Wide-bandgap (WBG) power semiconductor devices have become increasingly popular due to their superior characteristics compared to their Si counterparts. However, their fast switching speed and the ability to operate at high frequencies brought new challenges, among which the electromagnetic interference (EMI) is one of the major concerns. Many works investigated the structures of WBG power devices and their switching performance. In some cases, the conductive or radiated EMI was measured. However, the EMI-related topics, including their influence on noise sources, noise propagation paths, EMI reduction techniques, and EMC reliability issues, have not yet been systematically summarized for WBG devices. In this article, the literature on EMI research in power electronics systems with WBG devices is reviewed. Characteristics of WBG devices as EMI noise sources are reviewed. EMI propagation paths, near-field coupling, and radiated EMI are surveyed. EMI reduction techniques are categorized and reviewed. Specifically, the EMI-related reliability issues are discussed, and solutions and guidelines are presented.

A Survey of EMI Research in Power Electronics Systems With Wide-Bandgap Semiconductor Devices

A large number of factors such as the increasingly stringent pollutant emission policies, fossil fuel scarcity and their price volatility have increased the interest towards the partial or total electrification of current vehicular technologies. These transition of the vehicle fleet into electric is being carried out progressively. In the last decades, several technological milestones have been achieved, which range from the development of basic components to the current integrated electric drives made of silicon (Si) based power modules. In this context, the automotive industry and political and social agents are forcing the current technology of electric drives to its limits. For example, the U.S Department of Energy’s goals for 2020 include the development of power converter technologies with power densities higher than 14.1 kW/kg and efficiencies greater than 98%. Additionally, target price of power converters has been set below $3.3/kW. Thus, these goals could be only achieved by using advanced semiconductor technologies. Wide-bandgap (WBG) semiconductors, and, most notably, silicon carbide (SiC) based power electronic devices, have been proposed as the most promising alternative to Si devices due to their superior material properties. As the power module is one of the most significant component of the traction power converter, this work focuses on an in-deep review of the state of the art concerning such element, identifying the electrical requirements for the modules and the power conversion topologies that will best suit future drives. Additionally, current WBG technology is reviewed and, after a market analysis, the most suitable power semiconductor devices are highlighted. Finally, this work focuses on practical design aspects of the module, such as the layout of the module and optimum WBG based die parallelization, placement and Direct Bonded Copper (DBC) routing.

Power module electronics in HEV/EV applications: New trends in wide-bandgap semiconductor technologies and design aspects

Wireless power transfer is a state-of-the-art technology with the advantage of convenience and flexibility, as well as the capability of enabling fully automated charging. With power transfer levels increasing beyond 100 kW, many technical and risk management challenges emerge. Instead of focusing on the progress review of wireless power transfer technology, this paper discusses the future challenges and risks for high power wireless charging for light-duty electric vehicles. Aiming at 200 kW or higher wireless power transfer, we discuss technology and risk management challenges in the area of electromagnetic safety, resonant frequency determination, and cybersecurity risks in detail. As potential solutions to overcome these challenges, the latest technologies with an emphasis on advanced shielding solutions and recent progress on SiC converters from both industrial and academic institutions are reviewed, and some perspectives and propositions are provided.

Challenges of future high power wireless power transfer for light-duty electric vehicles----technology and risk management

Harmonic and electromagnetic interference (EMI) filters are the two important parts in the grid-connected inverter for the harmonic and EMI noise suppression. This article investigates the combined magnetic integration of the harmonic and EMI filters with the volume and weight reduction, which is defined as the integrated LCL–EMI filter in this article. Both common-mode (CM) and differential-mode (DM) models of the integrated inductor with EE-type magnetic core are built and analyzed. By designing the air gap of the center leg and arranging the windings properly, the distribution of magnetic flux on the magnetic branch can be controlled. As a result, harmonic inductors and a CM inductor can be effectively designed in the center leg and side leg, respectively. A symmetrical LCL filter is designed instead of the traditional asymmetrical structure with an integrated magnetic core. The current harmonic distortion analysis and EMI measurement results based on simulation and experiment results verify the effectiveness of the proposed integration method in the silicon carbide (SiC) MOSFET-based grid-connected inverter. Moreover, weight and volume comparisons between the integrated inductor and the traditional discrete inductors also reflect the superiority of the magnetic integrated LCL–EMI filter.

