A flexible virtual inertial control algorithm for ship with propulsion load and pulse load

This paper presents the application of a new method for controlling the formation flight of Unmanned Aerial Vehicles. Proposed algorithm is based on the leader follower configuration and uses the potential field to determinate desired heading for the follower UAV. Synthesis of the vector field control algorithm is closely described and presented in details. Proposed control system was carefully checked and verified during Hardware in The Loop (HIL) tests. During the HIL flights the longitudinal and lateral positions of the UAVs (Leader and Follower), orientation angles (pitch, roll, yaw), angular velocities (pitch rate, roll rate, yaw rate) and many other flight parameters were stored and logged. Obtained results validate the effectiveness of the potential field based formation flight control method.

Safety and fast-tracking assessment of an innovative SOFC/GT all-electric ship propulsion system under pulsed load

This paper describes the application of a controlled switching device to energize a 500 kV/230 kV/46 kV, 1200 MVA autotransformer in Manitoba. The development of a detailed electromagnetic-transient (EMT) simulation model of the transformer formed the basis of the work described. The transformer model includes an accurate representation of hysteresis and remanance, which was validated using recorded waveforms and manufacturer data. This paper discusses a feasibility study conducted using this transformer model to evaluate the suitability of controlled switching to energize this transformer. A series of real-time hardware in the loop tests was conducted using a real-time simulator as part of precommissioning tests. The real-time simulation (RTS) tests and phase 1 of commissioning tests conducted in October 2014 showed that the controlled switching device would produce inaccurate residual flux estimates when it integrates the secondary voltage waveforms of a capacitive voltage transformer. Based on these RTS test results and EMT simulations, the installation of a wound potential transformer (PT) was recommended. This paper also discusses simulation studies conducted to manually program the controller until the PT was commissioned. During phase 2 of testing conducted in October 2015, a wound PT was commissioned and the controller was tested. The recorded waveforms showed good agreement with simulation results. The controller has accurately predicted residual flux and minimized inrush currents during transformer switching events.

The vessel’s pulse load can intermittently produce pretty high power in a very short time. Considering their periodical charge-and-discharge process, the system variables of integrated power system (IPS) are characterized by a periodic alternating process rather than a single-equilibrium point. It is not suitable to evaluate the operational performance according to the equilibrium point. In this paper, a periodic orbit model of the IPS and its algorithm is proposed according to sensitivity analysis of end value of system variables to their initial value. The algorithm can be used for distributed compute of system variables, which adjust system variables according to the sensitivity to make the end value equal to the initial value. And, the calculation speed of the algorithm can be increased greatly. The model and the algorithm lay the foundation for assessing the operational performance of the IPS with pulse load. The proposed method has been verified by the simulation test.

Developing software for safety critical embedded systems requires extensive testing, and HIL (Hardware in the Loop) test has one of the most important roles in this testing process. Modern microcontrollers can provide opportunities to improve the efficiency and capability of traditional HIL testing. Many of these opportunities are connected to their internal so called Trace interfaces. This paper shortly introduces the capabilities of these Trace interfaces, and presents the way to integrate them into a professional HIL test development environment the NI VeriStand. The integration process starts with the acquisition of Trace signals, which requires a high speed FPGA based solution, and then a way to capture and process the data at the VeriStand engine level (usually runs on a real-time target), and at the Workspace level (Host PC) is described. The paper ends with the conclusion, which analyzes the throughput and capabilities of the integrated Trace interface and shows the possible application of the data captured by it.

The transition from big conventional bulk generation to small dispersed renewable electricity production coupled at medium and lower voltage levels resulted in bi-directional power flow and an active distribution network, which was previously considered to be a passive network. This paradigm shift brings many challenges for protection performances and coordination. As a result, this paper first investigates the impacts of Distributed Energy Resource (DER) integration on distribution protection and then applies the hardware SEL 451 relay for validation. Two of the most common protection failures with DER integration, namely, reverse power flow and sympathetic tripping cases, are examined for a microgrid in this study. Firstly, the system is modeled in PowerFactory for short circuit calculation and protection coordination study. With the help of PowerFactory simulation, coordinated relay settings are subsequently extracted for validation in hardware in the loop testing with SEL 451 relay in real-time digital simulation (RTDS). Both simulation case studies and hardware tests have shown that the DER contribution in healthy conditions as well as during the fault can result in maloperation of the relay. Different from the traditional power amplifier-based testing, the hardware in the loop testing in this work uses Low Energy Analog (LEA) signals output from the GTAO card of RTDS feed directly to SEL 451 relay. Two different feedback methods with Digital Input (DI) and IEC GOOSE signal are tested to compare the time of operation in each case.

