OPTIMIZED CONTROL OF THE PHYSICAL BATTERY SYSTEM

ABSTRACT


INTRODUCTION
To solve photovoltaic battery performance problems, a method is needed to get the highest power is shown by the photovoltaic system.Today, with the rapid development of power electronics and materials science, engineers have access to modern, compact power electronic systems that meet the needs of high-performance power converters.Thanks to the introduction of power electronics systems, the efficiency of photovoltaic PV cells is significantly increased, but the disadvantage of these systems is that they consume an additional amount of power.But because the cost of a photovoltaic battery system is still very high and the efficiency is still low, it cannot compete well in the electricity market and become the main source of energy.
The steady development of photovoltaic cell manufacturing techniques will make the use of this technology more widely available in practice.The application of MPPT algorithms aimed to further increase the efficiency of modules in photovoltaic cells.In this paper, an mINC algorithm based on the traditional INC algorithm with the optimal stepchange voltage has shown a good result in detecting the maximum power point with strong changes in environmental conditions.school.The simulation results have shown that the mINC algorithm is more efficient than the previous old algorithms.

Photovoltaic battery model
For convenience in calculation and design, an equivalent circuit is given to replace the photovoltaic battery.
There is Ns: The quantity of series-connected cells.
Np: Order to be connected in parallel.
2. Model of the grid-connected photovoltaic battery.In addition, in this photovoltaic system, there are power conversion and control blocks that support the goal of optimal control of the photovoltaic system as shown in figure 4 and figure 5.
 Photovoltaic battery system block

RESULTS
The graph of solar radiation used in the simulation is described in fig 10. Figure 10 shows that the change of solar irradiance with time leads to voltage increase and decrease as shown in figure 11, which shows that solar distance affects voltage change leading to efficiency rate will decrease in 0.2-0.3s.From Figures 10, figure 11, and figure 12.We see that when solar radiation changes, Vpv changes accordingly.
Figure 13.Graph showing the photovoltaic battery output current.
The voltage Vpv changes is decided by the MPPT controller and Vpv always ensures that Vpv = Vmpp, at radiation 1 (kW/m 2 ) the value of active power pumped into the grid reaches 4593 (W) and Vmpp = 676 (V), at radiation 0.4 (kW/m 2 ), the value of active power pumped into the grid reaches 1697 (W) and Vmpp = 628 (V), at radiation 0.8 (kW) /m 2 ) the value of active power pumped into the grid reached 3598 (W) and Vmpp = 663 (V).The response of the system is relatively fast within 2 cycles at the time the radiation changes (t = 2s and t = 3s) as shown in figure (11~14).
From the graph of the output current of the photovoltaic battery as shown in figure 14.We have the corresponding pump current to the grid through the inverter.From Figures 16 and figure 17.We can see that with the mINC algorithm, the current injected into the grid has low harmonic distortion (THD = 3.75%).Low grid voltage harmonic distortion (THD = 0.32%).According to the grid standard harmonic distortion should be less than 5 %.An inverter with a power factor of approximately 1 pumped into the grid can be considered as a simulation system that only pumps the active power component and does not pump the reactive power component to the distribution grid.

Figure 1 .
Figure 1.Equivalent photovoltaic battery circuit.The circuit comprises output current I, output voltage V, diode (DJ), leakage current resistor RSH, and series resistor RS A mathematical equation shown in formula 2.1 shows, to prove the relationship between the output voltage and current output of the photovoltaic cell and the voltage.It is shown in figure 1 and the equivalence between current and voltage.

Figure 3 .
Figure 3. Simulation of the photovoltaic battery block.
Figure 7 and figure 8, we can establish an improved INC algorithm as shown in figure 9.

Figure 10 .
Figure 10.The graph shows the change in solar radiation.

Figure 12 .
Figure 12.Graph showing the photovoltaic battery output power.

Figure 14 .
Figure 14.Graph of current pumped into the grid through the inverter.

Figure 16 .
Figure 16.Harmonic parameters of current pumped into the grid.
Photovoltaic battery system combining MPPT controller with advanced INC algorithm shows