Photovoltaics (PV)

Off-Grid PV System (Stand Alone Solar Power System)

It can be divided into systems for DC loads and AC loads.
Figure 1 shows a stand-alone PV system where all circuits, including the loads, operate on DC power.

When using a load that operates on AC power, such as home appliances, the solar inverter is used to convert the DC power generated by the solar cells into AC power, as shown in Fig.2 below.
A key limitation of off-grid systems is their dependence on battery capacity; power supply stops once the stored energy is depleted. Additionally, the system must account for the continuous power consumption of the inverter, which draws standby power even when no load is connected.

Grid-tied PV System (On-Grid Solar Power System)

The grid-tied PV system is a system where the photovoltaic (PV) system is connected to the utility grid. This allows for the sale of surplus generated power back to the utility company.

Figure 4 illustrates an example of a PV system that uses household batteries to store electricity.
Any shortfall in electricity can be purchased from the grid. Such systems, which combine solar power generation with battery storage and grid connection, are often integrated into a Home Energy Management System (HEMS). They are also commonly known as hybrid solar systems.

Solar Inverter

The electricity produced by solar panels is direct current (DC). This DC power needs to be converted to alternating current (AC) for use in homes and factories. Therefore, solar inverters are used to convert DC power to AC, as illustrated in the figure below.

The development of solar inverters requires a DC power supply capable of simulating solar cell behavior. While residential systems typically operate between 300 V and 600 V, modern commercial and utility-scale systems often require voltages up to 1000 V or 1500 V. In these testing scenarios, a programmable DC power supply with solar array simulation (SAS) capabilities is used on the input side, while an AC electronic load is connected to the output side.

IV characteristic curves of PV Cells and Panels

Measuring the I-V (current-voltage) characteristic curves of photovoltaic cells and panels typically involves electronic loads, four-quadrant power supplies, or DC-DC converters. Matsusada Precision offers optimized solutions for these applications. Specifically, our bipolar power amplifiers, such as the DOP series, are ideal for I-V curve measurement. Their four-quadrant operation allows for seamless sweeping through zero volts, enabling precise detection of the open-circuit voltage (Voc) and short-circuit current (Isc). By measuring the I-V curve, the maximum power point (MPP) of a PV cell can be determined, which is crucial for Maximum Power Point Tracking (MPPT) control in solar inverters.