The H-type gantry stage (HGS) is widely used in electric vehicle manufacturing and other fields. However, resulting from the existence of mechanical coupling, the synchronous control problem of HGS always troubles many engineers. Most synchronization schemes were either engaged in improving each motor’s tracking performance or committed to pure motion synchronization only. However, tracking and synchronous performance are interconnected, because of the mechanical coupling. In this paper, a rigid assumed system model of HGS, concerning the effects of mid-beam rotary inertia, mid-beam stiffness, and end-effector movement, is presented. Based on the proposed model, an adaptive robust synchronous control based on a rigid assumed model (ARSCR) is proposed to improve both synchronous and tracking performance of the HGS. From the Lyapunov analysis, the proposed ARSCR can achieve the convergence of synchronous error and tracking error, simultaneously. An HGS driven by dual linear motors is bui... [more]

In applications such as multiphase motor drives, classical predictive control strategies are characterized by a variable switching frequency which adds high harmonic content and ripple in the stator currents. This paper proposes a model predictive current control adding a modulation stage based on a switching pattern with the aim of generating a fixed switching frequency. Hence, the proposed controller takes into account the prediction of the two adjacent active vectors and null vector in the ( α - β ) frame defined by space vector modulation in order to reduce the (x-y) currents according to a defined cost function at each sampling period. Both simulation and experimental tests for a six-phase induction motor drive are provided and compared to the classical predictive control to validate the feasibility of the proposed control strategy.

The problem of secure load frequency control of smart grids is investigated in this paper. The networked data transmission within the smart grid is corrupted by stochastic deception attacks. First, a unified Load frequency control model is constructed to account for both network-induced effects and deception attacks. Second, with the Lyapunov functional method, a piecewise delay analysis is conducted to study the stability of the established model, which is of less conservativeness. Third, based on the stability analysis, a controller design method is provided in terms of linear matrix inequalities. Finally, a case study is carried out to demonstrate the derived results.

In scientific cabled seafloor observatories, branching units and optical repeaters are essential backbone devices, in which zener diodes are commonly used in their power supply circuits. However, the low efficiency of zener-diode-based power feeding modules under large currents makes for a significant threat to the long-term reliability of backbone devices. In this paper, a novel full-bridge DC-DC converter with a duty-cycle-overlap control (DCOC) strategy is proposed to achieve high-efficiency current-to-voltage conversion. The circuit design of the converter and the principle of the DCOC strategy are analyzed. A prototype of the converter is implemented to demonstrate the feasibility of the proposed power feeding approach for large-scale cabled seafloor observatories.

A thyristor-controlled series capacitor (TCSC) is employed to a transmission line in order to enhance the usable capacity of the present as well as upgraded lines, improve system stability, reduce losses, and improve power flow control capability. However, in an abnormal situation, the TCSC may transit from the existing operation mode to the other mode according to its control system and protection strategy. There is much difference in the impedance of the TCSC between each mode. This threatens the reliability of the conventional protection system, especially the distance relay, that works based on the measurement of line impedance. In this paper, we suggest a new protection scheme for a distance relay of a transmission line equipped with a TCSC. In the suggested method, in order to mitigate the effect of the TCSC in the fault loop, the TCSC injected voltage is subtracted from the measured phase voltage before supplying the voltage signal to the distance relay. The suggested scheme was... [more]

Photovoltaic virtual synchronous generator (PV-VSG) technology, by way of simulating the external characteristics of a synchronous generator (SG), gives the PV energy integrated into the power grid through the power electronic equipment the characteristics of inertial response and active frequency response (FR)—this attracts much attention. Due to the high volatility and low adjustability of PV energy output, it does not have the characteristics of a prime mover (PM), so it must be equipped with energy storage systems (ESSs) in the DC or AC side to realize the PV-VSG technology. However, excessive reliance on ESSs will inevitably affect the application of VSG technology in practical PV power plants (PV-PPs). In view of this, this paper proposes the PV power reserve control type VSG (PV-PRC-VSG) control strategy. By reducing the active power output of part of the PV-PPs, the internal PV-PPs can maintain a part of the active power up/down-regulation ability in real time, instead of relyi... [more]

This paper deals with a new control strategy for the programmable dynamometer to emulate dynamic loads. The main idea is to employ the disturbance-observer-based design and take the nominal model involved in the disturbance-observer design as the desired dynamics to be emulated. Compared to previous approaches, the proposed approach does not require exact system parameters of the motor under test, and the range of emulation parameters is wider than previous results. A rigorous stability analysis, as well as a constructive design incorporating system uncertainty and the steady state error bound are presented. An experimental system is developed to verify the performance of the proposed method, and it is demonstrated that up to 20-times of inertia emulation with relatively small emulation error (speed error less than 6 % ) is achieved and that various loads such as friction can be emulated.

