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Preferred 30~80kW String Type Photovoltaic Inverter Device Shiqiang Component E-commerce Solution Product Selection
- Sep 18, 2018 -

As one of the core components of the photovoltaic power generation system, the main function of the inverter is to convert the direct current generated by the photovoltaic module into alternating current. The traditional centralized PV inverter has high power, low harmonic content and high safety, but it has the problems of weak maximum power tracking (MPPT), low protection level (only IP20) and high failure rate. The string inverter has the advantages of no difference between the modules in the series and shadow blocking. The MPPT has a wide voltage range, a small volume, and low self-consumption.


According to the characteristics of the inverter, the selection method of the PV power plant inverter can be roughly summarized as follows: 220V project selects single-phase string inverter, 8KW-20KW selects three-phase string inverter, 50KW or more project The string inverter and the centralized inverter can be selected according to the actual situation.


Therefore, for the successful cases of the serviced leading enterprises and the nearly 100 European, American and Japanese outstanding brands of Shiqiang, Shiqiang Component E-commerce has exclusively created a high-efficiency medium-power string photovoltaic scheme for groups of 30~80kW. The string photovoltaic inverter adopts a multi-channel BOOST boost circuit to reduce the optimal working point of the photovoltaic cell component and the inverter, and maximize the power generation.




 

In the power conversion unit:


Shiqiang component EVs recommend Vincotech's IGBT module, Renesas' IGBT single tube, Wolfspeed MOSFET, Wolfspeed's SiC diode, Litetelefuse's Sic MOSFET, PI or Silicon Labs driver IC, Renesas' drive optocoupler, WIMA's filter capacitor, Melexis current sensors and other products.


Taking Vincotech IGBT module as an example, it is applied to BOOST boost circuit and inverter circuit with high integration. BOOST module integrates IGBT and SiC diode. The switching loss is very low. The IGBT required for integrating the single bridge arm of the inverter module continues. Flow diode. It can make the whole structure more compact, achieve higher power density, enhance reliability, and improve the efficiency of the whole machine.


The PI isolation driver IC (SID11x2K) is the largest gate current driver chip on the market, with a drive current of up to 8A, eliminating the need for an external push-pull circuit. The internal integrated driver side +15V regulator makes the peripheral circuit simpler, saving Bom cost and PCB layout space. At the same time, it also has the largest creepage distance (9.5mm) in the industry, integrated Vce back-saturation pressure drop detection, advanced soft-shutdown function, and higher reliability.


 Wolfspeed SiC MOS tubes and diodes are used in the photovoltaic inverter BOOST circuit. The gate charge of the SiC MOS tube is as low as 62nC, the switching loss is very low, and the switching frequency can be operated above 100kHz. The reverse recovery current of the SiC diode is zero, the high frequency switching circuit is supported, and the switching loss is extremely low, which can effectively reduce the switching loss and improve the efficiency of the whole machine.

 

In the auxiliary power module:


There are Wolfspeed's SiC MOSFETs, SG Micro's DC-DC and LDO recommendations.


Among them, Wolfspeed's SiC MOS tube and diode are applied to the photovoltaic inverter BOOST circuit. The gate charge of SiC MOS tube is as low as 62nC, the switching loss is very low, and the switching frequency can run above 100kHz. The reverse recovery current of the SiC diode is zero, the high frequency switching circuit is supported, and the switching loss is extremely low, which can effectively reduce the switching loss and improve the efficiency of the whole machine.


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