Zero Speed Research Articles

Stator Current-Based Model Reference Adaptive Control for Sensorless Speed Control of the Induction Motor

This paper described that the stator current-based model reference adaptive system (MRAS) speed estimator is used for the induction motor (IM) indirect vector speed control without a mechanical speed sensor. Due to high sensitivity of motor parameters variation at low speed including zero, stability analysis of MRAS design is performed to correct any mismatch parameters value in the MRAS performed to estimate the motor speed at these values. As a result, the IM sensorless control can operate over a wide range including zero speed. The performance of the stator current-based MRAS speed estimator was analyzed in terms of speed tracking capability, torque response quickness, low speed behavior, step response of drive with speed reversal, sensitivity to motor parameter uncertainty, and speed tracking ability in the regenerative mode. The system gives a good performance at no-load and loaded conditions with parameter variation. The stator current-based MRAS estimator sensorless speed control technique can make the hardware simple and improve the reliability of the motor without introducing a feedback sensor, and it becomes more important in the modern AC IM. The sensorless vector control operation has been verified by simulation on Matlab and experimentally using Texas Instruments HVMTRPFCKIT with TMS320 F28035 DSP card and 0.18 kw AC IM.

Research on Zero-speed Detector Based on INS / Wheel speed and Vehicle gear

The zero-speed detector is required for the correction of the positioning error and the initial static alignment of the autonomous vehicle. The zero-speed detector that only depends on the INS (Inertial Navigation System) has zero-speed misjudgment. The performance of the detector after the fusion of wheel speed has been improved, but the wheel speed is still not integrated in scenarios such as long periods of stationary, emergency stop and reverse. Because the wheel speed signal only outputs the vehicle speed when the vehicle reaches a certain speed, there is a long initial alignment time, and the wheel speed is not fused in the complex driving process. This paper proposes a Vehicle gear information added to the INS / wheel speed fusion zero speed detector to achieve a 10s increase in the initial alignment time, the effect of wheel speed fusion has been improved, and thus the zero speed The accuracy of detection.

Prediction of the Side Drift Force of Full Ships Advancing in Waves at Low Speeds

In this study, we analyze the experimental results of the mean sway (side drift) forces of six full type ships at low speeds in regular waves of various directions and compare them with numerical results of the in-house 3D panel code NEWDRIFT. It is noted that the mean sway force is most significant in relatively short waves, with the peak being observed at λ/LPP ≈ 0.5–0.6. For λ/LPP > 1.0, the corresponding value is rather small. We also observe a solid recurring pattern of the mean sway force acting on the analyzed full type ships. On this basis, we proceed to approximate the mean sway force with an empirical formula, in which only the main ship particulars and wave parameters are used. Preliminary validation results show that the developed empirical formula, which is readily applicable in practice, can accurately predict the mean sway force acting on a full ship, at both zero and non-zero speeds.

Surface acoustic wave propulsion system with acoustic radiation force

This study is based on the conventional dimension of U-IDT actuator to discuss the feasibility of swimmer propulsion system with surface acoustic wave (SAW). Acoustic radiation force with SAW has been widely used in the field of microfluidics. Acoustic radiation propulsion (ARP), a reaction force of acoustic radiation force (ARF), has rarely been discussed. This reaction phenomenon may actually play a significant role in the swimmer propulsion system. To investigate this phenomenon, a prototype swimmer is designed in this study. The swimmer converts ARP with SAW into movement and force in water. Rayleigh Wave is excited with a 128° Y-rotated X-propagation lithium niobate U-IDT actuator. The evidence of movement and propulsion are confirmed in water by the no load speed and zero speed propulsion measurements. ARP, based on acoustic impedance difference, can shift the gravity center of prototype swimmer every time. At 9.61 MHz, 100 mm/s no load speed and 4 mN zero speed propulsion are measured in water, when driving voltage is around 75 V0p. ARF with U-IDT actuator is estimated by the time average. The comparison between the calculation and measurement results had a similar response. In future, miniaturization and low voltage of ultrasonic actuator can be achieved with higher frequencies. Simultaneously, high power density will be maintained because the vibration velocity is not varied extremely. Moreover, wave vibration with ARP may maintain blood activation to reduce the possibility of thrombosis during and after surgery. Thus, the micro swimmer propulsion system with SAW deserves to be expected in blood vessels, based on the advantages of high power density, self-propelled and simple structure.

