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2.1
INTRODUCTION
This section outlines the major works reported so far in the electromagnetic interference noise Generation, Suppression techniques and the EMI filter circuits.
2.2
EMI NOISE GENERATION / EMISSION
Shaotang Chen (1999) proposed a theory to explain how EMI is generated. The theory states that the EMI can be produced from the system by two different mechanisms: Viz. parasitic capacitive coupling and inductive load current switching. Each of the EMI mechanism is discussed in detail.
Suppression methods are also suggested to help effectively to reduce the EMI emission. Validations of the theory and suppression methods are then performed experimentally, on a brushless motor drive.
Firuz Zare (2009) has discussed several aspects of high frequency related issues of modern AC motor drive systems, such as common mode voltage, shaft voltage and resultant bearing current and leakage currents.
Conducted and radiated emissions are major problems in modern motor drives that produce undesirable effects on electronic devices. In modern power electronic systems, increasing power density and decreasing cost and size of system are market requirements. Switching losses, harmonics and EMI are the

14 key factors which should be considered at the beginning stage of a design to optimise a drive system.
Thomas Ortmeyer et al (2000) have discussed the generation of the voltage in the PWM frequency range of the inverter, particularly for differential mode and common mode signals. A model is developed to study the propagation of these frequencies through the input and output leads of the inverter. The paper provides a discussion of the various techniques for reducing the inverter output in this frequency range, and it is shown that both common-mode and differential-mode noise reduction should be considered.
Chingchi Chen et al (2000) have proposed low cost and simple strategies to debug high-power converters. Instead of powering up the system to generate a noise disturbance, external disturbance is injected to simulate the converter noise, and the responses on various spots are observed accordingly.
By correlating the signals injected to the responses observed, the system characteristics can be estimated. Then, the EMC features under full-power operation can be predicted. Without a need to power up a system, novel debugging strategies are proposed to characterize the electromagnetic compatibility features of power converters. Simple strategies are introduced in this paper to characterize the equivalent noise source and the system distribution paths. Importantly, the distribution path features can be characterized by injecting an external noise into the system and then the distributed noise is monitored. By correlating the signal injected and the responses observed, the system characteristics can be estimated, making it a very useful tool for preliminary EMC screening / debugging.
Jih-Sheng Lai et al (2004) have discussed, a 12 V, 1.2 kW, permanent magnet AC motor drive, tested extensively at a wide frequency range, and the frequency spectra are partitioned for identification of the noise source and its propagation path. The identification of EMI source and path in

15 a low voltage high-current AC motor drive system is non-trivial. In this paper, the inverter switching related noise is identified through both measurement and simulation. The identification of parasitic inductance through time-domain reflectometer measurement helps verify the voltage spike during turn-off and the current spike during turn-on. The conducted EMI noise caused by the propagation path including parasitic components of bus capacitor, DC bus, and devices is proven to be identified in this paper. The ultimate goal of the EMI study is to understand the causes of EMI and find ways of alleviating or eliminating them.
Maxime Moreau et al (2009) deal with conducted electromagnetic interferences in adjustable-speed drive systems. For some years, the use of high-speed switching power devices in ASDs induces high-voltage (dv/dt) and high-current (di/dt) variations that excite the parasitic elements of the power circuit, inducing conducted emissions. The advent of these devices has thus generated several unexpected problems, such as premature deterioration of motor ball bearings and high increases in the EMI levels, which are caused by the circulation of the high-frequency currents. In order to evaluate the level of the common-mode and the differential-mode currents in the ASD system, it is necessary to use a precise model of the pulse width modulation inverter, power cable, and AC motor that takes into account various phenomena, which appear when the frequency increases. First, a PWM inverter and shielded four-wire power cable model is presented. Then, a new high-frequency modeling method of the AC motor is proposed. Finally, the ASD system is simulated and the results obtained are compared to the experimental measurements in the frequency and time domains.
Xuejun Pei et al (2003) have presented a study of conducted EMI emission in PWM inverter complying with the EMC standard in15KHz -
50MHz ranges. Major circuit components including switching IGBT, passive