Nowadays, wind turbines based on a doubly fed induction generator (DFIG) are a commonly used solution in the wind industry. The standard converter topology used in these systems is the voltage source inverter (VSI). The use of reverse-blocking insulated gate bipolar transistor (RB-IGBT) in the current source inverter topology (CSI), which is an alternative topology, opens new possibilities of control methods. This paper presents a novel power control system for a DFIG supplied by a CSI. The authors propose to use multi-scalar DFIG state variables. A nonlinear control method realized by feedback linearization was used to control the active and reactive powers of the generator. In the feedback linearization controls, the nonlinear DFIG model was taken into account. In the control system structure, classical proportional−integral controllers were used. The control variables were the output current vector components of the CSI. Such approach was named the “current control”. The proposed co... [more]

The three-port converter (TPC) obtains major attention due to its power density and ability to dispose different electric powers flexibly. Since the control models of the TPC are derived from particular steady state work point through small signal modeling method, the model parameters usually be deviated from their normal values with the change of operation and load conditions. Furthermore, there are couplings and interactions in power delivery between different ports, which have a significant influence in the dynamic control performance of the system. In this paper, the H∞ mixed sensitivity method is employed to design robust controllers for a TPC control system. Simulation results are given to demonstrate the effectiveness of the proposed scheme, and experimental studies are conducted on a prototype circuit to further validate the developed method. Compared to a traditional PI controller, it shows that a mixed sensitivity based robust controller manifest balanced performance in model... [more]

The need for greener and cleaner aviation has accelerated the transition towards more electric systems on the More Electric Aircraft. One of the key challenges related to the increasing number of electrical devices onboard is the control of bidirectional power converters. In this work, stability analysis and control of a buck−boost converter for aeronautic applications are presented. Firstly, stability of the buck−boost converter in the Lyapunov sense is proven by resorting to input-to-state stability notions. Then, a novel control design based on second order sliding mode control and uniting control, aimed at overcoming the difficulties generated by the nonlinear input gain function of the system not being sign definite, is presented. Extensive and detailed simulations, designed to emulate one of the possible energy management policies onboard a More Electric Aircraft, confirm the correctness of the theoretical analysis both in buck and in boost mode.

Investigation of power output from PV arrays under different fault conditions is an essential task to enhance performance of a photovoltaic system under all operating conditions. Significant reduction in power output can occur during various PV faults such as module disconnection, bypass diode failure, bridge fault, and short circuit fault under non-uniform shading conditions. These PV faults may cause several peaks in the characteristics curve of PV arrays, which can lead to failure of the MPPT control strategy. In fact, impact of a fault can differ depending on the type of PV array, and it can make the control of the system more complex. Therefore, consideration of suitable PV arrays with an effective control design is necessary for maximum power output from a PV system. For this purpose, the proposed study presents a comparative study of two intelligent control schemes, i.e., fuzzy logic (FL) and particle swarm optimization (PSO), with a conventional control scheme known as perturb... [more]

The problem of insufficient regulation ability in isolated microgrid operations in traditional master−slave control is targeted in this research. A hybrid master−slave control strategy is proposed to operate multiple distributed generators (DGs) in a microgrid with alleviated regulation characteristics. Firstly, a virtual synchronous generator control is adopted in the master DG to provide voltage and frequency support for the system; however, the lack of participation of the slave DG control in traditional PQ droop control in the system regulation makes a master DG susceptible to any load variation. The problem is resolved by proposing an improved droop control strategy, which ensures that the slave DG has similar output droop characteristics as the master DG and thus can respond to system load disturbances alongside the master DG. Secondly, virtual coordinate transformation and virtual impedance control are introduced to realize the decoupling and precise distribution of output power... [more]

The hydraulic heightening system is the core component of the shearer, and its stable operation directly affects the safety and reliability of the equipment, so it is of great significance to realize an efficient and accurate fault diagnosis. This paper proposes a fault diagnosis method combining a rough set and radial basis function neural network (RS-RBFNN). Firstly, the RS is used to discretize the original fault data set and attribute reduction, remove the redundant information, and mine the implicit knowledge and potential rules. Then, the topology structure of the RBFNN is determined. The mapping relationship is established between the fault symptom and category. The fault diagnosis is carried out with Python language. Finally, the method is compared with two diagnostic methods including a back propagation neural network (BPNN) and RBFNN. The research results show that the RS-RBFNN has the highest fault diagnosis accuracy, with an average of 98.68%, which verifies the effectivene... [more]