A Novel Strategy for Sensorless Control of IPMSM with Error Compensation Based on Rotating High Frequency Carrier Signal Injection

In the applications of rail transit and electric vehicles, sensorless control of interior permanent magnet synchronous motor (IPMSM) usually uses high frequency (HF) signal injection in low speed or zero speed. Rotating HF signal injection based on the stationary reference frame can identify the rotor position, but its accuracy is easily affected by various nonlinearities of the control system and stator resistance. In this paper, the causes of rotor position estimation deviation are analyzed and deduced in detail. It is proposed that the rotor position estimation deviation can be divided into high frequency phase deviation (HFPD) and stator resistance phase deviation. On the basis of these analyses, a novel sensorless rotor position estimation strategy for IPMSM is proposed. This strategy can theoretically eliminate the HF phase deviation caused by the nonlinearity of the control system and reduce the phase deviation caused by the stator resistance. Although the factors that cause the estimation deviation of rotor position may change with the time and the operation status of the motor, the proposed strategy has the characteristics of online calculation and real-time compensation, which can improve the accuracy of the estimated rotor position. In addition, this paper provides a detailed theoretical derivation of resolving rotor position considering stator resistance and HF phase deviation. Finally, the result analysis on an IPMSM demonstrate the correctness of the theoretical analysis and the effectiveness of the strategy.

Self-propelled swimmer via thickness-vibration-mode ultrasonic transducer

Acoustic radiation force (ARF) has been widely used in the field of microfluidics. Acoustic radiation propulsion (ARP), a reaction force of ARF, has never been proposed and discussed. This reaction phenomenon may actually play a significant role in swimmer propulsion system. To confirm and discuss this phenomenon, a prototype swimmer is designed in this study. The swimmer converts ARP into movement and force in water. Bulk acoustic wave is excited with a PZT thickness-vibration-mode ultrasonic transducer. The no load speed and zero speed propulsion of swimmer are measured and investigated. Acceleration is discussed by the no load speed and zero speed propulsion measurements to illustrate the fluid resistance and wire traction. Based on the advantages of high power density, self-propelled, simple structure, The swimmer propulsion with ARP deserves to be expected in blood vessels or other miniature pipeline environments.

Sensorless control based on the improved VM NN SC MRAS method for high performance SPIM drives using LPF

This paper proposes a novel Stator Current Model Reference Adaptive System based scheme using neural network (NNSM_SC_MRAS) for sensorless controlled of Six-Phase Induction Motor (SPIM) drives. For this scheme, the measured stator current components are used as the reference model and a two layer linear NN stator current observer is used as an adaptive model. The voltage model (VM) rotor flux identifier with value of stator resistor is update online is used to provide the rotor flux for the adaptive model, this helps to overcome the instability problem and enhance the performance of the observer. Especially, In order to eliminate the drift problems, the pure integrator of VM is replaced with a first-order low-pass filter, and the error due to this replacement is also compensated in proposed scheme. Simulation results have demonstrated that the performance of the proposed observer is significantly improved especially at low and near zero speed range.

Noise Spectrum Shaping of Random High-Frequency-Voltage Injection Based on Markov Chain for IPMSM Sensorless Control

The high-frequency (HF) voltage injection method can accurately estimate the rotor position of an interior permanent magnet synchronous motor (IPMSM) at low speed and zero speed. However, the fixed injection frequency for the traditional HF-voltage injection method will produce loud audible noise. The random HF-voltage injection method has a spread spectrum, which can reduce the audible noise. However, random HF voltages are controlled by constant probability rules, and it is inevitable that continuous multiple random numbers are larger or smaller than the mathematical expectation in the digital implementation, which will lead to spectrum concentration of the HF current. Thus, the random HF-voltage injection method cannot reduce the audible noise effectively. A novel random HF square-wave voltage injection method for an IPMSM based on the Markov chain (MC) is proposed to reduce the audible noise. The transition of the injected HF square-wave voltages obeys the MC instead of constant probability rules, which not only can shape the power spectrum of the HF current but also enable the explicit control of the HF current time-domain performance to reduce the audible noise. In order to reduce the position error caused by the phase mismatch between the HF current and the demodulation signal, an enhanced signal processing method is presented. Then, the power spectra density of the proposed method is analyzed to verify the effectiveness. Finally, the correctness and the effectiveness of the proposed method are verified by experiment on a 2.0-kW IPMSM drive platform.

