Design Consideration of a Novel Digital Bidirectional Constant Current Source Used in Hybrid Electric Vehicle

Two novel circuit topologies dedicating to system within storage battery as standby power supply and operating as bidirectional current source used in hybrid electric vehicle (HEV) are proposed in this paper, and both advantages and disadvantages between the two proposed topologies are investigated. Functions of both discharging process with large current from battery to the relative lower voltage load end and charging process with constant current to the reverse direction are realized by the presented circuit. Meanwhile, a strategy of digital control, which implements the control of constant current for the bidirectional circuit and furthermore realization of power management for battery is achieved, is proposed as well. In addition, an opening loop control scheme base on F2407A DSP chip is adopted when inductor current is in an intermittent condition. Characteristic of excellent current source for the very digital control circuit is verified in the experiment, and these circuit topologies and control scheme can be used in HEV system