 4

5 Introduction (3/9) Typically an AC generators operate with a constant speed drive (CSD) to generate a constant voltage and frequency 110 VAC and 400 Hz. The integrated drive generators (IDG) producing AC electrical power contains both generator and CSD in one unit. The next technology used in power systems for aircraft is variable speed concepts, typically referred to as VSCF systems. 5 5

6 Introduction (4/9) VSCF systems. Variable Speed Variable Frequency Rectifier DC link Inverter 115 VAC and 400 Hz Generator 6 6

7 Introduction (5/9) Insulate gate bipolar transistors (IGBT). Voltage [V] 3.5 kv 5 kv GTO Thyristor 2kV IGBT BT 1 khz 0.4 khz Current [A] 100 khz 10 khz 800 V MOSFET 1 MHz Frequency [Hz] 7 7

8 Introduction (6/9) Traditional Power System [31] Kamiar, J. Karimi, 2007, Future Aircraft Power Systems- Integration Challenges, The Boeing company presentation. 8 8

9 Introduction (7/9) Traditional Power System Future Power System Energy Flow Energy Flow Prof. Frede Blaabjerg, Power Electronics and Control of Renewable Energy Systems, EPE-PEMC 2010, Keynote presentation. 9 9

10 Introduction (8/9) New Power Electronics Concepts Bi-directional Power Flow Generator Power Converter Electrical Network [31] Kamiar, J. Karimi, 2007, Future Aircraft Power Systems- Integration Challenges, The Boeing company presentation. 10

11 Introduction (9/9) Future Power System 11 [31] Kamiar, J. Karimi, 2007, Future Aircraft Power Systems- Integration Challenges, The Boeing company presentation. 11

12 Aircraft Electrical Generators (1/4) DC Generator Brushes Brushless (BLDC) AC Generator suture Power System Induction Machine Synchronous Generators and PMG 12 12

13 Aircraft Electrical Generators (2/4) Induction Machine Gearbox Inductive generator Grid ac-dc and dc-ac P ref Q ref a) Gearbox Inductive generator ac-dc and dc-ac Grid P ref Q ref b) Figure 2. System of Induction Machine with a) Doubly-fed b) Squirrel-cage Rotor 13 13

14 Aircraft Electrical Generators (3/4) Synchronous Generators dc-ac Gearbox Synchronous generator Grid a) dc-ac Gearbox Synchronous generator ac-dc and dc-ac Grid P ref Q ref b) Figure 3. System Topologies of Synchronous Generators 14 14

15 Aircraft Electrical Generators (4/4) Synchronous Generators (PMG) PM synch. generator ac-dc and dc-ac Grid P ref Q ref c) Figure 3. System Topologies of Synchronous Generators 15 15

16 Power Electronics (1/8) VAC (f1) INPUT (3-phase varieble volatge and frequency) VAC (f2) OUTPUT (3-phase 115 VC and 400 HZ) VDC C a) Power Flow b) Figure 4. Back-to-Back Voltage Converter with a) Diode Rectifier b) PWM Rectifier 16 16

17 Power Electronics (2/8) Matrix configuration Bauer, P. Power Electronics and Drives on Aircraft, ET4365LR Introduction to EPE presentation

18 Power Electronics (3/8) I s VDC I s I s Figure 5. Effect of Single-phase Diode Rectifier 18 18

19 Power Electronics (4/8) (t) Id sin 1t sin5 1t sin 7 1t sin11 t is 1 VDC I s I s Figure 6. Effect of Three-phase Diode Bridge Rectifier 19 19

20 Power Electronics (5/8) Figure 7. Effect of Input Inductors Filtering of Three-phase Diode Bridge Rectifier 20 20

21 Power Electronics (6/8) b m f f f s 1 Figure 8. Effect of Three-phase PWM witch Switching frequency a) 0.75 khz and b) 2kHz 21 21

22 Power Electronics (7/8) L1 VDC Lg C b 22 22

23 Power Electronics (8/8) Multilevel Converter (5-leveL) 23 23

24 Effect of L g on Current Commutation (1/2) b sin (t) I 2 sin t... d 1 2 is

25 Effect of L g on Current Commutation (2/2) b 25 25

26 Efficiency Investigation for a High- Speed Generator Set (1/5) PMG ac-dc 26 26

27 Efficiency Investigation for a High- Speed Generator Set (2/5) + R c u,1lsigm a Ls R s,f e U i,1 + - Rcu,h Lsigma Rs,Fe Ui,m Ls Rr,F s 1m - Figure 12. Equivalent Circuit of PMG of a) Fundamental b) h-harmonics Time [20-22] 27 27

28 Efficiency Investigation for a High- Speed Generator Set (3/5) Rotor speeds [rpm] Figure 13. Losses Investigation versus Generator Speed 28 28

29 Efficiency Investigation for a High- Speed Generator Set (4/5) h-time harmonics of I s [-] Figure 13. Losses Investigation versus h-harmonics of I s [20-22] 29 29

30 Efficiency Investigation for a High- Speed Generator Set (5/5) A C B Efficiency [%] Rotor speeds [rpm] Figure 14. Efficiency investigation versus power electronics and rotor speed [20-22] 30 30

31 Electromagnetic Interference (1/3) Due to the harmonic currents are some problems such as: additional losses or errors of interference with communication and control signals, and so on. For instance, the communication system of L159 during developments shows as a series problem which was necessary to resolve by an active and tuned antenna

32 Electromagnetic Interference (2/3) f if f s f h f z f z ** 2f h f z * Shortly, test results of radio receiver LUN 3524 (L59) for 120 MHz setting. f if = 8MHz, f z =f s -2f if = 104 MHz, f s +2f mf = 136 MHz, f s /2= 60 MHz, f s /3= 40 MHz, f s /4= 30 MHz, f s /5= 24 MHz, f s /6= 20 MHz, f s -f if /2= 116 MHz, f s -3/2f if = 108 MHz and 3/2f s -f if = 172 MHz; these frequencies receiver successfully rejected

33 Electromagnetic Interference (3/3) Similarly, two-input signal of receiver test was applied to test spurious frequencies. Again, the radio setting was 120 MHz and spurious signals: 90 MHz and 52.5 MHz, brings interference and frequencies: MHz, MHz and MHz produce interferences. Really very interesting results can be obtained for input spurious frequencies: 110 MHz and 230 MHz, where frequencies mix ( MHz) brings interference of 120 MHz as well. From these we did tests of higher harmonics of 230 MHz, e.g. 230/20=11.5 MHz, and we found interference as well. The same receiver behavior can be obtained for really high-harmonics of 230 MHz, frequency khz

34 Conclusion (1/2) ) d) The feasibility of potential APU with variable high-speed PGM was investigated. Three different configurations of power converters were considered and discussed. Power electronics can add to the inherent power line disturbances by harmonics current injected into the grid and by producing EMI. High-frequency of high-speed generator-converter set for auxiliary power units has effect on the losses and harmonics contents producing EMI Due to the harmonic currents, there are some problems such as errors of interference with 34 communication and control signals. 34

35 Conclusion (2/2) Tell your boss, we have known where the designer was wrong! ) d)