Synchronous reluctance machines (SynRMs) are increasingly used in applications such as electric drives and energy conversion systems. In addition to standard control algorithms, certain applications, especially those that consider a priori rotating SynRMs, require a flying start procedure where the rotor speed and position should be estimated before the SynRM is connected to the converter. This synchronization between the converter and the SynRM minimizes the inrush current and prevents torque disturbances. In this paper, a novel method of flying start for SynRMs is proposed based on the application of symmetrical and opposite active voltage pulses together with two zero-voltage vectors and a generalized second-order integrator with a frequency-locked loop (SOGI-FLL). By applying such a voltage pattern to the terminals of a rotating SynRM, phase currents are induced whose sampled counterparts follow the sine waveform. Based on the derived machine model in the stationary $\alpha \beta$ reference frame for such discontinuous operation of the SynRM, the induced $\beta$-axis current is inherently free of DC offset and is directly used as input to the SOGI-FLL to estimate the rotor angle and speed. Moreover, the voltage pattern based on the opposite vector pulses followed by the zero-voltage vectors also reduces the current distortion and torque ripple, which improves the estimation accuracy and reduces the mechanical stress. The proposed method was first verified by simulations in MATLAB/Simulink and then experimentally validated in a laboratory setup, confirming the practical feasibility and robustness of the method.

The integration of artificial intelligence (AI) into industrial automation has led to the development of edge-deployable inference platforms. This paper presents a deployment methodology and performance evaluation of two neural network models running on the SIMATIC S7-1500 TM NPU 2.0 module: one for the classification of Siemens automation components and another for fruit classification using a public ONNX model. The AI Model Deployer environment was used to convert and deploy both models, enabling automation engineers to implement machine learning solutions without prior AI knowledge. The system architecture includes a GigE Vision camera, MicroPython-based runtime logic and shared memory communication with a PLC. Experimental results show real-time inference with high accuracy and robustness under realistic conditions. This work demonstrates the feasibility and flexibility of using both industrial and generic pretrained models on embedded NPUs in manufacturing environments.

Synchronous generators are an essential part of power systems, and the number of generators is increasing due to the growing electricity demand. Synchronous generators can operate synchronously with the grid or independently in island mode. In both cases, the generator rotation (speed or torque) and the generator excitation current must be controlled. This paper provides an overview of the laboratory setup, which consists of a brushless synchronous generator and an induction motor driven by a frequency converter. A rotating diode rectifier excites the synchronous generator, and a chopper controls the excitation current. The laboratory setup offers many possible applications in research and teaching. The laboratory setup is therefore evaluated, and the experimental results are presented in this paper.

Synchronous reluctance machines (SynRMs) are increasingly used in various applications, such as energy conversion systems and electric drives. In addition to standard control algorithms, some of these applications also require the implementation of flying start methods that aim to estimate the rotor speed and angle before the SynRM is connected to the converter. In this way, synchronization between the SynRM and the converter is achieved, and the inrush current is reduced. This paper proposes a new method for the flying start of SynRMs based on symmetric and opposite active voltage vectors and a second-order generalized integrator (SOGI) with a frequency-locked loop (FLL). Applying such a voltage vector pattern to the terminals of a rotating SynRM induces phase current spikes whose sampled counterparts have a sinusoidal waveform. According to the derived mathematical model of the SynRM in the stationary ass reference frame, the induced ss-axis current contains no DC offset and is therefore passed to the SOGI-FLL structure to estimate the rotor angle and speed. Moreover, applying the opposite active vectors ensures a lower current distortion, guarantees the accuracy of the estimation and reduces the generated torque. The proposed method was verified by simulations in Matlab Simulink.

In today's rapidly evolving cybersecurity landscape of industrial automation and control systems (IACSs), threat detection and prevention are more critical than ever. Compared to information technology (IT), the cybersecurity maturity of IACS is still low. Therefore, one way to increase the cybersecurity of IACS is to adopt and implement proven IT protection methods. Endpoint detection and response (EDR) and extended detection and response (XDR) tools have emerged as the means of protecting IT systems. Their exceptional threat detection, analysis, and response capabilities make them indispensable components for protecting critical infrastructures. The paper addresses the potential integration of EDR and XDR tools into IACS environments to strengthen their cybersecurity and protect them from new and existing threats. To demonstrate the feasibility of such a solution, we have implemented a chosen EDR tool on an industrial programmable logic controller (PLC). We have also analyzed the impact of such a solution on real-time PLC performance, which shows that such tools could be implemented in real-life IACSs.

