Gianluca Botto

Boosting the performance of PC-based software routers with FPGA-enhanced network interface cards

The research community is devoting increasing attention to software routers based on off-the-shelf hardware and open-source operating systems running on the personal-computer (PC) architecture. Todays high-end PCs are equipped with peripheral component interconnect (PCI) shared buses enabling them to easily fit into the multi-gigabit-per-second routing segment, for a price much lower than that of commercial routers. However, commercially-available PC network interface cards (NICs) lack programmability, and require not only packets to cross the PCI bus twice, but also to be processed in software by the operating system, strongly reducing the achievable forwarding rate. It is therefore interesting to explore the performance of customizable NICs based on field-programmable gate array (FPGA) logic devices we developed and assess how well they can overcome the limitations of todays commercially-available NICs

A multi-purpose control and power electronic architecture for active magnetic actuators

This paper shows the results related with the design and implementation of a multi-purpose electronic architecture used to drive magnetic actuators by means of a three-phase independent-legs module in place of the commonly used H-bridge modules. The typical application is the magnetic actuators drive used in active magnetic bearings. The architecture is composed of a control unit with a floating point Digital Signal Processor (DSP), a power board with six independent phase legs and a carrier board to interconnect them. When more than one module is required by the application, the communication between them is guaranteed by means of CAN bus interconnection. The proposed system allows to drive two pairs of opposite electromagnets, such as those typically used to control active magnetic bearings. The study is motivated by the opportunity of reducing the amount of power and control electronic components resulting in a more straightforward, efficient and cost reduction design.

Model and design of a power driver for piezoelectric stack actuators

A power driver has been developed to control piezoelectric stack actuators used in automotive application. An FEM model of the actuator has been implemented starting from experimental characterization of the stack and mechanical and piezoelectric parameters. Experimental results are reported to show a correct piezoelectric actuator driving method and the possibility to obtain a sensorless positioning control.

An FPGA Controlled DC/DC Step-Up Converter for Automotive Applications

In automotive applications piezoelectric actuators (used as injectors) typically require more than 150V in order to be driven in a smaller time with respect to magnetic actuators, allowing for example more precise injections in the same motor cycle. This is a big concern in automotive environment, where the 12V battery voltage is still the main power source available. In this paper an efficient high-step up DC/DC converter is presented for interfacing the standard 12V battery with the high voltage DCBUS used for piezoelectric actuators system. In the proposed converter, two coupled inductor boost converters are interleaved and controlled by an FPGA. Design and analysis of the proposed converter are presented. Finally experimental results are provided for verification of the proposed converter.

Open motion control: A model based development platform for rapid prototyping

In this paper, an integrated and open-architecture motion control (OMC) development environment is presented. The application is founded on a model-based technological approach which represents an effective way to focus on maximum theoretical performance in the mechatronic prototyping. In order to achieve openness flexibility, an open-architecture supported by a DSP/FPGA-based digital platform is provided.

Advanced Sensorless Control System for PMSM-based Automotive Application

Electrical drives are widely used in industrial applications like energy production, management and recovery. In this paper the control of PM motors for high speed automotive applications is investigated. Here, an improved DQ Control with a Sliding Mode Observer is implemented to guarantee high efficiency. As a result, comparisons are made between simulation and experimental test, illustrating the performance of the drive technique and the control design approach.

DC/DC Step-Up Converters for Automotive Applications: a FPGA Based Approach

One emerging application of power electronics is the driving of piezoelectric actuators. These actuators can be used for different kinds of application. They are employed for micro and nano positioning tasks as well as hydraulic or pneumatic valves, where they replace magnetic control elements. Piezoelectric actuators have some specific advantages such as high resolution of the displacement, excellent dynamic properties and energy consumption near to zero for static or quasi static operations. So, high performances, low emissions and less fuel consumption bring car designers to adopt new technologies in automotive systems. The use of piezoelectric actuators (used as injectors) allows less response time with respect to traditional magnetic actuators but requires high driving voltages in order to be driven in a smaller time. This is a big concern in automotive environment, where the battery voltage is still the main power source available. A switching amplifier for reactive loads generally consists of two components. A unidirectional DC/DC converter with a small input power loads and large buffer capacitor and, a second bidirectional DC/DC converter that controls the energy exchanged between the buffer capacitor and the reactive load. The requirements on the unidirectional DC/DC converter are few. It only needs to compensate the power losses of the two stages plus the energy dissipated in the actuator and the connected mechanical system. Second stage presents more problems, because it must be designed for full system power. Conventional DC/DC boost converter is not the best solution in piezoelectric based applications where high step-up ratio and high efficiency power conversion is required. The coupled inductor boost converter meets the demanding requirements of these applications, including high reliability, relative low cost, safe operation, minimal board space and high performance, therefore an excellent choice for interfacing the battery with the high voltage DCBUS used for piezoelectric actuator system. An FPGA based controller allows interleaving two phases reducing both peak primary current and output current ripple. Moreover, a quasi constant frequency hysteretic current control technique reduces EMI interferences and ensures control loop stability. A soft start sequence permits to limit average input current and guarantees start-up phase in a short time.