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This work reports a modeling methodology for the prediction of conducted emissions (CE) in a wide frequency range (up to 100 MHz), which are generated by dc/dc converters and propagate along the power buses of satellites. In particular, the dc/dc converter seen as a source of CE is represented by a behavioral model, whose parameters can be identifi...
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... Transmission lines have dedicated use in the aviation industry, worship, and satellites. 1 The electromagnetic fields interfere with the transmission lines and affect their performance drastically, which needs to be addressed. In the modern world, the dependency on electronic devices is increasing day by day; most of these devices utilize low power and operate at high frequencies, which increase their susceptibility to electromagnetic interference. ...
The coupling of electromagnetic pulse (EMP) with the star‐quad cable having reference conductor is analyzed by using the proposed model, which is based upon multi‐conductor transmission line theory. Expressions for common‐mode (CM) and differential‐mode (DM) currents are developed. Two cases are mainly discussed: the first case is the star‐quad cable with a central reference conductor, and the second case with the outside reference conductor. A rigorous comparison between these two cases shows that when the reference conductor is placed at the center, the magnitude of CM current is reduced dramatically, which is beneficial for electromagnetic compatibility (EMC). The CM current magnitude of the outside reference conductor is relatively very high due to the large CM current loop area, which is the least possible for the central reference conductor. There is no significant change in the DM current magnitude for both cases because the DM current has no direct dependence on the CM current loop area. A commercial software, FEKO, which utilizes the method of momentum (MoM), is used to compare the results of our proposed method, which are in good agreement.
... However, the fast rectangular switching action required for good efficiency also produces a wide interference spectrum, which can be a major problem [3]. The conducted noise of an SMPS will propagate in the harness of the power bus, which can lead to radiated noise [4]. There are various techniques that can be used to reduce the noise emission of an SMPS to make it comply with the aforementioned standards. ...
... The output current of both converters was 2 A. The power supplies of on-board devices can operate at similar duty cycles, but simultaneously the output power demands can be also different. In [4], there were measurements where the converter loads were asymmetrical, and it was shown that the interleaving method can still yield good results in these conditions. In our measurements, the switching frequency of both converters was chosen to be 100 kHz, since this is the traditional value used in most ESA missions [16]. ...
... The standards issued in [1] limit any on-board device emission in a 100 MHz bandwidth, but due to the limitations of the measurement setup The output current of both converters was 2 A. The power supplies of on-board devices can operate at similar duty cycles, but simultaneously the output power demands can be also different. In [4], there were measurements where the converter loads were asymmetrical, and it was shown that the interleaving method can still yield good results in these conditions. In our measurements, the switching frequency of both converters was chosen to be 100 kHz, since this is the traditional value used in most ESA missions [16]. ...
On board a satellite, there are different devices that operate from a common energy source called a power bus. Since there are many devices connected to the same power bus and they are in the close vicinity of each other, it is important that they are able to function adequately in the electromagnetic environment of the satellite without introducing intolerable electromagnetic interference to other devices. On-board devices often require voltage levels different from the bus voltage to function, and this is often produced by switching-mode power supplies (SMPS). Their switching-mode operation guarantees that there is less power loss during conversion; however, they also emit conducted and radiated noises into the direction of the power bus and the payloads. In the case of multiple SMPS powered by the same power bus, we can interleave their switching periods. Thus, their noises will cancel each other out on their common input. In this study, we are going to demonstrate the noise reduction of the interleaving method with a setup consisting of two DC-DC converters connected to a simulated power bus.
... Due to these advantages, behavioral modeling of power converters for EMC analysis has received increasing attention. Examples are in [13,14], where the power converter is represented at the output ports in terms of an equivalent circuit with a minimum number of active and passive components (Thevenin/Norton equivalent circuits), whose frequency response is extracted from measurements. Although such an approach offers several advantages, it inherently assumes that the system is linear and time-invariant (LTI) [15]. ...
G3-powerline communication (G3-PLC) is a robust communication protocol originally developed for smart metering in low-voltage power distribution networks. Modeling G3-PLC modems is an essential task to investigate electromagnetic compatibility (EMC) issues related to the coexistence of the PLC signal with the high-frequency noise affecting low-voltage networks, mainly due to the presence of power converters and non-linear loads. Since detailed information on the modem internal architecture is usually not available to the end-user, this work investigates the possibility of developing behavioral (black-box) models of G3-PLC modems, whose parameters can be estimated starting from measurements carried out at the modem output ports. To this end, suitable test benches are set up and used for model-parameter extraction as well as for validation purposes. Experiments have proven that an equivalent representation involving non-ideal voltage sources (i.e., in terms of extended Thevenin/Norton equivalent circuits) is no longer feasible for the transmitting modem, since the presence of a closed-loop control system invalidates the linearity assumption. Hence, while the receiving modem is still modeled through an impedance matrix (since it behaves as a linear device), an alternative representation is proposed for the transmitting modem, which resorts to the use of two ideal voltage sources in accordance with the substitution theorem. Experimental results prove that the proposed modeling strategy leads to satisfactory predictions of the currents propagating on the PLC system in the frequency interval of interest. Hence, it could be used in combination with high-frequency models of the other components in the network to investigate EMC and the coexistence of the PLC signal with the high-frequency noise generated by power converters.