Despite the escalating cyber threats and global efforts to raise cybersecurity awareness surrounding industrial automation and control systems (IACSs), the adoption of adequate cybersecurity solutions in these systems remains alarmingly low. The reasons for this significant problem range from an inability to understand cybersecurity risks to the complexity of implementing various cybersecurity solutions. This paper investigates possible factors contributing to user and organizational resistance towards the implementation of cybersecurity solutions in IACSs. Furthermore, we argue that most of the proposed cybersecurity solutions are inadequate in terms of usability and scalability in IACSs. The main contribution of this paper is a novel framework for evaluating the usability of potential cybersecurity solutions in IACSs. The framework could help IACS suppliers, owners, and operators to identify potential usability issues of the proposed cybersecurity solutions and select the most suitable solution.

This article deals with a sensorless control of permanent magnet generators (PMGs) including a method of flying start. Flying start involves synchronization between the voltages of the generator-side converter (GSC) and the PMG, as well as switching on the GSC. Without a proper flying start, inrush current and impact torque can cause undesirable side effects. In this article, a framework for the sensorless control of the PMG based on a sliding mode observer (SMO) is proposed, which includes the flying start method. The flying start is performed during a discontinuous operation of the GSC. This method ensures the flying start and continuous operation of the PMG, with few adjustments required between the two modes. In addition, the self-commissioning method is used to determine the PMG parameters required to tune the SMO and current controllers, and to reduce the SMO estimation error. The new method is verified experimentally on a 5.5-kW PMG.

This paper proposes a direct model predictive control method with a fixed switching frequency for stator flux control of a synchronous reluctance machine. Besides ensuring a fixed switching frequency, the main objective is to minimize the ripple of the stator flux. The objective function, which calculates the switching time instants within the switching period based on the stator flux gradients, is formulated as a standard constrained quadratic programming (QP) problem. Instead of using general-purpose QP solvers, an iterative algorithm based on the active-set method with Lagrange multipliers is proposed to solve this particular QP problem while reducing the computational complexity of the proposed algorithm and enabling successful implementation in real-time embedded systems. The proposed method has been successfully implemented on a laboratory model and the results are compared with a conventional indirect model predictive control. The experimental results show better performance in stator flux ripple and lower total stator current distortion factor for the proposed method compared to the conventional method. A 7.5 kW synchronous reluctance motor drive was used for the experimental validation of the proposed control method.

Electrical cabinets are assembled manually to a great extent. The existing wiring technology of electrical cabinets is a big consumer of plastic materials used for the wire ducts which make up a large portion of the cabinet volume. Also, the current electrical cabinet production requires a lot of human labor. This paper proposes a new laminated conductor technology used for connecting electrical cabinet components. The approach is based on alternately stacking conductive and insulating layers. The primary advantage of the new technology is the possibility of accomplishing a fully automated production by using laminated conductors of rectangular cross sections for interconnecting the components. Additional benefits are reduced size, approximately by 70%; and a simplified use and installation. Both thermal and mechanical simulation analyses were carried out in the study. The final product of this technological development and its application is a prototype, which was evaluated experimentally for its electrical and mechanical functionality. Thermal conditions were also tested. The tests that were performed in this study include also mechanical testing on the bolts in the circuit block and electrical current tests. The experimental results justify the application of the proposed technology.

The traditional technology used in the production of electrical cabinets is generally outdated and complex. Therefore, there is a need for a new production technology that minimises both production time and physical labour. As part of this research, a brand new, patented laminated conductor technology was used to connect electrical cabinet components. The assembly process is based on the alternating layering of conductive and insulating layers. By using laminated conductors with a rectangular cross-section, the main advantage of the implemented technology is the possibility to connect the components in a fully automated production process. Other advantages include reduced size as well as simpler installation and use. The basis of this technology is the web application used to upload circuit diagrams and configure the electrical cabinet. Before prototyping the electrical cabinet, a digital twin is created based on the previously collected plans. For research purposes, two prototypes were built, one with a AC power supply and the other with a DC power supply. The electromagnetic compatibility (EMC) test results are given in this study for both prototypes.

