Efficiency Analytical Characterization for Brushless Electric Drives

The paper is focused on the formalization of an experimental procedure aimed to char-acterize the efficiency behaviour of a Permanent Magnet Synchronous Motor-based drive. The characterization is intended to expose the analytical behaviour of the system efficiency by the actual operating condition assigned through torque/speed value. The availability of such a relation in a simple analytical form would allow for real-time adjustment by advanced power management strategies to maximize the whole system efficiency. The proposed method is based on a defined set of measures corresponding to several drive operating conditions. A straightforward elaboration procedure is then formulated with the aim to quantify the different parameters, which intervene in the efficiency characterization. The method has been applied on a 155 kW drive. The results show that good accuracy is achieved while keeping the analytical approach relatively simple

Performance analysis of a full order sensorless control adaptive observer for doubly-fed induction generator in grid connected operation

This paper focuses on the performance analysis of a sensorless control for a Doubly Fed Induction Generator (DFIG) in grid-connected operation for turbine-based wind generation systems. With reference to a conventional stator flux based Field Oriented Control (FOC), a full-order adaptive observer is implemented and a criterion to calculate the observer gain matrix is provided. The observer provides the estimated stator flux and an estimation of the rotor position is also obtained through the measurements of stator and rotor phase currents. Due to parameter inaccuracy, the rotor position estimation is affected by an error. As a novelty of the discussed approach, the rotor position estimation error is considered as an additional machine parameter, and an error tracking procedure is envisioned in order to track the DFIG rotor position with better accuracy. In particular, an adaptive law based on the Lyapunov theory is implemented for the tracking of the rotor position estimation error, and a current injection strategy is developed in order to ensure the necessary tracking sensitivity around zero rotor voltages. The roughly evaluated rotor position can be corrected by means of the tracked rotor position estimation error, so that the corrected rotor position is sent to the FOC for the necessary rotating coordinate transformation. An extensive experimental analysis is carried out on an 11 kW, 4 poles, 400 V/50 Hz induction machine testifying the quality of the sensorless control

Battery losses in a MMC for BEVS application

Objective: This paper analyses the Modular Multilevel Converter (MMC) topology, where each individual Sub Module (SM), in half bridge configuration, is directly fed by an elementary electrochemical cell. Methods: The aim is to investigate how the reference voltages influence the cells currents waveforms, determining how the active powers and the losses are distributed among the cells. Considering a 2-level Voltage Source Inverter (VSI) topology working in the same conditions, the ratio between the MMC total cells losses and VSI total cells losses is calculated. After showing the system architecture and mathematical model, the cells current waveform investigation is presented and detailed both for triangular and sinusoidal voltage reference waveform

Power Scheduling Method for Grid Integration of a PV-BESS CHB Inverter With SOC Balancing Capability

The paper deals with a single-phase photovoltaic (PV) inverter based on the Cascaded H-Bridge (CHB) topology for Low Voltage (LV) grid. A distributed architecture of PV sources integrated with battery energy storage systems (BESS) is proposed with the particularity of avoiding the use of dc-dc converters. A method of compensating for the short-term daily variability of PV energy is also presented. The control implements power scheduling to ensure that constant active power is fed into the grid at every predetermined time interval (e.g., every quarter of an hour). Furthermore, a dedicated hybrid modulation scheme based on a sorting algorithm for balancing the state of charge (SOC) of the single cells is proposed. Numerical investigations are carried out on a 19-level CHB inverter implemented in a PLECS®(i.e., the simulation platform for power electronic systems from Plexim) environment to validate the feasibility and effectiveness of the proposed control strategy

VRSTNN : visual-relational spatio-temporal neural network for early hazardous event detection in automated driving systems

Reliable and early detection of hazardous events is vital for the safe deployment of automated driving systems. Yet, it remains challenging as road environments can be highly complex and dynamic. State-of-the-art solutions utilise neural networks to learn visual features and temporal patterns from collision videos. However, in this paper, we show how visual features alone may not provide the essential context needed to detect early warning patterns. To address these limitations, we first propose an input encoding that captures the context of the scene. This is achieved by formulating a scene as a graph to provide a framework to represent the arrangement, relationships and behaviours of each road user. We then process the graphs using graph neural networks to identify scene context from: 1) the collective behaviour of nearby road users based on their relationships and 2) local node features that describe individual behaviour. We then propose a novel visual-relational spatiotemporal neural network (VRSTNN) that leverages multi-modal processing to understand scene context and fuse it with the visual characteristics of the scene for more reliable and early hazard detection. Our results show that our VRSTNN outperforms stateof- the-art models in terms of accuracy, F1 and false negative rate on a real and synthetic benchmark dataset: DOTA and GTAC

Hybrid Electric Aircraft Model Based on ECMS Control

The hybrid-electric propulsion control system plays a fundamental role to ensure the correct function of all components and to operate a performing energy management. Several control strategies have been proposed in the literature, but the challenge is to keep these techniques methodologically simple and easy to implement. In this paper, an analytical derivation of the Equivalent Consumption Minimization Strategy (ECMS) for energy management of hybrid-electric aircraft is presented, based on Pontryagin’s Minimum Principle (PMP). Simulation results obtained for a parallel hybrid electric configuration with a maximum take-off power of 134 kW are also presented