A Magnetic Integrated LCL–EMI Filter for a Single-Phase SiC-MOSFET Grid-Connected Inverter

This article proposes a high-performance, high-switching-frequency triangular-conduction-mode (TCM) bidirectional-interleaved buck converter for battery charging using digital control. Accurate conditions for achieving zero-voltage switching (ZVS) without zero-crossing detection (ZCD) are derived while considering the nonlinear parasitic capacitance of the switch components. This article also optimizes the method of calculating the switching frequency to reduce the delay time of pulsewidth modulation, thereby enhancing system stability. The conventional control method has inadequate resolution in the phase shift register of the digital controller under high switching frequency, hindering perfect interleaving of the two phases at 180°, which affects the characteristics of current ripple offset. The proposed control method effectively reduces the phase error between the two phases in an interleaving structure under high-frequency operation. In this way, full-range ZVS can be achieved when the circuit operates at the correct switching frequency. ANSYS Q3D Extractor software is employed to simulate the impedances of the power loops and investigate parasitic parameters, enabling optimization of the layout and modification of the switching frequency. An experimental prototype of a bidirectional buck converter using GaN switches was implemented with an output power of 1 kW, an input voltage of 66 V, an output voltage of 35–50 V, a switching frequency of 350 kHz–1 MHz, a highest efficiency of 97.52%, and a power density of 10 W/cm3.

High-Switching-Frequency TCM Digital Control for Bidirectional-Interleaved Buck Converters Without Phase Error for Battery Charging

A Grid-tied inverter utilizing wide bandgap devices can achieve higher switching frequency resulting in a power filter with reduced size and weight. However, the increased switching frequency may lead to more switching harmonics entering the electromagnetic interference (EMI) frequency range, which will increase the size of EMI filter. Interleaving paralleled converters can cancel some of the switching harmonics and reduce the size of EMI filter. However, nonideal interleaving will deteriorate the harmonic canceling effect. In this research, the nonideal effects are found to be from the small mismatch of the pulsewidth of the interleaving legs and the mismatch of the impedance between the interleaving legs. A modulation method is proposed to completely eliminate the pulsewidth mismatch. Compared with other solutions, the proposed method does not require the information of filter parameters, neither gate driver synchronization, and nor a special function block of the digital controller. The proposed modulation was implemented on a 150 MHz digital signal processor and a 100 MHz field-programmable gate array, and was experimentally verified on a 100 kW parallel coupled SiC PV inverter prototype.

Reduction of EMI Noise Due to Nonideal Interleaving in a 100 kW SiC PV Converter

The overvoltage caused by reflected wave phenomenon in motor drives becomes worse with the application of SiC devices due to the significantly higher $dv/dt$ compared with that of Si devices. This letter presents a low-loss and compact active reflected wave canceller (ARWC) to suppress the overvoltage at the motor terminal. The proposed ARWC circuit uses low current devices to break the rising and falling edges of the pulsewidth modulation voltage waveforms to two steps, whereas the second step cancels the first step reflection. In addition, the ARWC circuit does not require an additional dc power supply that allows the ARWC self-sustained. The experimental results on one phase 6 kVA application with and without proposed ARWC are provided and compared to verify the validity of proposed method.

A Low-Loss Compact Reflected Wave Canceller for SiC Motor Drives

Accurate measurement of common mode (CM) and differential mode (DM) noise is crucial for electromagnetic interference filter design. With the application of wide bandgap devices, the measurement results require higher accuracy at high frequency. This letter proposes a novel CM and DM noise separation method where a 20 dB attenuator is integrated to allow the measured results less sensitive to the parasitic parameters in the 150 kHz–30 MHz frequency range. The proposed method improves the flatness of the noise separator in the 150 kHz–30 MHz frequency range, which is 0.3 dB for common mode transmission ratio and 0.6 dB for differential mode transmission ratio. Simulation and experimental results are provided to validate the effectiveness of the proposed method.

EMI Noise Separation Method for Three-Phase WBG Inverters With Low Sensitivity to Parasitic Parameters

The high dv/dt associated with Wide-Bandgap (WBG) devices will lead to more serious reflected wave phenomenon, resulting in overvoltage at the load side. This paper proposes an active reflected wave canceller (ARWC) for SiC motor drives. The proposed solution mitigates the reflected wave phenomenon by injecting a controlled nanoseconds voltage pulse. The proposed ARWC can achieve smaller size and light weight utilizing WBG devices. A testbed has been built to experimentally demonstrate the operation principle of the proposed ARWC circuit.

A WBG Based Active Reflected Wave Canceller for SiC Motor Drives

Overvoltage caused by the reflected wave phenomenon is well known in motor drive systems with long cables, which becomes worse for Medium Voltage (MV) SiC motor drive systems. Passive dv/dt filters are widely used to alleviate this overvoltage phenomenon. This paper mustrates the passive dv/dt filter limitations for SiC MV motor drive systems. In addition, an active solution with low power loss is proposed in this paper to suppress the overvoltage resulting from the reflected wave phenomenon in SiC MV motor drives. Both simulation and experimental results are presented to validate the proposed method.

Yu Zhang

Papers

Reduction of EMI Noise Due to Nonideal Interleaving in a 100 kW SiC PV Converter

A Low-Loss Compact Reflected Wave Canceller for SiC Motor Drives

EMI Noise Separation Method for Three-Phase WBG Inverters With Low Sensitivity to Parasitic Parameters

A WBG Based Active Reflected Wave Canceller for SiC Motor Drives

Study of Passive dv/dt Filter and Proposed Active Solution for SiC MV Motor Drive