Fractional-order proportional integral derivative (FOPID) controllers are becoming increasingly popular for various industrial applications due to the advantages they can offer. Among these applications, heating and temperature control systems are receiving significant attention, applying FOPID controllers to achieve better performance and robustness, more stability and flexibility, and faster response. Moreover, with several advantages of using FOPID controllers, the improvement in heating systems and temperature control systems is exceptional. Heating systems are characterized by external disturbance, model uncertainty, non-linearity, and control inaccuracy, which directly affect performance. Temperature control systems are used in industry, households, and many types of equipment. In this paper, fractional-order proportional integral derivative controllers are discussed in the context of controlling the temperature in ambulances, induction heating systems, control of bioreactors, an... [more]

In power systems, capacitor banks play a significant role in improving voltage profiles, reducing losses, and adjusting power factors. Security measures must be implemented quickly and reliably to protect them from a wide range of threats. As a consequence of capacitor bank failures, finding and fixing the damaged units/elements is more difficult, which may lead to voltage control difficulties or the loss of any of these benefits. The paper shows the application of system-based testing methods for protection systems using RelaySimTest software, which works with OMICRON injection test sets. System-based testing methods are applied to test voltage differential protection for center-tapped shunt capacitor banks. The use of system-based testing methods has many advantages over conventional testing methods, which include distributed testing, transient state conditions testing, etc., which in turn result in cost savings during the commissioning and testing phase. The impact of external fault... [more]

The traction motor (TM) is an essential part of the high-speed train, the health condition of which determines the quality and safety of the vehicle. Hence, this study proposed a novel approach to diagnosing and predicting the TM stator interturn short-circuit fault (SISCF). Based on the Park vector (PV) of the stator current, this method could overcome the interference of current sensor errors, null shift, and motor frequency fluctuations in the actual conditions. More specifically, Park’s transformation was used to obtain the PV of the stator current. Then, the PV was fitted to obtain the elliptical trajectory and its parameters from which the negative sequence component of the stator current could be calculated. Finally, the SISCF diagnosis and prediction method were realized by the magnitude and trend of the negative current as well as the inclination of the trajectory ellipse. Furthermore, the performance of the proposed method was validated by a simulation model and a series of e... [more]

A pneumatic cylinder system is believed to be extremely nonlinear and sensitive to nonlinearities, which makes it challenging to establish precise position control of the actuator. The current research is aimed at reducing the overshoot in the response of a double-acting pneumatic actuator, namely, the IPA positioning system’s reaction time. The pneumatic system was modeled using an autoregressive with exogenous input (ARX) model structure, and the control strategy was implemented using a fuzzy fractional order proportional integral derivative (fuzzy FOPID) employing the particle swarm optimization (PSO) algorithm. This approach was used to determine the optimal controller parameters. A comparison study has been conducted to prove the advantages of utilizing a PSO fuzzy FOPID controller over PSO fuzzy PID. The controller tuning algorithm was validated and tested using a pneumatic actuator system in both simulation and real environments. From the standpoint of time-domain performance me... [more]

This paper presents a novel concept of the DC-AC system with the input voltage boost ability, seven-level output voltage modulation, and the input AC current reduction at the double frequency of the output voltage. The system integrates the NPC full-bridge inverter which is composed of four-level legs and an active input voltage balancer (AIVB). The DC-link is composed of three capacitors connected in a series. The source of the energy is connected directly to the middle capacitor while the upper and lower capacitors of the DC-link are charged by the AIVB. The operation of the AIVB leads to balancing of the DC-link voltage and a three-fold boosting of the input voltage. The AIVB utilizes a novel switched-capacitor (SC) topology and can be designed as a low-volume quasi-magneticless converter with a simple open-loop control. One of the proposed methods of the control of the AIVB allows for a double frequency reduction in the input current. The application of the AIVB allows for the use... [more]

Costs of cooling installations cause them to be very rarely used in residential buildings in countries located in heating-dominated climates, like Poland. Hence, there arises the need to assess indoor thermal comfort during summer and to indicate ways to reduce possible overheating. This paper presents an attempt to use the thermal network model of the building zone of EN ISO 13790 to assess indoor operative temperature during four warm months from June to September. The model of the naturally ventilated single-family residential building located in central Poland was used. Performed calculations for the base case resulted in 38 and 63 days within the comfort zone at 80% acceptance level in a total of 122 days in the analyzed period for EN 15251 and ASHRAE standards, respectively. Use of external shading on windows and the roof with lower solar absorptance resulted in 46 and 70 days with acceptable conditions, respectively. Further application of night ventilation resulted in the 38 an... [more]

