Hybrid energy storage management in ship power systems with multiple pulsed loads

• Modeling of lead acid, lithium ion and supercapacitor hybrid energy storage systems.
• Test and evaluation of 3 series-configured hybrid energy storage architectures.
• Laboratory modeling and evaluation of a system to serve 2 shipboard pulsed loads and constant load.
• Introducing “Rolling Charging” algorithm to charge each energy storage type individually.
• Specialized dispatch control scheme to coordinate dynamic charging and discharging and the control of individual energy storage units while in operation to extend runtime.

As various types of energy storage (ES) types continue to penetrate grid, electric vehicle, and Naval applications, a need arises in extending traditional analysis to cover the revised performance metrics associated with a hybrid energy storage system (HESS). Each ES device has its own respective power density, energy density, response time, and voltage stability under load. In some critical applications, such as ship power systems (SPS), it is recommended to combine two or more ES types to overcome the impediments of the other. In this paper, three different series-configured HESS are mathematically modeled, evaluated, and tested experimentally. Lead acid and lithium ion batteries as well as supercapacitor equivalent circuit models are defined as components for each mixed HESS configuration. The impulse response to a constant and pulsed load was used to evaluate each ES model. The charging of mixed ES technologies was then accomplished using a special controller to handle the unique charging constraints of each ES module. Moreover, this same controller was used to apply a “rolling charging” algorithm to extend the operating time of the HESS. The validity of the derived model and controller were validated experimentally through a hardware setup simulating a multi-pulsed load SPS profile.