Jing Xue

A Novel Filter Topology With Active Motor CM Impedance Regulator in PWM ASD System

This paper presents a novel hybrid output filter topology for the inverter-motor system. It is shown that the proposed filter drastically reduces the common mode (CM) voltage at the motor terminals. The proposed filter is composed of a conventional LC filter cascaded with an active motor CM impedance regulator. The active circuit, utilizing an integrated high-voltage op-amp, is very efficient in decreasing the motor CM equivalent capacitance, as well as damping the high common voltage on the motor terminal. Therefore, the motor impedance is also used as part of the filter, and the common voltage can be eliminated dynamically in the active impedance regulator by feedback control. Furthermore, the size of the passive filter can be reduced to a large extent. Experimental verification of the filter topology is provided with a laboratory system consisting of a 380-V inverter and a 0.37-kW induction motor.

On discussion of AC and DC side EMI filters design for conducted noise suppression in DC-fed three phase motor drive system

This paper discusses EMI filter design methodology for DC-fed three-phase motor drive system. An analysis of noise source and propagation path impedances of motor drive systems is conducted, a new filter design model for both AC side and DC side filter is proposed based on the impedance mismatching between the EMI filter impedances and noise source/load impedances. Using this model, the in circuit attenuation of EMI filter can be accurately predicted. The interaction between AC and DC filters is also studied in this analysis. By applying some constraint, EMI filters can be designed. This new design procedure is suitable for both DC and AC side EMI filters. Simulation and experimental results give a firm support to the proposed method.

EMI filter design and optimization for both AC and DC side in a DC-fed motor drive system

This paper proposes an EMI filter design and optimization method for both AC and DC side in a DC-fed motor drive system. Based on the noise generation and propagation mechanism, the analysis of common mode (CM) and differential mode (DM) EMI noise equivalent circuits is provided. Based on those equivalent circuits, this paper investigates the system EMI noise between AC and DC side, which shows the interaction between DM and CM noises and the interaction between adding AC and DC side filters. With these considerations, an optimized EMI filter design procedure is proposed to design CM and DM filters for both AC and DC sides. To minimize the impact on the EMI noise of one side caused by adding filter on the other side, certain order must be followed to design AC and DC CM and DM filters. Moreover, the EMI filter weight optimization method is also discussed to get the minimum weight of EMI filter and improve system power density. Simulation and experimental results verify the interaction between AC and DC filters and show that EMI filters can be designed to suppress both AC and DC EMI noise to meet the standard with the proposed EMI filter design method.

Design of output passive EMI filter in DC-fed motor drive

This paper focuses on the conducted electromagnetic interference (EMI) noise suppression solution at the ac output terminal of PWM motor drives. Dc-fed voltage source inverter (VSI) is selected as one typical topology. A practical output EMI filter design procedure is proposed. To ensure design accuracy, the procedure includes the system impedance characterization with offline measurement. Meanwhile, different damping methods are studied to avoid oscillation introduced by EMI filters. Prototype experimental results have verified the feasibility of the design procedure for both common-mode (CM) and differential-mode (DM) EMI noise suppression.

PWM impact on CM noise and Ac CM choke for variable-speed motor drives

This paper analyzes the common-mode (CM) current and CM filter size for the variable-speed motor drives with different PWM methods. The principle of CM current and CM choke saturation are studied. Some previous proposed CM deduction PWM methods such as active zero states PWM (AZSPWM) and near state PMW (NSPWM) can reduce the CM voltage peak value, However, they may not obviously reduce the CM current and CM choke volt-seconds, due to increased 3rd order switching harmonics and CM loop parameters. PWM methods should work properly with the CM loop impedance. Also, new CM volt-seconds relationship with PWM methods is proposed with consideration of CM modulation signals. Simulation and experimental results are presented to verify the analysis.

High density Modular Multilevel Cascade Converter for medium-voltage motor drive

This paper proposes a new Modular Multilevel Cascade Converter (MMCC) topology for future high density medium-voltage motor drive. The proposed topology utilizes the active ripple energy storage method for rectifier capacitance design. Simulation has been done in this paper and proves that the proposed topology works well, and the active energy storage method can significantly reduce the DC-link capacitor. Power density improvement is quantified for an example system to show the benefits of the proposed topology.

Single-phase vs. three-phase high density power transformers

In this paper, the design and comparison of single and three-phase transformers in Dual Active Bridge (DAB) Converter are carried out. DAB converter topology and operating schemes are introduced. And core-type transformers design optimization methods are proposed for both single and three-phase DAB converters (DAB1 and DAB3). Based on DAB topology assumptions, single and three-phase transformers are compared in volume with various design constraints. And analysis shows that comparison result varies at different cases of flux and thermal limits. Scaled-down DAB1 and DAB3 systems have been built and temperature rises of the transformers have been tested for verification.

Mixed-mode EMI noise in three-phase DC-fed PWM motor drive system

High density filter design for electromagnetic interference (EMI) noises is essential for the variable speed motor drive system in modern transportation applications. As often being one of the major causes of bulky and heavy filter designs, the mixed-mode (MM) noise phenomenon in the three-phase motor drive system is discussed in this paper. The generation schemes of the MM noises on both DC and AC sides of the system are analyzed. According to the three-phase voltage vector modulation, the MM noises at different switching conditions are compared and summarized. Based on experimental results from a specified prototype system, the existence of the MM noises and its impact on EMI filter design is verified. Investigations show that the implementation of both CM filter and balancing X-capacitors can help attenuate the MM noises effectively.

Modeling and design of common-mode inductor for conductive EMI noise suppression in DC-fed motor drive system

Single and three-phase common-mode (CM) inductors play a vital role in conductive CM noise suppression for motor drive system. In this paper, the CM conductive noise propagation path in the dc-fed motor drive system is analyzed. One measurement-based characterization method is discussed for determining the noise propagation path. Meanwhile, modeling methods for the impedance of both single and three-phase CM inductors are reviewed and verified experimentally. With the CM inductor impedance model and CM propagation path characterization, the suppression of both DC and AC CM noise is accurately predicted to be within a 5 dBμA design margin from 10 kHz to 30 MHz. Based on the modeling and verification, this paper also proposes a practical method for high density CM inductors design using MATLAB Optimization Toolbox®.

EMI noise mode transformation due to propagation path unbalance in three-phase motor drive system and its implication to EMI filter design

EMI filter design is often influenced by the noise transformations between the common-mode (CM) and differential-mode (DM), which is mainly due to the system unbalance. In this paper, the analysis of the intrinsic and EMI filter unbalance existing in the EMI noise propagation path of the dc-fed three-phase motor drive system is carried out. CM path unbalance in the circuit model is investigated with an example switching state in three-phase space vector pulse-width-modulation (SVPWM). Noise transformation from CM to DM is then verified with prototype experiments. The influence of the DM filter component unbalance on the DM propagation path is analyzed with simulation. After that, the transformation of the DM noise to CM is validated with tests. Influence of the unbalance and noise mode transformation on the EMI filter design is discussed and a comprehensive design procedure for high density EMI filter is proposed.