The development of hydrogen energy is an effective solution to the energy and environmental crisis. Hydrogen fuel cells and energy storage cells as hybrid power have broad application prospects in the field of vehicle power. Energy management strategies are key technologies for fuel cell hybrid systems. The traditional optimization strategy is generally based on optimization under the global operating conditions. The purpose of this project is to develop a power allocation optimization method based on real-time load forecasting for fuel cell/lithium battery hybrid electric vehicles, which does not depend on specific working conditions or causal control methods. This paper presents an energy-management algorithm based on real-time load forecasting using GRU neural networks to predict load requirements in the short time domain, and then the local optimization problem for each predictive domain is solved using a method based on Pontryagin’s minimum principle (PMP). The algorithm adopts th... [more]

In this paper, we present an implementation of selective harmonic elimination modulation technique in a 27-Level asymmetric multilevel converter. The main issue in this kind of converters is the generation of the gating patterns to obtain an optimized AC voltage waveform. State-of-the art solutions use deep mathematical analysis in the frequency domain by means of the Fourier series, but they are mainly applied for two-level or symmetric multilevel converters. On the other hand, the modulation for asymmetric multilevel converters is mainly focused on nearest level control or nearest vector control. In this work, we propose a novel modulating technique that takes advantage of the switching angles optimization for a 27-level waveform. In fact, different set of solutions are obtained and presented in order to define the modulation index as well as the value of the switching angles for the multilevel waveform. A modulation index sweep was performed for the entire operating region of the co... [more]

This paper presents a disturbance observer-based model predictive of super-twisting control for Soft Open Point (SOP). First, with the consideration of the disturbances caused by parameter mismatches and unmodelled dynamics, a super-twisting sliding-mode observer (STO) is proposed to observe the disturbances, and the observed disturbances are introduced into the inner-loop as the compensation to improve the anti-disturbance of SOP system. Second, the outer-loop controller is designed by applying the super-twisting sliding-mode control (STC) approach to improve the dynamic performance and robustness. Third, to deal with large current harmonics by traditional model predictive control (MPC), a Three-Vector-based MPC (TV-MPC) is proposed to increase the number of voltage vectors in a sampling time. Finally, it is verified by simulations that the proposed method can reduce current harmonics, DC-side voltage setting time and improve the dynamic performance of SOP system effectively. In case... [more]

In this paper, a Luenberger observer-based microgrid control strategy is proposed to enhance the power quality of microgrids, when the grid loads are mixed and strongly non-linear. To improve performance under this condition, a Luenberger observer is designed for three phase power grids. On the basis of the observer, the components of different frequencies and sequences of voltages and currents are obtained accurately. The virtual impedance of different frequencies and sequences is designed, which makes the equivalent line impedance meet the power-sharing condition, reducing the fundamental negative sequence voltages and harmonic voltages. The active power droop equation, meanwhile, is proposed, where the bus voltage is modified. The value range of virtual impedance is discussed in the complex frequency domain. The proposed control strategy does not require any communication lines, so the hardware structure is simplified. The simulations and experiments are provided to verify the effec... [more]

In order to solve the reactive power and voltage control problem caused by the high proportion of new energy connected to the power grid, this paper takes the minimum voltage deviation, minimum network loss and maximum dynamic reactive power margin of the whole system as the comprehensive optimization objectives and establishes a reactive power and voltage optimization model by considering the reactive power regulation ability of SVC (Static Var Compensator) and new energy units. In view of the continuous and discrete variables in the model, the traditional continuous FPA (Flower Pollination Algorithm) is discretized to form an improved continuous-discrete hybrid FPA, and the tournament selection mechanism is adopted to speed up the convergence. Through the example analysis of the IEEE-39 bus system, the feasibility of the proposed reactive power and voltage optimal control method in the new energy grid is verified. Compared with GA (Genetic Algorithm), the results show that the improv... [more]

This study introduces an online reconfigurable road-adaptive semi-active suspension controller that reaches the performance objectives with satisfying the dissipativity constraint. The concept of the model is based on a nonlinear static model of the semi-active Magnetorheological (MR) damper with considering the bi-viscous and hysteretic behaviors of the damper. The input saturation problem has been solved by using the proposed method in the literature that allows the integration of the saturation actuator in the initial system to create a Linear Parameter Varying (LPV) system. The control input meets the saturation constraint; therewith, the dissipativity constraint is fulfilled. The online reconfiguration and adaptivity problem is solved by using an external scheduling variable that allows the trade-off between driving comfort and road holding/stability. The control design is based on the LPV framework. The proposed adaptive semi-active suspension controller is compared to passive su... [more]