16 components and interconnects are modeled in high frequency domain.
Common mode and differential mode switching noise together with EMI’s filter design and topology are the key aspects that have been considered. In addition, the paper reports the conducted EMI measurement results for PWM inverter that have tamed to be decisive in the reduction of the conducted EMI.
Qingnan Li et al (2010) have discussed, a review of bridgeless boost Power Factor Correction (PFC) converters presented at first.
Performance comparison of conduction losses and common mode electromagnetic interference are analyzed between the conventional boost
PFC converter and members of bridgeless PFC family. Experimental results are given to validate the efficiency analysis and EMI model building.
Trzynadlowski et al (1998) have discussed with results of an experimental investigation of the impact of random pulse width modulation on the electromagnetic interference generated in inverter-fed drive systems.
They have presented a novel voltage space-vector RPWM technique employing a limited pool of switching frequencies. Experiments with an induction motor supplied from a voltage source inverter, performed in a certified shielded chamber, we focus on the electromagnetic noise conducted to the mains. In comparison with the deterministic modulation case, significant reduction of the noise, especially with regard to the quasi-peak values, is shown, demonstrating an important advantage of random pulse width modulation.
Satoshi Ogasawara et al (1997) have presented theoretical and experimental relationships between radiated electromagnetic noises and common-mode and normal-mode currents, paying attention to an induction motor drive system, fed by a voltage-source pulse width modulation inverter.
A method of reducing both currents is proposed, based on an equivalent model, taking into account parasitic stray capacitors inside an induction

17 motor. Electromagnetic interference radiated by a 3.7-kW induction motor drive system is actually measured, complying with the (Verein Deutscher
Electrotechniker German standard) VDE 0871 Class A [3m]. Experimental results verify that the combination of the already proposed common-mode transformer (CMT) and the normal-mode filters (NMF’s) being proposed in this paper is a practically viable and effective way to reduce EMI resulting from both common-mode and normal-mode currents.
Zhang et al ( 2002) have presented a dual-bridge inverter approach for reducing the conducted electromagnetic interference generated by pulsewidth modulated inverters in adjustable speed drive motor systems. The novel dual bridge inverter (DBI) is controlled to generate the balanced excitation of induction motors under PWM ASD operation. Thus, the inherently generated common-mode voltage is eliminated and the resulting common-mode conducted EMI is significantly reduced. Theoretical analysis and experimental results are presented to verify this concept.
2.3
EMI/EMC NOISE SUPPRESSION TECHNIQUES
Satoshi Ogasawara et al (2000) have proposed two different circuit configurations of the active common-noise canceller. One is characterized by its dc power supply isolated from the dc link of a PWM inverter. This configuration makes it possible to integrate the Active Common Noise
Canceller (ACC) with a medium-voltage PWM inverter. The other compensates a partial frequency component of the common mode voltage.
The purpose is not to achieve complete cancellation, but to restrict only the slope in the change of the common-mode voltage applied to an ac motor. As a result, the core size of the common-mode transformer used in the ACC becomes small considerably. Experimental results show good effects of the proposed active circuits on both ground current and conducted EMI.

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Satoshi Ogasawara et al (2001) have proposed a PWM rectifier/inverter system capable of suppressing not only supply harmonic currents but also electromagnetic interference. An Active Common Noise
Canceller (ACC) developed for this system is characterized by sophisticated connection of a common mode transformer which can compensate for common-mode voltages produced by both PWM rectifier and inverter. As a result, the size of the common-mode transformer can be reduced to 1/3, compared with the previously proposed ACC. A prototype PWM rectifier/inverter system (2.2 kW) has been implemented and tested. Some experimental results show reduction characteristics of the supply harmonic current and EMI.
Poon et al (2000) have discussed the cancellation methods, and classify the basic circuit configurations for ripple current cancellation. The basis of the discussion is a “nullification” process, which can be described effectively in terms of the ideal circuit element nullor. The initial focus is on differential-mode noise cancellation, but the basic technique can be applied equally for cancelling common-mode noise. The classification provides a clear guideline for synthesizing practical cancellation circuits. Both active and passive implementation examples are given and experimentally demonstrated.
Huibin Zhu et al (2001) have discussed an analysis approach based on empirical models of the inverter components and their associated various parasitic components. The power switching devices were modeled with a physics-based device modeling technique. Using time-domain reflectometry, we characterized the major parasitic in the device modules, passive components, cables, leads, and interconnect. Simulations of a full-bridge insulated gate bipolar transistor inverter were then carried out in the time domain under hard-switching and zero voltage switching conditions. The simulated EMI spectra were compared with the experimental counterparts

