Djilali Hamza

An Improved Layout Strategy for Common-Mode EMI Suppression Applicable to High-Frequency Planar Transformers in High-Power DC/DC Converters Used for Electric Vehicles

Presently, there is an immense impetus in the automotive industry to develop plug-in electric vehicles (PIEVs) to reverse the ever increasing green house gas emissions from fossil fuels and depleting fossil fuel resources. High-frequency ac-dc converters with an isolated output are one of the essential building blocks for transferring power from utility mains to the traction battery packs which store energy for propelling the EV. Generally, the ac/dc converters used in EVs include a PFC stage at the input side and an isolated dc/dc converter at the battery side. Due to the switching nature of the converter, electromagnetic compatibility (EMC) of these converters is an essential requirement, to ensure not only its own operation but also the safe and secure operation of surrounding electrical equipment. EVs possess a lot of sophisticated electronic circuits in the vicinity of the battery charging power converters. Thus, strict EMC standards of the on-board power converters must be met according to the CISPR 12 or SAEJ551/5 relevant EMC standards. Conventional passive filters used for EMI mitigation in power converters, comes at the expense of cost, size and weight, power losses, and printed circuit board real estate. In this paper, an electromagnetic interference (EMI) filter embedded into the main high-frequency planar transformer used in the dc/dc converter is proposed as a very cost-effective and efficient solution for EVs. The proposed structure is able to significantly suppress the common-mode (CM) EMI noise generated in the dc/dc converter. Experimental results have been obtained from a 3-kW prototype in order to prove the feasibility and performance of the proposed EMI filter. The results show that the proposed embedded EMI filter can effectively suppress the CM noise particularly for high switching frequency power converters. The proposed structure can be a very simple and cost-effective EMI filtering solution for future PIEVs.

Implementation of a Novel Digital Active EMI Technique in a DSP-Based DC–DC Digital Controller Used in Electric Vehicle (EV)

With ever increasing green-house gas emissions from fossil fuel-driven automobiles leading to acute environmental pollution, and ever depleting reserves of fossil fuel, today need for the development of pure electric vehicle (EV) is of utmost importance. Presently, there is an immense impetus to develop plug-in EVs. High switching frequency and high-power ac-dc PFC converter with an isolated output and a dc-dc isolated converter are essential systems for transferring from utility mains to the different battery packs which store energy for propelling the EVs. Electromagnetic compatibility (EMC) with strict regulatory standards is an essential requirement which any switch mode power converter must comply with not only for its own operation but also for safe and secure operation of surrounding electrical equipment. EVs possess many sophisticated electronic circuits in the vicinity of the battery charging power converters, so strict EMC standards of the on-board power converters should be met. For a cost-effective design approach, EMC should be considered at the primitive stages of the power converter design. The most commonly used passive electromagnetic interference (EMI) filters used for EMI mitigation in power converters come at the expense of cost, size and weight, power losses, and printed circuit board (PCB) real estate. In this paper, a novel embedded digital active EMI filter (DAEF) integrated into the DSP-based digital controller of a dc-dc converter applicable for charging the low-voltage battery bank of an EV is proposed and analyzed. Experimental results and comparison of the performance of the proposed embedded DAEF with a conventional EMI filter are presented in this paper so as to validate the feasibility of the proposed EMI filter and its advantages over the conventional one.

Conducted EMI noise mitigation in DC-DC converters using active filtering method

Electromagnetic interference (EMI) noise mitigation is an important issue that should be addressed and emphasized when designing DC/DC converters. These later, are known to be the primary culprit of the EMI noise generation in most of the electronic systems, mainly due to the switching action of the MOSFET circuitries. Passive input EMI LC filters have been the intuitive solution for EMI noise mitigation; hence they have been integrated in almost every DC/DC converters. However, their size, weight and cost can cause a significant constraint in some applications. To overcome these constraints, an input active EMI filter is proposed. The active filter is based on the noise current phase shift and the injection of this noise current back to the DC input bus. However, the combination of the input active and the passive filters shows a substantial attenuation of the conducted emissions as compared to the passive filter only, which in turn contributes to the reduction of the size and weight of the input passive EMI filter. The proposed combination provides a design solution for compliance engineers where the PCB real-estate is an issue. Experimental results to demonstrate the performance and the effectiveness of the input active EMI filter in DC/DC converters are presented.

Application and Stability Analysis of a Novel Digital Active EMI Filter Used in a Grid-Tied PV Microinverter Module

This paper presents a novel technique to suppress common-mode electromagnetic interference (EMI) using a digital active EMI filter (DAEF). The DAEF control technique is concurrently implemented with a digital controller of a grid-tied photovoltaic microinverter. A brief description of the microinverter architecture and its inverter circuit is illustrated. The inverter stability is investigated using the overall transfer function. Accordingly, the system compensation is designed based on the direct quadrant (DQ) reference frame control technique. Finally, the proposed digital controller is tested on a grid-connected 200-W dc-ac microinverter. The experiment results validate the effectiveness of the proposed technique. Compared with the conventional passive EMI filter, the proposed digital controller can achieve an equivalent or better performance in terms of EMI suppression and maintain stability within the operation bandwidth. Therefore, the embedded DAEF can significantly reduce the size, cost, and space of the overall power inverter printed circuit board without the need of a conventional passive EMI filter.

