Explore the advantages, disadvantages and application prospects of string photovoltaic inverters

In solar power generation systems, photovoltaic inverters are essential components.Compared with general inverters, their characteristics are mainly reflected in their maximum power point tracking (MPPT) function and low voltage ride-through capability for grid security.String and centralized solar inverters are the two primary categories of typical photovoltaic inverters available today.

String photovoltaic inverter
The string photovoltaic inverter converts the DC power generated by the photovoltaic modules directly into AC power, aggregates it, boosts it, and then connects it to the grid. As a result, this kind of inverter's power is comparatively low, making it appropriate for solar power plants with power outputs under 50kW.

Advantages of string photovoltaic inverter:

1. It minimizes the discrepancy between the inverter's best operating point and the photovoltaic cell module, maximizing power generation, as it is not affected by module variances or shadow occlusion between strings.
2. MPPT has a wide voltage range and more flexible component configuration, making it suitable for power generation in rainy weather conditions.
3. Small size, less floor space, no need for a dedicated machine room, and flexible installation.
4. Minimal self-power consumption and minimal failure impact.

Problems with string photovoltaic inverters:

1. There is little electrical clearance for power devices, and the application is not very strong in high-altitude regions.
2. Multiple components are integrated together, resulting in slightly poor stability.
3. Multi-inverter layout makes system monitoring more difficult.

centralized solar energy inverter

The direct current produced by solar modules is transformed into alternating current, amplified, and connected to the grid by centralized photovoltaic inverters. In comparison, the power of this type of inverter is relatively large and is usually used in photovoltaic power stations above 500kW.

Centralized solar inverters have the following benefits: 

1. Excellent stability, low quantity, easy to handle, high power, and simple maintenance.
2. Full protection features, little harmonic content, excellent power quality, and elevated safety.
3. It features excellent grid control, low voltage ride-through, and power factor adjustment functions.

Problems with centralized photovoltaic inverters:

1. It is not feasible to create every component at the ideal functioning point, the MPPT voltage range is limited, and the component arrangement is rigid.
2. It is rigid to install, takes up a lot of space, and needs a separate computer room.
3. It consumes a lot of power and requires a lot of ventilation and heat dissipation in the computer room.

In summary, string PV inverters offer greater benefits in terms of system security, operation and maintenance expenses, and failure rate. This is why buyers in large photovoltaic systems are increasingly inclined to choose string photovoltaic inverters. instead of centralized photovoltaic inverters.