Conference Agenda

To ensure electromagnetic compatibility (EMC) of drive inverters, electrical machine emulators can serve as cost-effective equivalent loads, enabling testing under realistic load conditions. However, EMC-compliant electrical machine emulators shall have negligible self-emission, while accurately emulating the radio-frequency (RF) behavior of the emulated electric machine. A key challenge arises from the switching behavior of the emulator, which introduces significant emissions. This paper presents methods to assess the emission and impedance behavior of emulators, highlighting the challenges associated with their RF behavior. To adress this, the analysis compares the characteristics of a drive inverter when connected to a motor versus a state-of-the-art emulator.

Automotive drives are considered a major source of electromagnetic interference (EMI) in the high-voltage system of an electric vehicle (EV). The recent advances in semiconductor technology towards more compact and faster switching devices bring an increasing challenge to meet the stringent electromagnetic compatibility (EMC) requirements that are applied in the automotive industry. Multilevel inverters have received increasing interest due to their benefits of lower losses and higher voltage capability. Specifically, the three-level inverter shows a good balance between these benefits and low complexity and high technological maturity. However, it is still not widely studied how it performs compared to the standard 2-level counterpart when their radio-frequency (RF) emissions are evaluated. This paper presents comparative simulations of conducted emissions at the DC-side of drives with 2-level and 3-level inverters. The electrical machine of the drive system has been modelled utilizing scattered (S) parameter measurements of a real machine in order to simulate accurately the common-mode (CM) current flow. The results showcase over the frequency range of 9kHz - 100MHz the EMC benefits of using a 3-level inverter.

The amount of electric vehicles is rapidly increasing in all countries of the EU. As a high availability of charging infrastructure is crucial for success of traffic electrification the new EU commission is investing a high amount of money to expand the charging infrastructure with a focus on DC fast charging stations [1]. The increase in charging voltage and power have a huge impact on the electromagnetic emissions generated which must comply with the emission limits in IEC 61851-21-2 [2]. In the standard a generic load is described in the exemplary setup with the main aim to sink the power generated by the charger. For gaining more realistic results a load representing the impedance of the electric vehicle is essential. As electric vehicle impedances in the frequency range between 9 kHz and 30 MHz are not known, this work uses an inductively decoupled impedance measurement procedure [3], [4] to determine the vehicle’s impedance in DC charging mode [5]. This impedance is used to develop an impedance network modelling the impedance of the vehicle. Finally, after a verification measurement the developed network is compared to other loads in the setup.

Pulsewidth modulation (PWM) strategies for DC-fed motor drives are employed to optimize performance factors such as current ripple, efficiency, and DC bus utilization. The integration of wide bandgap (WBG) devices has further improved the efficiency and power density of these systems. However, the critical issue of conducted emission (CE) at high switching frequencies has rarely been comparatively evaluated in such systems. This paper investigates the effects of various PWM techniques— such as sinusoidal PWM (SPWM), space vector PWM (SVM), discontinuous PWM (DPWM), active zero-state PWM (AZPWM), and near-state PWM (NSPWM) — on common-mode (CM) noise in a three-phase DC-fed motor drive system. The effects of modulation index and switching frequency on CM noise levels are analyzed, with their impact on EMI filter size evaluated through corner frequency calculations. The results demonstrate that, at higher switching frequencies, appropriate selection of PWM strategy can significantly enhance the power density of the EMI filter. The findings from the numerical EMI model are validated through experimental results obtained from a 1.5 kW, 300 V SiC-based induction motor drive.