Improvement of the multifunctional converter of the photoelectric system with a storage battery for a local object with connection to a grid

Abstract

The issues of improving the multifunctional converter with the combination of the function of the active filter for a photoelectric power system with a storage battery for a local object with a connection to the grid are considered. The principles of autonomous operation mode implementation with the use of the current value of the short-circuit current of the photovoltaic battery and the regulation of load power are developed. The control system of the unit with alterable structure of regulators is improved. It contains: internal current control loop of grid inverter, external voltage stabilization loop at the inverter input at work with grid and circuit with regulator of load voltage in autonomous mode. Depending on the power of the photovoltaic battery and the load, the maximum and actual value of the current of the photovoltaic battery, the degree of charge of the storage battery, limiting the current of the grid, the voltage stabilization is provided by regulating the current of the grid or current of a photovoltaic battery or current of a storage battery. This is carried out by one of the three voltage regulators, determined by the control unit. In autonomous operation mode, to maintain the possibility of recharging the storage battery, simultaneous operation of the channels for regulating the current of the photovoltaic battery and the storage battery current is possible while reducing the load voltage within acceptable limits; the maximum power mode of the photovoltaic battery is set according to the measured value of the short-circuit current of it. There is a mode of compelled storage battery charge for multi-zone tariffing. The results of simulation of the system “grid - converter - load” confirm the efficiency of the proposed solutions.