Parallel Pairs Of Fuel Cell Engine Control System Design

As the greenhouse effect and air pollution become more and more serious in recent years, clean energy draws much attention. Fuel cell is a kind of clean and green power generator, and fuel cell technology is hot research area. In order to improve the fuel cell output power, often apply the way fuel cell modules in series, but with the number of fuel cell in series increase, the output voltage will lead to higher, the common DC/DC converter can not meet the application requirements, and also causes the output voltage characteristics of a more soft overall. To solve the above problems, this thesis proposes the fuel cell engines parallel scheme, and studies the parallel fuel cell engine control system. The main content includes the following:First introduces the basic principles of fuel cell, describe the fuel cell engine system structure, and analysis the composition and functions of various systems, then study the series and parallel structure of fuel cell engine, compare the advantages and disadvantages of series and parallel, for practical application, propose the scheme of fuel cell engines work in parallel.Then design the control system hardware of parallel fuel cell engine. Based on the master-slave control scheme, designed the main controller, the air supply system, hydrogen supply system and temperature control system humidification system controller respectively, including signal acquisition and processing circuit, control circuit design and communication interface circuit, design USB communication interface circuit to satisfy the needs of data collection, establish CAN communication network, developed a TTCAN network communication protocol.For the dual parallel fuel cell engines features, designed algorithm model control strategy for the control of air flow; for the temperature that have greater lag, nonlinear, time-variation feature, proposed a fuzzy-PID control algorithm, and conducted the simulation, achieved good results in practice; to protect the fuel cell, made four working mode for parallel fuel cell, adaptive control algorithm was designed to coordinate the air supply, so that parallel fuel cell engine output as consistent as possible.The control system has been applied on a parallel fuel cell engine developed independently by Wuhan University of Technology, the experimental results show that the control system runs stability, the control strategy play a good performance on the fuel cell engine in parallel.