19 with the separation of common-mode and differential-mode EMI. The comparisons verified the validity of the proposed modeling approach over most of the EMI frequency range. Also discussed in the paper are the softswitching effects on the inverter’s EMI.
Jean-Luc Schanen et al (2002) have discussed how to reach the best possible layout, satisfying simultaneously the minimal surface, all technological constraints due to the geometry of the components, and a reduced EMC signature. The method proposed in this paper is based on analytical or semi-analytical models for EMC prediction, and can thus be easily implemented in a common mathematical tool as MathCAD. For a given structure, it leads to the best possible layout, providing the minimum surface while satisfying simultaneously technical constraints and EMC constraints.
First of all, only geometrical constraints are taken into account of this only implies the good parameterization of the layout, taking into account the technological constraints, which is not very difficult. The consequence of this first optimization is obviously the layout corresponding to the minimal surface (17.8 mm). Adding an EMC model, with high computation performances allows imposing an additional constraint on the layout, related to the EMC spectrum of the line impedance stabilizing network. This modeling is light enough to be implemented in a MathCAD sheet. The new layout with better EMC performance is larger (29.6mm
2
), but takes advantage from insulated metal substrate by increasing the "internal" capacitances, which allows the "recycling" of common mode current. Obviously, some additional capacitor could improve far more this EMC behavior.
Yo-Chan Son et al (2002) have proposed a new active commonmode EMI filter to give better attenuation of the common-mode noise and to enhance the performance of additional passive filters .
In the variable-speed drive, the PWM inverter is used to change the input frequency of the machine.

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The existing constant-speed drive with on–off control is being replaced by variable-speed drive to attain greater efficiency and better performance.
Despite its benefits, the PWM inverter causes radio frequency disturbance, which makes it difficult to use. A large amount of high-frequency noise is generated by the switching operation of the PWM inverter and is transmitted into the source in the form of the conducted and radiated emission .The common-mode EMI has been suppressed first to secure the possible low limit of the total EMI, where the common-mode EMI spectrum is separately measured to check its reduction only. A new active common-mode EMI filter has been proposed to produce the effective attenuation in the common-mode circuit while it overcomes the limitation of the passive filter. That is, the proposed circuit provides good attenuation results without increasing the lowfrequency leakage current. Also, it can have wider application irrespective of the operating voltage. Next, the normal-mode EMI has been suppressed using pre-existing leakage inductances and proper installation of -capacitors, which finally meet the limit line of the total EMI spectrum. By analyzing empirical data, the characteristics of noise sources and their propagation paths have been analyzed, which provides a way of effectively mitigating the conducted
EMI.
Nobuyoshi Mutoh et al (2004) have proposed a four-layer printed power circuit technique that controls the differential mode noises by symmetrically forming the structure of the positive and negative power transmission lines of the power converter. Using this method the simulations show that differential mode currents appearing between the terminals of the power converters and the smoothing capacitors can be almost completely eliminated and the common mode currents are shunted into the artificial ground plane. Another method is also proposed that controls the shunted common mode currents so as to prevent series resonance phenomena by inserting damping impedance between the frame of the machine and the

21 ground .
The control methods were studied to suppress EMI noises appearing in motor drive systems. Features of the developed methods are summarized as following. The differential mode noise produced by switching operations could be suppressed by the multi-layer printed power circuit technique. The common mode currents appearing in the motor drive system were almost completely controlled by installing the damping factors between the frame of the machines and the system ground so as to suppress series resonance phenomena.
Qian Liu et al (2004) have proposed a new frequency-domain electromagnetic interference noise prediction method for switching power converters with variable operating conditions such as DC-AC converters.
Thevenin Equivalent Frequency-domain Source Model (TEFSM) is developed at one switching period. The prediction methods for both differential-mode and common-mode noise are studied. The methodology is verified by simulations and experiments using a half-bridge converter. This approach can be applied to converters with different switching control schemes. Also it can be applied to a variety of converters, such as DC-DC converters and three-phase pulse-width modulation inverters. This paper applies the previously developed EMI noise TEFSM in a half-bridge DC-AC converter. The prediction and test results verify that the proposed method can accurately and effectively prevent EMI noise. The EMI noise level is mainly determined by the device structure, device operating condition and propagation path. The proposed method is easier, faster and more general than the timedomain method for obtaining the EMI noise spectrum. It is more accurate and generic than the existing frequency domain approach. The EMI noise of converters with other kinds of devices (such as Metal Oxide Semiconductor Field Effect
Transistors) can also be predicted. The prediction results can help to optimize
EMI filter design and provide the possibility to study EMI noise interactions between converters in a complex power electronics system.

