Study on the Kinetics of a Special Particle Swarm

For randomly-moving-particle swarm, the past researches only focused on its whole behavior and few people have studied the special particle swarm formed in it, which leading to the phenomenon and reasons for the spontaneous aggregation of particles in the special particle swarm being still unknown. For such a special particle swarm, we have previously studied the causes of its special relativity phenomenon. Here we show the causes of spontaneous aggregation of “randomly moving” particles. The diffusion kinetics of particles in a special circumstance (that is, in a moving reference frame $\mathcal{R}_u$ relative to the stationary reference frame $\mathcal{R}_0$) are studied theoretically. For the first time, the effects of the location aggregation and velocity direction aggregation of randomly moving particles on the diffusion coefficient are considered, and the corresponding generalized diffusion equation is deduced employing concise mathematical logic and Mathematica software.

Optimization of Permanent Magnet Structure Parameters in Tubular Permanent Magnet Synchronous Linear Motor for HF Square-Wave Injection Sensorless Algorithm

The high frequency (HF) square-wave injection sensorless algorithm uses saliency to estimate the motor position affected by the inductance. The structure of the permanent magnets will affect the inductance of the motor, then affect the position estimation performance of the sensorless algorithm. This paper studies the relationship between the inductance and the position estimation accuracy of the HF square-wave injection sensorless algorithm for tubular permanent magnet synchronous linear motor (TPMSLM). Through the finite element simulation, the distribution law of the TPMSLM inductance with the change of the PM structure is quantitatively analyzed, and the influence of the PM structure parameters on the differential amplitude of the HF current is given. The HF square-wave voltage is injected into the stationary reference frame, and the frequency is half of the PWM switching frequency. The HF current differential equation is obtained without any filter, and the estimated position of the mover is extracted by a phase-locked loop. Finally, the experiment of sensorless position estimation is carried out by two prototypes with different PM structure parameters at different speeds, verifying the effectiveness of the analysis.

Model Predictive Control with Modulator Applied to Grid Inverter under Voltage Distorted

This research paper presents a model of predictive control with a modulator for the inverter linked to the electrical grid, using the stationary reference frame and operating under grid distorted voltage. The stationary reference frame model for the system is obtained in its fundamental frequency and then the model predictive technique is implemented, which predicts the system actions using the obtained system model without the need of any other harmonic consideration. The controller calculates the voltage vector of the inverter through the minimization of the cost function. Thus, the proposal demonstrates, through experiments, its positive results regarding the low impact of the distorted voltage in the grid current without using any harmonic consideration on the model. Experimental results and comparisons carried out endorse the proposal of this work.

Control Strategy Based on Arm-Level Control for Output and Circulating Current of MMC in Stationary Reference Frame

This paper proposed a control method for output and circulating currents of modular multilevel converter (MMC). The output and circulating current are controlled with the help of arm currents, which contain DC, fundamental frequency, and double frequency components. The arm current is transformed into a stationary reference frame (SRF) to isolate the DC and AC components. The AC component is controlled with a conventional proportional resonant (PR) controller, while the DC component is controlled by a proportional controller. The effective control of the upper arm and lower arm ultimately controls the output current so that it delivers the required power to the grid and circulating current in such a way that the second harmonic component is completely vanished leaving behind only the DC component. Comparative results of leg-level control based on PR controller are included in the paper to show the effectiveness of the proposed control scheme. A three-phase, five-level MMC is developed in MATLAB/Simulink to verify the effectiveness of the proposed control method.

Rotor Current Feedback Based Direct Power Control of a Doubly Fed Induction Generator Operating with Unbalanced Grid

The paper presents a decoupled direct power-controlled (DPC) of a doubly fed induction generator (DFIG) connected to an unbalanced power grid, executed in an orthogonal stationary reference frame related to the stator side. The control allows to maintain constant electromagnetic torque despite stator connection to the unbalanced power grid and to achieve controllable low-voltage ride through (LVRT) capability. The control does not require any signal decomposition into positive and negative sequence order, which allows to reduce its complexity and computational requirements. Then, the paper presents positive influence of rotor current feedback in the stator-controlled reference frame on control performance. It facilitates significant transient reduction and minor steady state control improvement. All the mentioned functionalities were validated both in simulation and in laboratory conditions and the obtained results are described in the paper.

Stator Fixed Deadbeat Predictive Torque and Flux Control of a PMSM Drive with Modulated Duty Cycle

Conventional deadbeat control strategies for permanent magnet synchronous machines (PMSMs) are commonly developed reference frames, however, coupling dynamics affect the performance drive, and rotational transformations are required for the synthesis of the final voltage vector (VV). To improve robustness against parameter variations and to directly synthesize the reference voltage vector, in this paper a deadbeat predictive torque and flux control for a PMSM is presented. The proposed controller is developed in the stationary reference frame (α−β). First, the reference VV is obtained from a predictive deadbeat controller. Then, the reference VV is applied to the power inverter by the combination of two voltage vectors. A duty cycle optimization is employed to calculate the required time for the application of each voltage vector. Experimental results based on an FPGA and a comparison of the conventional and the proposed deadbeat controller are presented to validate the proposed methodology.

Allocentric and Egocentric Controllers: Similarities and Differences

Gestural instruments can be divided into two categories based on the type of the reference frame used by the controller. An egocentric controller uses a reference frame that is centered on and follows a point of the performer's body to measure the body point positions relative to some other body points. An allocentric controller uses a stationary reference frame attached to an object other than the performer's body. The allocentric option is the more commonly used by gestural instrument designers. The egocentric option has been used and explored less frequently. This paper studies, at a low level and high level: 1- The similarities and differences between egocentric and allocentric controllers for gestural instruments from the perspective of performer and instrument designer. 2- The affordances and constraints of egocentric and allocentric controllers as they, to a large degree, define the characteristics of an instrument. The paper presents the initial results of a subjective experiment to encourage the future discussion and study of the subject.