An Optimal Control Strategy for DC Bus Voltage Regulation in Photovoltaic System with Battery Energy Storage

Table 3

Simulation parameters.

Model parameter	Value	Symbols/comments
PV system	200 kWp	𝑃PV
BES system	48 kWh	𝑃BES
BES terminal voltage	240 V	𝑉bes
BES total capacity	200 Ah	𝐶bes
System loads	100 kW	𝑃𝐿
PCC system voltage	11 kV	𝑉pcc𝐿𝐿,𝑅𝑀𝑆
G-VSC AC side voltage	0.23 kV	𝑉𝑡𝐿𝐿,𝑅𝑀𝑆
DC bus voltage	500 V	𝑉dc
Capacitor	10,000 uF, 50,000 uF	𝐶PV, 𝐶dc
Inductor	10 mH, 0.12 mH, 0.4 mH	𝐿1,𝐿2,𝐿𝑓0
Transformer (TR1)	0.1 MVA, 0.1 p.u.	Rating and leakage inductance
PI1, PI2 controller gains; (G-VSC voltage mode)	1, 0.005, 0.2, 1	𝑘pdc1,𝑘idc1,𝑘pq2,𝑘iq2
PI3, PI4, PI5, PI6 controller gains; (G-VSC current mode)	2, 0.001, 0.6, 0.05,; 0.1, 20, 5, 0.05	𝑘pd3,𝑘id3,𝑘pq4,𝑘iq4,𝑘pd5,𝑘id5,𝑘pq6,𝑘iq6
PI7, PI8 controller gains; (BES DC/DC converter)	1.2, 0.2, 1, 0.5	𝑘pb7,𝑘ib7,𝑘𝑝8,𝑘𝑖8
SOC limits	Max 0.95 p.u.; Min 0.5 p.u.	^aSOC𝐻,SOC𝐿
𝑉dc limits	Max 0.525; Min 0.475	^b𝑉dc,𝐻,𝑉dc,𝐿
Switching frequency	2500 Hz	DC/DC (MPPT/buck-boost) and G-VSC
Simulation time step and; running duration	0.05 ms, 4 s	Δ𝑡,𝑇𝐹

aMaximum 45% useable capacity, b5% 𝑉_dc droop characteristic.