# Effective Management System for Solar PV Using Real-Time Data with Hybrid Energy Storage System
## 3 Structure and Control Configuration of the Proposed System
### Reference Current Generation  
Case (i): the generation of \(P_{b1}\) is based on the power management algorithm (PMA) shown in Figure 7. The variables \(P_{s(t-1)}\), \(P_{b,r}\), \(SOC_{t}\), \(SOC_{max}\), \(SOC_{min}\) in PMA are the \(P_{s}\) at previous \(t_{cal}\), battery rated power, battery state of charge (SOC), maximum and minimum SOC, respectively.  
The ramp-limit control will work only if the solar power fluctuates more than the threshold limits. Thus, the battery does not operate, and the \(P\) runs remain same as the preceding value. When the variation rate is severe, the \(P_{s}\) is updated to consider limit rate, and the process continues to the next step. The maximum and minimum of SOC limits vary between 0.9 and 0.1. The battery b1 does not  
Figure 7: Power management algorithm for battery-1.  
operate when the SOC limitation is violated as a given value. When the rated power of b1 limitation is violated, the battery b1 charge/discharge power is equal to the rated power. Hence, the \(P_{b1}\) is calculated, and the value is transferred to the PMA. The generation of reference power for battery b1 is the difference between the \(P_{s}\) and \(P_{pv}\). The required amount of power per \(t_{cal}\) is based on the setting limit rate [27]. Then the \(P_{limit}\) is calculated based on the following equation,  
\[P_{limit}=\frac{t_{cal}\times\left(P_{pv,rated}\right)}{60} \tag{9}\]  
where \(P_{limit}\), \(t_{cal}\), \(P_{pv,rated}\) are the ramp-limit power, calculated time-step, and rated PV power, respectively.  
Case (ii): the power stability in the \(\upmu\)G is stated by utilizing the DC link controller [2]. Figure 8 describes the functioning of a DC link controller.  
The proposed system control configuration is shown in Figure 9. The voltage controller output is reflected by the variations in DC link voltage. Thus, the storage converters can supply the net current (\(i_{net}\)) to obtain the power balance at the DC link.  
Due to the difference in the PV/load power (i.e., \(P_{pv}>P_{l}\) (or) \(P_{pv}<P_{l}\)), the voltage controller output will vary, respectively, to regulate the \(I^{*}_{b2}\), which is the \(i_{net}\) to be provided with a battery toward sustaining the reference voltage. The battery charge or discharge depends on the PV power variations. The battery converter reference current can be taken by employing the PI-based controller resulting net current equation,  
\[i_{net}=K_{p}v_{e}+K_{l}\int v_{e}dt \tag{10}\]  
where \(v_{e}=V_{dcrdf}-V_{dc}\), is the reference and actual DC link voltage difference, which is owing to inflow and outflow power variation in the DC link. \(K_{p}\) and \(K_{l}\) are the proportional and integral constants of the voltage control loop. The \(i_{net}\) can be divided into average current (\(i_{avg}\)) and transient current (\(i_{trs}\)) to  
Figure 8: DC link controller.  
Figure 9: Control configuration of the proposed system.  
restrain the batteries from reacting to sudden changes in it. The \(i_{\text{r}\text{r}\text{g}}\) is achieved by employing a low pass filter (LPF) based on the equation below,  
\[i_{\text{r}\text{g}}(t)=\frac{1}{1+s\tau_{c}}i_{\text{net}}(t) \tag{11}\]  
In the above equation, \(\tau_{c}\) is the time constant of the LPF. The current \(i_{\text{r}\text{r}\text{s}}\) is taken by the difference between the \(i_{\text{net}}\) and \(i_{\text{r}\text{g}}\), as given below,  
\[i_{\text{r}\text{r}\text{s}}(t)=\bigg{(}1-\frac{1}{1+s\tau_{c}}\bigg{)}i_{\text {net}}(t) \tag{12}\]  
The above current \(i_{\text{r}\text{s}}\) equation is used to get the reference current for the SC converter.