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Meng Jin et al (2008) have presented the most common solution for modern adjustable speed drives. It is the use of induction motors fed by voltage-source inverters. The inverters using fast switching insulated gate bipolar transistors generate pulse-width modulated voltage pulses. The high carrier frequency along with fast rise and fall time of the PWM switching results in nontrivial common-mode or ground currents noise. The current component can cause electromagnetic interference noise to neighbor equipments and installations by either radiation from the motor cable or by cross-talk (inductive and capacitive coupling) with other conductors. This paper discusses the inductively coupled EMI noise from an ac drive system where susceptible devices and a common ground plant are present. The model describing the sophisticated EMI phenomenon is proposed and results measurements obtained by are presented.
Rao et al (1999) have presented a modified single phase inverter topology which has been introduced for the purposes of reducing conducted
EMI. The proposed single phase inverter topology introduces an additional bidirectional switch to the conventional topology, which allows the choice of the zero state, without necessitating unbalanced switching. The primary objective of active cancellation techniques is to balance the switching pattern of the converter under consideration, thereby attenuating the common mode voltage applied to the load. Active cancellation, therefore, aims to mitigate
EMI at its source. Since the mechanism by which common mode EMI is generated by power electronic converters varies with topology and modulation strategy, it follows that no single topological modification can be prescribed as a solution. A topological modification for common mode voltage cancellation is proposed. Two additional switching devices
(configured to form a single bi-directional device) augment the conventional topology. These devices and a carefully considered commutation strategy significantly attenuate common mode voltage applied to the load without

23 affecting the differential mode performance of the inverter. The common mode voltage applied to the load was attenuated by up to 27 dB/V by the proposed topology. The conducted emissions (measured across a LISN) were attenuated by up to 20 dB/V. The large attenuation in common mode voltage resulting from the proposed topology translates into a substantially cheaper and smaller EMI filter needed to meet regulatory specifications.
Bertrand Rovel et al (2011) deal with a simple model that can be used to forecast EMC, taking into account various control strategies. Today, electromagnetic compatibility seems to be one of the major constraints of power electronic converters and especially for variable speed drives.
Unfortunately, it is too often regarded as the last phase of the development of a converter since it represents the last step of its marketing. The estimation of the conducted and radiated disturbances by simulation offers a considerable gain from the economic point of view. These models are validated on an experimental setup, and can be used during the design of a variable speed inverter motor association. The objective is to approach by “fast” simulations the conducted emission to consider optimization processes. It is then imperative to take into account the environment of the converter which implies the modeling of cables, motors and naturally filters. The prediction method proposed permits fast and robust simulations taking into account all passive components. This method consists of replacing the switching cells of an inverter by current and voltage sources, defined in the frequency domain.
This permits to highlight the negative effects of stray elements of the structure and the importance of the motor and cable propagation paths. The results of the model agree with the experiments conducted in the radio bandwidth (150 kHz–30 MHz).
Muttaqi et al (2008) have investigated the negative effects of electromagnetic interference due to fast switching power devices (high dv/dt

24 and di/dt) used in power electronic converters and industrial equipment.
Mitigation techniques have been explored to reduce EMI noise effectively.
Remedial measures to reduce the risk of equipment malfunction and health risk due to EMI have been explored. In this paper, EMI generation and propagation mechanism, high rates of change of voltage and current in fast switching power devices (such as IGBT), modeling and identifying EMI noise sources and coupling paths have been discussed. The errors due to the frequency characteristics of LISN, transmission line, amplifier, and antialiasing filter is corrected by signal processing. For the measurement of EMI noise current, a current probe with a very wide frequency bandwidth can be used. A practical EMI measurement system has been suggested to extract more information from EMI noise through analysis in frequency-domain and time-domain, and to test equipment emitting EMI to comply with electromagnetic compatibility standards. Different filter topologies have been investigated for minimizing EMI noise and the effect of high dv/dt and di/dt due to high frequency switching.
Wei Chen et al (2005) have presented a simple frequency-domain model to predict the differential-mode conducted electromagnetic interference noise in three-phase PWM inverter. The main DM EMI source in the threephase inverter includes two currents i) the load current and ii) the reverse recovery current of the diode. The amplitude spectrum of the DM EMI source is analyzed and modeled by current source in the frequency-domain. The parasitic components are identified using network analyzer. The calculated
DM EMI result is compared with the experimental data. It is verified that the model presented in this paper can be used to predict the DM EMI generated by the three-phase PWM inverter.
Domingo-Perez et al (2011) have described a system for voltage dips testing according to IEC 1000-4-11 norm and it also tests the supply

