A proton exchange membrane (PEM) fuel cell is an electrochemical device that produces “clean” electricity from a chemical reaction between hydrogen and oxygen with only water and heat as byproducts. Mismanagement of the heat generated in the cells drops performance and jeopardizes reliable and safe operations.In a classic system the coolant controls for a PEM fuel cell stack uses a feedback control that is based on the actual temperature value measured at the outlet of the coolant channel. This is known as a “bang-bang” or proportional-integral (PI) controller. However such controls cannot completely reject the heat generated. The Auburn control system employs an extra three-way valve and control strategies based on state feedback controls. These controls follow variations in the current load and can effectively reject the generated heat. Simulations show that this invention suppresses temperature rise in the stack at sudden high load by achieving three-times faster recovery time and four-times faster supply of coolant than that attainable through existing classic PI controls. As a result the ideal oxygen excess ratio using better feedback control was sustained at a set value and the volume of certain thermal management components (such as heat exchangers) can be reduced.
Further Development: Further development opportunity areas include controls real time dynamic models Hardware-in-the-Loop simulations and advanced testing (diagnostics and prognostics).
- Increases overall efficiency by improving fuel cell performance
- Reduces total power consumption in components (7%) accomplished by controlling air blower (2%) and bypass valve (5%)
- Improves temperature and heat management increasing safety and reliability
- Reduces size of fuel cell system potentially lowering costs and improving portability
- Provides an improved dynamic response to sudden load changes improving sensitivity
Patent applications have been filed in the United States (US20090126902) and Korea.