Improvement of Flux Regulation with Adaptive PI Controller and DTHB based Direct Torque Control of Induction Machine

This paper presents an adaptive PI based two control strategies of Dynamic Hysteresis Torque Band (DHTB) for improving flux regulation at low speed and zero speed in lookup table based Direct Torque Control (DTC) of an Induction Machine (IM). This is achieved by varying the band value of torque dynamically but it is limited with flux error range. With the conventional HTB based DTC, at low and zero speed, the regulation of flux will not be good. To overcome this drawback, a small alteration in the structure is done, i.e., DTHB, thus retaining the simplicity of DTC algorithm. The performance is verified by varying the speed at low values. At low speeds of IM, the flux regulation and the speed is improved with adaptive PI controller based DHTB-II compared to DTC with DHTB-I and DHTB-II.

Research on Rotor Position Self-Sensing Control System of a PMSM for Electric Vehicles

There are many problems existing in the traditional rotor position self-Sensing control. To overcome these problems, a hybrid approach of rotor position self-sensing control based on a PMSM for Electric Vehicles is investigated in this paper. The proposed method has good robustness and position tracking performance at full speed including zero speed. Based on the proposed algorithm, a PMSM position self-Sensing control system is set up. Simulation and experiment are implemented on the platform. The results verify the feasibility and effectiveness of the proposed method.

Speed Sensor Fault Tolerant PMSM Machines: From Position-Sensorless to Sensorless Control

New sensorless observers (i.e., from stator currents/voltages measurements only), to be included into a simple observer-based sensorless control for the tracking of non-definitely zero speed references in nonsalient-pole surface permanent magnet synchronous machines (PMSMs), are proposed. They are obtained through a “minimum distance” modification from recently presented position-sensorless observers (i.e., from rotor speed and stator currents/voltages measurements only). The rotor speed estimate is here directly provided by the phase locked loop (PLL)-based third-order steady-state linear kalman filter (SSLKF) that has been previously used to mitigate the distortions on the estimated position. Experimental results illustrate the effectiveness of the proposed approach in a speed sensor fault-tolerant scenario.

Development of procedures for determining the parameters of an aircraft servo actuator

Main trends in the use of electro-hydraulic actuators and requirements to parameters were discussed. Necessity of using automatic methods for testing an electro-hydraulic actuator together with the standard hardware of the electronic control unit was substantiated. The procedures for testing the control loop of an electro-hydraulic actuator set forth in this study make it possible to eliminate effects of mutual influence of dynamic and static characteristics of the actuator and hardware of the electronic control unit. Procedures for automatic identification of the actuator model and procedures for automatic determination of main parameters and characteristics of the actuator such as zero shift, dead space, amplitude-frequency, phase-frequency and speed characteristics have been proposed. When introducing the proposed procedures, the problem of processing high-speed characteristics of the actuator having high noisiness associated with the pulse nature of the derivative of the discrete signal of the actuator position (12 bits) was solved. In order to avoid introduction of errors in the waveform, in addition to standard digital filtering methods, it was proposed to approximate the noisy actuator characteristic by means of the Bezier curve. A procedure was proposed to record hysteresis of the speed characteristic by means of a cycle of continuous change of speed of movement of the output link of the actuator during the working stroke. The method for automatic identification of a simplified actuator model can significantly reduce labor costs in processing of experimental data. The parameters of the actuator model obtained for various deviations in parameters and various actuator operating conditions (external factors) can improve quality of synthesis of control algorithms

