An Improved Control Strategy for Three-Phase Power Inverters in Islanded AC Microgrids
Abstract
:1. Introduction
2. Network Model
Mathematical Model
3. Proposed Control Strategy
3.1. Power Flow Control
3.2. Frequency & Voltage Regulation
4. Results and Discussion
- The system voltage is 230 V, 50 Hz.
- Two 60-KVA DG units are applied with output filter inductor Lf = 250 μF is to reduce ripples.
- A three-phase RL & C load is applied of value 0.8 Ω, 0.15 mH and 120 μF, respectively.
4.1. Case 1: P, Q Measured at Inverters Terminals
4.1.1. Equal Line Impedance
4.1.2. Unequal Line Impedance
4.2. Case 2: P, Q Measured at Terminal Vload
4.2.1. Equal Line Impedance
4.2.2. Unequal Line Impedance
5. Conclusions
Author Contributions
Conflicts of Interest
References
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Types of Line | R (Ω/km) | X (Ω/km) | R/X |
---|---|---|---|
Low voltage line | 0.642 | 0.083 | 7.7 |
Medium voltage line | 0.161 | 0.190 | 0.85 |
High voltage line | 0.06 | 0.191 | 0.31 |
Parameter | Symbol | Value |
---|---|---|
Nominal frequency | f* | 50 Hz |
Nominal voltage | V* | 230 V |
Switching frequency | fs | 16 KHz |
Ratings of each DG unit | VA | 60 KVA |
dc voltage | Vdc | 700 V |
Voltage loop | Kpv, Kiv | 20, 50 |
Current loop | KpI, KiI | 40, 100 |
Frequency droop | mP1, mP2 | 0.0034 rad/w |
Voltage droop | nQ1, nQ2 | 0.001 rad/w |
Equal line impedances | Line 1, Line 2 | 0.05 + j1.099 Ω |
Unequal line impedance | Line 1, Line 2 | 0.05 + j1.099 Ω, 0.05 + j1.3 Ω |
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Khan, M.Z.; Khan, M.M.; Jiang, H.; Hashmi, K.; Shahid, M.U. An Improved Control Strategy for Three-Phase Power Inverters in Islanded AC Microgrids. Inventions 2018, 3, 47. https://doi.org/10.3390/inventions3030047
Khan MZ, Khan MM, Jiang H, Hashmi K, Shahid MU. An Improved Control Strategy for Three-Phase Power Inverters in Islanded AC Microgrids. Inventions. 2018; 3(3):47. https://doi.org/10.3390/inventions3030047
Chicago/Turabian StyleKhan, Muhammad Zahid, Muhammad Mansoor Khan, Huawei Jiang, Khurram Hashmi, and Muhammad Umair Shahid. 2018. "An Improved Control Strategy for Three-Phase Power Inverters in Islanded AC Microgrids" Inventions 3, no. 3: 47. https://doi.org/10.3390/inventions3030047