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As utility-scale photovoltaic projects continue to grow in size, solar tracker manufacturers and EPC contractors face increasing demands for efficient installation, dependable field operation, and simplified system integration. Tracking accuracy and communication functions are important, but the way each tracker control unit receives and manages power also has a direct impact on project design.

A string-powered architecture offers a practical alternative to conventional arrangements that rely on external power supplies or dedicated charging panels. By drawing operating power from the PV string, this approach can reduce additional power infrastructure at the tracker-row level and support a more integrated electrical layout. The TCU String Powered is designed for this type of application, combining PV-side power input with battery management and multiple control and communication functions.

Why Power Supply Design Matters in Solar Tracking Systems

A solar tracker control unit performs several essential tasks. It processes tracking instructions, controls motor movement, monitors equipment status, and exchanges information with other field devices or the plant-level monitoring system. All these functions depend on a stable and appropriately designed power source.

Traditional tracker installations may use an independent grid connection, an external power supply, or a separate solar charging panel. These arrangements can work well in certain applications, but they may also require additional wiring, mounting components, connection points, and maintenance procedures.

The impact becomes more significant when a PV plant contains hundreds or thousands of tracker rows. Even relatively small installation requirements can accumulate across a large site, increasing the complexity of field construction and equipment management.

A string-powered controller takes a different approach by sourcing its operating power directly from the PV array's DC side. This reduces the need for a separate grid power connection or dedicated charging panel for the controller, helping simplify the row-level power arrangement.

For projects in remote locations or large open areas, reducing supplementary power infrastructure can be an important consideration during system planning. However, the DC connection, electrical protection, isolation arrangements, and maintenance procedures still need to follow the project's engineering and safety requirements.

Wide DC Input Voltage for Different PV Configurations

PV string voltage varies according to module characteristics, temperature, string design, and operating conditions. A tracker controller intended for direct PV-side power input must therefore support the voltage range specified by the project.

The TCU String Powered supports an input voltage range of 300/400 to 1500 Vdc. This broad operating range gives system designers flexibility when matching the controller with different utility-scale PV configurations.

Before selecting a string-powered tracker control unit, engineering teams should verify several points:

• Actual string voltage: Check the expected voltage range under the project's operating and temperature conditions.

• DC system compatibility: Confirm that the controller's supported input range matches the PV system design.

• Electrical protection: Review overvoltage, undervoltage, and overcurrent protection requirements.

• Power continuity: Understand how the controller operates when PV-side power availability changes.

• Battery configuration: Check the battery capacity and charging strategy against the expected operating conditions.

The S350 configuration integrates a 25.6 V LiFePO4 battery, with available capacities of 3.4 Ah and 6 Ah. Its charging method uses CC-CV (constant current-constant voltage) control.

The battery forms part of the controller's power-management arrangement. When evaluating the complete system, it is important to consider PV input conditions, battery charging, backup operation, and the controller's own energy requirements together rather than treating them as separate specifications.

Reducing Additional Power Infrastructure at Tracker Rows

Installation efficiency is an important factor in large-scale solar construction. A project with many distributed tracker rows can involve substantial work in power cabling, equipment mounting, and electrical connections if each controller depends on a separate supply arrangement.

With string-powered technology, the controller receives operating power from the associated PV string DC bus. This removes the need for an independent grid connection or a dedicated charging panel for the controller itself.

Potential project-level benefits include:

• Fewer supplementary power-supply components.

• Reduced requirements for separate controller power wiring.

• A more integrated power arrangement at individual tracker rows.

• Greater flexibility when deploying control equipment across extensive PV sites.

These advantages should be considered alongside the electrical design. Direct connection to a high-voltage PV string requires suitable isolation, protection devices, cable selection, and installation procedures. Project teams should also plan for safe access during inspection and maintenance.

The purpose of a string-powered architecture is not simply to eliminate equipment. It is to create a power arrangement that is practical to install, compatible with the PV system, and manageable throughout the project's service life.

Coordinating Tracking Algorithms with Motor Control

A reliable tracker controller must do more than maintain its own power supply. It also needs to coordinate tracker positioning with solar movement, mechanical conditions, and project-specific operating requirements.

The SurgeTrack TCU S350 combines an astronomical tracking algorithm with position-sensor feedback. The algorithm calculates the expected solar position, while the sensor provides information about the tracker's actual orientation. Using both inputs allows the controller to manage positioning based on calculated targets and measured feedback.

Its specified tracking accuracy is less than ±1°, with an operating tracking range of -60° to +60°.

Motor compatibility is another important part of system integration. The S350 supports brushed and brushless motors, with adjustable motor speed. This allows the controller to be considered for different tracker drive configurations, subject to confirmation of the motor's electrical and control requirements.

Available operating modes include:

• Automatic tracking

• Fault mode

• Night mode and night return

• Fixed-angle operation

• Heavy-rain protection mode

• Strong-wind protection mode

• Heavy-snow protection mode

• Maintenance and stop modes

• Farm mode for applicable installations

Backtracking is also supported to help address row-to-row shading under suitable site conditions.

For EPC contractors and tracker manufacturers, these functions should be assessed in relation to the complete mechanical and electrical system. Motor specifications, tracker geometry, site layout, and environmental conditions all influence the appropriate control configuration.

Communication Options for Distributed Tracker Networks

Communication is essential when individual tracker controllers need to operate as part of a coordinated solar plant. A large PV site may contain numerous distributed control units, so the communication network must support data exchange between field devices and higher-level monitoring equipment.

The S350 supports Sub-1GHz, LoRa Mesh, RS485, and Bluetooth communication, together with the Modbus RTU protocol. It also supports a self-forming mesh network.

