STUDY ON SENSOR-BASED CONTROL METHOD FOR HARMONIC DRIVE SYSTEM

A new type of robust traje ctory tracking control for harmonic using joint torque sensor and joint acceleration sensor information is concerned with.Joint torque sensor information is used to compensate the uncertainty of link and load parameters. Joint acceleration feedback control will enhace the robustness of the driving system, resist the dynamic uncertainties and disturbing torque acted on the joint axis within definite bandwidth, improve the joint tracking performance, and resist the vibration of the load side of the harmonic drive system. Experimental studies are carried out and comparison of several controllers , such as PD and sensor- based control, the experimental results clearly illustrate the effectiveness of the proposed methods.

New trajectory linearization control for nonlinear systems undergoing harmonic disturbance

This paper presents a new trajectory linearization control scheme for a class of nonlinear systems subject to harmonic disturbance. It is supposed that the frequency of the disturbance is known, but the amplitude and the phase are unknown. A disturbance observer dynamics is constructed to estimate the harmonic disturbance, and then the estimation is used to implement a compensation control law to cancel the disturbance. By Lyapunov＇s direct method, a rigorous poof shows that the composite error of the closed-loop system can approach zero exponentially. Finally, the proposed method is illustrated by the application to control of an inverted pendulum. Compared with two existing methods, the proposed method demonstrates better performance in tracking error and response time.

A new model of the harmonic control based on Hadamard product

In terms of Hadamard product, a new model is proposed for the control of connection coefficients of the state variables of the systems. The control law to stabilize the systems via the regulations of connection coefficients is obtained via a Hadamard product involved bilinear matrix inequalities. This new control model may be of significant applications in many fields, especially may be of some special sense in the emergency control such as isolation and obstruction control.

Low Phase Noise VCO using Novel Harmonic Control Circuit Based on Quad-band Composite Right/Left-handed Transmission Line

In this paper, a novel Voltage-Controlled Oscillator （VCO） using the harmonic control circuit based on the quad-band Composite Right/Left-Handed （CRLH） Transmission Line （TL） is presented to reduce the phase noise without the reduction of the frequeacy tuning range and miniaturizing the circuit size. The phase noise has been reduced by the quad-band harmonic control circuit which has the short impedance for the second- and third- and fourth- and fifth-hannonic components. The CRLH TL with two Left-Handed （LH） （backward） and two Right-Handed （RH） （forward） pass bands are used to design the quad-band harmonic control circuit. The high- Q resonator has been used to reduce the phase noise, but it has the problem of the frequency timing range reduction. However, the frequency tuning range of the proposed VCO has not reduced because the phase noise has reduced without the high-Q resonator. The miniaturization of the circuit size is achieved by using the quad-band CRLH TL instead of the conventional RH TL, The phase noise of VCO is - 124.43～ - 122.67 dBc/Hz at 100 kHz in the tuning range of 5. 729 ～5.934 GHz.

Harmonic amplitude-phase adaptive control and its application in three-axis simulators

This paper proposes a compensation method for using the Harmonic Amplitude-Phase Adaptive Control(HAPAC)to increase the precision of sinusoidal motion simulators. It also expounds on the HAPAC principle and structural disposition, develops the HAPAC control laws and analyzes the system stability in the HAPAC. A method for further improving the precision using online identification of the system’s frequency-response models is presented. The tested data and tracking errors of the simulator demonstrate that the HAPAC makes the sinusoidal motions achieve higher precision than the common classical controls. The HAPAC can also be used in other tracking systems of precision sinusoidal motions.

Contribution to Harmonic Depollution Control by the Use of Adaptive Hybrid Filter Type TLC: Case of Control by Modulated Hysteresis

In this article, we propose a topology of a TLC-HAPF power filter as a harmonic compensator for an optimization of the pollution control of electrical networks. This filter consists of an active part and a passive part in order to reduce or limit switching losses during current injection into networks thanks to its TLC module. This topology also provides solutions dynamic performance issues, resonance and lack of compensation capacity for imbalance cases. It also offers a greater range of compensation than conventional active models which do not offer as well as an intermediate circuit voltage in the order of 105 V to 109 V relatively lower than others models (600 v). A modulated hysteresis control of this topology is therefore also developed in this article and allows to obtain a network analysis on the three phases at three levels: source side, load side, and finally at the connection of the filter to the network, allowing to specify for these different positions the value of the current spectrum and its THD at this well-defined moment.

A type of inverter power supply based on harmonic elimination PWM control

In order to output sine wave with small degree of distortion and improve stability,a type of inverter power supply is designed based on harmonic elimination pulse-width modulation(PWM)control.The rectifier and filter are added to input circuit of the inverter.Single-phrase full-bridge inverter performs the function of converting direct current into alternating current(DC/AC).In the control circuit,single chip micyoco(SCM)AT89C2051 is used for main control chip to accomplish the hardware design of the control system.A given value of output frequency of the inverter is input in the way of coding.According to the output frequency code which is read,SCM AT89C2051 defined harmonic elimination PWM control data which will be selected.Through internal timing control,the switches are switched under this provision of PWM control data.Then the driving signals of the switches in the inverter are output from I/O of SCM AT89C2051 to realize harmonic elimination PWM control.The results show that adding Newton homotopic algorithm of harmonic elimination PWM control to corresponding software of the control system can make the quality of output voltage of the inverter higher and it will have broad application prospects.