25 current harmonic distortion according to the limits given in IEC 61000-3-2.
The system equipment is described also with the test process. The created system so used to test the dip immunity of different topologies of PWM rectifiers and proposes a new method for representing the results using power acceptability curves. The harmonic distortion is represented in a bar chart compared with the IEC 61000-3-2 limits.
Kempski et al (2005) deal with an analytical approach for decomposition of total phase EMI noises through algebraic calculations and also the fourier transform has been presented. The results of calculations have been compared to EMI currents measured on the motor side of the PWM drive system. The proposed approach can be useful in a comparative analysis of the influence of inverter control algorithms onto spectra of CM currents in a given drive system.
2.4
ELECTROMAGNETIC INTERFERENCE NOISE FILTER
Cadirci et al (2005) deal with the design of an EMI filter, including the proper selection of components, for a 4-kW boost PFC converter.
However, the filter has been designed without considering the noise source impedance though a 10-k noise source impedance value has been assumed for both CM and DM noise in the simulations.
Hirofumi Akagi et al (2002) have discussed, integrating a smallsized passive EMI filter with a voltage source PWM inverter. The purpose of the filter is to eliminate both high-frequency common-mode and normal-mode voltages from the three phase output voltages of the inverter. This solution effectively eliminates the line to-neutral common-mode voltage and shaft voltage.

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Takahashi et al (2002) have developed an active EMI filter that bypasses the zero-sequence current from the ground wire to reduce the ground leakage current. This paper focuses on integration of a small-sized, speciallydesigned passive EMI filter into a voltage source PWM inverter operated at a carrier or switching frequency as high as 15 kHz. The motivation of this research is based on the well-known fact that higher is the carrier or switching frequency, the smaller and the more effective is the EMI filter. The integration of the EMI filter makes both lines to neutral and line to line voltages sinusoidal as if the inverter were an ideal variable voltage, variable frequency power supply, when the inverter is viewed from the motor terminals. Hence, it is possible to solve all of the EMI issues caused by highfrequency common-mode and normal mode voltages. The purpose of the EMI filter is to eliminate both high-frequency common-mode and normal-mode voltages from the ac output voltage of the inverter. The viability and effectiveness of the EMI filter has been verified by a 5kVA laboratory model.
Integration of the filter into the inverter makes both line-to-line and line toneutral output voltages look purely sinusoidal as if the inverter were an ideal three phase variable-voltage, variable frequency power supply.
Rengang et al (2003) have proposed an implementation of the integrated EMI filter, based on the planar integrated inductance – capacitance structure. In power electronic converters for distributed power system frontend applications, the power electromagnetic components and the interconnections among them normally determine the total size and profile of the overall system. To reduce the size and profile of the passive components and to solve the interconnection and space utilization problems, electromagnetic integration has been a topic of research over the last few years. Their applications in resonant and PWM DC/DC converters have been presented. However, for most of the cases, the EMI filters are still implemented by using discrete passive components. A planar integrated EMI

