Zero grid with microinverters: how to minimize flux reversal?

The need to control the injection of energy into the grid is no longer an option but a requirement in numerous projects. But how can this solution be implemented with the modularity and safety of microinverters without creating an integration nightmare?

The answer lies in an ecosystem where communication is key, offering flexibility that caters to everyone from residential customers to the most complex industrial plants.

The regulatory foundation that few people talk about.

Many integrators wonder if the "zero grid" practice has a regulatory basis. The answer is yes, and it's found in the PRODIST (Distribution Procedures) of [organization name]. ANEEL (National Electric Energy Agency).

Although it doesn't use the term "zero grid," PRODIST, especially in Module 3 (Access to the Distribution System), allows projects to be approved with export limitations. The condition for this is clear: the system must have "adequate control and measurement devices."

TSUNESS presents the market with a robust zero-grid solution, combining a complete portfolio of microinverters with a high-quality communication and metering infrastructure.

TSUNESS models available in Brazil

Microinverters designed for flexibility

The foundation of any high-performance system is the inverter, which determines the parameters extracted from the module based on its MPPT characteristics and voltage and current limits.

Aligned with this concept, the TSUNESS line was developed to broadly meet market demands, as it is compatible with high-power modules, robust enough to operate in diverse scenarios, and complies with the latest applicable standards.

• Compatibility: With an input current of 18A and a voltage of 60V, they are compatible with the most modern modules;
• Robustness: With an IP67 protection rating and operating temperature from -40°C to +65°C, they withstand adverse conditions;
• Safety: Operating with a maximum DC voltage of 60V, the entire line meets the most stringent safety requirements, in accordance with NBR 17193:2025.

The exclusive feature: integrated RS485 communication.

TSUNESS microinverters have a distinctive technical feature: the ability to integrate an RS485 industrial communication port directly into the microinverter body.

Integrated RS485 port

It is this physical component that makes the difference. As highlighted in the image, the RS485 port is integrated directly into the microinverter chassis. By specifying this version at the time of purchase, the integrator ensures access to an industrial communication architecture, eliminating the need for external adapters and guaranteeing robustness and flexibility to the project.

Important: To ensure complete robustness and eliminate Wi-Fi dependency, the microinverter, DTU, and Power Meter must all be interconnected via RS485 cable. This topology creates a closed and secure ecosystem.

This exclusivity opens up a range of practical benefits for each type of client:

• For Residential Customers: With the RS485 wired connection, there is no longer any concern about connection drops that could compromise zero-grid control, as it is a physical, stable, and dedicated connection;
• For Retail: In stores, offices, or small businesses, the RS485 connection ensures reliable operation, independent of the site's IT infrastructure. Direct communication with the meter simplifies installation and maintenance, reducing the total cost of ownership and avoiding technical calls due to network problems.
• For Industry: In the industrial environment, RS485 is the native language. The integrated port allows the photovoltaic system to connect directly to SCADA systems and energy management platforms. Furthermore, immunity to electromagnetic noise makes wired communication a reliable choice for production environments.

The control ecosystem: meters and DTUs

For injection control, a fast and reliable measurement and management system is necessary. Therefore, TSUNESS offers an ecosystem of original components designed for integration.

Solution 1: Smart Wi-Fi meter

This single-phase smart meter communicates with the system via Wi-Fi, sending real-time consumption data so that the microinverter generation can be adjusted instantly, avoiding injection into the grid.

• Application: For single-phase networks only;
• Ideal for: Small residential and commercial projects where speed of installation is a priority.

Solution 2: RS485 power meter

Available in single-phase (ADL200N-CT) and three-phase (ADL400N-CT) versions, this meter connects via RS485 cable, ensuring interference-free communication and reliability for precise zero-grid control. Ideal for projects requiring stability and integration with automation systems.

DTU (Data Transfer Unit)

For large-scale projects, the DTU acts as the central communication hub. It collects data from up to 64 microinverters via RS485, communicates with the single-phase (ADL200N-CT) or three-phase (ADL400N-CT) Power Meter for zero-grid control, and sends all monitoring information to the cloud, enabling complete management of large plants. Ideal for commercial and industrial installations with multiple microinverters, ensuring scalability and centralized management.

Communication architectures

Diagram 1: Zero-grid architecture via Wi-Fi

This diagram illustrates the simplicity of the wireless solution. The microinverter and the Smart Meter communicate via the local Wi-Fi router. The cloud-based system receives consumption and generation information and commands the microinverter to adjust its output, ensuring that the energy generated does not exceed the unit's consumption.

Diagram 2: Zero grid architecture via RS485 (Direct Connection)

The RS485 communication line connects the microinverter directly to the Power Meter. This dedicated physical communication ensures an instant response and is the ideal choice for those seeking greater reliability.

Diagram 3: Zero grid architecture via RS485 (Large Installations with DTU)

This is the architecture for commercial and industrial projects seeking maximum reliability. In it, microinverters (up to 64 units per DTU) connect to the DTU and the Power Meter through a 100% wired communication network via RS485.

Safety and complete autonomy

The great advantage of this topology is that, by interconnecting microinverters, DTUs, and Power Meters via RS485 cable, the system guarantees zero-grid operation in a completely local and independent manner.

This means that network injection control continues to operate with absolute precision even without an internet connection. Physical communication ensures that the system remains stable and secure 24 hours a day, immune to Wi-Fi signal fluctuations or internet provider outages.

Conclusion

Implementing a zero-grid system can be simple, as demonstrated above, if you have the right equipment for each type of application. In this regard, TSUNESS offers a complete and technically versatile solution.

The optional RS485 port and measurement ecosystem provided by TSUNESS enable integrators to design safer, more efficient, and more reliable systems for all market segments.

The opinions and information expressed are the sole responsibility of the author and do not necessarily represent the official position of the author. Canal Solar.