In marine integrated power systems (IPS), dc/dc converters have been widely used to buffer the power of pulsed loads. However, limited by ship space and safety, its buffering capacity and volume are conflicting and need to be balanced. Existing methods usually oversimplify the switching dynamic process caused by the different switching periods between the pulsed loads and converters, leading to oversizing or underpowering issues of the converts. To overcome this hurdle, this article proposes a millisecond-time-scale-based state-space averaging mode (MTS-SSAM) to analyze the dynamic process by taking pulsed loads period instead of the traditional converter period as the averaging operator. Based on MTS-SSAM, taking the system allowable voltage and current fluctuation rate and converter volume as the objective function, the converters’ parameters are optimized considering the balance between buffering capacity and volume. The proposed parameters optimization method can save 49% converter volume compared with existing methods. The simulation and experimental results are presented to verify the proposed SSAM and optimization method.

Modern military aircraft are developing larger pulsed power loads varying from new weapon technologies to advanced avionics and other electrical equipment. Pulsing power loads emulate a pulse width modulated signal which have non-linear destabilizing effects on the electrical system. Additionally, these devices have thermal properties that can induce electrical stability issues at low and high temperatures and various pulsing load conditions. These non-linear electrical stability issues carry through to the mechanical and thermal systems of the aircraft and can damage components. The MATLAB/Simulink workspace is used to simulate a non-linear model of an aircraft’s electrical-mechanicalthermal (EMT) system. This system includes electrical generation with constant and pulsing power loads, mechanical fluid pumping, and thermal cooling systems. The goal of the EMT model is to demonstrate the destabilizing effects caused by both the thermal coupling of the pulsing load and the large signal analysis of the PWM signal. An operational boundary of the power pulsed device is found by varying the duty cycle for a given pulse period and power load based on bus voltage transients and voltage drop limits. The system is defined metastable for a given set of parameters if the system experiences periods of stability and instability based on varying operating points. Regions of complete stability, metastability, marginal metastability, and instability are determined based on bus voltage transient tolerances. Analyzing the marginally metastable boundary layer, thermal analysis is performed at different points of equivalent average power and varying pulse energy. Post processing the results determines the most efficient operational region of the system given thermal and electrical requirements.

For pulsed power load (PPL) accommodation in a medium‐voltage DC (MVDC) shipboard power system (SPS), the charging control of energy storage systems (ESSs) and the generation control of distributed generators (DGs) need to be properly coordinated. Targeting the important but not well‐studied problem, an optimal output‐constrained control algorithm for the offline PPL accommodation strategy is presented. Three control objectives including realising the generation and charging control references, maintaining the DC bus and supercapacitor voltages within the safe operating ranges, and minimising the total generation cost of DGs, are fulfilled concurrently. First, an SPS model with multiple DGs, a supercapacitor ESS, and regular loads is developed. By restricting the DC bus and supercapacitor voltages within pre‐defined constraints, both the transient‐ and steady‐state performances of the SPS are guaranteed. Furthermore, by incorporating the cost minimisation objective into designed virtual control signals, the third control objective on energy efficiency is realised. The stability of the presented algorithm is rigorously proven based on the Lyapunov method. Finally, detailed case studies are conducted to validate the performance of the designed algorithm.

Preliminary design and validation of a Real Time model for hardware in the loop testing of bypass valve actuation system

A new transient stability control strategy for the Line-Commutated-Converter based High-Voltage-Direct-Current (LCC-HVDC) receiving-end system based on the gradient of dynamic energy is proposed to deal with this problem. Firstly, in the whole process from fault occurrence to fault removal, a dynamic energy function representing the stability of the system is constructed. On this basis, considering the influence of Direct Current (DC) inverter side controller, the dynamic energy gradient expression under three-phase and single-phase short-circuit fault scenarios is deduced in detail. The influence of control parameters on dynamic energy accumulation or consumption is analytically described. Then, the function term related to the inverter side controller is extracted from the dynamic energy gradient expression, the trigger pulse on the inverter side is controlled to keep the dynamic energy gradient of the DC port at the minimum. Finally, the hardware in the loop test is carried out on RT-LAB. The test results show that in the process of receiving end fault, the DC port will inject dynamic energy to the receiving end system, making the system tend to be unstable. This method is able to reduce the dynamic energy accumulation rate of system and increase the critical clearing time of system.

