In grid-tied solar inverters, the start voltage is typically higher than the minimum operating voltage. This design choice is based on specific technical reasons and the characteristics of solar modules.
- Characteristics of Solar Modules: Before the inverter starts, solar modules are in an open-circuit state, resulting in higher voltages. Once the inverter starts, the modules enter an operational state, and the voltage decreases. To prevent the inverter from frequently restarting, the start voltage is set higher than the minimum operating voltage. For example, in the morning, when sunlight begins to shine, a module’s open-circuit voltage might reach 90V, but after the inverter starts, the operational voltage may drop to around 60V. If the inverter starts at an open-circuit voltage exceeding 100V, the operational voltage will be above 70V, ensuring continuous inverter operation.
- Preventing Frequent Starts: Setting the start voltage above the minimum operating voltage helps avoid frequent starting and stopping of the inverter during voltage fluctuations. This design protects the inverter’s electronic components and extends its lifespan.
- Inverter Operating Mode: After starting, the inverter does not immediately output power. Instead, it first performs self-checks to assess the state of the solar modules and the grid. The inverter will only begin outputting power when the solar power exceeds its standby power.
- Design of Technical Parameters: The maximum DC input voltage of the inverter is usually higher than the maximum operating voltage of the MPPT (Maximum Power Point Tracking). Similarly, the start voltage is higher than the minimum MPPT operating voltage, which corresponds to the open-circuit state of the modules. The open-circuit voltage of the modules is generally about 20% higher than the operating voltage.
Conclusion
The reason the inverter’s start voltage is higher than the minimum operating voltage is primarily due to the characteristics of solar modules and the operational modes of the inverter. This design enhances the stability and efficiency of the system. Understanding these technical parameters is crucial for the design and maintenance of solar systems. Geepower is dedicated to providing efficient and reliable solar inverter products to meet diverse customer needs while ensuring optimal performance of solar systems.