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DAVIDE TEBALDI

Ricercatore t.d. art. 24 c. 3 lett. A
Dipartimento di Ingegneria "Enzo Ferrari"

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Pubblicazioni

2024 - A Generalized Procedure to Model Complex Time-Varying Physical Systems [Relazione in Atti di Convegno]
Tebaldi, Davide; Zanasi, Roberto
abstract

This paper addresses the systematic modeling of complex physical systems involving constant and time-varying interactions of physical elements in different energetic domains. The proposed procedure provides two different dynamic models of the considered system: a full-order one and a reduced-order one, where the latter is obtained when some of the system dynamical elements are properly disregarded. The matrices and vectors of the two dynamic models are automatically computed following the proposed rules and algorithms, thus reducing the chances of making computation mistakes. The proposed procedure is applied to two different case studies: an hydraulic continuous variable transmission for powertrain dynamics and a crank-connecting rod system in the mechatronic field.

2024 - A unified methodology for the power efficiency analysis of physical systems [Articolo su rivista]
Tebaldi, Davide; Zanasi, Roberto
abstract

In this paper, the problem of power efficiency evaluation for ports physical systems is investigated. The efficiency analysis that we perform highlights the necessary and sufficient conditions for the system to be passive, and outlines the guidelines for the efficiency maps computation. After addressing the problem from a formal point of view, the analysis is deepened for the case of two-ports linear and nonlinear physical systems, and for the cases of three and four-ports linear systems. The efficiency analysis and the computation of the efficiency maps are addressed as a function of the power variables characterizing all the energetic ports of the considered systems. Furthermore, the salient properties of the efficiency are highlighted and discussed. The theoretical analysis which is developed is then applied to some physical systems of interest for industries and engineers working in the electromechanical, hydraulic and automotive fields: a DC electric motor driving an hydraulic pump for the two-ports systems class, a single-stage planetary gear set for the three-ports systems class, and a Ravigneaux planetary gear set for the four-ports systems class.

2023 - Power-Oriented Gearbox Modeling and Gearshift Strategy Optimization Using Dynamic Programming [Relazione in Atti di Convegno]
Tebaldi, Davide; Villani, Manfredi; Rizzoni, Giorgio
abstract

In this paper, two main subjects are addressed. The first subject is the description of the considered hybrid electric propulsion system together with the power-oriented modeling of the employed gearbox. The gearbox modeling is performed by differentiating the cases of gearshift taking and not taking place, and the resulting model can be directly implemented in the Simulink environment using standard libraries. The second subject is the development of a new algorithm for determining the vehicle gearshift strategy in order to optimize the efficiency of the electric machine driving the transmission. The algorithm, which is causal and real-time implementable, is derived from an off-line benchmark optimal solution computed using dynamic programming, which, although being optimal, is a-causal and not real-time implementable. On the selected case study driving scenario the algorithm shows good performance, achieving an electric machine average efficiency that is only 2.1% lower than the optimal off-line dynamic programming solution.

2023 - Systematic modeling of complex time-variant gear systems using a Power-Oriented approach [Articolo su rivista]
Tebaldi, Davide; Zanasi, Roberto
abstract

This paper addresses a methodology for the systematic modeling of complex gear systems. The methodology is based on the use of a unified general model, working for all complex gear systems: time-variant as well as time-invariant, having parallel or oblique rotation axes. The model equations are automatically written following the outlined procedure and applying the presented algorithms, making this approach less prone to mistakes with respect to other approaches. Next, a reduced model assuming rigid gear connections and introducing no loss of information is proposed, which directly gives the kinematic relations between the gears angular speeds and input torques. In order to show some case studies, the proposed methodology is applied to three systems of interest for vehicle dynamics and powertrain modeling. The considered case studies are a differential structure having a bevel gearing system with non-perpendicular gear shafts, a vehicle differential and a full toroidal variator, which is suitable for applications such as KERS (Kinetic Energy Recovery System) and IVT (Infinitely Variable Transmission). Furthermore, the control of a full toroidal variator acting as a KERS with reference to an automotive case study and the comparison of the proposed modeling methodology with two other approaches are addressed.

