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ABSTRACT: The compliance with standards calls for proper designed EMI filters. EMI typically comprises common mode (cm) and differential mode (dm) noise. A systematic optimization of EMI filters requires the knowledge of the contribution and distribution of these two noise sources. The paper discusses different methods that allow the independent measurement of cm and dm noise. One suitable method described in detail integrates the separation set-up into the Line Impedance Stabilization Network (LISN). However, a correct interpretation of the measured results requires a characterization of the unavoidable modal conversion of the complete set-up - i.e. the measured level at the dm output in case of pure cm excitation and vice versa. As shown in this paper, the implementation of a standard LISN introduces a high amount of imperfections causing the undesired modal conversion. Thus, for the first time, this paper describes the characterization of the whole set-up including the LISN.
Energy Conversion Congress and Exposition (ECCE), 2010 IEEE; 10/2010
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ABSTRACT: The cumbersome derivation of the steady-state characteristics of resonant converters can be simplified by means of the state-plane analysis. Under the assumption of ideal components, a closed-form solution can be derived in case of the series resonant converter above the resonant frequency. However, losses due to parasitic resistances cannot be easily included within this approach. Nevertheless, a more precise prediction of the converterpsilas output characteristics taking the conduction losses into account is desirable. Therefore this paper describes a simple extension to the regular approach that leads to better agreement with measurements. This approach is based on the results derived under ideal assumptions, thus avoiding a more complicated and tedious analysis including the conduction losses.
Power Electronics and Motion Control Conference, 2008. EPE-PEMC 2008. 13th; 10/2008
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ABSTRACT: Several different approaches for the investigation of the steady-state properties of resonant converters have been published. In addition to solving the occurring equations in the time domain, which turns out to be quite cumbersome, the designer can make use of approximate approaches in the frequency domain. Two of these methods are compared to the exact solution with regard to their accuracy and mathematical complexity within this paper for the multi-resonant LCC converter with inductive output filter. Additionally, a minimized set of nonlinear equations is derived in case of the exact solution based upon the state-plane technique.
Power Electronics Specialists Conference, 2008. PESC 2008. IEEE; 07/2008
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ABSTRACT: Electronic ballasts are necessary to use light emitting diodes (LEDs) for illuminating purposes powered from the mains. As a consequence this paper shows an examination of two white LEDs considering the resulting losses in luminous efficiency if the LEDs will be driven with different current waveforms as they typically occur in switch-mode power supplies. Therefore it is possible to estimate to which extend more circuitry effort is advisable.
Industry Applications Conference, 2007. 42nd IAS Annual Meeting. Conference Record of the 2007 IEEE; 10/2007
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ABSTRACT: This paper investigates a DSP-platform for the purpose to control a switch mode power supply digitally. As the PWM module and the A/D-converter are the interfaces of the digital controller to the analog power supply, both modules will be examined with regard to their performance but also to possible sources of errors. As occurring delay times in the digital controller will have an effect on the stability, the delay times will be calculated and verified by small signal measurements.
Power Electronics and Applications, 2007 European Conference on; 10/2007
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ABSTRACT: Several different approaches for the investigation of the steady-state properties of resonant converters have been published to date. In addition to solving the occurring equations in the time domain, which turns out to be quite cumbersome, the designer can make use of approximate approaches in the frequency domain. Two of these methods are compared to the exact solution with regard to their accuracy and mathematical complexity within this paper for the parallel loaded resonant LC converter with capacitive output filter. Some practical aspects are discussed by means of measured voltage conversion ratios.
Power Electronics and Applications, 2007 European Conference on; 10/2007
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ABSTRACT: Regulations like IEC 1000-3-2 impose limits on the line input current harmonics. Passive solutions to obtain mains harmonic reduction still dominate the consumer and PC market segment. Typically linear inductors are used in this application. However, some inductors found in practical designs operate in the saturation region even at power levels to be tested for compliance. On the other hand, nearly all publications dealing with design of the passive MHR circuits assume a linear inductor. This paper investigates the usefulness of non linear inductors in passive MHR circuits by extracting the non linearity and modeling the inductor. A given non linear inductor was built in a typical bridge rectifier - electrolytic capacitor configuration. The measurements confirm the compliance with the regulation. A comparison of the measurement with simulations based on the derived model reveals the usefulness of the model. Thus simulations allow for a sensitivity analysis of the air gap size with respect to compliance of the IEC 1000-3-2. This calculation requires a reasonable scaling of the measured inductance for other air gap sizes. The paper describes a suitable scaling method. A MATLAB program simulates the steady state input current wave form of the passive MHR circuit implementing the scaled non linear inductor and verifies whether the regulation is fulfilled or not. The simulations reveal the range of air gap size leading to a valid design. While the linear inductor needs either a larger number of turns in case of a larger air gap or is no longer able to comply with the IEC 1000-3-2 the non linear inductor allows for a certain variation. The sensitivity analysis demonstrates that the non linear inductor allows for some manufacturing tolerance of the air gap if designed accordingly
Power Electronics Specialists Conference, 2005. PESC '05. IEEE 36th; 02/2005