This article reviews the results of measurement of optical properties of oil, such as polarimetry, refractometric, luminescent-bituminological research, IR-spectrometry and UV-visible-NIR spectrometry used to solve geo-bituminology development of hydrocarbon deposits. The authors pay special attention to optical research in the field of UV-visible-NIR electromagnetic radiation, the results of which allow us to estimate the residual oil reserves, separate production for each formation during the operation of multi-layer objects, determine the producing gas-oil ratio, density and content of hydrocarbons, efficiency of hydraulic fracturing, flow-reducing technologies, and injection of solvents of heavy oil sediments, etc. The published approaches to methods of optical research, which are carried out by laboratories or in-well devices, have been analyzed. This article analyzes the main advantages and disadvantages of current technologies for determining the optical properties of oil. The a... [more]

In multi-seam mining, the residual coal pillar (RCP) in the upper gob has an important influence on the layout of the roadway in the lower coal seam. At present, few papers have studied the characteristics of the surrounding rock of gob-side entry driving (GED) with different coal pillar widths under the influence of RCP. This research contributes to improving the recovery rate of the extra-thick coal seam under this condition. The main research contents were as follows: (1) The mechanical parameters of the rock and coal mass were obtained using laboratory experiments coupled with Roclab software. These parameters were substituted into the established main roof structure mechanics model to derive the breakage position of the main roof with the influence of RCP, and the rationality of the calculation results was verified by borehole-scoping. (2) Based on numerical simulation, the evolution laws of the lateral abutment stress in the lower working face at different relative distances to t... [more]

Detecting intrusions from the supervisory control and data acquisition (SCADA) systems is one of the most essential and challenging processes in recent times. Most of the conventional works aim to develop an efficient intrusion detection system (IDS) framework for increasing the security of SCADA against networking attacks. Nonetheless, it faces the problems of complexity in classification, requiring more time for training and testing, as well as increased misprediction results and error outputs. Hence, this research work intends to develop a novel IDS framework by implementing a combination of methodologies, such as clustering, optimization, and classification. The most popular and extensively utilized SCADA attacking datasets are taken for this system’s proposed IDS framework implementation and validation. The main contribution of this work is to accurately detect the intrusions from the given SCADA datasets with minimized computational operations and increased accuracy of classifica... [more]

This article outlines an integrated functional safety and cybersecurity evaluation approach within a framework for business continuity management (BCM) in energy companies, including those using Industry 4.0 business and technical solutions. In such companies, information and communication technology (ICT), and industrial automation and control system (IACS) play important roles. Using advanced technologies in modern manufacturing systems and process plants can, however, create management impediments due to the openness of these technologies to external systems and networks via various communication channels. This makes company assets and resources potentially vulnerable to risks, e.g., due to cyber-attacks. In the BCM-oriented approach proposed here, both preventive and recovery activities are considered in light of engineering best practices and selected international standards, reports, and domain publications.

Vehicle driving safety is an important performance indicator for vehicles, and there is still much room for development in the active safety control of electric vehicles. Vehicles are susceptible to rollover when making sharp turns or overtaking at high speed. In order to improve the anti-rollover stability of electric vehicles (EV), this study proposes a real-time motor control strategy, mainly according to the acquisition of vehicle attitude data and real-time monitoring of the vehicle’s operating state. The lateral load transfer rate was defined as the vehicle rollover evaluation index. When the real-time rollover indicator exceeded the limit safety threshold this article set, the motor speed would be reduced through active control to avoid rollover or reduce the risk of rollover. Both simulation results in Carsim and Simulink showed that the motor control strategy is highly reliable and real-time capable, and the active safety of EV was improved significantly.

Recently, a novel high-starting torque scalar control scheme (HST-SCS) for induction motor(s) (IM) emerged. It expands the scalar control application field beyond centrifugal pumps, blowers, and fans, moving, for instance, some conveyor belts with nominal torque loading. This paper proposes a normalized model reference adaptive control (N-MRAC) applied to HST-SCS for IM. First, the proposal extends the MRAC, resulting inn a class of nonlinear systems encompassing the IM dynamical model. It uses a normalized information vector, jointly with a direct control approach, reducing the trial and error adaptive controller tuning. Second, a properly designed N-MRAC is applied to regulate the starting stator current within the variable speed drive under investigation. As a result, the proposed methodology keeps the HST-SCS as a simple control scheme without needing variable observers or parameter estimators and employing tuning information only from the motor nameplate and datasheet. Test bench... [more]

This study presents the effects of using two centerbodies arranged in tandem on the flow and velocity properties of swirling jets. The centerbodies are installed concentrically downstream of the jets to modify the wake. Smoke flow visualization was employed to illustrate the flow behaviors, while the particle image velocimetry technique was utilized to investigate the velocity fields, turbulent properties, vorticities, and Lagrangian time and length scales. The toroidal recirculation and vortex shedding are found near the field using one centerbody. The recirculation zone is evolved from the edge of the centerbody, while the vortex shedding is formed by the interaction between the central and the annular jets. Since two centerbodies are installed, two four-way saddles are located near the rim of the upstream centerbody to associate two pairs of vortices. A large momentum of the annular jet dominates the flow field; therefore, the central jet forms dual-rotating vortices at downstream c... [more]

