String inverters and hybrid inverters are becoming indispensable components in solar photovoltaic power stations. Although both are inverters, they have significant differences in design, application, performance, and more.
String inverter&hybrid inverter
- Definition and Principles
- String Inverter : A type of power equipment used in solar photovoltaic systems that converts direct current (DC) energy into alternating current (AC) energy. Its principle involves converting the DC electricity emitted by photovoltaic panels into AC electricity to meet the electricity needs of homes and industries. It typically consists of a transformer, a set of electronic components, integrated circuits, and more, capable of converting the DC electricity generated by the photovoltaic panels into the AC electricity commonly used in our daily lives.
- Hybrid Inverter : Apart from converting DC to AC, it also has the function of storing electricity using battery or energy storage devices. When needed, it can release the stored electricity. Hybrid inverters usually feature bidirectional power conversion, high-efficiency charging and discharging, allowing for the utilization and supply of various energy sources.
- Application Scenarios
- String Inverter: Mostly used in industrial areas and residential areas with solar photovoltaic systems. It is primarily used to transmit the electricity generated by photovoltaic panels through AC to the areas where electricity is used. Additionally, large-scale solar power stations also require string inverters to convert the generated DC electricity into AC.
- Hybrid Inverter: Mainly used in energy storage systems or in the power grid, especially in industries with abundant renewable energy sources like solar and wind energy. They facilitate effective management and regulation of the power grid’s utilization of these new energy sources. Hybrid inverters can store energy using batteries and other devices, providing energy to grid operators during nighttime or cloudy periods.
- Working Principles
- String Inverter: The working principle is similar to that of regular inverters, converting DC into AC. However, string inverters also need to adjust both the voltage and frequency of the DC electricity to convert it into AC electricity suitable for applications. Additionally, string inverters have other functions such as smoothing power fluctuations, protective devices, data recording devices, and more.
- Hybrid Inverter: The working principle differs from string inverters and features characteristics between regular inverters and bidirectional DC/AC converters. Hybrid inverters can collect electricity from renewable energy systems like solar and wind, storing it in batteries. When needed, this stored energy can be released to the power grid or directly converted into output power. Furthermore, hybrid inverters manage and protect battery groups by controlling parameters such as current, voltage, power, temperature, and more during the charging and discharging processes.
- Performance Metrics
- String Inverter: Key performance metrics include:
- Efficiency: The efficiency of a string inverter refers to its ability to convert DC electricity into AC electricity, with higher efficiency leading to lower power conversion losses. Generally, string inverters are required to have an efficiency of 90% or above.
- Power Density: String inverters need to meet certain power requirements during operation, making power density an important metric. Typically, the power density is required to be between 1.5 to 3.0W/cm2.
- Protection Rating: String inverters should have good environmental adaptability, with external structures possessing capabilities such as waterproofing, dustproofing, earthquake resistance, fire resistance, and more. Current domestic and international standards require a protection rating for string inverters of no less than IP54.
- Hybrid Inverter: Performance metrics for hybrid inverters include:
- Response Speed: Hybrid inverters should have fast and stable response characteristics. When the system load changes, they should be able to respond quickly.
- Conversion Efficiency: The energy conversion efficiency of hybrid inverters should be relatively high to ensure efficient storage and discharge.
- Energy Storage Density: To achieve efficient storage functionality, the energy storage density of hybrid inverters should be as high as possible.
- String Inverter: Key performance metrics include:
- Costs
- The costs of string inverters and hybrid inverters also vary significantly. Generally, the number of string inverters required is much higher than that of hybrid inverters, and the price of string inverters is relatively lower
- On the other hand, hybrid inverters are higher-end products with prices generally starting from several hundred thousand yuan. They require a large number of batteries and complex technical tuning, resulting in higher operating costs.
So when selecting between the two for practical applications, it is important to consider the actual needs comprehensively, and welcome to your contact if anything you wanna discuss with us