In this paper, a new strategy for voltage balancing of distinct dc buses in cascaded H-bridge rectifiers is presented. This method ensures that the dc bus capacitor voltages converge to the reference value, even when the loads attached to them are extracting different amounts of power. The proposed method can be used for an arbitrary number of series H-bridges, different voltage levels, and different power levels in unidirectional or bidirectional rectifiers. To reduce the current harmonics and distortion, the input current is programmed to be sinusoidal and in phase with the input voltage; however, it is possible to adjust the input power factor to control both the active and reactive powers. In the proposed approach, both the low frequency (stepped modulation) and high frequency [pulse-width modulation (PWM)] switching methods are utilized to improve the performance of the rectifier. Using theoretical analysis, the acceptable load power limits for a rectifier with N-H-bridge cells are derived. The validity of the proposed method is verified by simulation and experimental results.

Today, electromagnetic compatibility (EMC) seems to be one of the major constraints of power electronic converters, particularly 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 conducted and radiated disturbances by simulation offers a considerable gain from the economic point of view. This paper shows how relatively simple models can be used to forecast EMC, taking into account various control strategies. 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, the filters.

Online accurate estimation of supercapacitor State-of-Health (SoH) and State-of-Energy (SoE) is essential to achieve efficient energy management and real-time condition monitoring in Electric Vehicle (EV) applications. In this paper, for the first time, Unscented Kalman Filter (UKF) is used for online parameter and state estimation of the supercapacitor. In the proposed method, a nonlinear state-space model of the supercapacitor is developed, which takes the capacitance variation and selfdischarge effects into account. The observability of the considered model is analytically confirmed using a graphical approach (GA). The SoH and SoE are then estimated based on the supercapacitor online identified model with the designed UKF. The proposed method provides better estimation accuracy over KF and Extended KF (EKF) algorithms since the linearization errors during the filtering process are avoided. The effectiveness of the proposed approach is demonstrated through several experiments on a laboratory testbed. An overall estimation error below 0.5% is achieved with the proposed method. In addition, Hardware-in-the-Loop (HIL) experiments are conducted and real-time feasibility of the proposed method is guaranteed.

A new approach for easy and fast modeling of EMI filter in aircraft application is proposed, in order to be used in an optimization process. A modular description in a user friendly environment allows describing the model and taking into account all the technological parameters of the system, i.e., the control strategy, the inverter model (semiconductors, layout, etc.), the filter, the cables, and the ac machine. The frequency model is automatically built from this description, as well as its gradients according to its inputs. In a second step, by using this model, an optimization of the filter values can be carried out, using various algorithms, to reach the smallest volume. This early design methodology can also be used to investigate the impact of some technological choices of the electrical drive (control strategy or cable characteristics for instance) on the filter volume.

The reduced switching times of silicon carbide (SiC) components compared to Si components in similar conditions are a great advantage from the point of view of efficiency, but, due to the high dv/dt and di/dt, conducted electromagnetic emissions are increased. Therefore, the availability of a method which can predict these emissions is increasingly necessary. To the best of the authors' knowledge, a model that can predict differential mode as well as common mode for a converter including sic devices has not yet been published. the novelty of the work presented here is the integration of different modeling approaches to form a circuit model of a SiC-based buck dc-dc converter working in frequency range from 40 Hz to 30 MHz. A modeling approach of the passive parts of the converter is presented. Then, the model obtained is used in simulations to predict the drain-to-source voltage and the drain current for the JFET. Conducted emissions received by the line impedance stabilization network are also computed. Simulation results are compared to measurements for different duty cycles and different gate resistors in the time and frequency domains. A good agreement is obtained. In the frequency domain, in all cases, differences are less than 5 dBμV up to 30 MHz excepted in the JFET source current.