... Approximated linear behavioural models composed of frequency-dependent impedances and sources are available in literature [1], [2]. Unitedly with circuit representations of line-impedance stabilization networks (LISNs), energy sources, and cables, these frequency-domain techniques provide a valuable tool for CE analysis [2], [4]. ...
... Behavioral models are black-box equivalent circuits identified from characterization measurements [1]- [4]. Namely, any power-electronic converter is treated as a linear, active, multi-terminal element [1] composed of current/voltage sources Manuscript and immittances, whose frequency response is identified by suitable measurement procedures in controlled test setups, involving frequency-domain [2] or time-domain instrumentation [3]. ...
... Namely, any power-electronic converter is treated as a linear, active, multi-terminal element [1] composed of current/voltage sources Manuscript and immittances, whose frequency response is identified by suitable measurement procedures in controlled test setups, involving frequency-domain [2] or time-domain instrumentation [3]. The obtained models are valid above the fundamental switching frequency, inherently include parasitic effects (e.g., stray capacitances) and enable computationally efficient CE predictions by frequency-domain computer codes [4]. As a limitation, the low-frequency functional working point (e.g., the variable dc/ac power) cannot be modeled and associated with the predicted CE. ...
... Additionally, as mentioned in Sec. I, several CE modeling approaches presented in the literature [1]- [4] are based on the extraction (by measurement or simulation) of linear active and/or passive behavioral models of power-electronic equipment, suggesting that at, the frequency of interest for CE analysis, the behavior of those systems can be reasonably predicted in the frequency domain. ...
This article investigates the conducted-emission (CE) suppression characteristics of electromagnetic interference (EMI) filters used in power-electronic equipment by time-domain circuit simulation. An operational definition of insertion attenuation is introduced by comparing the CE in the absence and in the presence of the EMI filter. For the sake of exemplification, the analysis focuses on switched-mode dc–dc converters. It is shown that the EMI-filter attenuation behaves differently from the standard insertion loss (IL) and exhibits peculiar properties in these circuits. Namely, its response is known at discrete frequencies where the converter generates CE and may strongly depend on the harmonic index so to jump between quite different levels from a harmonic component to the next one, with a pseudoperiodic behavior, which can be related to the duty cycle. This effect is caused by circuit nonlinearity and is partially mitigated if the simulation accounts for two practically relevant aspects: random instability of the duty cycle and resolution bandwidth of the EMI receiver. The dependence of the common-mode (CM) and differential-mode attenuations on the loading conditions and duty cycle is analyzed, and it is shown that linear IL models provide reasonable predictions of CM attenuation only. Finally, experimental evidence of the unveiled phenomena is presented.
... For effective characterization of power-electronic equipment as CE sources in the frequency domain, experimental methods to identify approximate, linear behavioral models composed of frequency-dependent impedances and sources were presented in [3], [4]. Together with circuit representations of lineimpedance stabilization networks (LISNs), energy sources, lumped or distributed-parameter models of cables, these frequency-domain techniques proved to be effective for CE analysis in complex systems [5], [6]. Manuscript Circuit simulation in the time domain (e.g., in the SPICE environment) is more challenging than frequency-domain analysis, as it involves detailed, component-level representation of power converters (including valves and their switching activity) [7]. ...
... It was shown that frequency-domain circuit simulation can be used to predict the filter IL for arbitrary load and line impedances. In perspective, this opens the way to the assessment of filter performance through broadband linear models of CE sources and loads [3]- [6]. The full potential of the proposed technique becomes explicit when modeling of EMI filters is to be run in combination with nonlinear, time-variant power-electronic systems, through component-level representations and time-domain circuit simulation [1], [7]- [10]. ...
A procedure for the derivation of a black-box model of electromagnetic interference (EMI) filters is proposed and discussed. The modeling approach is assessed by resorting to a real EMI filter. The equivalent circuit of the filter is directly obtained from a rational approximation of the scattering-parameter matrix measured at the filter ports. Therefore, the modeling procedure does not require any information on the internal structure of the filter (e.g., components, electrical/magnetic properties of the involved materials, connections leads, etc.). The circuit model is compatible with SPICE solvers and can be used for the prediction of conducted emissions in both the frequency and time domain. Specifically, the proposed modeling approach allows time-domain simulation and performance analysis of EMI filters in combination with power-electronic equipment (i.e., nonlinear, time-variant circuits).
... For this purpose, the black-box modelling technique in [12], which was originally adopted for modelling DC-DC converters in a satellite power system, is extended in this work. The model aims to predict the CE peaks related to the switching frequency and its harmonics exiting the AC side of a three-phase inverter connected to a PV panel. ...
