The solar-powered (DC) power supply system uses solar energy as its core energy source, integrating intelligent control and grid-connected power technologies. It mainly consists of the following core components:
Photovoltaic modules: These are typically installed outdoors in open, well-lit locations near communication base stations, such as rooftops or open spaces around the base station. Their working principle is based on the photoelectric effect of semiconductors, converting solar energy into direct current (DC) electricity to provide the initial energy input for the entire system. Common photovoltaic modules include monocrystalline silicon, polycrystalline silicon, and amorphous silicon. Monocrystalline silicon modules are widely used in base station PV systems due to their high photoelectric conversion efficiency and stability.
Superimposed light controller
MPPT charging module: This is one of the core components of the solar panel controller. It can track the maximum power point of the solar panel in real time. By dynamically adjusting the operating parameters, it ensures that the solar panel maintains optimal output under different light intensities and temperature conditions, generally improving the output efficiency by 15%-25%.
Input circuit breaker + surge protection: The input circuit breaker is used to quickly disconnect the circuit in the event of overload, short circuit, or other faults, protecting the system equipment. The surge protection device effectively prevents damage to the system caused by the instantaneous high voltage generated by lightning strikes, ensuring the system's safety under adverse weather conditions.
Output fuse: When the system experiences abnormal conditions such as overcurrent or short circuit, the output fuse will immediately trip to disconnect the output circuit and prevent the abnormal current from causing irreversible damage to the DC load equipment in the base station.
DC power meter: Real-time monitoring of solar power generation and load power consumption data. This data not only helps to understand the system's operating status, but also provides basic data for energy consumption analysis, making it easier for maintenance personnel to optimize system configuration and management.
The RTU 4U module integrates remote monitoring capabilities and supports integration with the base station's environmental monitoring system. Through this module, maintenance personnel can remotely monitor various operating parameters of the optical fiber superposition system in real time, enabling unattended operation and maintenance, significantly improving efficiency and reducing costs.
DC load power supply network
Power supply targets: Primarily DC loads such as base station main equipment and transmission equipment. Unlike traditional AC power supply which requires an inverter stage, this system can directly power these devices from the solar energy system, effectively avoiding AC inverter losses and achieving a total link efficiency of ≥95%.
Voltage compatibility: The system outputs DC48V and supports a wide range of adjustment from 42V to 60V, which can well adapt to the voltage requirements of various communication devices and ensure stable operation of the equipment.
Mains power supplement system: When solar power generation is insufficient due to weather or other reasons, the mains power supplement system comes into play. It rectifies the existing switching power supply system, converting AC power into DC power to supplement the power supply, achieving seamless switching with solar power supply and ensuring the continuous and stable operation of base station equipment.
Supporting brackets and cables: Supporting brackets are used to securely install photovoltaic modules, ensuring they maintain the correct orientation and angle under different environmental conditions to obtain optimal sunlight. Cables are responsible for connecting the various components in the system and transmitting electrical energy. Their specifications need to be reasonably selected based on factors such as the system's power and transmission distance to reduce line losses.
When sunlight is abundant, photovoltaic (PV) modules convert solar energy into direct current (DC) power. The output DC power first passes through a photovoltaic (PV) controller. The MPPT charging module optimizes the power output, tracking and capturing the maximum power output of the solar panels. A portion of the processed DC power directly powers the DC loads within the base station. Any surplus can be stored (e.g., connected to a battery) or fed back to the mains grid (provided relevant policies and equipment support are available), depending on the system configuration. When sunlight weakens and solar power generation cannot meet the base station's load demands, the mains power supplement system automatically activates. The existing switching power supply system rectifies the mains power and works in conjunction with the solar power supply to power the base station equipment. The entire switching process is fast and seamless, without affecting the operation of the base station equipment. Throughout the operation, the DC power meter monitors power generation and load consumption in real time, and the RTU 4U module transmits system operation data to the monitoring center in real time, facilitating remote monitoring and management by maintenance personnel.
High efficiency and energy saving: Adopting a direct DC power supply mode avoids the AC-DC conversion losses in traditional AC power supply, greatly improving energy utilization efficiency. Simultaneously, photovoltaic modules directly utilize solar energy to generate electricity, reducing dependence on grid power and lowering energy costs. For example, for a site with an average DC load power of 2kW, assuming 4 hours of sunshine per day (more than half of the provincial capitals in China have more than 4 hours), using a tandem photovoltaic scheme can save 2920 kWh of electricity annually.
Cost Reduction: In the long run, reducing grid power consumption can significantly lower electricity costs. For example, at one operator's site, the payback period for adopting a solar power system is approximately 5.5 years. Furthermore, in some regions, solar power generation may receive subsidies from national and local governments; for instance, Zhejiang Province provides a subsidy of 0.42 yuan per kilowatt-hour of solar power generation, further shortening the payback period.
High reliability: During periods of daylight, the system can continue to power the base station using solar energy when the mains power is interrupted. Even at night or on cloudy days, the battery can be connected in parallel with the solar system to extend the battery life and significantly reduce the risk of base station outages due to power failures. It is estimated that sites using this solar-powered system can reduce on-site emergency power generation costs by more than 80%.
Easy installation: The system can be modified without interrupting the power supply, and can be directly superimposed on the original switching power supply system. There is no need to power down and reconfigure the entire base station, which reduces the modification time and cost, and it is suitable for switching power supply systems from various manufacturers and models.
Significant environmental benefits: Using solar energy, a clean energy source, can greatly reduce carbon emissions. For example, a system equipped with 18 SPV modules is estimated to generate 7,671 kWh of electricity annually, accounting for 35.5% of the load's electricity consumption. Compared to generating electricity using fossil fuels, this can reduce carbon emissions by 4.374 tons per year.
As an innovative low-carbon energy solution, the tandem photovoltaic (DC) power supply system for base stations has demonstrated enormous application potential in the field of communication base station power supply due to its advantages such as high efficiency and energy saving, reduced costs, high reliability, convenient installation, and significant environmental benefits. With the continuous advancement of photovoltaic technology and further cost reductions, as well as relevant policies supporting the application of clean energy, the tandem photovoltaic (DC) power supply system is expected to be more widely promoted and applied in the future, injecting new vitality into the sustainable development of the communications industry and helping to achieve the "dual-carbon" goals of the communications sector. At the same time, this technology also provides a reference for power supply optimization in other high-energy-consuming locations such as data centers, possessing broad market prospects and social value.
