Mohamed Wissem Naouar

FPGAs in Industrial Control Applications

The aim of this paper is to review the state-of-the-art of Field Programmable Gate Array (FPGA) technologies and their contribution to industrial control applications. Authors start by addressing various research fields which can exploit the advantages of FPGAs. The features of these devices are then presented, followed by their corresponding design tools. To illustrate the benefits of using FPGAs in the case of complex control applications, a sensorless motor controller has been treated. This controller is based on the Extended Kalman Filter. Its development has been made according to a dedicated design methodology, which is also discussed. The use of FPGAs to implement artificial intelligence-based industrial controllers is then briefly reviewed. The final section presents two short case studies of Neural Network control systems designs targeting FPGAs.

FPGA-Based Current Controllers for AC Machine Drives—A Review

The aim of this paper is to present the interest of implementing digital controllers using field-programmable gate array (FPGA) components. To this purpose, a variety of current control techniques, which is applied to alternating current machine drives, is designed and implemented. They consist of on-off current controllers, proportional-integral current controller, and predictive current controller. The quality of the regulated current is significantly improved. It is mainly due to a very important reduction of the execution time delay. Indeed, in all described techniques, the execution time of the designed hardware architectures is only a few microseconds. This time reduction derives directly from the possibility offered by FPGAs to design very powerful dedicated architectures. Numerous experimental results are given in order to illustrate the efficiency of FPGA-based solutions to achieve high-performance control of electrical systems.

FPGA-based Controllers

This article presents the benefits of using field-programmable gate array (FPGA)-based controllers for power electronics and drive applications. For this purpose, an algorithm perspective is first proposed, where it is stated that, depending on the intrinsic parallelism properties as well as level of complexity, it makes sense to implement each control algorithm on a specific hardware and/or software architecture to get the best performances in terms of execution time or the best ratio performance versus cost. Then, an application perspective is proposed where the constraints specifically linked to the control of power converters are discussed.

Fully Integrated FPGA-Based Controller for Synchronous Motor Drive

The aim of this paper is to present a fully integrated solution for synchronous motor control. The implemented controller is based on Actel Fusion field-programmable gate array (FPGA). The objective of this paper is to evaluate the ability of the proposed fully integrated solution to ensure all the required performances in such applications, particularly in terms of control quality and time/area performances. To this purpose, a current control algorithm of a permanent-magnet synchronous machine has been implemented. This machine is associated with a resolver position sensor. In addition to the current control closed loop, all the necessary motor control tasks are implemented in the same device. The analog-to-digital conversion is ensured by the integrated analog-to-digital converter (ADC), avoiding the use of external converters. The resolver processing unit, which computes the rotor position and speed from the resolver signals, is implemented in the FPGA matrix, avoiding the use of external resolver-to-digital converter (RDC). The sine patterns used for the Park transformation are stored in the integrated flash memory blocks.

Easy and Fast Sensor Fault Detection and Isolation Algorithm for Electrical Drives

This paper focuses on sensor fault detection and isolation (FDI) for electrical systems. A new, easy and fast FDI algorithm is proposed, keeping system performances unchanged under certain faulty sensor conditions when reconfigurations are available. The proposed FDI algorithm is derived from a parity space approach and is based on temporal redundancies. It is insensitive to parameter variations since no model knowledge is required. Also, it is available for a large class of electrical systems such as single- or three-phase power converters, dc or ac electrical drives, etc. Moreover, the residual threshold used for FDI is accurately defined and is suitable for the whole operating range. Simulations results are presented to illustrate the good functionality of theoretical developments. Numerous experimental results are also shown to validate the effectiveness of the proposed FDI algorithm and to highlight its advantages for the control of electrical systems.

