Centralized photovoltaic (PV) inverters are a type of PV inverter that features an integrated power frequency design, a wide selection of components, comprehensive heat dissipation and protection designs, extensive protection features, and redundant backup designs, resulting in high reliability. Below, we will introduce the advantages and disadvantages of centralized PV inverters.
The main advantages of centralized photovoltaic inverters are:
1. Fewer inverters are required, making management easier.
2. The inverter has fewer components and higher reliability.
3. Low harmonic content, low DC component, and high power quality.
4. The inverter has high integration, high power density, and low cost.
5. The inverter has a full range of protection functions, ensuring high power station safety.
6. It has power factor regulation and low voltage ride-through functions, and good grid regulation.
The main disadvantages of centralized photovoltaic inverters are:
1. The DC combiner box has a high failure rate, affecting the entire system.
2. Centralized inverters have a narrow MPPT voltage range, typically 450-820V, and inflexible module configuration. In areas with cloudy, rainy, or foggy weather, the power generation time is short.
3. Inverter room installation and deployment are difficult and require dedicated rooms and equipment.
4. The inverter itself consumes power, and the computer room ventilation and heat dissipation consume power, making system maintenance relatively complex.
5. In a centralized grid-connected inverter system, the module array reaches the inverter through two convergences. The inverter's maximum power point tracking (MPPT) function cannot monitor the operation of each module, so it is impossible to ensure that each module is at its optimal operating point. When a module fails or is shaded, it will affect the power generation efficiency of the entire system.
6. Centralized grid-connected inverter systems have no redundancy; if a fault occurs and the system shuts down, the entire system will stop generating electricity.
Centralized photovoltaic inverters have a power output between 50kW and 630kW, using high-current IGBTs as power devices. The system topology employs a DC-AC first-level power electronic device conversion full-bridge inverter with a power frequency isolation transformer. The protection level is generally IP20. They are relatively large and designed for indoor vertical installation.