The present paper offers a complete, flexible and adaptable solution for electric vehicles industrial developers to test their designs from all the perspectives required by a V-mode development approach. Construction of high accuracy mechanical and electrical real-time digital-twin models fuzzing dedicated software was proven to be the proper solution to reach results confirmed by actual measurements. Methods for transitioning from real-time simulations to emulations or hardware in the loop testing are presented in detail. The digital-twin solution performing real-time simulations are considered to be the virtual test facility presented in the paper. For actual validation, preliminary the battery is studied via hardware emulation and hardware testing. The same approach is then applied to the vehicle motor together with its electronics and control. The added value of the paper is brought by several aspects such as the real-time co-simulation, performed using National Instruments VeriStand software aggregator, the methods of virtual, emulation and hardware testing of the same assemblies, all being confirmed by comparative analysis. The increased precision obtained, proved by actual measurements, estimates the value and usefulness of this study for those working in electric vehicles development. The content of the paper is an extended genuine study giving hands-on solutions for different types of approaches when it comes to developing and testing mechanical or electrical assemblies. The paper gives a theoretical background pushed to the application side confirmed by actual laboratory testing.

This paper presents a methodology for satellite sensors' fault detection and diagnosis (FDD) in a fault-tolerant attitude determination system using a nonlinear interacting-multiple-model approach (IMM). Moreover, the fault-tolerant attitude determination system utilizes the IMM approach in the presence of sensors' total fault to estimate faulty sensors and attitude states. This methodology relies on the most conventional satellite attitude sensors including magnetometer, sun sensor, and gyroscope measurements. The presented scheme leads to a significant computational time-saving method due to considering a pre-filter Kalman for fault detection, hence, the proposed FDD approach consists of two stages. In the first stage, the pre-filter Kalman detects any sensor fault and attitude states. In contrast, in the next stage, fault diagnosis and optimal attitude estimation are obtained through the IMM approach. Therefore, the IMM algorithm will be activated to extract the optimal estimation and identify faulty sensor(s). A Monte Carlo type approach is used to verify this technique for various initial conditions. Through numerical and Monte Carlo simulations, it is shown that the proposed scheme is robust against sensors' total fault, and the system is capable of detecting and isolating accurately the faulty sensor. Hardware in the loop tests using satellite dynamics simulator are also used to validate the presented system performance.

Real-time simulation and its use in Hardware in the Loop and Power Hardware in the Loop testing may not be realized with one single hardware platform. Instead, multiple systems are needed to realistically address the analysis and testing needs of the smart grid. This is particularly the case when the target system is the future electrical distribution grid, with its multi-physic, hybrid nature, its pervasive power electronics and communication. The approach adopted at the authors' laboratory is presented to exemplify the interface and integration challenges when such platform is extended to realize relevant scenarios.

<div class="section abstract"><div class="htmlview paragraph">Automotive industry is inclined towards connected, comfortable, environment friendly, efficient and smarter systems. Advanced Driver Assist System (ADAS) technology assist drivers to achieve a safer as well as better ride by automation and improvisation of the vehicular systems. With the advent of ADAS system, there is a significant focus not only in the development of Electronic Control Units (ECUs) and its features to cater to the emerging market but also on the information that could be displayed to meet the functional as well as safety requirements. This ADAS information display ensures timely notification to the driver with unique alerts that can be acoustic or visual. These systems should be tested thoroughly to ensure reliability as failures may impose severe risk on the OEM. Hardware in the loop testing has been largely adopted by industry against manual testing in lieu of the testing constraints imposed by the latter. This paper discusses on the existing test methods for ADAS information display system testing using HIL. It also details on the automation trends adopted and highlights the key challenges associated with the development as well as reusability of the conventional test methods. It discusses an Artificial Intelligence based strategy for automation of cluster objects teaching, evaluation and illustrates the adoption of the same for ADAS HIL testing and brings out the efficiency and benefits achieved by the proposed strategy.</div></div>