Enhanced operation of stand-alone “Photovoltaic-Diesel Generator-Battery” system

• Frequency and voltage control of stand-alone “Photovoltaic (PV)-Diesel Generator (DG)-Battery” system.
• Takagi–Sugeno fuzzy based dc voltage controller is proposed to extract maximum power under partial shading condition of PV.
• Deloaded operation of PV from its maximum power point is incorporated.
• Inverter control is proposed to reduce oscillations in generator torque under condition of unbalanced loads.
• Since, inverter supplies the reactive power required by the load, DG needs not to supply. Hence, diesel consumption reduces.

In this paper, enhanced operation of stand-alone “Photovoltaic (PV)-Diesel Generator (DG)-Battery” system is presented. Fluctuations in output power due to weather conditions and partial shading are the common problems in PV system. Therefore, Takagi–Sugeno (TS) fuzzy based dc voltage control is proposed to extract maximum power under the conditions of fluctuating weather and partial shading. Under light load condition, deloaded operation of PV from its maximum power point (MPP) is incorporated to maintain real power balance of system. The novel inverter control helps in maintaining balanced PCC voltages and balanced DG currents under the condition of unbalanced load. Making DG currents balanced reduces the oscillations in generator torque which increases the fatigue life of shaft. Moreover, with inverter control it is achieved that inverter should supply the reactive power required by the load. Hence, DG needs not to supply reactive power which will reduce the diesel consumption. The detailed MATLAB results are presented by considering different case studies and few Real Time Digital Simulator (RTDS) results are also presented in support of theory.