Research Of Influence Of Parasitic Parameters On Conducted Electromagnetic Interference Of Power Converter

With the development of power electronics, the development direction of the electronic equipment is high-frequency, high-capacity, scholars and engineers pay more and more attention on electromagnetic compatibility of power converter. The strong electromagnetic interference (EMI) is produced by converter not only affect the normal operation of other electronic devices, but also affect human health when they prolonged exposure. At the same time, as the international electromagnetic compatible regulations increasingly stringent, the demanding of products’electromagnetic compatibility (EMC) is more and more strict. In order to reduce interference between electrical equipment, creating an electromagnetic environment, every country has developed the respective EMC standards for electrical manufacturers reference. GB9254-1998provides the limit of industrial equipment electromagnetic interference from0.15-0.5MHz is79dBμV, and frequency from0.5-30MHz the limit is73dBμV. Under laboratory conditions, electromagnetic interference of the three-phase power converter is researched in this paper.This paper takes three-phase power converter as a researched object. Construct resistors’, inductors’, capacitors’high-frequency models, and measured by an impedance analyzer, then calculate parasitic parameters. And a high-frequency simulation modeling circuit is established with them. Using SABER software simulates the circuit, analysis the effects of passive circuit parasitic, the IGBT collector of heatsink parasitic capacitance parameter to common mode interference and differential interference. IGBT collector relative heatsink parasitic capacitance greater impact on the common-mode interference, and fully demonstrates the common mode interference is mainly because of the large voltage transitions works on heatsink capacitance, generate a lot of interference current, bigger capacitance, worse interference. High di/dt works on stray inductance in the circuit caused differential mode interference, mainly depending on the stray parameters in the circuit loop. In addition, using spectrum analyzer to measure the power converter EMI, compare EMI under different control algorithms and switching frequency and identify appropriate control algorithms.Because of the parasitic inductance in the bus bar and large transient currents the switching process, the over-voltage on IGBT has been formed and cause some damage to the IGBT performance. This paper, based on the partial element equivalent circuit (PEEC), analysis the power converter of bus bar row, extract the parasitic inductance and parasitic resistance, and then bus bar structure is optimized. In the saber software to build the three-phase equivalent circuit of the converter to analyze the impact of the bus bar’s parasitic inductance to the system electromagnetic interference. The results of simulation show that the bus bar’s parasitic parameters have a greater impact on the DC side of the differential mode electromagnetic interference, and the parasitic parameters of optimized busbar reduce about one order of magnitude, significantly reducing differential electromagnetic interference at high frequency. It has significance for the design and reliability analysis of the converter main circuit.