... For the characterization of the passive part, most of the methods available in the literature foresee impedance measurement with the converter switched off through Impedance or Vector Network Analyzer (VNA) [15]. For instance, the method in [12] involves the use of a VNA to measure the scattering parameters then converted into admittances with the converter off, (see Figure 1a). Besides, the current sources are obtained starting from the measurement of output currents of the converter by connecting the converter to the power network through a LISN required by the standard measurement setups of conducted emissions. ...
... The first plot, Figure 7a, shows When the black-box modelling approach is applied to the DC side to assess CEs to PV panels, current probes can be used to measure the currents directly (see Figure 1a). This approach was carried out in [12] to build the black-box model of a DC/DC converter and was validated by experiment. ...
Electromagnetic interference (EMI) from renewable power systems to the grid attracts more attention especially in the low-frequency range, due to the low switching frequency of high-power inverters. It is significantly important to derive EMI models of power inverters as well as to develop strategies to suppress the related conducted emissions. In this work, black-box modelling is applied to a three-phase inverter system, by implementing an alternative procedure to identify the parameters describing the active part of the model. Besides, two limitations of black-box modelling are investigated. The first regards the need for the system to satisfy the linear and time-invariant (LTI) assumption. The influence of this assumption on prediction accuracy is analysed with reference to the zero, positive and negative sequence decomposition. It is showing that predictions for the positive/negative sequence are highly influenced by this assumption, unlike those for the zero sequence. The second limitation is related to the possible variation of the mains impedance which is not satisfactorily stabilized at a low frequency outside the operating frequency range of standard line impedance stabilization networks.
... For the sake of modelling, the behavioral model in [25,26] is exploited for the dc-dc converter. Accordingly, the active part of the converter is represented by means of two current sources (connected between each wire in the power line and ground), whose frequency spectra are exacted from measurement data. ...
... For the specific dc-dc converter here considered, the spectra of such current sources are shown in Figure 6. Moreover, the passive part of the converter is modelled by a 2 × 2 matrix of admittances, whose frequency response (not reported here for the sake of brevity) was retrieved from the scattering parameters measured at the input pins of the dc-dc converter switched off. Figure 6: Frequency spectra of the equivalent current sources S1 , S2 modelling the active part of the dc-dc converter [25,26]. ...
This work presents a hybrid random/fuzzy approach for uncertainty quantification in electromagnetic modelling, which combines probability and possibility theory in order to properly account for both aleatory and epistemic uncertainty, respectively. In particular, a typical intrasystem electromagnetic-compatibility problem in aerospace applications is considered, where some parameters are affected by fabrication tolerances or other kinds of randomness (aleatory uncertainty) and others are inherently deterministic but unknown due to human’s lack of knowledge (epistemic uncertainty). Namely, a differential-signal line in a satellite is subject to crosstalk due to a nearby dc power line carrying conducted emissions generated by a dc-dc converter in a wide frequency range (up to 100 MHz). The nonideal features of the signal line (e.g., weak unbalance of terminal loads) are treated as random variables (RVs), whereas the mutual position of signal and power line is characterized by possibility theory through suitable fuzzy variables. Such a hybrid approach allows deriving a general and exhaustive description of uncertainty of the target variable of interest, that is, the differential noise voltage induced in the signal line. The obtained results are compared versus a conventional Monte Carlo simulation where all parameters are treated as RVs, and the advantages of the proposed approach (in terms of completeness and richness of information gained about sensitivity of results) are highlighted.
... The fundamental role of electrically long buses was mentioned in Section 4 to justify the development of a circuit model starting from a distributed-parameter representation. Actually, the impact of long-cable effects is fundamental in CE analysis of inverter-fed motor systems [5,[10][11][12], as well as other powerelectronics devices such as dc/dc converters in space satellites [19,20]. A quantitative estimation of the impact of the length of the dc power bus can be exemplified here by exploiting the proposed model.To this aim, the length of the dc power bus in Fig. 10 was halved (from 3.7 m to 1.85 m) by removing 10 lumped Π cells (out of a total number of 20). ...
In the general framework of intelligent transportation, the increasing use of informationcommunication technology in full or hybrid electric vehicles requires careful assessment of electromagnetic compatibility, with specific reference to the conducted emissions (CE) generated by the inverter in a broad frequency range (10 kHz-100 MHz). To this aim, this work reports a modelling approach for the prediction of CE in electric powertrains, which is based on circuit representation of each single subsystem, that is, the battery, the inverter, the three-phase synchronous motor, and the power buses composed of shielded cables. The proposed models are able to represent both low-frequency functional aspects and high-frequency parasitic effects of paramount importance for CE analysis, and can be implemented into a Simulation-Programme-with-Integrated-Circuit-Emphasis (SPICE) solver. The proposed modelling approach is exploited to simulate virtual CE measurements according to international standard CISPR 25, and to investigate the impact of setup features, including grounding connections of shields, the propagation of CE in electrically long power buses, the operating point (power, torque, speed) of the motor-drive system.
