| Along with the development of semiconductor integrated circuit, device's operating frequency is increased, which makes the electromagnetic interference (EMI) problems severe. Based on the EMI characteristic of short-time and transient state, the key problems of EMI's mechanism analysis and integrated suppression are the forward and inverse transient electromagnetic problems in the power inverters. Electromagnetism forward problems pay attention to explore the electromagnetism transient characteristic of microstrips and corrugation surface structure. Electromagnetism inverse problems are optimizing suppression of T-shaped microstrip line's crosstalk, radio emission of pillar-teeth heatsink problems and so on.Firstly, based on analysis of scattering field on conductor covered by medium layer, the paper combines the PML-FDTD method and measure, then investigates PCB microstrip structure's scattering properties to the surface wave. Investigation results show the direct reason which generates crosstalk is the surface wave mode sustained by microstrip structure's PCB. Open triangle orifice on T shaped microstrip line is presented. Crosstalk between microstrips is suppressed. It is of reference value to high speed integrate circuit design, EMI mechanism analysis and suppression.Thirdly, transient electromagnetic characteristic of rumple surface structure, which is another emission structure of power inverter in motor system, is researched by using PML-FDTD method. The scattering fields above and in rumple space are analyzed. On this basis, the electric field distributions excited by transient electrical source around heatsink are obtained. Then the influence of heatsink's structure parameters on the heatsink antennas gains is studied. And the relations between crosstalk of Multi-heatsinks and their relative position parameter are discussed. Investigation result shows that the crosstalk is inversely proportional to their distance. In low frequency band, the crosstalk is independent of the direction of teeth and slots, and the surface wave on PCB is the main path that causes the disturbance to the close-by heatsink. In high frequency band, however, the crosstalk is greatly affected by the direction of teeth and slots. It shows that space radiation is the main path that causes the disturbance to the close-by heat sink, and the antenna gain in the direction vertical to teeth and slots is larger than that in the direction parallel to teeth and slots.Finally, based on the analysis of transient electromagnetic characteristic forward problems of microstrip line and rumple surface structure, system structure is optimized synthetically and EMI emission is suppressed. The transient electromagnetic inverse problem is explored preliminarily and a self-adaptive fuzzy genetic algorithm is proposed. Based on conventional genetic algorithm, this algorithm provides fuzzy controller, which self-adaptively adjusts the probability of genetic operator dynamically. Compared to conventional genetic algorithm, it shows distinct effectiveness, higher rapidity of convergence and better global performance. Based on the characteristic of suppression surface wave by PBG structure ground, this algorithm is combined with the unsplit PML-FDTD method and fitness function containing T shaped microstrip's signal integrity information (crosstalk, distortion, return loss) is calculated. The PBG structure ground is reconstructed. Simulation results show that: (1) PBG structure ground is effective on suppressing the crosstalk between T-shaped microstrips, and reduces the return loss and signal distortion effectively; (2) This method can adjust the weight of each signal integrity index by specifying S parameter's weight coefficient, consequently optimizes the system's PBG structure.
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