2022 - Efficiency Map-Based PMSM Parameters Estimation Using Power-Oriented Modeling [Articolo su rivista]
Tebaldi, Davide
abstract

This paper deals with two subjects. The first one is the presentation of a Matlab App created for PMSMs (Permanent Magnet Synchronous Motors) parameters estimation, both in the electrical and in the mechanical energetic domains. The second one is the presentation of a generalized PMSM Simulink superblock equipped with a user-friendly interface allowing to select options and to input the model parameters. The Matlab App and the PMSM superblock can be easily interfaced with each other. Finally, two simulation case studies are reported for the PMSM superblock.

2022 - PMSM Simulink Superblock And Matlab App For PMSM Parameters Estimation [Banca dati]
Tebaldi, Davide
abstract

This dataset contains two subjects. The first one is a Matlab App created for PMSMs (Permanent Magnet Synchronous Motors) parameters estimation, both in the electrical and in the mechanical energetic domains. The second one is a generalized PMSM Simulink superblock equipped with a user-friendly interface allowing to select options and to input the model parameters. The Matlab App and the PMSM superblock can be easily interfaced with each other.

2021 - Modeling Control and Robustness Assessment of Multilevel Flying-Capacitor Converters [Articolo su rivista]
Zanasi, Roberto; Tebaldi, Davide
abstract

When performing AC/DC-DC/AC power conversions, multilevel converters provide several advantages as compared to classical two-level converters. This paper deals with the dynamic modeling, control, and robustness assessment of multilevel flying-capacitor converters. The dynamic model is derived using the Power-Oriented Graphs modeling technique, which provides the user with block schemes that are directly implementable in the Matlab/Simulink environment by employing standard Simulink libraries. The performed robustness assessment has led to the proposal of a divergence index, which allows for evaluating the voltage balancing capability of the converter using different voltage vector configurations for the extended operation of the converter, namely when the number of output voltage levels is increased for a given number of capacitors. A new variable-step control algorithm is then proposed. The variable-step control algorithm safely enables the converter extended operation, which prevents voltage balancing issues, even under particularly unfavorable conditions, such as a constant desired output voltage or a sudden load change. The simulation results showing the good performances of the proposed variable-step control as compared to a classical minimum distance approach are finally provided and commented in detail.

2021 - Modeling Control and Simulation of a Parallel Hybrid Agricultural Tractor [Relazione in Atti di Convegno]
Tebaldi, Davide; Zanasi, Roberto
abstract

The modeling, the control and the simulation of a parallel hybrid architecture for an agricultural tractor propulsion system are performed in this paper. The systems involved in the considered architecture are: an Internal Combustion Engine (ICE), two Permanent Magnet Synchronous Motors (PMSMs), a supercapacitor playing the role of the energy storage device, a clutch allowing to enable/disable the electrical power path, and finally the transmission system from the gearbox to the wheels of the vehicle. A control strategy aiming at minimizing the ICE specific fuel consumption is then proposed and tested by presenting some simulation results.

2021 - Modeling Control and Simulation of a Power-Split Hybrid Wheel Loader [Relazione in Atti di Convegno]
Tebaldi, Davide; Zanasi, Roberto
abstract

This paper addresses the modeling control and simulation of a power-split hybrid propulsion system for driving a Wheel Loader. The modeling is performed exploiting the Power-Oriented Graphs (POG) graphical modeling technique. The main elements involved in the system are: an ICE (Internal Combustion Engine), two PMSMs (Permanent Magnet Synchronous Motors) controlled using a vectorial control and powered by a DC bus, a planetary gear set, a DC/DC converter, a supercapacitor acting as energy storage device and the transmission system of the vehicle, including all the physical elements from the gearbox to the vehicle wheels. A control strategy aiming at reducing the ICE operating point fluctuations caused by the transmission load and minimizing the ICE specific fuel consumption is proposed. Simulation results with reference to a typical driving cycle for this type of vehicle are finally presented and commented in detail.