In-Situ Domestic Load Harmonic Detection and Reduction Based on GLRM Algorithm for Optimum Filter Excerpt

Power Quality measures the reliable operation between the system and to the connected loads of same system. A poor power quality causes physical damage to the equipment and also results in lower productivity with increase in energy costs. Power disturbances range from micro seconds to hours and the prolonged disturbances in hours would damage the equipments. The power quality decreases due to growth of nonlinear loads in domestic appliances, such as home Uninterrupted Power Supplies (UPS), Induction stove, Television etc. Nowadays Domestic loads are controlled or powered with power electronic devices. The power electronic devices with Direct Current (DC) components generate high frequency signal for DC-Alternating Current (AC) conversion. The conversion introduces multiple frequencies in the AC power supply. The multiple frequencies in AC power supply are called as harmonics. The harmonics in AC supply affects the lifetime of home appliances, consumes more electric current, affects the power factor, transformer efficiency, and other electricity supply systems. Till now, to avoid harmonics, the filters are erected only in industrial loads or in the substations. In this paper a novel method to detect and control harmonics in domestic appliances is proposed. Harmonic control with various filters in the filter bank, based on detection of harmonic voltage let out from the domestic appliances for power saving. To select the appropriate filter to improve power quality, we apply a novel Genetic Algorithm based Linear Regression Method (GLRM) algorithm for optimum Filter Selection. From the results we were able to reduce the total harmonic distortion level to 3.68%.The current consumption of each household appliance is reduced considerably and finally the electricity bill is reduced to 15% and overall system efficiency improves to 85%.

Power-Sharing Enhancement Using Harmonized Membership Fuzzy Logic Droop Control Based Micro-Grid

The contribution of Renewable Energy Resources(RER)in the process of power generation is significantly high in the recent days since it paves the way for overcoming the issues like serious energy crisis and natural contamination.This paper deals with the renewable energy based micro-grid as it is regarded as the apt solution for integrating the RER with the electrical frameworks.As thefixed droop coefficients in conventional droop control approaches have caused various limitations like low power-sharing and sudden drops of grid voltage in the Direct Current(DC)side,the Harmonized Membership Fuzzy Logic(MFL)droop control is employed in this present study.This proposed droop control for the hybrid PV-wind-battery system with MFL assists in achieving proper power-sharing and minimizing Total Harmonic Distortion(THD)in the emer-gency micro-grid.It eradicates the deviations in voltage and frequency with itsflexible and robust operation.The THD is reduced and attains the value of 3.1%compared to the traditional droop control.The simulation results of harmo-nized MFL droop control are analogized with the conventional approaches to vali-date the performance of the proposed method.In addition,the experimental results provided by the Field Programmable Gate Array(FPGA)based laboratory setup built using a solar photovoltaic(PV)and wind Permanent Magnet Synchro-nous Generator(PMSG)reaffirms the design.

Research on Comprehensive Control of Power Quality of Port Distribution Network Considering Large-Scale Access of Shore Power Load

In view of the problem of power quality degradation of port distribution network after the large-scale application of shore power load,a method of power quality management of port distribution network is proposed.Based on the objective function of the best power quality management effect and the smallest investment cost of the management device,the optimization model of power quality management in the distribution network after the large-scale application of large-capacity shore power is constructed.Based on the balance between the economic demand of distribution network resources optimization and power quality management capability,the power quality of distribution network is considered comprehensively.The proposed optimization algorithm for power quality management based on Matlab and OpenDSS is proposed and analyzed for port distribution networks.The simulation results show that the proposed optimizationmethod can maximize the power qualitymanagement capability of the port distribution network,and the proposed optimization algorithm has good convergence and global optimization finding capability.

Controlling nonadiabatic spectral redshift of high-order harmonic using two orthogonally polarized laser fields

We investigate the nonadiabatic spectral redshift of high-order harmonic of He driven by two time-delayed orthogonally polarized laser fields. It is found that the nonadiabatic spectral redshift can be observed by properly adjusting the time delay of the two laser fields when the controlling pulse is added in the raising part of the driving pulse in the vertical direction. That is because the controlling pulse in the vertical direction prevents the ionized electrons from returning to the vicinity of parent ions and then reduces the recombination probability. This leads to the high-order harmonic generated mainly in the falling part of the driving pulse. Meanwhile,we also find that the quantity of redshift can be effectively controlled through accommodating the positive time delays. In addition, this scheme can also be used to produce nonadiabatic spectral blueshift.

