Mitsubishi Electric announced today new advanced battery-control technology that estimates fluctuations in renewable power sources, such as photovoltaic and wind-turbine generation, and controls battery charge/discharge to minimize power frequency deviation, thereby ensuring high-quality power systems that make extensive use of renewable energy. Conventional battery control technology for micro-grids is based on the frequency feedback method. This method controls battery charge/discharge only after frequency deviation is detected, so the level of frequency-control performance is relatively low. Another method maintains constant tie-line power flow at the renewable energy site, but has the drawback of requiring equipment to be installed at every site.
Mitsubishi Electric’s new technology estimates total fluctuation based on information about the local power system, controls battery charge/discharge to compensate for fluctuations before frequency deviation occurs. The technology already has been deployed by Kyushu Electric Power Company on a demonstration basis using wind turbines and lithium-ion batteries in Iki, Nagasaki Prefecture, Japan. Mitsubishi Electric has also developed a technology to maximize battery performance. Battery performance deteriorates due to inhomogeneous characteristics that can develop after a long period of use. New monitoring technology from Mitsubishi Electric accurately estimates each battery’s state of health (SOH) by monitoring charge/discharge current, voltage etc., as well as using other evaluation data. The estimated SOH can be used to control the battery for maximized performance, regardless of type or make of battery.
