As the core device in the photovoltaic system, the solar inverter is responsible for converting DC power into AC power. Its electromagnetic compatibility (EMC) is crucial to the stable operation of the entire system. Electromagnetic interference (EMI) may not only affect the performance of the inverter itself, but may also cause adverse effects on surrounding electronic equipment. Here are a few ways to eliminate electromagnetic interference from solar inverters:
- Grounding
Grounding is one of the basic methods to eliminate electromagnetic interference. The metal shell of the inverter should be properly grounded to ensure that current can be safely conducted in the event of current leakage, reduce the risk of electric shock, and effectively reduce electromagnetic interference between equipment. Grounding design needs to consider ground wire layout and impedance at different frequencies to ensure effective discharge of static electricity.
- Filtering
Filtering is an important means to control the transmission of electromagnetic interference. The input and output ports of the inverter should be designed with EMI filters, such as X capacitors, Y capacitors and common mode inductors. They can effectively filter out high-frequency interference signals and prevent the inverter from emitting noise interference to the outside world. At the same time, Suppress external interference from entering the system.
- Blocking
Shielding is the isolation of electromagnetic interference by using a housing made of conductive material. The inverter can be packaged in metal such as aluminum or iron to block the propagation path of electromagnetic interference. Shielding can effectively suppress electromagnetic interference propagated through space and reduce the leakage of electromagnetic energy radiated inside the inverter.
- Soft switching technology
Soft switching technology can effectively reduce the rate of change of voltage and current and reduce electromagnetic interference. Soft switching reduces the magnitude of electromagnetic interference by reducing the loss during switching action. But soft-switching technology may increase circuit complexity and cost.
- Optimize inverter design
The PCB layout and design of the inverter has a significant impact on electromagnetic compatibility. Properly designing the trace width and length of the PCB board, adopting a tic-tac-toe mesh wiring structure, and using decoupling capacitors and other measures can reduce electromagnetic interference.
- Control algorithm optimization
The control algorithm of the inverter has a direct impact on the harmonic content. By increasing the switching frequency and adopting multi-level inverter technology, the harmonic content of the output current can be effectively reduced, thereby reducing electromagnetic interference.
- Parallel harmonic cancellation
When multiple inverters work in parallel, due to differences in line impedance, the harmonics generated by different inverters can cancel each other out, thereby reducing the harmonic value of the overall system.
- Electromagnetic compatibility standards
The inverter should comply with relevant electromagnetic compatibility standards, such as GB4824-2004, etc. These standards set forth limit requirements for the conducted emission and radiated emission of the inverter to ensure that the harmonic current of the inverter at different load rates does not exceed specified value.
9.Isolation measures
The use of isolation transformers or photoelectric isolators can cut off the conduction path of electromagnetic noise. Isolation transformers use the principle of electromagnetic coupling to achieve electrical isolation and reduce electromagnetic interference.
- Magnetic ring application
Using magnetic rings on the input and output wires of the inverter can reduce radiation interference on the wires and prevent interference signals from being transmitted outward.
in conclusion
Through the above method, the electromagnetic interference of the solar inverter can be effectively eliminated and the stability and reliability of the system can be improved. Inverter manufacturers should pay attention to electromagnetic compatibility design and ensure that their products comply with relevant electromagnetic compatibility standards. At the same time, users should also take appropriate measures when installing and using inverters to reduce the impact of electromagnetic interference on system performance.