Patent Application
20070259222
The present invention relates to a method of managing fuel cells, and more particularly, to a distributed control method applied to fuel cell systems.
Prior arts about fuel cell systems almost all describe the deployment of hardware in fuel cells; for example, they discuss how to construct stacked fuel cell systems or planar fuel cell systems. These prior arts contribute to the facility in configuring hardware of fuel cell systems, but fail to disclose how to manage fuel cell systems efficiently so that the fuel cell systems continue functioning at an optimal status through control.
Managing electricity well can make electrical devices like notebooks or cellular phones have longer time of use and more stable power supply. Similarly, fuel cells face the challenge of controlling electricity when applied to electrical devices. That is the reason why good control is important to advance fuel cells in the future.
In view of the aforesaid disadvantages and the importance of electricity management, a distributed control method for controlling fuel cell systems and a fuel cell system thereby are needed.
It is a primary object of the invention to provide a distributed control method for a fuel cell system and the fuel cell system operated thereby. The fuel cell system can continuously and steadily output power.
In accordance with the aforesaid object of the invention, a distributed control method for a fuel cell system is provided. An auxiliary power source first supplies power for a main control unit and a power management unit while the fuel cell system is turned on. The main control unit repeatedly receives status data of fuel cells from the power management unit or actively inquires of the power management unit to determine whether the fuel cell system is abnormal, and real-time regulates the system to maintain it in an optimal condition. The power management unit detects the status of the fuel cell using sensors, to produce the corresponding status data, and then respond the status datum to the main control unit. While the fuel cell system is turned off, fuels residual in flow channels of a fuel cell and un-drained products produced by the electrochemical reaction of a fuel cell are cleaned up, and the last status of the fuel cell before shut off is stored. According to the method, the main control unit and the power management unit keep being actuated no matter whether the fuel cell system is turned on or off. Therefore, the status of fuel cells is monitored continuously, securing the performance thereof.
The foregoing aspects, as well as many of the attendant advantages and features of this invention will become more apparent by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein:
After the power management unit 205 is actuated, a sensing module 205a composed of various sensors detects the current conditions of a fuel cell module 201. For example, the present temperature of the fuel cell module 201, the remaining content of fuels in flow channels and the concentration thereof are detected by a temperature sensor, a level sensor and a concentration sensor, respectively. Next, the power management unit 205 transmits the sensed data to the main control unit 203.
The step 102 is executed by the power management unit 205. In the step 102, the power management unit 205 repeatedly detects the status of the fuel cell module 201 using manifold sensors, and generates respondent data, such as the information about residual content of fuels, concentration of fuels, temperature in the operated fuel cells, and so forth. Besides, in the step 102, the power management unit 205 continually transfers the latest sensed data out of the fuel cell module 201 to the main control unit 203 for managing the operation of the system 20.
The step 103 is executed by the main control unit 203. In the step 103, the main control unit 203 receives the latest status data of the fuel cell module 201 from the power management unit 205 continually, and decides whether the fuel cell module 201 is abnormal based on the status data and the information about original configuration. If some abnormality occurs, warning signals will be sent out or the fuel cell system 20 will be suspended. In one aspect, the main control unit 203 in the step 103 repeatedly receives the latest status data of the fuel cell module 201 from the power management unit 205, and real-time regulates the fuel cell system 20 to maintain it in optimal operation according to the status data and the information about original configuration. In another aspect, the main control unit 203 inquires of the power management unit 205 about the latest status of the fuel cell system 20 at the same time. The main control unit 203 in the step 103 instantaneously compares the data responded by the power management unit 205 with determined settings. Warning messages may be sent out based on predetermined settings, for example, alarms flashing when the sensed temperature is out of the operational range. Or, error messages may be returned back to electrical devices, and the fuel cell system 20 is paused or stops generating electricity during a determined period of time. If the system 20 includes a temperature control system (not shown), the temperature control system will be actuated to control the operational temperature within an adequate range. Furthermore, the main control unit 203 real-time monitors the content of fuels and the concentration remaining in the fuel cell module 201. The main control unit 203 calculates these data and other data like the content of fuels and the concentration in the fuel storage device 301, and computes the optimal amount and concentration of fuels refilled into the fuel cell module 201. A fuel supply device 303, such as a pump, is driven to deliver the required fuels to the fuel cell module 201.
The step 103 performed by the main control unit 203 further comprises storing the status data of the present operated fuel cell system 20 regularly, such as percentage of the residual fuels, concentration, percentage of remaining power, and etc., through which the main control unit 203 traces and manages the operation of the system 20.
The step 104 is performed to turn off the fuel cell system 20. While the fuel cell system 20 is turned off in the step 104, the system 20 cleans up fuels inside the flow channels and residual products formed by electrochemical reactions of a power-generating unit 209. In order to prevent the power-generating unit 209 that keeps performing electrochemical reactions from being affected when users shut off the fuel cell system 20, it is noted that the procedure for turning off the system 20 should finish before the power-generating unit 209 stops working completely, such that the fuel cell module 201 does not lose its control over residual heat and water. In the procedure for turning off, some fuels may remain in flow channels of the fuel cell module 201 despite the termination of fuel supply, and the fuel cell module 201 continues operating until the remaining fuels are exhausted. The systems for controlling heat and water keep performing as well prior to the exhaustion of fuels, and hence the system 20 is less influenced by abrupt drop in temperatures or insufficient flow rates induced by shutting off the system 20, avoiding a waterlogged cathode of the power-generating unit 209.
The auxiliary power source 207 may be a primary battery, for example, dry batteries, carbon-zinc batteries or alkaline batteries. Alternatively, the auxiliary power source 207 may be a secondary battery, for example, lead acid batteries, nickel cadmium batteries, nickel hydrogen batteries, lithium ion batteries, or polymer lithium batteries. Alternatively, the auxiliary power source 207 may be other kinds of power suppliers, such as solar cells, super capacitors, or AC/DC converters.
According to the aforementioned distributed control method 10, the main control unit 203 and the power management unit 205 keep being actuated, no matter whether the fuel cell system is turned on or off. Therefore, the status of fuel cells is monitored continuously, securing the performance thereof.
These and other changes can be made to the present systems and methods in light of the above-detailed description. In general, in the following claims, the terms used should not be construed to limit the invention to the specific embodiments disclosed in the specification and the claims, but should be construed to include all power systems and methods that read in accordance with the claims. Accordingly, the invention is not limited by the disclosure, but instead its scope is to be determined entirely by the following claims.
