Paolo Bolognesi

Improved dead beat control of a shunt active filter for aircraft power systems

This paper investigates the application of an improved dead beat digital control strategy to a 3-phase shunt active filter used for compensation of load harmonics in aircraft power systems. Due to the high rated frequency (400 Hz) such applications result particularly demanding for both power and control devices. To compensate the inherent delay of digital control systems, a simple method for predicting the values of relevant variables is proposed and analyzed. The converter topology, its analytical modeling and its control are described. Significant results obtained by experimental tests are finally reported and commented, referring to a prototype system purposely implemented.

Dual-function wheel drives using rotary-linear actuators in electric and hybrid vehicles

Electric and hybrid vehicles represent the future of ground transportation. In such vehicles, electric motor/s provide the propulsion thrust — eventually aiding the engine in case of parallel and mixed powertrains. On the other hand, x-by-wire technologies are spreading, typically using electric drives to also perform actions such as steering, braking, active suspension etc. Any active wheel may then feature up to 4 related degrees of freedom, usually managed by separated drives. This paper proposes to use multi-degree-of-freedom drives, in particular rotary-linear, to integrate more of such basic movements inside a single motor, thus achieving potential benefits on size, weight, cost, complexity etc. Different combinations of functions are examined and the main types of rotary-linear machines found in the literature are briefly recalled and commented, finally focusing on a brushless isotropic rotary-linear machine.

Role and Technology of the Power Split Apparatus in Hybrid Electric Vehicles

Hybrid electric vehicles (HEVs) are an in-between step for the transition from the conventional high-consumption, high- pollution vehicles to the future efficient and clean vehicles. In this paper the main HEV architectures are at first reviewed, focusing on the series-parallel one and the key role played by the power split apparatus within this architecture. Then the two solutions used for implementing the power split, namely the mechanical solution, which is built up around a planetary gear, and the electric one, which is constituted by an electric machine with both rotating members, are read up. At last, a performance comparison of the two solutions is given.

A low-complexity rotary-linear motor useable for actuation of active wheels

The combination of a rotary and linear motion along the same axis is used in several applications, including tooling machines, robotics, automation etc. It may be also used to conveniently manage pairs of basic functions of active wheels in electric and hybrid vehicles. In such cases, rotary-linear machines may represent an interesting alternative to the usual employ of a separated actuator per each basic motion. Anyway, such machines often rely on a structure that is either not suited to be conveniently realized using common materials and manufacturing techniques, or exhibits a complex behavior not permitting an effective decoupled control of force and torque. This paper presents some results concerning the structure, theoretical modeling, FEM analysis, magnetic circuit modeling and drive control for an isotropic brushless machine recently proposed.

Structure and theoretical analysis of a novel rotary-linear isotropic brushless machine

Since the combination of a rotary and linear motion along the same axis is conveniently used in several applications, rotary-linear motors, able to provide both torque and force, represent one of the most interesting types of multi-degree-of-freedom machines. This paper deals with a novel type of rotary-linear permanent magnets synchronous machine that was recently proposed aiming to achieve a good controllability and inexpensive manufacturing using common solutions. The machine structure is illustrated as well as its ideal theoretical model derived from the usual sinusoidal approximated approach, highlighting the ideal possibility to simply achieve a decoupled linear control of force and torque by adjusting the d-q Park current components. Finally, considerations about regulation criteria and capability of the machine are reported.

A distributed driving and steering system for electric vehicles using rotary-linear motors

The paper presents the activities ongoing in the framework of a two-year Italian National Research Project aimed at developing a distributed Driving and Steering (DaS) system for Electric Vehicles (EVs). The system is built up around an actuation module embedding a rotary-linear motor and including a power converter and a local Electronic Control Unit (ECU) to supply and control the motor. The actuation module is intended to make a wheel active so as to give it propelling and steering capabilities. The DaS system, in turn, includes a central ECU and a fieldbus to govern and network the system, and a power supply stage. The Project under consideration is focused on a DaS system with two active wheels for a light-duty EV.

A novel rotary-linear brushless machine using standard active parts

Rotary-linear motors, able to simultaneously provide torque and force, represent one of the most interesting types of multi-degree-of-freedom machines. In fact, in several applications the combination of a rotary and a linear motion along the same axis is used. This paper presents the basic concepts and the theoretical analysis of a novel rotary-linear machine, purposely conceived to be assembled using common active parts easily found on the market. The machine structure is described and its analytical model is derived and commented, developing considerations concerning several aspects including control strategy, capability and preliminary design.

FEM modeling and analysis of a novel rotary-linear isotropic brushless machine

In several applications, ranging from industrial robotics to advanced automotive, a combination of rotary and linear motions along the same axis is ultimately required. Rotary-linear motors, providing both torque and force, may permit to fulfill the related requirements more effectively than conventional solutions using 2 distinct normal actuators. This paper presents the FEM modeling and analysis of a novel rotary-linear permanent magnets synchronous machine, whose structure, analytical modeling and control are presented in companion papers. Such machine was purposely conceived to be manufactured using common affordable technologies or even by assembling standard parts. A 3-D parametric model purposely developed to permit a detailed analysis of the machine operation is described. Several simulation results concerning various operative conditions are reported and commented, confirming the substantial validity of the basic idea and highlighting the secondary effects due to non-ideal aspects of machine behavior.

Advanced Variable Structure PI controllers

With the advance of digital control hardware the simple but effective proportional-integral-derivative (PID) control technology is moving towards a higher level of performance and robustness. A more general class of Variable Structure (VS) PID has derived from original PIDs to improve their performances and capabilities. This paper revises the main properties of VS regulators and proposes a novel VS PI controller that combines the advantages of popular PIs with the more flexibility of VS controllers. The proposed regulator is compared with the classic PI over several examples taken from the literature, including first, second and fourth order dynamical systems. An experimental set-up is implemented on purpose using AVR® 32 Microcontrollers in a hardware in the loop approach to validate the simulation results in a more realistic environment.

Effects of saturation on eccentricity force in permanent magnet synchronous machines

Permanent magnets synchronous machines are nowadays widely employed. In case of symmetrical construction, aligned mounting of the rotor and balanced supply, the distributed surface magnetic actions on the rotor feature a null resultant. Anyway, in case of defective assembly or when bearings exhibit a reduced or variable stiffness, the eccentricity of rotor determines a resultant force depending on angular position and currents. This paper investigates such phenomenon for a surface-magnets machine, using FEM analysis to permit keeping into account saturation. Simulation results are reported and commented, highlighting that such force may be affected from stator currents in a counter-intuitive way when magnetic saturation of the core becomes appreciable: in such event, the worst-case scenario required for design purposes must be carefully singled out.