Description of the "PV System (avg)" component from the Residential Energy Library.

Modeling Description

The "PV System (avg)" component implements a PV Panel interfaced to the grid through an average inverter model. The average modeling approach can reproduce the fundamental harmonic waveform inverter behavior according to the PV and grid conditions with no power electronics HIL core resources. The Figure 1 shows the block diagram of the "PV System (avg)" component modeling. The model is divided into two sub-circuits. The DC Side represents the PV (and eventual dc-dc converters). An MPPT algorithm (Perturb and Observe Method) provides the voltage reference to the DC voltage bus. As a result, the DC power measured from the PV Panel is used as the active power reference for the inverter control, while the reactive power is set to zero. A generic current controller in the dq-frame is used as the inner loop for the inverter control.

pv avg block diagram
Figure 1. Block diagram of the "PV System (avg)" component.

Component Description

The "PV System (avg)" component is found under the Sources Category of the Residential Energy library. Table 1 shows the schematic symbol and properties window of the component. The "General" tab contains the inverter’s nominal parameters ratings: power, AC voltage, frequency, number of phases, and ground connection. The "Number of phases" and the "Ground-connected" properties change the number of power ports of the component. For the single-phase operation, just two terminals are available to the user to connect either an external grounding or an external phase to the L- port, the "Nominal AC voltage" properly configured to the adopted grid connection.

Under the "Filter" tab, the user configures the DC capacitance and the AC filter (type of filter and its parameterization). The controller parameterization is done under the "Controller" tab.

A signal-processing input port "en" at the top of the component icon turns all the loads on/off. Besides that, internal Scada Inputs are created to turn each load on/off separately.

Table 1. "PV System (avg)" in the Residential Energy library
Component Component dialog window Component parameters

pv icon

pv mask1 pv mask2 pv mask3

  • General tab:

    • Power rating [kVA]

    • Nominal AC voltage [Vrms]

    • Nominal frequency [Hz]

    • Number of phases

    • Ground-Connected

  • Filter tab:

    • AC Filter Type (L, LC, LCL)

    • Resistance RL1 Branch [Ω]

    • Inductance RL1 Branch [H]

    • Resistance RC Branch [Ω]

    • Capacitance RC Branch [F]

    • Resistance RL2 Branch [Ω]

    • Inductance RL2 Branch [H]

    • DC Capacitance [F]

  • Controller tab:

    • Current Controller Kp (Inner Loop) [pu]

    • Current Controller Ki (Inner Loop) [pu]

    • General execution rate [s]

    • MPPT Voltage step (dc) [V]

    • MPPT Initial voltage (dc) [V]

    • MPPT Execution rate [s]

References

[1] - Amirnaser Yazdani, Reza Iravani. (2010). Voltage-Sourced Converters in Power Systems: Modeling, Control, and Applications. Wiley-IEEE Press.