Robert Horvat

PMSM sliding mode FPGA-based control for torque ripple reduction

This paper presents a torque ripple reduction approach to the direct torque control of a permanent magnet synchronous motor, using a sliding mode control technique. A distinctive feature of this approach is that, by appropriately parameterizing and implementing the sliding mode controller, the discontinuous nature of the voltage source inverter may be directly incorporated into the design process. The key idea is to incorporate the benefits of the variable structure systems control design and the event-driven sequential control structures in order to raise the systems performance and control efficiency. A predictive sliding-mode controller has been developed, designed as finite-state automata, and implemented using a field-programmable gate array (FPGA). This new FPGA logic regarding torque and speed control has been developed, analyzed, and experimentally verified.

FPGA-Based Predictive Sliding Mode Controller of a Three-Phase Inverter

This paper proposed a novel predictive variable-structure-switching-based current controller for a three-phase load driven by a power inverter. The design specifications are robustness to load electrical parameters, fast dynamic response, reduced switching frequency, and simple hardware implementation. In order to meet previous specifications, a sliding mode controller has been developed, which is designed as finite-state automata, and implemented with a field-programmable gate array (FPGA) device. The switching strategy implemented within the state transition diagram provides for a minimum number of switches by the three-phase inverter that is confirmed through simulation and experimental results. Its regulation using the proposed control law provides good transient response by the brushless ac motor control. However, this does not limit the wider applicability of the proposed controller that is suitable for different types of ac loads (rectifier and inverter) and ac motors (induction, synchronous, and reluctance). A new logical FPGA torque and speed controller is developed, analyzed, and experimentally verified.

A Switching Control Strategy for the Reduction of Torque Ripple for PMSM

This paper proposes the field-programmable gate array (FPGA) implementation of a variable structure system predictive sequential switching control strategy, as applied to a permanent magnet synchronous machine. In the case of ac motor drives, in contrast to conventional vector control where the inverter is not taken into consideration by the controller, the proposed control integrates the inverter model and the inverter states. It allows obtaining faster torque dynamics than vector control algorithms. The main design specifications are a reduced switching frequency and simple hardware implementation. A predictive sliding mode controller has been developed, designed as finite-state machine, and implemented with a FPGA. This new logic FPGA torque and speed controller has been developed, analyzed, and experimentally verified.

An Event-Driven Approach to the Current Control of a BLDC Motor Using FPGA

A mechatronic system consists of a mechanical system and electric actuators. The presented event-driven control of a mechatronic system has been implemented on a field-programmable gate array (FPGA) platform. The supervisor provides robust, safe, and transparent control, where the finite-state machine (FSM) defines all the possible directions for implementation. In order to make the supervisor more transparent, the FSM has been divided into three main parts, each signified by a main color (green, yellow, and red - semaphores). These colors indicate the condition of the system. The supervisor has been upgraded with a graphical user interface with indicators that directly show the state of the FSM. The interface includes additional logical I/O signals, in order to make the system more useful. The supervisor is executed parallel to the basic motor control on the FPGA. This paper introduces a robust current controller of a brushless ac (BLAC) motor, upgraded with a proportional-integral velocity controller. The application of the proposed event-condition-action-based method is illustrated using the example of the FSM motion control of a BLAC motor with integrated I/O signals.

Finite-State Machine Motion Controller: Servo Drives

Digital controllers are used for modern power converter control and industrial automation. The functionality of the finite-state machine (FSM) provides an ideal platform for building a high-frequency field-programmable gate array (FPGA) controller for power electronics applications. This article develops the design of a current-control loop and the selection of switching logic for three-phase switching converters and ac electrical machines. The main design specifications are robustness to load and electrical parameters, fast dynamic response, reduced switching frequency, and simple hardware implementation. A discrete-event-type controller is proposed to meet previous specifications, designed as finite state automaton and implemented with an FPGA device. Furthermore, the actual controller architecture is based on the FPGA Spartan 3E. The experimental results are presented using a brushless ac (BLAC) motor as the converter load. However, this does not limit the wider applicability of the proposed controller, as it is suitable for different types of ac loads (rectifiers, inverters).

Nonlinear Torque Control of BLAC Motor

Abstract This study presents the implementation of a hybrid control strategy applied to a brushless AC (BLAC) motor drive. Hybrid control is a general approach for control of a switching-based Hybrid Systems (HS). This class of HS includes a continuous process controlled by a discrete controller with a finite number of states. The overall stability of the system is shown using Lyapunov technique. The Lyapunov functions used contain a term penalizing incremental energy of control error, torque and stator current, enhancing the stability. The closed-loop system with the proposed control low provides good transient response and good regulation the BLAC motor control. A new logical FPGA torque controller based on Lyapunov theory are developed, analyzed and experimentally verified.

The Role of Accounting in a Society: Only a techn(olog)ical solution for the problem of economic measurement or also a tool of social ideology?

Abstract The contribution juxtaposes the traditional neutralistic view on the role of accounting in a society as an activity of independent and unbiased measurement and presentation of real economic phenomena with the extended view on accounting as a socio-political practice and ideology. It also shows how the latter view impacts the understanding of the role of accounting and its reactions in light of the recent global financial crisis.

Sharing business partner behavior

Purpose – The new concept of business partner behavior sharing practice is addressed from three perspectives: technical/technological, legal and ethical/moral with the aim to elaborate its sharing feasibility, value added, legal restrictions and moral considerations. Research results are synthetized to present an overview on business partners behavior sharing direct and indirect value added, costs and risks and proposing mitigation strategies. The paper aims to discuss these issues. Design/methodology/approach – To evaluate technical feasibility, a real-life sharing experiment is conducted. Using a sharing agency data are collected, summarized and reported. For the purpose of legal evaluation, relevant legislation is analyzed. Ethicality/morality is assessed utilizing theoretical applied-ethics analysis. Two major normative moral theories – teleology and deontology – are selected for this purpose. The synthesis of the research results is represented in system dynamics model. Findings – Results show no sig...

Application of hybrid system theory to switching control of a three-phase inverter

A novel discrete event based current controller for three-phase load driven by power inverter is proposed. Main design specifications are robustness to load electrical parameters, fast dynamic response, reduced switching frequency and simple hardware implementation. To meet previous specifications a switching two types of controllers are developed: hysteresis type and Lyapunov type. The voltage source inverter (VSI) is represented as event driven system with 23 modes of operation. The switching among these modes is governed by the supervisory control approach. The overall stability of the system is shown using Lyapunov technique. The Lyapunov functions used contain a term penalizing incremental energy of control error, torque and stator currents, enhancing the stability. The regulation with the proposed control law provides good transient response of the brushless BLDC motor control. A new logical FPGA torque controller based on Lyapunov stability theory are developed, analyzed and experimentally verified.

FPGA hybrid controller for unity power factor

With introduction of recent standards on limiting harmonic pollution of electrical power distribution system, three-phase PWM converters are being considered as prime candidates for interfacing high-power electronic equipment to power supply lines. In these applications, converters can provide input currents without distortion and with unity power factor. In this paper, a unified discrete event model is given for power electronic circuits based on a hybrid system theory. Based on this model, FPGA switching control strategy for a three phase converter is developed. The functionality of a three phase converter is discussed from a discrete-event point of view. Recently developed hybrid based approach for modeling of discrete event systems is applied for modeling, simulations and implementation of a power factor control, protection and steering functionality three-phase converter. A DSP / FPGA based digital control platform for converter system, built in the laboratory, is presented and discussed.