The frequency regulation rate and operation stability of a doubly fed induction generator (DFIG) based on a virtual synchronous generator (VSG) strategy decreases under large-power-angle conditions, which reduces the grid frequency support capacity. This paper proposes the compound adaptive parameter (CAP) and coordinated primary frequency regulation (CPFR) strategies to improve the grid frequency support capacity in terms of multiple dimensions of the transient properties, operation condition range, and regulation duration. Mathematical and small signal models of the DFIG-VSG system are constructed. The effect of large-power-angle conditions on the transient properties under grid frequency perturbations is analyzed based on these models, and the CAP strategy for excitation control and virtual damping is formulated. The constraints of the rotor kinetic energy and the load increase capacity of the grid-side converter are analyzed, and the CPFR strategy is formulated based on this. Final... [more]

Decision-making in energy retrofit of existing buildings needs to consider the economic and technical criteria, as well as social and environmental ones. The main problems are to define and to aggregate these contradicting issues to support a measurable and verifiable decision process. The working hypothesis of this paper is that the ELECTRE Tri method would respond to the problem. The paper proposes and tests in a real professional environment the ELECTRE Tri method to help choose a retrofit program for collective residential buildings. The evaluation criteria used as performance indicators are defined in consultation with the decision maker and weighted by using the revised Simos’ cards method. The paper proposes to construct the renovation scenarios by combining individual actions that are mutually compatible. The methodology, the proposed criteria and the scenarios were successfully applied on a renovation project of a residential assembly composed of three buildings (67 apartments... [more]

With the increased development of electrical subsystems onboard modern transportation platforms, e.g., more electric aircrafts or more electric ships, the need for electric generation systems has increased. Since many motors require electric starting capability, the application of the starter/generator has been the focus of several studies. The peculiarity of such a system is its requirement for high torque at low speed (for the starting) as well as an extended operation range during the normal generation operations. This mismatch between maximum torque and speed comes at the expense of the power density of the electronic converter, which needs to be designed for the worst case situation and, due to the electric machine optimization, often requires field weakening operations. A new winding reconfiguration is proposed to achieve speed extension and provide more potentiality for high-speed applications. This work compares different power trains in terms of efficiency current stress for e... [more]

This paper presents an analysis of the energy consumption of a continuous flow ohmic heater (CFOH) with advanced process controls for heating operations in the food and drinks industry. The study was carried out by using operational data collected from a CFOH pilot plant that was designed and constructed at the National Centre of Excellence for Food Engineering (NCEFE), Sheffield Hallam University. The CFOH is controlled by a PC and includes an onboard Programmable Logic Controller (PLC) and a Human Machine Interface (HMI) so that it can be operated as a stand-alone unit with basic on/off and power setting control but without any advanced control features. The technical solution presented in this paper for heating foods demonstrates significant energy saving compared with conventional heating methods. Using the CFOH, the electric current generated in the food products by the Joule effect produces a rapid temperature increase with very high energy efficiency. This technique eliminates t... [more]

An energy-efficient thermal control management method for space remote sensors using optical, mechanical, electrical, and thermal integration is proposed. The satellite power resources are insufficient, so an energy-efficient loop heat pipe (LHP) is designed for six intermittently operating detectors. The charge-coupled device (CCD) has a total heat generation of 72 W and operates for 8 min per orbital cycle. The LHP includes a capillary pump, six cold plates, and two radiators. The working fluid of the LHP is high-purity ammonia and the material of the wick is ceramic. The drive power on the capillary pump evaporator automatically switches between 30 W and 90 W depending on the operating mode of the remote sensor, resulting in an average power saving of about 58.2% compared to a conventional LHP. For the optical structure, a three-stage insulation technology was developed to save heater power and improve temperature stability. A transient numerical simulation model of the LHP was deve... [more]

