Single-Phase Synchronverter for DC Microgrid Interface with AC Grid

Transcription

1 The First Power Electronics and Renewable Energy Workshop (PEREW 2017) March 1-2, Aswan Faculty of Engineering, Aswan Egypt Single-Phase Synchronverter for Microgrid Interface with AC Grid Presenter: Eng. Tarek Younis APEARC, Faculty of Engineering, Aswan University, Aswan 81542, Egypt 1

2 Outline Introduction Synchronverter principle of operation Modes of operation Proposed Single-Phase Synchronverter Code Size and TET investigation. Enhanced Dynamics and Power Limitation. Current Limitation Capability. Experimental Results Summary 2

3 Introduction 3

4 Introduction PV array Fuel cell Wind turbine Microturbine AC AC Microgrid Static switch AC Bi-directional inverter Utility Grid AC AC Loads Loads Batteries Electric vechile VSM: Virtual Synchronous Machine / Synchronverter 4

5 Introduction PV array Fuel cell Wind turbine Microturbine AC AC Microgrid Static switch AC Bi-directional inverter Utility Grid AC AC Loads Loads Batteries Electric vechile VSM: Virtual Synchronous Machine / Synchronverter 5

6 Introduction VSM: Virtual Synchronous Machine / Synchronverter 6

7 Synchronverter principle of operation Virtual Machines Virtual Synchronous Machine: Virtual Synchronous Machine (VSM/VISMA). Virtual Synchronous Generator (VSG). Synchronverter. Virtual induction machine (Inducverter). 7

8 Synchronverter principle of operation L inv,r i inv L g,r g inv i g V dc e C f R d v inv R L v g i inv v g Synchronverter Controller PWM 8

9 Mathematical model Synchronverter principle of operation Mechanical part Electrical part Electronic part Power part Active power regulation Reactive power regulation Instantaneous power calculation 9

10 E sin θ Synchronverter principle of operation PI S P ω set E set V g P set D q S Q Q set D P 1/Js Q K iq /s ω θ P 1/s E e v g PWM i s 1/(sLR) i g 1 2 S C P=0.5(e d i d e q i q ) Q=0.5(e q i d -e d i q ) P Q 10

11 Mathematical model E sin θ Synchronverter principle of operation E set V g P set D q SQ Q set PI SP ω set D P θ 1/Js Q K iq /s 1/s ω P e P=0.5(e d i d e q i q ) Q=0.5(e q i d -e d i q ) P Q E Electronic part v g 1/(sLR) i g PWM i s 1 2 SC Mechanical part Electrical part Active power regulation Power part Reactive power regulation Instantaneous power calculation 11

12 E sin θ Mathematical model Synchronverter principle of operation Mechanical part Electrical part Mechanical Part Electronic part Active power regulation Power part Reactive power regulation Instantaneous power calculation PI SP ω set E set V g P set D q SQ Q set D P 1/Js Q K iq /s ω θ P 1/s E e v g PWM i s 1/(sLR) i g 1 2 SC P=0.5(e d i d e q i q ) Q=0.5(e q i d -e d i q ) P Q d J Tm Te Dp 0 dt 12

13 E sin θ Mathematical model Synchronverter principle of operation Mechanical part Electrical part Electrical Part Electronic part Active power regulation Power part Reactive power regulation Instantaneous power calculation PI SP ω set E set V g P set D q SQ Q set D P 1/Js Q K iq /s ω θ P 1/s E e v g PWM i s 1/(sLR) i g 1 2 SC P=0.5(e d i d e q i q ) Q=0.5(e q i d -e d i q ) P Q di u Ri L e dt 13

14 E sin θ Mathematical model Synchronverter principle of operation Mechanical part Electrical part Active Power Regulation Electronic part Active power regulation Power part Reactive power regulation Instantaneous power calculation PI SP ω set E set V g P set D q SQ Q set D P 1/Js Q K iq /s ω θ P 1/s E e v g PWM i s 1/(sLR) i g 1 2 SC P=0.5(e d i d e q i q ) Q=0.5(e q i d -e d i q ) P Q 14

15 E sin θ Mathematical model Synchronverter principle of operation Mechanical part Reactive Power Regulation Electrical part Electronic part Active power regulation Power part Reactive power regulation Instantaneous power calculation PI SP ω set E set V g P set D q SQ Q set D P 1/Js Q K iq /s ω θ P 1/s E e v g PWM i s 1/(sLR) i g 1 2 SC P=0.5(e d i d e q i q ) Q=0.5(e q i d -e d i q ) P Q 1 E k pq kiq Qref Q ke E0 E s 15

16 E sin θ Mathematical model Synchronverter principle of operation Mechanical part Electrical part Power Calculation Electronic part Active power regulation Reactive power regulation Power part Instantaneous power calculation PI SP ω set E set V g P set D q SQ Q set D P 1/Js Q K iq /s ω θ P 1/s E e v g PWM i s 1/(sLR) i g 1 2 SC P=0.5(e d i d e q i q ) Q=0.5(e q i d -e d i q ) P Q 16

17 Mathematical model Synchronverter principle of operation Mechanical part Electrical part Power Part Electronic part Power part Active power regulation Reactive power regulation Instantaneous power calculation Single-phase full-bridge inverter LC filter Coupling inductor and circuit breaker for grid connection 17

18 E sin θ Modes of Operation Grid-connection Switch Standalone Power regulation Droop P Q P Q S C Pos. 1 Pos. 2 S P ON ON -- OFF -- S Q OFF -- OFF -- ON PI S P ω set E set V g P set D q S Q Q set D P 1/Js Q K iq /s ω θ P 1/s E e v g PWM i s 1/(sLR) i g 1 2 S C P=0.5(e d i d e q i q ) Q=0.5(e q i d -e d i q ) P Q 18

19 Pros & Cons of Synchronverter Feature Smooth transition between standalone and grid connected modes Emulate the characteristics of synchronous generator. Self-tracking. a) Virtual inertia. b) Droop. Inject constant amount of power to the grid regardless of variations of voltage frequency, angle and amplitude. Doesn t require a PLL. Current Limiting. Availability Yes Yes Yes Yes Yes No 19

20 E sin θ Proposed Controller Active Power Loop PI S P ω set Q P E set V g P set D q S Q Q set Reactive Power Loop D P 1/Js Q K iq /s ω θ P 1/s E e ref v g 1/(sLR) i ref θ dq e ref,dq i ref,dq i inv,dq P=0.5(e d i d e q i q ) Q=0.5(e q i d -e d i q ) e dq e Current Controller PWM i inv S C e ref,dq i ref,dq i inv,dq PI e dq dq/ab eb e a e dq e θ 20

21 Experimental Results V dc AC e i inv i inv DSPACE L inv,r inv R d C f v g v inv L g,r g i g vg Parameter Value 160V V dc v g f g S max L L inv L g 100Vrms 50Hz 100VA 100mH 9mH 2.75mH C f 1µF R f r 5Ω 5Ω 21

22 Experimental Results Sensors Inverter LCL filter 22

23 Experimental Results Sensors Inverter LCL filter 23

24 Experimental Results Sensors Inverter LCL filter 24

25 Experimental Results Sensors Inverter LCL filter 25

26 Summary A single-phase self-synchronized synchronverter with: Enhanced Active Power Dynamics. Active power limitation. Current limiting capability. The proposed controller maintains all the merits of the original controller besides the current limiting feature. Simulation and experimental results are carried out that verified the effectiveness of the proposed controller. 26

27 27