FPGA-Based Predictive Current Controllerfor Synchronous Machine Speed Drive

In this paper, a field programmable gate array (FPGA)-based speed controller for a synchronous machine with an internal current control loop based on a predictive current controller is presented. Due to their complex computation schemes, predictive current controllers implemented in a full digital system are characterized by an inevitable delay in calculating and applying the switching states to the inverter. Consequently, their performances are affected and the achieved sampling frequency is limited. These digital control limitations are mainly due to the processing speed versus computational complexity trade-off. To cope with this problem, specific digital hardware technology such as FPGA can be used as an alternative digital solution to ensure fast processing operation and to preserve performances of predictive current controllers in spite of their complex computation schemes. Such performances can be preserved thanks to the high flexibility and high computation capabilities of FPGAs. In order to illustrate this, an FPGA implementation of a synchronous machine speed controller based on a predictive current controller is presented and fully analyzed in this work. The obtained execution time is only of few microseconds for the whole control algorithm. Experimental results are shown to prove the efficiency of FPGA-based solutions to achieve high performances.

FPGA-Based Dynamic Reconfiguration of Sliding Mode Current Controllers for Synchronous Machines

This paper presents the concept of dynamic reconfiguration between two sliding mode current controllers for synchronous motor drives. The first one is a Direct Sliding Mode (DSM) current controller, which is based on a switching table synthesized via sliding mode theory. The second one is an Indirect Sliding Mode (ISM) current controller that computes a reference voltage vector via sliding mode theory. The computed reference voltage is then applied to the terminals of the synchronous machine through a Pulse Width Modulation (PWM) process. This item studies and discusses the reconfiguration criteria and presents the main interest of using FPGA digital solutions for dynamic reconfiguration process implementation between the two sliding mode current controllers. Numerous experimental results are presented in order to confirm the interest and performances of the proposed reconfigurable sliding mode current controller.

FPGA-based torque controller of a synchronous machine

The performances of the field programmable gate array (FPGA) increase continually, thus in many applications they can be an interesting alternative to DSPs and microcontrollers. The aim of this work is to present the implementation of a torque control for synchronous machine, as an approach to the design of reusable and reconfigurable architectures for the control of electrical systems. This approach is based on an appropriate design methodology that offers considerable design advantages. Experimental results carried on a prototyping platform are given to illustrate the efficiency and the benefits of the proposed approach.

FPGA-Based Fault-Tolerant Space Vector-Hysteresis Current Control for Three-Phase Grid-Connected Converter

This paper investigates the field-programmable gate array (FPGA) implementation of a fault-tolerant space vector-hysteresis current control (SV-HCC) for three-phase grid-connected converter. The proposed control ensures continuous operation despite of an open-circuit fault in one grid current measurement circuit (caused by defected cables, lines or connectors at the output of the current measurement circuit). It is based on hardware redundancy of current measurement circuits for fault detection and isolation. The faulty measured current is identified through the computation of residuals with well-defined thresholds. Thanks to the high computation capabilities of FPGAs, the implemented fault-tolerant SV-HCC is executed with a very high sampling frequency and very low execution time. As a consequence, the defined theoretical thresholds remain available for the experimental tests. Several experimental results, carried out on FPGA-based prototyping platform, are given in order to illustrate effectiveness and reliability of the proposed fault-tolerant SV-HCC.

Predictive control strategies for wind turbine system based on permanent magnet synchronous generator.

In this paper, Model Predictive Control and Dead-beat predictive control strategies are proposed for the control of a PMSG based wind energy system. The proposed MPC considers the model of the converter-based system to forecast the possible future behavior of the controlled variables. It allows selecting the voltage vector to be applied that leads to a minimum error by minimizing a predefined cost function. The main features of the MPC are low current THD and robustness against parameters variations. The Dead-beat predictive control is based on the system model to compute the optimum voltage vector that ensures zero-steady state error. The optimum voltage vector is then applied through Space Vector Modulation (SVM) technique. The main advantages of the Dead-beat predictive control are low current THD and constant switching frequency. The proposed control techniques are presented and detailed for the control of back-to-back converter in a wind turbine system based on PMSG. Simulation results (under Matlab-Simulink software environment tool) and experimental results (under developed prototyping platform) are presented in order to show the performances of the considered control strategies.