Balancing method and the device for state of charge (SOC) of energy storage system

• Main Authors: ZHANG JURUI, LI ZHIJIAN, WU JUNYONG, YANG HAILONG, HAO LIANGLIANG, FENG BAOQUAN, CHEN RUIJUN, MEI DONGSHENG, ZHANG XIWEI, AN KE
• Format: Patent
• Language: English
• Published: 17.02.2016
• Subjects: CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTINGELECTRIC POWER; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER; ELECTRICITY; GENERATION; SYSTEMS FOR STORING ELECTRIC ENERGY

An embodiment of the invention provides a balancing method and the device for the SOC of an energy storage system. The method comprises the steps that the average value of SOC values of all energy storage units on each phase circuit in three phases of circuits of a gird is calculated respectively so that the average value of the SOC values corresponding to each phase circuit is obtained, and the average value of the SOC values of the three phases of circuits is calculated according to the average value of the SOC values corresponding to the three phases of circuits; a first triangle is formed taking the average value of the SOC values of the three phases of circuits as a center line, and the gravity center hasor of the first triangle is obtained; a second triangle is formed taking the average value of the SOC values corresponding to the three phases of circuits as a center line, and the gravity center hasor of the second triangle is obtained; reference zero sequence voltage is calculated according to the gravity center hasor of the first triangle and the gravity center hasor of the second triangle; the reference zero sequence voltage is added to voltage of the three phases of circuits respectively. According to the scheme, interphase SOC is balanced through the added reference zero sequence voltage, complicated time-consuming operation such as table-referring calculation and 3/2 conversion is avoided, and software calculation burden is reduced.