Research On Digital AC Power In Diesel Generator

This paper designed a single phase inverter power system based on diesel generator as primary power source, which converted three-phase AC power source of diesel generator into single phase 50Hz sinusoidal AC power. And the overall structure of the system, including hardware constitution and software algorithm, were discussed in detail.The advantages and disadvantages of various control strategies were emphatically analyzed and compared. And the method of designing double closed loop control system, namely the instantaneous voltage value outer loop and inductor current inner loop, was given in the full digital domain. The design steps of calculating the parameter of double PI controllers based on pole assignment was described in detail. Then the controllers were discredited so as to achieve high level performance for the whole system. To consummate the of performance double closed loop, several kinds of compensation technology such as DC link voltage feed-forward compensation and load current feed-forward compensation were adopted. In addition, in order to save cost, current observer was established to estimate actual load current.The basic theory and structure of repetitive control technique was introduced for the sake of overcoming the repetitive distortion induced by rectifier-type nonlinear loads. The simulation and experiment results indicated that repetitive control could reduce the influence caused by dead time and non-linear load. The fundamental cycle control delay in the repetitive control strategy seriously impact on the system's dynamic performance. Thus, double closed loop control strategy was added to the repetitive control strategy to form composite control strategy. This paper explained the structure and parameter designing of composite control strategy in detail. Results showed that composite control strategy integrated the advantages of double closed loop and repetitive control, which greatly improved the performance of the inverter system.At last, a 5KW prototype was designed, which adopted TMS320F28335 as main controller. The results showed the system achieved perfect dynamic and steady performance and meet the design task indicators with composite control strategy.