Origin of the Universe: The Zero Speed Approach

Origin of the Universe: The Zero Speed Approach

Various Aspects of Bollard Pull Tests and Analysis of Test Results

The static force exerted on a hawser at zero ship speed by a vessel, otherwise known as the bollard pull, is one of the key performance indicators of Tugs, Anchor Handling Tugs (AHTs) and Anchor Handling Tug Supply Vessels (AHTSVs). The value of bollard pull is considered critical as it defines the functionality and performance of the vessel. When a company decides on chartering a vessel, a definite prerequisite considered is the value of the bollard pull. The value may be obtained via three ways: calculations, model-testing, and full-scale trials. The latter is often used officially to certify the vessel's bollard pull rating, with the presence of the vessel's owners, surveyors, and any other third parties. The tests and trials follow a set of guidelines provided by classification societies but do not have a standardized set of rules. Therefore, disagreements often arise over the results of such tests and trials. Tests are often carried without any load cells measuring the shaft power to ascertain the brake horsepower (BHP). Simply, engine rpm/ rating is used to fix the 100% maximum continuous rating (MCR) which often in the range of 105–108% MCR. Some of the parties involved in certifying the correct bollard pull tests (BPTs) do not even understand what is all about the bollard pull. Everybody is looking for a higher figure for the bollard pull on the certificate when the reality is different. The author examines and discusses the broad spectrum of factors that affects the "true" value of the bollard pull and explains why such a standardized set of mandatory BPT and the trial code is deemed necessary. The author also presents some of the interesting BPTs data to show the differences in various ways of conducting BPTs. 1. Introduction The bollard pull (BP) is the zero speed pulling/pushing capability of a vessel, i.e., Tugs, Anchor Handling Tug (AHTs), Anchor Handling Tug/ Towing Supply Vessel (AHTSVs), trawlers, etc. It is considered as one of the key practical performance indicators of the above-mentioned vessels, measuring the usefulness of the vessel in a stranding scenario or in holding large vessels such as tankers or towing a rig.

Self-Sensing Control of PMSM at Zero and Low Speed

The paper deals with control of Permanent Magnet Synchronous Motor (PMSM) without a rotor position sensor. In the low and zero speed region, the rotor saliencies are utilized to obtain the information about the rotor position. Self-sensing control techniques employ high frequency (hf) signal injection to excite the saliencies. The proposed algorithm enables tracking the saliency and allows PMSM control at zero and low speed. The theoretical assumptions were experimentally verified including the initial rotor position detection.

Roll Attitude Controller Design for Ships at Zero Speed

A longitudinal flapping zero-speed fin stabilizer system is applied to reduce the roll motion of ships at zero speed. The righting moment model of the longitudinal flapping fin stabilizer is improved by considering the eddy resistance. According to the hydrodynamic characteristics of the model, the angular velocity of the fin stabilizer is chosen as a manipulated variable to control the ship roll motion at zero speed. A master–slave control method is used to solve problems of the multi-constrained strong nonlinear relationship with fin angle, angular speed, and angular acceleration and dynamic memory function in input nonlinearity. The fuzzy sliding mode controller is conducted as the master controller to deal with parameter uncertainties and unpredictable disturbance upper bound. The output tracking feedback slave controller is used to realize the nonlinear backstepping from the roll moment to the angular velocity of the fin stabilizer, and the actual control variable is obtained. A ship with the longitudinal flapping foils is considered and the effectiveness of the proposed strategy is verified by simulations.

Vehicle Electromagnets Energy Supply of A.C. Combined Levitation and Traction System

