Optimal Design and Control of 4-IWD Electric Vehicles based on a 14-DOF Vehicle Model

A 4-independent wheel driving (4-IWD) electric vehicle has distinctive advantages with both enhanced dynamic and energy efficiency performances since this configuration provides more flexibilities from both the design and control aspects. However, it is difficult to achieve the optimal performances of a 4-IWD electric vehicle with conventional design and control approaches. This work is dedicated to investigating the vehicular optimal design and control approaches, with a 4-IWD electric race car aiming at minimizing the lap time on a given circuit as a case study. A 14-DOF vehicle model that can fully evaluate the influences of the unsprung mass is developed based on Lagrangian dynamics. The 14-DOF vehicle model implemented with the reprogrammed Magic Formula tire model and a time-efficient suspension model supports metric operations and parallel computing, which can dramatically improve the computational efficiency. The optimal design and control problems with design parameters of the motor, transmission, mass center, anti-roll bar and the suspension of the race car are successively formulated. The formulated problems are subsequently solved by directly transcribing the original problems into large scale nonlinear optimization problems based on trapezoidal approach. The influences of the mounting positions of the propulsion system, the mass and inertia of the unsprung masses, the anti-roll bars and suspensions on the lap time are analyzed and compared quantitatively. Some interesting findings that are different from the `already known facts' are presented

Continuous Monitoring of Transmission Lines Sag through Angular Measurements Performed with Wireless Sensors

High voltage transmission lines are crucial infrastructure that are demanded to supply an increasing request of electric energy. In the design and operations stages, sag represents a key parameter which must respect specific constraints. Therefore, sag continuous monitoring is becoming essential to guarantee the correct functioning of the line and to optimize the current flow. Different solutions have been proposed in literature, but they are still lacking efficiency and reliability to be used during operations. In this work, a simple and efficient method, based on conductor parabolic approximation, is developed and used to compute the sag through the measurement of the conductor slope in proximity of the span extremities. The angular measurements are obtained using wireless sensors equipped with MEMS accelerometers developed by authors and employed for HVTL conductor vibration monitoring. The proposed method and its implementation in the monitoring system was tested in a laboratory environment on a real conductor. The values of sag at different tensile loads have been obtained and compared to the measured ones, with satisfactory results according to the accelerometer resolution. The solution developed therefore represents a complete and innovative tool to be adopted in the field to monitor, in real time, both the sag and the level of vibration due to the wind action, allowing to increase the performance reliability of HVTL

Constrained Long-Horizon Direct Model Predictive Control for Grid-Connected Converters with LCL Filters

This paper presents a direct model predictive control algorithm for a three-level neutral point clamped converter connected to the grid via an LCL filter. The proposed controller simultaneously controls the grid and converter currents as well as the filter capacitor voltage, while meeting the relevant grid standards. Moreover, output constraints are included to ensure operation of the system within its safe operating limits. This is achieved by formulating the direct MPC problem as a constrained integer least-squares optimization problem, wherein the output constraints are mapped into input constraints. The presented results verify the effectiveness of the proposed method.acceptedVersionPeer reviewe

An Indirect Model Predictive Control Method for Grid-Connected Three-Level Neutral Point Clamped Converters with LCL Filters

This article presents a model predictive control (MPC) algorithm for a three-level neutral point clamped converter connected to the grid via an LCL filter. The proposed long-horizon MPC method, formulated as a multicriterion quadratic program (QP), simultaneously controls the grid and converter current as well as the filter capacitor voltage, while meeting the relevant grid standards. To achieve the latter, a carrier-based pulsewidth modulation stage is employed. Finally, soft constraints are included to ensure operation of the system within its safe operating limits, particularly with regards to a potential overcurrent or overvoltage trip during transient operation. The presented simulation results based on a medium-voltage system as well as experimental studies based on a scaled-down prototype verify the effectiveness of the proposed method.acceptedVersionPeer reviewe

Indirect Model Predictive Control for a Grid-Tied Three-Level Neutral Point Clamped Converter with an LCL Filter

The paper presents a model predictive control (MPC) algorithm for a three-level neutral point clamped converter connected to the grid via an LCL filter. The proposed long-horizon MPC, formulated as a multi-criterion quadratic program (QP), simultaneously controls the grid and converter current as well as the filter capacitor voltage, while meeting the relevant grid standards. To achieve the latter, a carrier-based pulse width modulation (CB-PWM) stage is employed. Finally, soft constraints are included to ensure operation of the system within its safe operating limits, particularly with regards to a potential overcurrent or overvoltage trip during transient operation. The presented results verify the effectiveness of the proposed method.acceptedVersionPeer reviewe

Design of a Hybrid Acoustic Device Based on Proof-mass Actuators

The paper deals with the design of a device for sound reproduction to be fixed to a supporting surface. The device is made up of two different types of acoustic actuators based on different technologies that allow good sound reproduction in the range of frequencies from 20Hz to 20kHz. The generation of sound at high frequencies is demanded to a magnetostrictive actuator, while a more traditional magnetodynamics actuator is used to generate sound at low frequencies. The coupling between these two actuators leads to a device having small overall dimensions and high performance