A self-forming network can simplify deployment by reducing the need to configure each TCU individually for mesh-network formation. This can be useful during commissioning when a project includes a large number of controllers distributed over a wide area.

The communication interfaces serve different purposes:

• Sub-1GHz and LoRa Mesh: Wireless communication options for distributed field devices.

• RS485: A wired interface for compatible control and monitoring architectures.

• Bluetooth: Local communication for setup and debugging-related operations.

• Modbus RTU: A protocol for exchanging information with compatible equipment and monitoring systems.

Debugging is supported through PC, mobile devices, and NCU equipment.

When integrating a tracker controller into a solar tracker SCADA system, engineers should verify communication coverage, network topology, gateway requirements, data points, and register mapping. Modbus RTU support alone does not ensure automatic compatibility with every SCADA platform; interface configuration and system-level testing are still necessary.

Depending on the project layout and communication design, a network communication box or gateway may also be required.

Outdoor Protection for Demanding Solar Plant Environments

Tracker controllers are generally installed outdoors, where they may be exposed to dust, moisture, temperature fluctuations, and prolonged sunlight. These conditions make enclosure protection and operating-temperature limits important selection criteria.

The S350 features an IP67-rated enclosure and is specified for ambient temperatures from -35°C to 60°C. Its rated installation altitude is below 4,000 meters.

These specifications provide a reference for evaluating its suitability for different project locations. Engineers should also consider actual site exposure, mounting arrangements, cable-entry protection, and the environmental requirements of the overall installation.

Electrical protection features include overcurrent, overvoltage, and undervoltage protection. Additional environmental protection functions can be configured according to project needs.

It is important to distinguish between supported functions and the sensors needed to activate them. For example:

• Wind protection requires an anemometer.

• Snow protection requires a snow-depth sensor.

• Rain protection requires a rain gauge.

These sensors should be identified during system design and included in the equipment and integration plan where required. Confirming the sensor interfaces and control logic in advance can help avoid configuration gaps during commissioning.

Understanding Energy Consumption and Battery Requirements

The auxiliary energy demand of distributed control equipment is one consideration in the overall electrical design of a PV plant. The S350 has a specified daily energy consumption of 0.05 kWh/day, providing a reference for estimating the controller's operating requirements.

This figure should be considered together with the selected LiFePO4 battery capacity, PV input conditions, charging behavior, and periods when solar generation is limited.

It is also necessary to separate controller consumption from the energy used by the tracker drive motor and other connected equipment. Motor operation can have different power requirements and should be evaluated independently when calculating the complete row-level energy demand.

A proper assessment of a string-powered control unit therefore includes the PV input, battery, protection circuits, motor interface, and communication equipment as parts of one integrated system.

A Practical Checklist for Selecting String-Powered Tracker Controllers

Comparing controllers based on one or two headline specifications may overlook important compatibility issues. Before procurement, solar tracker manufacturers and EPC contractors should review the power architecture, drive system, communication interfaces, and environmental requirements as a complete package.

Evaluation item	Points to verify
Power architecture	Compatibility with direct PV string power
DC input	Supported 300/400–1500 Vdc range
Battery	25.6 V LiFePO4, available 3.4 Ah or 6 Ah capacity
Tracking performance	Specified accuracy below ±1° and -60° to +60° range
Motor interface	Brushed or brushless motor compatibility
Communication	Sub-1GHz, LoRa Mesh, RS485, and Bluetooth
Communication protocol	Modbus RTU and project interface requirements
Enclosure protection	IP67 rating
Operating temperature	-35°C to 60°C
Environmental functions	Sensor requirements for wind, rain, and snow protection
Commissioning	PC, mobile device, and NCU debugging support
Energy demand	Daily consumption and battery operating requirements

This checklist provides a starting point for technical evaluation. Project-specific details such as wiring diagrams, communication coverage, sensor selection, protection settings, and commissioning procedures should also be confirmed with the control-system supplier.

Developing Integrated Solar Tracking Control Solutions

Solar tracking technology brings together power electronics, embedded systems, control algorithms, mechanical equipment, and communication engineering. Reliable operation depends on how these elements work together under real project conditions.

Shanghai SolarSurges Technology Co., Ltd. focuses on intelligent solar tracking control systems, combining hardware and software development with AI-driven tracking technologies. With more than 10 years of industry experience and a portfolio of proprietary patents, the company develops integrated control solutions for photovoltaic tracking applications.

Its multidisciplinary team includes specialists in power electronics, embedded systems, AI algorithms, and communication engineering. The company's development approach emphasizes continuous improvement in tracking algorithms and hardware design, as well as product testing under demanding outdoor conditions.

SolarSurges reports that its TCU solutions have been deployed across more than 30 PV plants within four years. Its product philosophy also places emphasis on reliability, including dual-power backup strategies and ruggedized equipment design, while working with customers to address different project requirements.

For solar tracker manufacturers, EPC contractors, and PV project developers, the TCU String Powered offers a control-unit option that combines a wide DC input range, LiFePO4 battery management, multiple communication interfaces, tracking functions, and an IP67-rated enclosure.

As utility-scale solar projects become larger and more geographically distributed, the power architecture of each tracker row deserves careful attention. Evaluating string-powered control equipment as part of the complete tracking system can help project teams develop a more integrated installation plan and identify electrical, communication, and environmental requirements before deployment. The TCU String Powered is one solution to consider when designing a practical power and control arrangement for utility-scale PV tracking applications.

http://www.solarsurges.com
Shanghai SolarSurges Technology Co., Ltd

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