Introduction. The combined levitation and traction system (CLTS) with alternating current represents a kind of electrodynamic suspension system in which the traction and levitation force are created by one set of onboard electromagnets, and the lifting force is provided at any speeds of the crew, including the zero speed. The disadvantages of the system are the low energy factor and the complexity of controlling the start-brake regimes. The scope of such a system can be passenger transportation within large cities and urban agglomerations for distances up to 100 km with speeds up to 150-200 km / h. Goal. The aim of the work is the solution of the complex problem of providing CLTS onboard electromagnets with electric power with an increased energy factor and the ability to control all driving regimes. Method (methodology). Mathematical modeling of electromagnetic and electromechanical processes with subsequent evaluation of technical and economic parameters of the CLTS were used. Results. A practically realizable version of the power supply system for the on-board electromagnets CLTS is proposed. Practical significance. The proposed version of the power supply system has significant advantages over previously considered ones: the ability to flexibly control all modes of CLTS traffic with an increased energy factor. Conclusion. The system of power supply of the CLTS with alternating current from the traction network of constant voltage 3 ... 5 kV with placement of autonomous inverters onboard the crew allows to reduce the mass of the on-board electrical equipment by 10-20%, to minimize the consumption of inactive power and to flexibly control all modes of the crew's movement.

VEHICLE ELECTROMAGNETS ENERGY SUPPLY OF A.C. COMBINED LEVITATION AND TRACTION SYSTEM

Introduction. The combined levitation and traction system (CLTS) with alternating current represents a kind of electrodynamic suspension system in which the traction and levitation force are created by one set of onboard electromagnets, and the lifting force is provided at any speeds of the crew, including the zero speed. The disadvantages of the system are the low energy factor and the complexity of controlling the start-brake regimes. The scope of such a system can be passenger transportation within large cities and urban agglomerations for distances up to 100 km with speeds up to 150-200 km / h. Goal. The aim of the work is the solution of the complex problem of providing CLTS onboard electromagnets with electric power with an increased energy factor and the ability to control all driving regimes. Method (methodology). Mathematical modeling of electromagnetic and electromechanical processes with subsequent evaluation of technical and economic parameters of the CLTS were used. Results. A practically realizable version of the power supply system for the on-board electromagnets CLTS is proposed. Practical significance. The proposed version of the power supply system has significant advantages over previously considered ones: the ability to flexibly control all modes of CLTS traffic with an increased energy factor. Conclusion. The system of power supply of the CLTS with alternating current from the traction network of constant voltage 3 ... 5 kV with placement of autonomous inverters onboard the crew allows to reduce the mass of the on-board electrical equipment by 10-20%, to minimize the consumption of inactive power and to flexibly control all modes of the crew's movement.

Production of cold CN molecules by photodissociating ICN precursors in brute-force field**Project supported by the National Natural Science Foundation of China (Grant Nos. 11504112, 91536218, and 11604100).

We theoretically investigate the production of cold CN molecules by photodissociating ICN precursors in a brute-force field. The energy shifts and adiabatic orientation of the rotational ICN precursors are first investigated as a function of the external field strength. The dynamical photofragmentation of ICN precursors is numerically simulated for cases with and without orienting field. The CN products are compared in terms of their velocity distributions. A small portion of the CN fragments are recoiled to near zero speed in the lab frame by appropriately selecting the photo energy for dissociation. With a precursor ICN molecular beam of ∼ 1.5 K in rotational temperature, the production of low speed CN fragments can be improved by more than 5 times when an orienting electrical field of 100 kV/cm is present. The corresponding production rate for decelerated fragments with speeds is simulated to be about and CN number densities of 108–1010 cm−3 can be reached with precursor ICN densities of ∼1012–1014 cm−3 from supersonic expansion.

A Robust EKF Based Speed Estimator and Fuzzy Optimization Technique for Sensorless Induction Motor Drives

<p>The speed estimation technique of induction machines has become a non-trivial task. For estimating the speed of an induction motor precisely and accurately an optimum state estimator is necessary. This paper deals with the performance analysis of induction motor drives using a recursive, optimum state estimator. This technique uses a full order state space Extended Kalman Filter (EKF) model where the rotor flux, rotor speed and stator currents are estimated. A major challenge with induction motor occurs at very low and at near zero speed. In such cases, information about the rotor parameters with respect to stator side become unobservable while using the synchronously rotating reference frame. To overcome this lost coupling effect, EKF observer linearizes the non-linear parameter in every sampling period and estimates the states and machine parameters simultaneously. The proposed algorithm is tuned to obtain least error in estimated speed. Any error found is further optimized using a non-linear fuzzy controller to obtain improved performance of the drive.</p>