The setup for testing radiated disturbance induced by insulated gate bipolar transistor (IGBT) and auxiliary circuits was established. The radiated disturbance characteristics of auxiliary circuits and methods to suppress the radiated electromagnetic interference(EMI) were experimentally studied. The radiated EMI bandwidth of the auxiliary circuit was concentrated in 30-300 MHz. The mathematical model for an IGBT was proposed based on the setup, which includes all the structures of the IGBT in detail. The electric fields were calculated from the IGBT model using the method of moments (MOM). Moreover, the characteristics of the radiated disturbances due to the IGBT operation and the effects of metal on the radiated electric fields were experimentally and calculatingly studied in the frequency 1-30 MHz. The metal shielded box can increase the radiated electric fields by approximately 10-30 dB in 1-30 MHz. The electric fields for all frequencies decreased rapidly with the increase of distance. Additionally, methods to shield the IGBT in order to suppress the radiated EMI were proposed. The effective radiated EMI reduction from a shielded net was approximately 20 dB, and that of a shielded box was around 30 dB.

Parasitic mutual inductance between capacitors is critical for the high-frequency performance of electromagnetic interference filter. In this article, a new cancelation method is proposed to eliminate mutual inductance completely without adding additional components. The principle of the cancelation method is to design the layout of input and output traces, and the mutual coupling of traces can be equivalent to adding a negative inductance on the transfer branch of the filter to cancel the mutual inductance between capacitors. The two cancelation designs of the filters with small and large capacitor spacing are proposed, respectively. Then, the filter model is established in the finite-element method analysis tool, and the mutual inductances under different layout parameters are calculated to explore the recommended layout, which is to make the negative mutual inductance of traces fully offsets the positive mutual inductance between capacitors. Finally, the effectiveness of cancelation method and the accuracy of model are verified by experiments. The method can significantly improve the filter performance without extra costs and is expected to become a filter design that can be widely promoted.

Insulated gate bipolar transistor (IGBT) has been widely used in the voltage-source-converter-based high-voltage direct current (VSC-HVDC). However, the electromagnetic interference (EMI) generated by its fast switching process affects the normal operation of the surrounding power equipment. The switching voltage and current of IGBT are the main sources of EMI. Different driving circuit parameters result in different IGBT switching characteristics. In this article, the switching model of IGBT is introduced first and the influence of driving parameters on EMI sources is analyzed. Based on the conducted EMI experiment platform of an IGBT module, the time-domain waveforms of switching voltage and current under different driving parameters are obtained and compared with the model. Then the interference voltage spectrums are measured by an EMI receiver under different driving parameters. The influence of driving parameters on conducted EMI in 0.15-30 MHz is then analyzed and explained by combining the result of time domain and frequency domain. This article comprehensively analyzes the relationship between driving parameters and EMI sources and summarizes the influence characteristics of driving parameters on common-mode (CM) and differential-mode (DM) noise. The conclusions can help the parameters design of driving board, which can effectively reduce the conducted EMI of the converter.

3D calculation method of ion flow field is required for the crossing issue of high-voltage direct-current (HVDC) transmission lines. Appropriate computational regions and boundary conditions are critical to the calculation. In this paper, a novel method combining charge simulation method-flux tracing method (CSM-FTM) and finite element method (FEM) is proposed to optimize the ion flow field calculation. The advantage of CSM-FTM in dealing with opening domain is fully utilized. Quadratic charges are applied in CSM to assure the calculation accuracy of space-charge-free electric field. In addition, a hemisphere calculation region is adopted in order to model the HVDC lines with arbitrary cross angle. The Dirichlet boundary condition on the spherical surface in FEM calculation is obtained based on FTM. Finally, the electric field of ±800kV and ±500kV lines at a cross angle of 60° is analyzed as an example. By utilizing the proposed method, the calculation area is substantially reduced and the calculation accuracy is significantly improved.

This paper aims at developing a simulation method for the ion-flow field when HVDC transmission lines cross over HVAC transmission lines. A time-domain 3-D method is proposed in this paper, where the 3-D finite-element method and 3-D finite volume method are used to solve the Poisson's equation and the charge conservation law, respectively. The implicit temporal discretization scheme is used to accelerate the computation. An indoor test model is set up in this work, and the simulation results agree well with the measured results from this test model, which validates the proposed method. The proposed method is then used to calculate the ground-level electric field and ion current density under the crossing of ± 800-kV HVDC transmission lines and 500-kV HVAC transmission lines. The presence of HVAC transmission lines is found to have a significant influence on the ion-flow field under the crossing.

In this study, the corona‐induced vibration and audible noise (AN) on stranded conductor from positive and negative corona discharges were measured and analysed. The experiments were conducted in a semi‐anechoic chamber to reduce the inferences from environment. For the measurement of vibration, the conductor was kept in dry condition without water drops on the conductor, which is different from previous investigations and can reveal the contributions of corona‐generated space charges on the corona‐induced vibration. Besides, the measurement of vibration on the conductor was performed by using a laser vibrometer which was a non‐contact measurement device for measuring the vibration velocity. Furthermore, waveforms of corona‐induced vibration and AN were measured simultaneously to analyse the correlation between them. The time and frequency domains characteristics of the vibration velocity and AN from negative and positive corona discharge are carefully analysed and no correlated relationship in time and frequency domains can be found in the two corona effects. It can be concluded that disturbance of air molecules caused by the vibration of conductor does not contribute the corona‐generated AN.