Investigation of Current Control Techniques of AC-DC Interleaved Boost PFC Converter

This paper presents the comparison of various current control strategies employed for an interleaved power factor correction (PFC) boost converter for improving the power quality. The major control strategies discussed in this paper are: peak current control, average current control, hysteresis control, borderline current control and non-linear control. These strategies are implemented in MATLAB/SIMULINK and the performance of the proposed converter is compared under open loop and closed loop operation. From the results, the input current waveform was close to input voltage waveform implying improved power factor and reduced total harmonic distortion for nonlinear current control technique. Experimental results validate the proposed method.

Communication-less harmonic compensation in a multi-bus microgrid through autonomous control of distributed generation grid-interfacing converters

This paper proposes a novel approach to compensate buses voltage and current harmonics through distributed generation(DG)interfacing converter in a multibus microgrid.The control approach of each individual DG unit was designed to use only feedback variables of the converter itself that can be measured locally.In the proposed approach,the adjacent bus voltage is indirectly derived from the measured DG converter output voltage,DG line current and line impedance.A voltage closed-loop controller and a current closed-loop controller are designed to achieve both functions of DG real power generation and harmonics compensation.Therefore,the traditional harmonic measurement devices installed at the bus as well as the long distance communication between the bus and the DG converter are not required.The proposed approach can compensate the current harmonics,mitigate the buses voltage distortion and enable the customer devices to be operated in normal conditions within the multi-bus microgrid,and meanwhile relieve the burden of power quality regulator installed at the point of common coupling.Matlab simulations and experimental results are presented to show the operational effectiveness of the proposed approach.

Control of soft X-ray high harmonic spectrum by using two-color laser pulses

We demonstrate the suppression of soft X-ray high harmonics generated by two-color laser pulses interacting with Ne gas in a gas cell. We show that harmonic suppression can occur at the proper combination of the propagation distance and gas pressure. The physical mechanism behind is the phase mismatch between ＂short＂-trajectory harmonics generated at the early and later times through the interplay of geo- metric phase, dispersion, and plasma effects. In addition, we demonstrate that the position and depth of harmonic suppression can be tuned by increasing the gas pressure. Furthermore, the suppression can be extended to other laser focusing configurations by properly scaling macroscopic parameters. Our investigation reveals a simple controlling soft X-ray Laser Press and novel experimental scheme purely relying on the phase mismatch for selectively tabletop light sources without adopting the filters for applications.

Adaptive Harmonic Virtual Impedance Control for Improving Voltage Quality of Microgrids

The effects of nonlinear loads on voltage quality represent an emerging concern for islanded microgrids.Existing research works have mainly focused on harmonic power sharing among multiple inverters,which ignores the diversity of different inverters to mitigate harmonics from nonlinear loads.As a result,the voltage quality of microgrids cannot be effectively improved.To address this issue,this study proposes an adaptive harmonic virtual impedance(HVI)control for improving voltage quality of microgrids.Based on the premise that no inverter is overloaded,the main objective of the proposed control is to maximize harmonic power absorption by shaping the lowest output impedances of inverters.To achieve this,the proposed control is utilized to adjust the HVI of each inverter based on its operation conditions.In addition,the evaluation based on Monte Carlo harmonic power flow is designed to assess the performance of the proposed control in practice.Finally,comparative studies and control-in-the-loop experiments are conducted.

Active control for performance enhancement of electrically controlled rotor

Electrically controlled rotor （ECR） system has the potential to enhance the rotor perfor- mance by applying higher harmonic flap inputs. In order to explore the feasibility and effectiveness for ECR performance enhancement using closed-loop control method, firstly, an ECR rotor performance analysis model based on helicopter flight dynamic model is established, which can reflect the performance characteristics of ECR helicopter at high advance ratio. Based on the simulation platform, an active control method named adaptive T-matrix algorithm is adopted to explore the feasibility and effectiveness for ECR performance enhancement. The simulation results verify the effectiveness of this closed-loop control method. For the sample ECR helicopter, about 3% rotor power reduction is obtained with the optimum 2/rev flap inputs at the advance ratio of 0.34. And through analyzing the distributions of attack of angle and drag in rotor disk, the underlying physical essence of ECR power reduction is cleared. Furthermore, the influence of the key control parameters, including convergence factor and weighting matrix, on the effectiveness of closed-loop control for ECR performance enhancement is explored. Some useful results are summarized, which can be used to direct the future active control law design of ECR performance enhancement.

On-Line Adaptive Repetitive Controller for Power Factor Correction Systems

When the fundamental frequency is shifting, it is hard for traditional repetitive controller to work at the resonant frequencies. In this paper, a novel adaptive repetitive controller for power factor correction systems is proposed to suppress the current harmonics. Through the controller, the shifting sampling times of the repetitive controller in a fundamental period can be obtained. Mathematical analysis, simulations and physical experiments have validated the effectiveness of the adaptive repetitive controller.