Patent ID: 9153974
Filing Date: 2015-10-06
Classification: H02J,Y02T

Abstract:
1. A battery parallel balancing device for regulating current to or from an attached battery pack, said device comprising: a charging field effect transistor (FET) and a discharging FET connected in series and oriented in opposite directions; a current sensor in series with the FETs, for measuring an actual current through the FETs, and the current sensor positioned between the charging FET and the discharging FET; and a control stage for adjusting a resistance of the charging FET and a resistance of the discharging FET, where the charging FET regulates the actual current to a charging target current value when the battery pack is charging and the discharging FET regulates the actual current to a discharging target current value when the battery pack is discharging, where the control stage includes a first proportional-integral control loop for the charging FET and a second proportional-integral control loop for the discharging FET, and where each of the control loops computes a control signal based on an error between the target current value and the actual current value through the FETs and provides the control signal to a gate terminal of the FET which it controls.