This article deals with coupled, state, and parameter estimation for lithium-ion batteries described by an equivalent circuit model, including polarization dynamics. Since the model parameters depend on the battery state-of-charge (SoC) and temperature operating point, as well as on the battery state-of-health, all states and parameters need to be estimated simultaneously for an accurate overall estimation during the battery lifetime. The proposed estimation algorithm is structured in two timescales: 1) slow-scale, sigma-point Kalman filter (KF)-based estimation of battery capacity and 2) fast-scale, dual-extended KF-based estimation of SoC and model parameters. A particular emphasis is on the adaptive parameterization of SoC and capacity estimators, which provides robust coupling between two timescales and ensures favorable convergence and robust capacity tracking in conditions of SoC and model parameters' estimation errors. In support of estimation accuracy analysis, an algebraic observability analysis of impedance parameters is conducted. Also, by introducing an observability index calculated in each simulation timestep, a comparison of degrees of observability of different impedance parameter subsets is allowed for. The proposed estimation algorithm is verified both by simulation and experimentally for an electric scooter Li-NMC battery pack.

In modern power systems, the integration of renewable energy sources and the increasing use of power electronic devices can lead to harmonic distortions, imbalances and other power quality issues. These issues can lead to equipment failures, overheating and increased energy losses. Active filters can mitigate these issues by injecting a compensating current into the power system to compensate for harmonics and improve the power factor. Shunt Active Power Filters (SAPF) play an important role in the smart grid by helping to improve power quality. The aim of this paper is to present a simple model of a SAPF that has one current control loop with an LCL filter output current as a feedback signal and a PI controller. The development of the prototype model and its design with all the necessary parameters to build a simulation model are presented in detail. The simulation model is also verified experimentally and a comparison between the simulation and experimental results is presented.

Critical infrastructure (CI), such as energy and water distribution systems, is essential for the stability and well-being of the modern society. Industrial automation and control systems (IACSs) form the backbone of CIs and enable the operation of such systems in a safe and reliable manner. However, with the increasing use of industrial Ethernet communication protocols, such as Modbus-over-TCP (Modbus/TCP), once air-gapped IACSs are becoming vulnerable to potential cybersecurity threats. This paper presents a novel method for enhancing the cybersecurity of Modbus/TCP-based IACSs by implementing an authentication method based on message authentication codes (MACs). To provide partial protection of communication even when communicating with legacy Modbus/TCP peers, we propose a novel supervising device that analyzes exchanged messages and verifies the authenticity of the protected messages. To experimentally verify the protection method, a water-treatment cyber-physical system (CPS) was implemented as a digital twin in a programmable logic controller (PLC). The underlying MAC is the Chaskey-12, lightweight MAC defined in IEC 29192-6. It was implemented in the PLC program using the programming languages defined in IEC 61131-3. As an additional contribution, the presented implementation allows protection of communication between PLCs and other Modbus/TCP peers installed in existing IACSs without hardware or firmware modifications. The results show that the method provides protection against network attacks without significantly affecting performance, also demonstrating the feasibility of such protection in IACSs.

This paper derives a small-signal model of a three-phase synchronous reference frame phase-locked loop for use in system frequency response studies assuming a system of balanced three-phase voltages. The small-signal model is described by a second-order transfer function which relates the actual to the estimated grid frequency. The small-signal model behaves identically to the large-signal model for small disturbances. Simulation results demonstrate that phase-locked loop dynamics can be neglected in the high-inertia scenarios, while in the low-inertia scenarios they have a significant impact on the grid frequency and should be included in models.