Implementation of an EMI active filter in grid-tied PV micro-inverter controller and stability verification

This paper presents a novel technique to suppress Common-mode EMI using digital active EMI filter (DAEF). The DAEF control technique is concurrently implemented with a digital controller of a grid-tied photovoltaic (PV) micro-inverter. A brief description of the micro-inverter architecture and its inverter circuit is illustrated. The inverter stability is investigated using the overall transfer function. The experimental results validate the feasibility of the proposed technique. Compared with the conventional passive EMI filter, the proposed embedded DAEF can significantly reduce the size, cost and space of the overall power inverter PCB without while improving the overall efficiency of the micro-inverter.

Digital Active EMI Control Technique for Switch Mode Power Converters

A novel electromagnetic interference (EMI) suppression technique based on field programmable logic array technology is proposed to provide a significant EMI noise attenuation for switch-mode power converters. This technique uses noise acquisition at very high-sampling rate. The noise signal is processed to invert its phase angle and reconstructed with high fidelity to counteract the noise signal before reaching the line impedance stabilization network. Thus, high noise attenuation is achieved. The new technique is validated through simulation and experimental results of a single-phase ac-dc converter. The proposed technique can be extended to dc/dc converters to replace the conventional passive EMI filter where the PCB space is restricted. This technique can be a desired contingent in industrial applications where space is a major design constraint.

Conducted EMI in grid-tied PV system

This paper focuses on the conducted electromagnetic interference emissions generated in a building grid-tied PV power system. It emphasizes on the inverter AC side, including the building power grid, as being the interference source and the PV side as the victim circuit, having the inverter as the coupling path. The applicable standards of the grid-tied PV system as being a fixed installation are discussed.

Conducted EMI simulation for a high power Ultra-precision PMSM driven by PWM converter

The conducted electromagnetic interference (EMI) and overvoltage characteristics for a spindle permanent magnet synchronous motor (PMSM) driven by pulse width modulation (PWM) converter are comprehensively presented. The high power, ultra-precision PMSM is applied to a computer numerical control (CNC) grinding machine. The conducted EMI prediction model mainly includes multi-core shielded cable, high frequency (HF) converter and PMSM models. The multi-transmission line (MTL) theory is employed to establish the multi-core shielded cable considering their coupling effect caused by the control pairs. The parasitic capacitance for the PWM converter is calculated by using the analytical formula. The HF equivalent circuit model of the PMSM is obtained combining the methods of impedance measurement and vector fitting method. The influence of the rotor position on the PMSM impedance measurement is considered. The common mode (CM) and differential mode (DM) interference voltage and current both for the output of inverter and the input of PMSM terminals are conducted by using the prediction model. The parametric influence of the long multi-core shielded cables on the overvoltage for the PMSM terminal is discussed.

High frequency analysis of an integrated planar transformer with common mode EMI suppression capability

High frequency transformers are one of the essential building blocks to provide galvanic isolation for power converters. Due to the switching nature of the converter, electromagnetic compatibility (EMC) of these converters is an essential requirement, to ensure not only its own operation but also the safe and secure operation of surrounding electrical equipment that are connected to same power distribution network. Thus, strict EMC standards such as CISPR 12 or SAEJ551/5 are imposed to provide safe and reliable operation of the power converters. Conventional passive filters used for EMI mitigation in power converters, comes at the expense of cost, size and weight, power losses and PCB real estate. In this paper, an integrated EMI filter embedded into the main high frequency planar transformer used in the DC/DC converter is proposed as a very cost-effective and efficient solution. The proposed structure is able to significantly suppress the Common-Mode (CM) EMI noise generated in the DC/DC converter. In order to evaluate the performance of the integrated transformer, a high frequency simulation through HFSS has been performed. Also, a prototype has been implemented to assess the feasibility of the proposed structure and confirm the HFSS simulation results. The results obtained from a 3KW prototype show that the proposed integrated EMI filter can effectively suppress the CM noise particularly for power converters operating at high switching frequency. The proposed structure can be a very simple and cost-effective EMI filtering solution for many applications such as future plug-in electric vehicle.

Interface impedance consideration in the design of an input EMI filter for grid-tied PV micro-inverter

Inverters adopted in centralized PV power generation have inherent problem of islanding forcing the entire system shutdown and resulting in costs of downtime. Nowadays, the distributed systems using micro-inverters at each PV panel, has been an adequate method to address this issue. The major difference between the centralized inverters and the distributed micro-inverters reside in their rated power. However, they share a common issue of being generators of conducted EMI. This paper proposes an intermediate EMI filter design using impedance interactive approach at both PV-side and front-end DC converter interface. This method provides sufficient margin to ensure the converter stability at Maximum Power Point Tracking (MPPT) and satisfy the applicable EMC specifications. The experimental results show that the implementation of the EMI filter at the DC feed has effectively attenuated the EMI noise to an acceptable level, while providing good stability under the input voltage and load variations.