27 filter structure for a DPS front-end converter is presented in this paper, based on the planar integrated (Inductance – Capacitance) L-C technology.
Compared with the discrete EMI filter, the integrated version has smaller profile and volume, better DM performance and similar CM performance.
Effective methods to reduce the equivalent parallel winding capacitance of the
CM inductor and Equivalent Series Inductance (ESL) of the DM capacitor are discussed and verified by experimental results. The experimental results are given; showing that the integrated DM filter is better than the discrete DM filter, while the integrated CM filter approaches similar behavior.
Gao et al (2007) explained a novel passive filter installed at PWM inverter output terminals proposed with an objective of reducing the high common-mode and differential mode voltage dv/dt value generated by PWM inverter simultaneously. For determining the parameters of the passive filter, the filter transfer function was utilized to achieve a desirable filtering performance. The detailed design procedure of the filter parameters was given. The validity and effectiveness of the proposed filter were supported by the simulation and experimental results carried out on 380V/3kW induction motor system. Further investigations also demonstrate that by making the line-to-line output voltage of inverter sinusoidal, the proposed filter permits motor to be connected with inverter through a long cable. By lower the dv/dt value of CM and DM voltage, the side effects induced by them such as shaft voltage, bearing current CM leakage current and over-voltage at motor terminals could be mitigated effectively. The waveform of line-to-line voltage is almost sinusoidal when viewed from motor side. By eliminating the dv/dt value of DM voltage, the phenomena of voltage reflection has been cancelled by the proposed filter, thus enables the motor to be connected with inverter through a long cable. It can also be concluded that the common-mode transformer makes no contribution to DM voltage.

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Yaxiu et al (2006) proposed an induction motor drive system capable of suppressing shaft voltage and electromagnetic interference. A filter developed for this system is characterized by sophisticated connection of two small passive filters between inverter output and motor which can compensate for common mode voltages produced by PWM inverter and between motor neutral point and rectifier input which can suppress leakage current and EMI.
As a result small passive filter with ability of reducing EMI in mains side and shaft voltage is approached. Experimental results show the reduction characteristics of the shaft voltage, common mode voltage and EMI.
Hongfei et al (2004) explained that the voltage source PWM inverters generate high frequency common-mode voltage, which induces high shaft voltage, leads to bearing current, and results in premature failure of the bearing. The generating mechanism of common-mode voltage of voltage source PWM inverter is discussed, which illustrates that common-mode voltage is ladder-type high dv/dt and high frequency step voltage and its amplitude varies with the states of switching devices. According to theoretical analysis and based on conventional sinusoidal output filter, common-mode connection is introduced, i.e., the neutral point of filter Y-connected RC network is connected to the midpoint of DC bus of the inverter. Thus, an improved common-mode sinusoidal output filter is achieved, which can eliminate over-voltage and suppress common-mode voltage. Thus the differential-mode and common-mode problems can be solved synchronously.
Results of simulations and experiments indicate the effectiveness of the proposed common-mode filter.
Tallam et al (2010) have proposed a new filter design, which has integrated differential-mode and common mode impedance with damping matched to typical cable surge impedance. This eliminates reflections of both differential-mode and common-mode traveling waves, and also reduces peak

29 cable charging currents. Experimental results are provided to demonstrate that the new filter has improved performance to reduce motor differential-mode and common-mode voltage, and drive output common-mode current, thus mitigating the issues specifically seen with low power AC drives.
Consoli et al (1996) have explained the development of a detailed model of a three-phase induction motor useful to evaluate separately, common-mode and differential-mode currents. The proposed approach simplifies the decoupling of the common-mode and differential-mode current spectra, using the stationary reference frame transformation, and allowing a separate analysis of the phenomena, which is useful for EMI filter design. The proposed model can also be used to evaluate new inverter modulation techniques in terms of current harmonic generation.
Takahashi et al (1997) have proposed an active EMI filter to compensate common mode current using high frequency transistors as active elements and a high frequency common mode CT. It works just as a power active filter in the harmonic compensation in the power system. The leakage current is actively suppressed to under 1/50 of the uncompensated circuit. The proposed method is also effective to decrease the EMI more than 40 dBpV.
Balan (2009) has formulated the general problem of EMI filters used for harmonic perturbations generated by the PWM converters and In particular has presented the design aspects and experimental results for EMI filter connected between the active filter and the low voltage network. For a typical solution of three phase EMI filter, a FEM modeling of magnetic circuit is performed. For the designed filter, the measured transfer characteristics, both in differential and common modes are given. Also are presented the resistive and inductive drops on the load connected at one of the phases.

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2.5
SUMMARY
A detailed literature survey has been made with respect to the different types of EMI noise generation, suppression techniques and EMI noise filters. From the literature survey, it has been found that most of the works are dealing with load side passive and active filter connection. To accomplish the objective of the research work, an Active Common mode EMI
Filter for Switched Mode PWM Inverter-fed AC drive has been proposed.
This EMI filter is introduced in the source side. This proposed filter is not affected by any load variations.