This paper presents a novel observer-based robust fault predictive control (OBRFPC) approach for a wind turbine time-delay system subject to constraints, actuator/sensor faults, and external disturbances. The proposed approach is based on an augmented state-space representation that contains state-space variables and estimation errors. The proposed augmented representation is then used to synthesize a robust predictive controller. In addition, an observer is developed and used to estimate both state variables and actuator/sensor faults. To ensure that the proposed approach has disturbance rejection capabilities, the disturbance estimates were merged with the prediction model. In addition, the disturbance rejection capabilities and fault tolerance were insured by formulating the control process as an optimization problem subject to constraints in terms of linear matrix inequalities (LMIs). As a result, the controller gains are acquired by solving an LMI problem to guarantee input-to-sta... [more]

The study on morphology and distribution of sublacustrine fan are necessary for the exploration of oil and gas, which could help to effectively predict the reservoirs of sublacustrine fans. In this paper, the distribution and geomorphology of sublacustrine fans of Dongying Formation in Liaoxi uplift (Bohai Bay Basin, East China) and their controlling factors (including shape and formations) have been analyzed in detail based on seismic, core, and logging data. The main conclusions achieved in this study are: (1) During the sequence of the third member of Dongying Formation (SQd3), two types of sublacustrine fan, including channelized fan (in channel shape) and non-channelized fan (in tongue shape and lobe shape), developed on the eastern slope of Liaoxi uplift, which inherited the characteristics of sediments structural maturity in braided river delta front (good sandstone sorting and high structural maturity); (2) Steep slope was favorable for forming tongue shape sublacustrine fans w... [more]

The main goal of Fault Detection and Diagnosis (FDD) processes is to identify faults, determine their sources, and recognize solutions before the system is further harmed or service is lost [...]

In photovoltaic (PV) systems, inverters have an essential role in providing an energy supply to meet the demand with power quality. Inverters inject energy into the grid considering that a renewable source is available; however, during intermittent periods or in the absence of power generation, the inverter remains inactive, which decreases the performance of the PV system. One way to increase the operation of inverters is to operate them as Volt-Amps Reactive (VAR) compensators to generate reactive power in the absence of renewable sources. The paper presents the development of a control scheme that allows the PV system’s inverter to improve the power factor in the electrical system with or without PV power generation. The proposed control is based on using a sliding mode controller (SMC) current control loop and PI-based voltage control loop. The control scheme is developed in MATLAB/SIMULINK, and for real evaluation, a PV prototype is implemented. The control strategy efficiency is... [more]

A photovoltaic (PV) system is composed of a PV panel, controller and boost converter. This review article presents a critical review, contributing to a better understanding of the interrelationship of all these internal devices in the PV system, their respective layouts, fundamental working principles, and architectural effects. The PV panel is a power-generating device. A controller is an electronic device that controls the circulating circuits in a PV system to collect as much PV output as possible from the solar panel. The boost converter is an intermediate device that regulates the PV output based on the duty cycle provided by the controller. This review article also updates readers on the latest information regarding the technological evolution of these interconnected devices, along with their predicted future scope and challenges. Regarding the research on PV panels, this paper explains in depth the mathematical modeling of PV cells, the evolution of solar cell technology over ge... [more]

Multiphase electric machines are increasingly used in various industries and for electromobility. Complex systems have been developed for the control and powering of multiphase machines, which require verification. The quality of control and the power supply of electric machines is usually evaluated by analyzing various electrical parameters. On the other hand, taking into account the fact that a motor is an electrical-mechanical object, its full diagnostics should also include the analysis of vibration signals to verify the operation of the motor as a mechanical device. In this paper, a sensorless control algorithm was studied and applied to a 5-phase induction motor. Various scenarios were considered; in particular, the operation of the studied motor in the absence of one or two phases and in the case of the introduction of the third harmonic to increase the torque was analyzed. In the scenarios considered, the motor was connected to another machine and operated with no load as well... [more]

A comprehensive test system for proton exchange membrane fuel cells (PEMFCs) is designed and developed for monitoring and controlling the inlet and outlet parameters and safety issues of fuel cells. The data acquisition and output instruction rely on the connection between PLC (programmable logic controller) and OPC (object linking and embedding for process control). Based on Siemens S7-200 series PLC and PID (proportion integration differentiation) technology, the margin of error in relative humidity of inlet air is controlled at less than 0.7%. Furthermore, a hydrogen recycling system and an alarm module are introduced, considering the hydrogen or nitrogen solenoid valve power failure, cooling fan power failure, temperature anomaly, and hydrogen leakage. This developed test system is evaluated by the experimental investigation of PEMFC performance. The results show that the test system has very good test and control performances. At a cell temperature of 40 °C, enhanced performance i... [more]