Modelling and Simulation of Grid-connected Inverter

Most of the connection and control schemes for connecting inverters to the network propose for MPPT tracking the connection of a Boost converter connected to the inverter in the power circuit. Another way of coupling is the single stage topology in which the MPPT tracking is also of the Boost converter type to obtain the reference voltage. Most control strategies use the transformation of three-phase quantities in Synchronous Reference Frame Control and power control. This paper deals with strategic control of the DC-link voltage in Stationary Reference Frame Control (SRFC) with the single stage topology in which the MPPT tracking is the Buck converter type to obtain the reference voltage. The control strategy consists of applying to the grid-side converter of two cascaded loops. Firstly, there is a fast response internal current loop responsible for power quality, which regulates the grid current, and an external voltage loop, which controls the dc-link voltage. The dc-link voltage controller is designed for balancing the power flow in the system. The design of this controller aims for system stability having slow dynamics having where the proportional gain is realized by damping controller (negative gain), which is a renewed controller to control the grid voltage and current based on negative imaginary approach.. The tests in temperature limit conditions (−10°C and +70°C) performed under STC and Nominal Module Operating Temperature (NMOT), irradiance of 800 W/m2, satisfy the requirements for good operation of the inverter.