Sliding mode control for overturning prevention and hardware-in-loop experiment of heavy-duty vehicles based on dynamical load transfer ratio prediction

Aiming at the rollover risk of heavy-duty vehicles, an adaptive rollover prediction and control algorithm based on identification of multiple road adhesion coefficients is proposed, and the control effect has been verified by hardware-in-the-loop experiments. Based on the establishment of a 3 DOFs (Degree of freedom) vehicle dynamic model, the roll angle of the vehicle dynamic model is estimated in real time by using Kalman filter algorithm. In order to ensure the real-time operation of anti-rollover control strategy for multi-body dynamic heavy vehicle model, a sliding mode variable structure controller for anti-rollover of vehicles is designed to determine the optimal yaw moment. Specially, the recognition algorithm of road surface type is integrated into the control rollover algorithm. When the control system with road recognition algorithm recognizes whether the vehicle is in danger of rollover, it can not only adjust the state of the vehicle, but also shorten the time to reach the stable area of the vehicle's lateral load transfer rate by about 2 s. In order to further improve its adaptability and control accuracy, a Hardware-in-loop test platform for three-axis heavy-duty vehicles is built to verify the proposed anti-rollover control strategy. The results prove that the proposed control strategy can accurately predict the rollover risk and control the rollover in time.

Variable DC Approach in Fuel cell And Battery Powered Marine Power Systems: Control of The Fuel Cell Power Converter

Previously, the Variable DC approach concept was proposed for operation of hybrid fuel cell and battery powered marine vessels. The concept was shown to provide significant efficiency improvement, and consequently improved hydrogen fuel savings. However, although the general concept and the control of battery DC/DC converter has been detailly described in previous works, the operation of fuel cell DC/DC converter in different Variable DC approach control modes has not been presented. This paper proposes a fuel cell DC/DC converter control system specifically designed for operation in the three Variable DC approach control modes. The functionality of the proposed fuel cell DC/DC converter and the Variable DC approach in general is verified using a hardware-in-loop test setup consisting of virtual power stage models and real converter controllers. The system is shown to function well in both normal operating conditions and various fault conditions.

An Enhanced Control Strategy for Mitigation of State-Transition Oscillation Phenomena in Grid-Forming Self-Synchronized Converter System with Islanded Power System

This paper proposes an enhanced control strategy for mitigating state-transition oscillations in active and reactive power responses of self-synchronized converter system to secure the islanded power system stability. The self-synchronized converter is well known for “grid-forming” that is able to operate to stand-alone mode (SAM) providing grid voltage and frequency without phase synchronization units. Although the grid-forming (GFM) is self-synchronized, the inherent synchronization principle causes system degradation in which should maintain a point of common coupling (PCC) voltage for critical loads as well as transitions from grid-connected mode (GCM) to SAM and vice versa. Therefore, this paper focuses on resolving the inherent oscillatory issues in GFM self-synchronized converter system (especially adopted ‘synchronverter’ principle), and proposes a control strategy for controllability improvement based on stability analysis for smooth state-transition under islanded power system. The efficacy of the proposed control method is verified through a high-fidelity electromagnetic transient (EMT) simulation with case studies on 30kW synchronverter system and further experimental hardware-in-loop system (HILS) test with Opal-RT (OP-5707) platform.

ESO-Based Vibration Control for All-Clamped Plate Using an Electrodynamic Inertial Actuator

This paper proposes a disturbance rejection method with extended state observer (ESO) and a tracking differentiator (TD) to realize vibration suppression of all-clamped plate structure in the presence of lumped disturbance, i.e. internal dynamic uncertainties, unknown external forces and accelerometer measurement noises. First, the structure is modeled as two degrees of freedom system based on vibration characteristics. Second, an ESO is employed to ensure the vibration suppression performance by estimating the lumped disturbances and compensating these disturbances via real-time feedforward mechanism. Meanwhile, a TD is introduced to eliminate the influence of the measurement noises. Moreover, the stability of the closed-loop system is discussed in detail. Finally, the proposed controller is verified on the hardware-in-loop plat-form based on NI PCIe-6343 data acquisition card. Theoretical analysis and experimental results show that the proposed method possesses good vibration suppression performance.

Novel Protection Coordination Scheme for Active Distribution Networks

Distribution networks are inherently radial and passive owing to the ease of operation and unidirectional power flow. Proper installation of Distributed Generators, on the one hand, makes the utility network active and mitigates certain power quality issues e.g., voltage dips, frequency deviations, losses, etc., but on the other hand, it disturbs the optimal coordination among existing protection devices e.g., over-current relays. In order to maintain the desired selectivity level, such that the primary and backup relays are synchronized against different contingencies, it necessitates design of intelligent and promising protection schemes to distinguish between the upstream and downstream power flows. This research proposes exploiting phase angle jump, an overlooked voltage sag parameter, to add directional element to digital over-current relays with inverse time characteristics. The decision on the direction of current is made on the basis of polarity of phase angle jump together with the impedance angle of the system. The proposed scheme at first is evaluated on a test system in a simulated environment under symmetrical and unsymmetrical faults and, secondly, as a proof of the concept, it is verified in real-time on a laboratory setup using a Power Hardware-in-loop (PHIL) system. Moreover, a comparative analysis is made with other state-of-the-art techniques to evaluate the performance and robustness of the proposed approach.