Classification of Photovoltaic Inverters

From a power perspective, photovoltaic inverters can be roughly divided into three levels:

1. High-power three-phase inverters with an output power greater than 6kW.

2. Medium-power single-phase inverters with an output power between 1kW and 6kW.

3. Micro-inverters with an output power between 200W and 500W.

In recent years, medium and small-power inverters have received more attention in the photovoltaic power generation market. Since the power of medium and small inverters is not high, they are mostly used in distributed solar power generation systems within microgrids.

As a node of the microgrid, these inverters are widely distributed in certain areas. For example, in Europe and the United States, many households install such medium and small-power inverters on rooftops. Similarly, at train stations or factory rooftops, a large number of these inverters are used to build small power stations.

Need for Communication and Management

To ensure efficient, safe, and stable operation, inverters in a certain area need to be managed. This allows them to respond to demands in a timely manner. The management method involves equipping inverters with communication modules, enabling real-time monitoring, control, and scheduling via an upper-level control system.

Key Communication Methods for Photovoltaic Inverters

A high-reliability, low-cost, and easy-to-maintain communication method is crucial for photovoltaic inverter communication. The most common methods currently include:

1. Wireless (RF) Communication

• Advantages: No wiring required, reducing costs of communication cables and installation.

• Disadvantages: High cost and strict environmental requirements, with significant interference from solar panels and electromagnetic waves.

2. RS485 Communication

• Advantages: Stable communication and strong anti-interference capability.

• Disadvantages: High cost in both installation and long-term maintenance.

3. Power Line Communication (PLC)

• Uses existing power lines for data transmission, eliminating the need for additional cabling.

• No need to invest in new wiring, saving labor and cost.

• More reliable than RF communication.

• Advantages:

By integrating PLC modules, photovoltaic inverter systems can function as microgrid nodes, capable of receiving any data transmitted through the smart grid, facilitating future functional expansion.