2021 - Power-Oriented Modeling of Epicyclic Gear Trains [Relazione in Atti di Convegno]
Zanasi, Roberto; Tebaldi, Davide
abstract

Model-based simulations are important in the automotive industry to study and evaluate the vehicle behavior. In this paper, the Power-Oriented Graphs (POG) technique is used as a tool for modeling epicyclic gear trains. A full elastic dynamic model of the system is first derived, which can then be reduced by neglecting the elastic contact points between the gears while still being able to recover the time behaviors of the spring tangential forces. The proposed modeling method is then applied to two epicyclic gear trains, and the design of a suitable control allowing to minimize the system dissipations is presented and applied to the second case study.

2020 - Estimation of Physical Parameters Using a New Discrete-time Derivative Algorithm [Relazione in Atti di Convegno]
Tebaldi, Davide; Morselli, Riccardo; Zanasi, Roberto
abstract

The paper presents a parameters estimation procedure for physical systems modeled using the POG (Power-Oriented Graphs) technique. The coefficients defining the constitutive relation for both static and dynamic physical elements within the system can be estimated, as well as the coefficients describing energy conversions taking place either within the same energetic domain or between two different energetic domains. The evolution of the state vector over time is supposed to be known, whereas its first derivative is supposed to be unknown and is obtained by using a new algorithm for computing the discrete-time derivative of a sampled signal, which is effective even in presence of disturbances affecting the signal samples. As long as the unknown parameters appear linearly within the system differential equations, the system is allowed to exhibit any nonlinear function of the state vector and its first derivative. The procedure is finally applied to two different case studies: a linear one and a nonlinear one.

2020 - Instantaneous Gearshift Model Based on Gear-dependent Angular Momentum [Relazione in Atti di Convegno]
Tebaldi, Davide; Zanasi, Roberto
abstract

The paper presents a new gearbox dynamic model for the effective simulation of simultaneous multi-clutches lock/unlock, by exploiting the Power-Oriented Graphs (POG) modeling technique. The generalized structure of the proposed model allows to simulate various gearbox configurations, which may foresee a change in terms of equivalent moment of inertia on the primary or secondary shaft, depending on the internal clutches configuration being function of the currently engaged gear. The peculiarity of the model lies in the instantaneous engagement of the new gear by skipping the slipping transient related to change of the internal clutches configuration, while preserving the natural loss of energy associated to it. The effectiveness of the presented gearbox model is finally tested and compared with classical gearbox modeling solutions with the aid of some simulation results.

2020 - Modeling and Simulation of a Multiphase Diode Bridge Rectifier [Relazione in Atti di Convegno]
Tebaldi, Davide; Zanasi, Roberto
abstract

In this paper, an analytical approach for modeling a multiphase diode bridge rectifier suitable for control purposes is presented. The model has been implemented in Matlab/Simulink by means of a function performing the AC/DC current conversion and takes into account the main non-idealities of semiconductor diodes, such as the turn-on voltage and the on/off resistances. The developed Matlab function makes the simulation of the multiphase diode bridge rectifier very straightforward and its effectiveness has been tested by comparing the simulation results with those obtained by using the rectifier model provided by the PLECS circuit simulator.

2020 - Modeling Control and Simulation of a Series Hybrid Propulsion System [Relazione in Atti di Convegno]
Tebaldi, Davide; Zanasi, Roberto
abstract

This paper deals with the modeling control and simulation of a series hybrid propulsion system for driving a Wheel Loader by relying upon the Power-Oriented Graphs (POG) modeling technique. The considered propulsion system is composed of the following elements: an ICE (Internal Combustion Engine), two controlled PMSMs (Permanent Magnet Synchronous Motors), a supercapacitor as energy storage device and the transmission system of the vehicle itself from the gearbox all the way down to the vehicle wheels. A strategy for the control of the considered hybrid architecture is studied, with the objective of minimizing the ICE specific fuel consumption. Simulation results showing the operation of the presented strategy are finally reported and commented in detail.

