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This paper proposes a grid-forming control strategy with a generic implementation approach to meet the transmission system requirements asking for the massive integration of power electronic devices into the power systems. In this context, several grid-forming controls have been proposed in the literature either with or without a Phase-Locked Loop (PLL). The PLL-based techniques allow decoupling the different control functionalities (i.e. inertia emulation, frequency support, active power setpoint tracking in steady-state) while the PLL-free schemes, which aim to avoid the PLL drawbacks, create a compulsory coupling between the control functionalities. The proposed grid-forming control in this paper is able to decouple the control functionalities without any dedicated PLL, which makes it more advantageous compared to what have been already proposed in the literature. Since the power converters are exposed to the small and large grid events, the presented control has been tested in both situations. For the small grid events, a simplified small-signal model is developed to assess the active power and frequency dynamics. In case of large grid events, a current limitation algorithm is included to the control in order to protect the power converter. To deal with the transient stability issues linked to the current limitation and enhance the converter performance during the post-fault, a method based on adaptive inertia constant is proposed. To validate the overall approach, time-domain simulations (in Matlab-Simulink) and experimentations are performed. INDEX TERMS Active power regulation, current limitation, fast frequency response, grid-forming control, inertial effect, transient stability. This article has been accepted for publication in a future issue of this journal, but has not been fully edited. Content may change prior to final publication. Citation information: DOI 10.1109/ACCESS.2020.3034149, IEEE Access T. Qoria et al.: Preparation of Papers for IEEE TRANSACTIONS and JOURNALS Rc, Lc i gabc v gabc Rg, Lg

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is an open access repository that collects the work of Arts et Métiers ParisTech researchers and makes it freely available over the web where possible.This is an author-deposited version published in: https://sam.ensam.eu Handle ID: .http://hdl.handle.net/10985/6794 To cite this version :Paul SANDULESCU, Fabien MEINGUET, Xavier KESTELYN, Eric SEMAIL, Antoine BRUYEREFlux-weakening operation of open-end winding drive integrating a cost effective high-power charger -IET Electrical Systems in Transportation -Vol. 3, n°1, p.26 -2013 Any correspondence concerning this service should be sent to the repository Interior Permanent Magnet Synchronous Machine (IPMSM) designed for the traction of an electric vehicle is studied in flux-weakening operation. The topology allows the functionality of a high power charger to be obtained, without adding any other supplementary power devices. On the other hand, since there are three independent currents, the control structure has to handle not only the two dq current components but also a zero-sequence current. If neglected, in comparison with wye-coupled three-phase drive, this zero-sequence component can cause a higher maximum peak value of the phase currents, additional stator Joule losses, torque ripple, inverter voltage saturation and IGBT oversizing. The proposed control strategy consists in adapting a conventional method used for wye-connected machines particularly in flux-weakening operation. This strategy allows the closed-loop control of the zero-sequence current to be maintained in the whole speed range and therefore inverter saturation is avoided. Simulations and experimental results are presented and analyzed. IntroductionPermanent magnet synchronous machines (PMSMs) have been demonstrated to be a good solution for a wide range of applications because of their high power to weight ratio, compactness, high efficiency and ease of control [1]. In the past decade, Although the number of switching components is twice the number used for the classical wye-configuration, the topology allows the application of the full DC-link voltage across the phases and increases base speed and power output, as presented in [5]. In spite of these advantages, the additional costs linked to the three supplementary power legs curbs the industrial development of the topology, especially for large scale production such as car manufacturing.In the context of an electric vehicle with a metric horsepower of around 40 to 50 kW, this drawback can be removed by adding a high-power charger functionality (>40kW) to the traction functionality, as described in [12] -[15]. No supplementary power device has to be added to achieve the power charger functionality. It is obtained through the addition of three supplementary outputs for electric grid connection (Figure 1). This is an advantage over [16] where the use of additional high-power contactors is obligatory. In addition, the ease of access and control of all three windings of the machine makes possible not only single For the system under study, the s...

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For Electric Vehicles (EV), the charger is one of the main technical and economical weaknesses. This paper focuses on an original electric drive [1]-[3] dedicated to the vehicle traction and configurable as a battery charger without need of additional components. This cheap solution can outfit either electric or plug-in hybrid automotive vehicles, without needing additional mass and volume dedicated to the charger. Moreover, it allows a high charging power, for short duration charge cycles. However, this solution needs specific cares concerning the electrical machine control. This paper deals with the control of this drive [1], focusing on traction mode. In introduction, a review is done about topologies of combined on-board chargers. Then, the studied topology is introduced; using a 3-phase brushless machine supplied with a 6-leg Voltage Source Inverter (VSI). A model for its control is defined in the generalized Concordia frame, considering the traction mode. Then, an analysis of this model is established using a multimachine theory and a graphical formalism (the Energetic Macroscopic Representation denoted EMR). Using EMR, a description of energy flows shows specific control constraints. Indeed, numerical simulations illustrate the perturbations on the currents and the torque when controlling the machine with standard control methodologies. An improved control, deduced from the previous analysis, shows good performances, strongly reducing currents and torque ripples.

This paper investigates the effect of using phaselocked loop (PLL) on the performance of a grid-forming controlled converter. Usually, a grid-forming controlled converter operates without dedicated PLL. It is shown that in this case, the active power dominant dynamics are highly dependent to the grid short circuit ratio (SCR). In case of using PLL, the obtained results illustrate that the SCR has a negligible effect on the dynamic behavior of the system. Moreover, the power converter will not participate to the frequency regulation anymore; therefore, the converter response time can be adjusted independently to the choice of the droop control gain, which is not possible without PLL. A simple equivalent model is presented which gives a physical explanation of these features.

This paper deals with the modeling and the control of a new high power 12V Integrated Starter Alternator (ISA). This system is used to bring micro-hybrid functions to standard Internal Combustion Engine (ICE) vehicles. The drive is composed of a seven-phase synchronous claw-pole machine with separate excitation, supplied with a seven-leg Voltage Source Inverter (VSI) designed for low voltage and high current. The system is modeled in a generalized Concordia frame and a graphical description is used to highlight energetic properties of such a complex system. A control scheme is then deduced from this graphical description. Two controls are achieved in generator mode and compared: one is using the VSI in a square-wave mode, the other in a Pulse Width Modulation (PWM) mode. Experimental results are provided.