Estudo e desenvolvimento de paralelismo de inversores para aplicação fotovoltaica conectados à rede elétrica

Abstract

Photovoltaic systems have been spreading globally as a clean energy technology that can be used in most of the planet Earth. This makes it a very interesting system for distributed generation. The key to the use of photovoltaics in distributed generation inverter is connected to the power grid. Thus the performance of this equipment directly influences the use of energy generated by the photovoltaic panels and consequently the time that the system pays for itself. The seasonal behavior of power generation, where the drive works most of the time between 10% and 90% of capacity, especially in systems without tracking, does not allow the drive to be evaluated not only by their performance at full load, but the full yield curve throughout the operating range. The proposed method improves the system performance at low power is the use of low power inverters connected in parallel to mains electricity working in installments. Thus, in the low power output is higher than if a single drive were used. This work also evaluated the consequences of parallelism in the rate of harmonic current distortion and benefits of expanding the life of the equipment and the use of redundancy . We implemented four inverters 300W output full bridge topology with switching frequency of 21.6 kHz and sampling, each controlled by a Freescale 56F8014 DSC, and a device for monitoring the inverters using a PIC18F4520 microcontroler. All devices have isolated communication interface UART with LIN protocol. The inverters were tested in operation mode continuous power sharing , where all the inverters operate with identical plots power, and staggered where the inverters come into operation upon the demand of power being processed. The results show an improvement of 3,7% in revenue sharing system between the power and continued staggered valued at weighted yield of the system (IEC-61836).