This paper presents power quality analysis at different points in a data center. Electrical distribution network scheme and data center description are also given. The method of measurements performed is briefly described and the results of real measurements of current and voltage Total Harmonic Distortion (THD) are presented and compared with IEEE 519-2014 recommended practice and requirements for harmonic control in electric power system. All measured values comply with the standard but measurements at downstream levels closer to the nonlinear loads have larger THD.

Modbus over TCP (Modbus/TCP) is a very popular protocol in industrial automation and control systems (IACS), but at the same time it is completely unprotected in terms of cybersecurity. This allows adversaries to manipulate controlled processes by forging or modifying process values in the Modbus protocol data unit (PDU), potentially causing damage to IACSs. In this paper, we propose the use of a misuse-based intrusion detection system (IDS) to detect out-of-bound process values and in that way make it difficult for an adversary to manipulate process values. To test the feasibility of this approach, a cyber-physical system was created, simulating an IACS water treatment plant. The implemented rule-based alarms and warnings were based on the industrial process and an adversary threat model, focusing on the process values of the IACS. This approach shows a promise as an additional safety mechanism to standard IACS cybersecurity solutions.

The paper investigates cyber threats and potential solutions for protecting industrial control systems (ICS). On the cyber threats side, different off-the-shelf offensive solutions, both hardware and software, are analysed and tested. The goal of the paper is to increase cyber threat awareness by showing how such off-the-shelf solutions, well known to IT security experts, can be utilised as (or inspire) attack vectors to gain access to generally unprotected industrial plants. After obtaining an accessing point, Man-in-the-Middle (MITM) and Legal-Client-to-Server (LCSA) types of attacks from reconnaissance, client-to-server and server-to-client categories are demonstrated. For this purpose, a Modbus communication protocol implemented in a real compressor station is used as basis. Regarding potential protection solutions, the paper proposes a simple-to-implement and cheap hardening methodology applicable inside almost any industrial plant. A novel, PLC-based ICS cyber security protection method, made of a signal validity monitoring mechanism and a control system integrity check mechanism is also discussed and demonstrated. Both penetration testing and hardening methodology are verified experimentally, using real PLC and HMI devices.

A new innovative technology for control cabinets is being developed to simplify production, installation and use. The result is a significant reduction in plastic consumption, simplified wiring system and reduction in the occupied space required at the installation site. A new solution is based on connecting components with laminated conductors of rectangular cross-section sandwiched between multiple layers of insulation. The interconnection of the layers and devices is achieved by conductive screw connections that pass through the plates. The number of these layers is chosen to meet the requirements of the relevant standards. While a prototype of this innovation is currently under development, this study investigates the thermal characteristics of the assembly, obtained using computational fluid dynamics simulation software (CFD) called „FloEFD". By defining input and output current values in the assembly with a rated diversity factor (RDF), the temperature rise was simulated. In addition to determining the total amount of heat generated by the Joule effect as well as conduction, convection and radiation processes, the results also indicated critical heating points. In conclusion, the simulation provided encouraging results that will be useful in further experimental prototype testing.

This paper presents a comparative study of four different rotor position and speed estimation methods for sensorless vector control of synchronous reluctance machines (SynRMs). The estimation methods are based on the active-flux concept, the different sliding-mode observers (SMOs) and locked loops. For SMO control vectors, a signum function and a super-twisting algorithm are used. The SMOs are combined with phase-locked loop (PLL) and dual second-order generalized integrator frequency-locked loop (DSOGI-FLL) for position and speed extraction from observed active flux derivatives. The methods are verified and compared by simulation tests in MATLAB Simulink. The saturable SynRM model is used, and parameter sensitivity analysis is performed.

In this paper, a finite control set model predictive torque control of synchronous reluctance machine in the field weakening region is proposed. The machine’s future behavior is predicted for a finite set of voltage vectors that the power converter can generate, and then an optimal voltage vector is selected based on a cost function. The cost function is designed considering torque reference tracking and field weakening operation for speeds above rated, while the system constraints are handled as soft constraints and included in the cost function. The proposed control scheme is verified by simulation tests in MATLAB Simulink, and the impact of inductance error on torque reference tracking is investigated. The simulation results have shown the effectiveness of the proposed control scheme. The magnetic saturation effect of the machine is considered and incorporated into the simulations using flux maps.