A Battery Pack Port Voltage Series Compensation Circuit and Its Control Strategy Design

In order to meet the demand for a stable power supply for some critical equipment and loads, it is necessary to install batteries as a back-up power source to cope with power outages caused by sudden accidents or grid failures. However, the output voltage of the battery will fluctuate considerably with the change of the battery state of charge (SOC), which may lead to the failure of some critical loads that have strict requirements for voltage stability, and then cause serious consequences. In order to ensure that the battery maintains a constant bus voltage throughout the discharge cycle, this paper proposes a DC bus series compensation scheme, i.e., a compensation device is connected in series with the output port of the battery. Through the reasonable design of the control strategy, this scheme can realize the stable regulation of the DC bus voltage, thus effectively improving the reliability of the power supply system. Finally, the topology of the proposed DC bus series compensation scheme and the effectiveness of its control strategy are verified by a hardware-in-the-loop testbed.

I. Introduction

With the development of science and technology, the power system has become an indispensable part of production and life, and many key equipment and systems have very high requirements for stable power supply. When faced with unexpected situations such as sudden power outages or grid failures, standby power is particularly important for the normal operation of production and life [1] - [3]. Batteries have become the preferred solution for backup power in many places due to their advantages of fast response, no noise, no pollution, etc., and their ability to quickly take over the power supply in case of a sudden grid failure to ensure the normal operation of critical equipment.