2020 - Modeling of Complex Planetary Gear Sets using Power-Oriented Graphs [Articolo su rivista]
Zanasi, Roberto; Tebaldi, Davide
abstract

In this paper, a systematic approach for the dynamic modeling of complex planetary gear sets is presented. The approach relies upon a set of rules for building the system matrices and vectors of the system full dynamic model for any planetary gear set. A congruent state-space transformation is applied to obtain a reduced-order rigid model of the system, which allows for faster simulations. The behavior of the tangential forces accounting for the gears interactions is proven to be obtained from the reduced-order model. Furthermore, the kinematic relations of the considered planetary gear set are automatically generated when developing the reduced-order rigid model. As an example, two systems of interest in the vehicle industry are then modeled with the proposed approach and simulated in Matlab/Simulink: a Ravigneaux planetary gear set and a double-stage planetary gear set.

2019 - Modeling and Control of a Power-Split Hybrid Propulsion System [Relazione in Atti di Convegno]
Tebaldi, Davide; Zanasi, Roberto
abstract

In this paper, the Power-Oriented Graphs (POG) technique is used to model a Hybrid Propulsion System for driving an agricultural tool. The main elements present in the system are: an ICE (Internal Combustion Engine), two PMSMs (Permanent Magnet Synchronous Electric Motors) equipped with two inverters in order to be properly driven, a planetary gear, an energy storage device and an agricultural tool. Based on the system dynamic model, a dedicated control strategy has been developed allowing to efficiently control the system by reducing the ICE specific consumption as much as possible. Simulation results showing the operation of the control strategy are finally reported and commented in detail.

2019 - Planetary Gear Modeling Using the Power-Oriented Graphs Technique [Relazione in Atti di Convegno]
Zanasi, Roberto; Tebaldi, Davide
abstract

In this paper, the Power-Oriented Graphs (POG) technique is used to model Planetary Gear transmission systems. The full elastic dynamic model of the system is obtained using a fast and direct method which can be easily applied to any type of planetary gear. The rigid and reduced dynamic model of the system when the stiffness coefficients go to infinity is then obtained using a POG congruent state space transformation allowing the user to select which angular speeds are to be maintained in the reduced model. Another interesting aspect of the presented method is that the obtained reduced model is still able to provide the time behaviors of the tangential forces present between each couple of gears of the considered planetary gear system. The presented fast and direct method is then applied to two practical case studies, and simulative results in Matlab/Simulink showing the effectiveness of the method are finally reported and commented.

2019 - Power Flow Efficiency of Linear and Nonlinear Physical Systems [Relazione in Atti di Convegno]
Zanasi, Roberto; Tebaldi, Davide
abstract

In this paper, an analytical procedure to derive the efficiency of linear and nonlinear physical systems is presented. This procedure allows to compute the efficiency map both on the plane of the input power variables and on the plane of the output power variables. Additionally, the paper highlights the parameters to be adjusted in order to enlarge the high-efficiency region of the system. The presented procedure can also be used in conjunction with a least square algorithm in order to estimate the unknown parameters of the considered physical system. The effectiveness of the procedure has been tested in Matlab/Simulink to estimate the parameters of an actual PMSM electric motor. The obtained results show a very good matching between the actual and the estimated efficiency maps.

2019 - Study of the Bidirectional Efficiency of Linear and Nonlinear Physical Systems [Relazione in Atti di Convegno]
Zanasi, Roberto; Tebaldi, Davide
abstract

In this paper, a study of the bidirectional efficiency of linear and nonlinear physical systems is performed. The methodology to compute the bidirectional efficiency map of the system is described, highlighting which is the power flow orientation giving the maximum system efficiency. The designer can therefore easily evaluate whether a physical system, such as for instance an electric machine, is more suitable for being used in forward motor mode rather than in reverse generator mode or viceversa. Three different types of physical systems are modeled and simulated in Matlab/Simulink, and the different characteristics they exhibit in terms of efficiency are highlighted. Finally, the properties that the efficiency maps exhibit if the linear system is affected by symmetric or nonsymmetric nonlinearities are studied and commented in detail.