Chee Lim Nge

PV with battery in smart grid paradigm: Price-based energy management system

Smart grid that employs demand response model can indirectly control the load consumption and the distributed power generation via price signals. This paper presents a price-based EMS suitable for roof-top PV installations with battery and local load. The power output of the PV/battery systems is scheduled based on the time-varying price signals that correspond to the demand in the electricity networks. Simulation results show that the proposed EMS maximizes the total sum of revenues from the energy flow into the grid over 24-hour period.

Power management of grid-connected photovoltaic inverter with storage battery

With increased penetration of PV generation in the power grid, it becomes necessary to control the PV generation similar to the conventional power sources. Grid-connected PV systems equipped with storage batteries are capable of active power control. PV power generation can be either fed into the grid or stored in the battery. This paper presents a deterministic power management algorithm that uses closed-form approximations derived from analytical loss models. It can be configured to maximize the efficiency or the revenue in a liberalized electricity market. The battery controller emulates an optimum load-line in which the PV power is autonomously shared between the battery and the feed-in power converters.

Power loss analysis for single phase grid-connected PV inverters

This paper presents a method for power loss analysis applied on single-phase grid-connected PV inverter. The often neglected current ripple effects are included in power device switching and conduction losses. The relationships amongst component losses, output inductance, switching frequency and dc-link voltage are investigated. It is shown that current ripple effect is important to power loss analysis due to varying irradiation. The closed form solutions of component losses are proposed and verified with SPICE simulation results.

Maximum power point tracking method under partial shading conditions

The occurrence of multiple local maximum due to partial shading conditions poses a challenge to MPPT techniques. Scanning approach is able to search for global MPPs but incurs power loss during the scanning. This paper presents a strategy that reduces the scanning period by skipping parts of the voltage range. The operating principle is based on the simplified analysis of the PV characteristics. In order to account for rapidly changing atmospheric conditions, real-time MPPT technique is employed between the scanning intervals. Boost converter is developed to experimentally verify the proposed MPPT method under various partial shading conditions.