Grid-forming converters are attracting attention for their significant advantages in terms of stability in a weak grid and simulated inertia. However, while they offer great flexibility due to the use of power semiconductors, they are also affected by their low current-carrying capacity. This means that during a fault, instead of the usual voltage control, a current limiting control is active, which changes the dynamic performance of the converter and influences transient stability. This manuscript focuses on the dynamic performance of grid-forming converters during the restart phase at the post-fault period, and proposes an initial phase threshold to prevent the converter from going into current saturation. Based on this, the manuscript proposes several restart strategies during the post-fault period, by using some fast resynchronization methods in order to meet the requirements of the converter’s stable operation and fast active power restoration. Finally, the above findings and the... [more]

Modular multilevel converters (MMCs) are primarily adopted for high-voltage applications, and are highly desired to be operated even under fault conditions. Researchers focused on improving current controllers to reduce the adverse effects of faults. Vector control in the DQ reference domain is generally adopted to control the MMC applications. Under unstable grid conditions, it is challenging to control double-line frequency oscillations in the DQ reference frame. Therefore, active power fluctuations are observed in the active power due to the uncontrolled AC component’s double line frequency component. This paper proposes removing the active power’s double-line frequency under unbalanced grid conditions during DQ transformation. Feedforward and feedback control methods are proposed to eliminate ripple in active power under fault conditions. An extraction method for AC components is also proposed for the power ripple control to eliminate the phase error occurring with the conventional... [more]

Bearing fault is the most common failure in rotating machines, and bearing fault diagnosis (BFD) has been investigated using vibration, current, or acoustic signals. However, there are still challenges in some existing approaches. This study proposes a novel BFD method based on natural observer. Based on the analysis of the effects on the load torque signal caused by bearing faults in the permanent magnetic synchronous machine (PMSM), a modified natural observer was designed to reconstruct the load torque signal from electrical signals, acquiring a novel indicator without the additional sensor installed. Angular resampling was implemented to convert the non-stationary load torque signal into a stationary one to reduce the computational complexity. For full-auto diagnosis without human involvement, a threshold determination algorithm was also modified. Experimental validations were carried out under speed-varying and torque-varying conditions and were compared with phase current and q-a... [more]

This paper uses a two-level model predictive control-based approach for the coordinated control and energy management of an integrated system that includes photovoltaic (PV) generation, energy storage, and building loads. Novel features of the proposed local controller include (1) the ability to simultaneously manage building loads and energy storage to achieve different operational objectives such as energy efficiency, economic cost efficiency, demand response and grid optimization through the design of specific power trajectory tracking performance functionals, (2) an energy trim function that minimizes the impact of solar forecasting errors on system performance, and (3) the design of a state of charge controller that uses day-ahead forecast of solar power and building loads to intialize energy storage at the start of each day. The local controller is tested in simulation using an exemplary system with PV generation, energy storage and dispatchable building loads. Two sample days wi... [more]

An algorithm was developed detect the partial demagnetization of permanent-magnet synchronous motors (PMSMs) under both stationary and nonstationary conditions. On the basis of the recursive least-squares (RLS) method, the vital component of fault-related harmonics in the current could be extracted on the line, and its proportion to fundamental component could be regarded as the indicator of partial demagnetization faults. The proposed algorithm is fairly easy to realize and could substitute conventional and complicated signal processing methods such as Fourier transform and wavelet transform when detecting partial demagnetization. Experiments with inverter-fed healthy and partially demagnetized PMSMs are carried out to substantiate the effectiveness of proposed algorithm under both stationary and nonstationary conditions. At the end, a way to eliminate the impact of eccentricity fault on the partial demagnetization diagnosis is given.

The success of modular multilevel converters (MMCs) in high-voltage direct current (HVDC) applications has fueled the research on modular converter topologies. New modular converter topologies are often proposed, discussed, and sometimes applied in HVDC, as well as other industrial application such as STATCOMs, DC/DC HVDC, medium-voltage direct current (MVDC), etc. The performance evaluation of new modular converter topologies is a complex and time-consuming process that typically involves dynamic simulations and the design of a control system for the new converter topology. Sadly, many topologies do not progress to the implementation stage. This paper proposes a set of key performance indicators (KPIs) related to the cost and footprint of the converter and a procedure designed to rapidly evaluate these indicators for new converter topologies. The proposed methodology eliminates the need for dynamic simulations and control-system design, and is capable of identifying whether a particul... [more]