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In this paper, in order to replace a conventional electric linear actuator which is consist of rotary PM machine and ball screw, a novel double-sided five-phase modular linear permanent magnet synchronous machine (MLPMSM) is proposed and designed with the same volume. The basic structure of the machine is firstly described and the major dimensions of one module are then optimized to acquire the largest...
Distributed generation (DG) is connected through three-phase inverter to the microgrid. The virtual power based droop control can guarantee the pure decoupling between active and reactive power irrespective of low-voltage or high-voltage microgrid application if the line-impedance information is known in advance. However, unbalances are commonly existent in practice so that this conventional control...
In this paper, control system and simulation of an arc-linear permanent-magnet synchronous machine with normal armature windings and compensation windings are researched. Considering the special structure of the machine, the mathematical model of the machine is investigated and established. The control scheme and the control system for the machine are also researched to reduce the torque ripple for...
In this paper, a novel 5-phase double-sided C-core modular linear permanent-magnet synchronous machine (MLPMSM) used for the linear steering engine is researched. Firstly, the structure of the MLPMSM is depicted. Then the thrust produced by one module and the total thrust force of the machine are deduced and analyzed. In the ideal condition, all the harmonics in the thrust force can be eliminated...
Modular multilevel converters (MMC) have shown a great potential in the area of medium-voltage drives, for it can produce excellent output waveform with low average switching frequencies. A key issue of MMC is that it requires a complex voltage balancing method to balance the capacitor voltage of each submodule (SM). In this paper, a medium-voltage motor drive based on diode-clamped modular multilevel...
In this paper, a modular multilevel converter (MMC) integrated ultracapacitors energy storage system (UCESS) and the control strategy are proposed for Power Router. Half bridges integrated with UC modules are utilized as the sub-module (SM) of the converter. Due to the integration of UCESS, the input power and output power can be decoupled, which means that the power relationship of the Power Router...
In the applications like aerospace, it is very important to drive the motor with high precision and high efficiency. The traditional switching inverter drives output pulse mode voltage which results in lots of harmonics and influences the stability of motor drives. A multilevel-switching-linear hybrid (MSLH) scheme is proposed in the paper for the permanent magnet synchronous motor (PMSM) drives....
In this study, titanium (Ti) added Sn58Bi solder alloys were synthesized. Microstructure evolution and mechanical property change during 1008 h thermal aging were compared with those of eutectic Sn58Bi and Ti-added Sn58Bi alloys. According to the results, yield strength (YS) and ultimate tensile strength (UTS) decreased, while even after aging, the Ti-added Sn58Bi alloy maintained the highest YS and...
A kind of arc-linear axial flux permanent-magnet synchronous machine (AL-AF-PMSM) used for scanning system is researched in this paper. Due to the characteristics of the three-dimensional (3-D) magnetic field, 3-D finite element method (FEM) is usually required to analyze the AF-PMSM. However, 3-D FEM is generally too time consuming. In order to avoid this problem, an approximate equivalent 2-D calculating...
Chinese Traditional Medicine Rotation-Traction manipulation is an effective treatment of Cervical Spondylosis. However, incidence of medical malpractice is relatively high in the rotation-traction therapy when the unfledged internship physicians give the therapy. But the conventional pedagogy is inefficient for lack of experimental platform. So it is crucial to develop an experimental platform to...
In this paper, we study the event-triggered consensus problem for heterogeneous multi-agent systems with general linear dynamics under a general directed graph. As the states of each agent are unavailable, we propose a decentralized event-triggered consensus control strategy based on observer and internal model principle such that the outputs of all agents achieve consensus, without requiring continuous...
Our goal is to analyze the way information flows in the social network and to draw a conclusion for the relationship between the information spread and public opinion. First, by utilizing K-Means Algorithm with PCA (Principal Component Analysis), we build a comprehensive assessment system of information development. Second, based on the traditional SIR Model in epidemic field, we build a SIER dissemination...
In this paper, a robust H∞ decentralized controller is proposed for attitude coordination of spacecraft formation flying with external disturbance based on the relative attitudes and angular velocities of neighboring spacecraft. The controller is composed of nonlinear terms for performance enhancement and linear terms for attitude coordination and stabilization. The proposed control method guarantees...
In this paper a combined controller composed of the H∞ virtual controller and the sliding mode controller is proposed to improve the rigid spacecraft robustness. Considering the strong nonlinearity of the spacecraft dynamics, tensor product (TP) transformation is applied on the linear parameter varying (LPV) model which is obtained from the attitude kinematics system. The TP-based H∞ controller can...
Under the coupling effect between guidance system and control system, the performance of traditional guidance and control method is limited. Therefore, integrated guidance and control (IGC) method is proposed to solve the problem. This method is characterized by the guidance loop and control loop which are considered as a whole part in accordance with the information of the relative motion between...
This paper presents nonlinear robust trajectory tracking strategies for the hypersonic vehicle whose ailerons are stuck at an unknown angular position. Firstly, a time-varying sliding mode control strategy for general second-order systems is introduced, and the chattering of sliding mode controller is alleviated. Secondly, the dynamics of hypersonic vehicle are transformed into two second-order systems...
For distributed generation (DG) network, it is important to estimate the real-time states. The information-centric networking (ICN) is established to take charge of the communication of DG network. However, the assumption of ideal communication between sensors and the estimation center cannot be guaranteed due to the communication constraints of ICN with the increasing DG network. A conventional algorithm,...
The attitude control for reusable launch vehicles (RLV) is responsible for the robust operation to avoid the major deterioration from uncertainties of parameters and external disturbances in the reentry phase. Targeting for these practical issues with the study of the feedback-linearized RLV rotational equations of motion, two global sliding mode control (SMC) strategies are proposed with modified...
Three-phase inverter is a very important interface in microgrid. Droop control and virtual impedance are widely used to improve the power sharing capability and stability of such system, which however becomes ineffective under unbalanced conditions and may even cause potential stability problems. This paper proposes a fully self-adjusted virtual impedance design to guarantee the decoupling of active...
The dynamic voltage restorer (DVR) is a fast and efficient solution to voltage sag problems. This paper proposes a new configuration of DVR which is based on the parallel diode-clamped modular multilevel converter (parallel-DCM2C). In the parallel-DCM2C topology the capacitor voltages distributed in the sub-modules (SMs) can be balanced automatically without any balancing control algorithms. Additionally...
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