New Method For Compensation Research Articles

КОМПЕНСИРОВАНИЕ ПОТЕРЬ КОНТАКТНОЙ СЕТИ ЗА СЧЕТ ПРИМЕНЕНИЯ БОРТОВОГО НАКОПИТЕЛЯ ЭНЕРГИИ

The authors have analysed methods for energy loss reduction in catenary. Currently, there are at least two traditional methods: the first is aimed at decrease of distance between a power source and a consumer, the second - at reduction of resistance of a contact wire. The authors suggest a new method for compensation of catenary losses by installing on a board of electric motive power of an accumulating device that will compensate required power in case of energy shortage. The method allows reducing energy losses due to accumulated energy of the power source and, consequently, allows compensating it in the recuperation mode. As an accumulating device the authors have selected a Russian made supercondencer that can compensate more than a half of traction power system losses. It is equal to construction of an additional traction substation on a section with single-way feed. A simpler and a less expensive realization and high efficiency are the advantages of the proposed method.

Proposed High-Performance Digital Distance Relay (Dept.E)

This paper proposes a new design for high-performance digital distance relay. It is equipped with a dedicated decaying dc component estimation algorithm and a new method for compensation of ground fault resistance. The proposed relay algorithm can estimate and eliminate the dc decaying component from fault current signals within one cycle from the fault instant. Then, it uses fast Fourier transform to extract accurate phasor quantities of fault currents. Also, an innovative algorithm for compensation of fault resistance is introduced. The later technique is based on supposing a virtual distance relay at the other end of the line. Using the preliminary estimation of the apparent relay-to-fault impedance at both sides, the unknown fault resistance and its related error are determined. Hence, this error can be compensated in computing the actual relay-to-fault impedance. Many test cases are performed under different fault locations and several values of ground fault resistance to confirm the efficacy of the proposed relay.

Converter Monitoring Unit for Retrofit of Wind Power Converters

A converter monitoring unit (CMU), which will enable condition monitoring of wind turbine converters is presented in this paper. Reducing the cost of corrective maintenance by means of condition monitoring is a way of lowering operation and maintenance costs for wind turbine systems. The CMU must be able to detect a broad range of failure modes related to Insulated Gate Bipolar Transistor (IGBT) power modules and associated gate drives. IGBT collector-emitter on-state voltage ( vceon ) and current ( ic ) is sampled in the CMU and used for detection of emerging failures. A new method for compensation of unwanted inductive voltage drop in the vceon measurement path is presented, enabling retrofitting of CMUs in existing wind turbines. Finally, experimental results obtained on a prototype CMU are presented. Experimentally the vceon dependency to IGBT junction temperature and deterioration of gate drive voltage is investigated. The proposed method shows good detectability of both thermally related degradations of the power module and detectability of deterioration of gate drive voltage. It is also expected that the proposed method will enable detectability of other failure mechanisms.

Improving the accuracy of derivation of the Williams’ series parameters under mixed (I+II) mode loading by compensation of measurement bias in the stress field components data

A new method for compensation of bias in the stress field components measurement data used for Williams’ series parameters derivation was presented. Essential increase of accuracy of derivation of SIF-related leading terms in series under mixed (I+II) mode loading was demonstrated. It was shown that a relatively low value of bias in the stress field components data error could result in the essential deviation of the values of derived Williams’ coefficients and the crack tip coordinates.

A new method for compensation of the effect of charging transformer's leakage inductance on PFN voltage regulation in Klystron pulse modulators

The Line type modulators have been widely used to generate high voltage rectangular pulses to power the klystron for high power RF generation. In Line type modulator, the Pulse Forming Network (PFN) which is a cascade combination of lumped capacitors and inductors is used to store the electrical energy. The charged PFN is then discharged into a klystron by firing a high voltage Thyratron switch. This discharge generates a high voltage rectangular pulse across the klystron electrodes. The amplitude and phase of Klystron's RF output is governed by the high voltage pulse amplitude. The undesired RF amplitude and phase stability issues arises at the klystron's output due to inter-pulse and during the pulse amplitude variations. To reduce inter-pulse voltage variations, the PFN is required to be charged at the same voltage after every discharge cycle. At present, the combination of widely used resonant charging and deQing method is used to regulate the pulse to pulse PFN voltage variations but the charging transformer's leakage inductance puts an upper bound on the regulation achievable by this method. Here we have developed few insights of the deQing process and devised a new compensation method to compensate this undesired effect of charging transformer's leakage inductance on the pulse to pulse PFN voltage stability. This compensation is accomplished by the controlled partial discharging of the split PFN capacitor using a low voltage MOSFET switch. Theoretically, very high values of pulse to pulse voltage stability may be achieved using this method. This method may be used in deQing based existing modulators or in new modulators, to increase the pulse to pulse voltage stability, without having a very tight bound on charging transformer's leakage inductance. Given a stable charging power supply, this method may be used to further enhance the inter-pulse voltage stability of modulators which employ the direct charging, after replacing the direct charging with the resonant charging.

A new method for compensation and rematch of cavity failure in the C-ADS linac**Supported by China ADS Project (XDA03020600) and Natural Science Foundation of China (11575216)

For proton linear accelerators used in applications such as accelerator-driven systems, due to the nature of the operation, it is essential for the beam failure rate to be several orders of magnitude lower than usual performance of similar accelerators. A fault-tolerant mechanism should be mandatorily imposed in order to maintain short recovery time, high uptime and extremely low frequency of beam loss. This paper proposes an innovative and challenging way for compensation and rematch of cavity failure using fast electronic devices and Field Programmable Gate Arrays (FPGAs) instead of embedded computers to complete the computation of beam dynamics. A method of building an equivalent model for the FPGA, with optimization using a genetic algorithm, is shown. Results based on the model and algorithm are compared with TRACEWIN simulation to show the precision and correctness of the mechanism.

역공학기반의 프레스 부품 변형 보정에 관한 연구

본 연구에서는 프레스 부품의 스프링 백을 보정하기 위한 새로운 방법론을 제안하였다. 먼저, CAD 데이터와 측정데이터 사이의 오차를 비교하였다. 새로운 방법은 스프링 백을 보정하기 위한 수동적인 모델링 공정 대체가 가능한 3차원 측정데이터 기반의 자동 모델링을 제안하였다. 본 연구를 통해 프레스 부품의 스프링 백 보정을 위한 새로운 방법론을 적용하면 실제 공정에 소요되는 시간 및 비용 절감이 가능할 것으로 기대된다. In this study, we suggested new method for compensation on spring back of press part. At first, we compared between error on CAD data and scanning data. The new method can be substituted for manual modeling process in compensation on spring back. The new method is available for automatic modeling based on 3D scanning data. From the study, the results expect that time and cost reduction for process applying new method for compensation on spring back of press part.

COMPENSATION OF MACHINE TOOL THERMAL ERRORS BASED ON TRANSFER FUNCTIONS

This paper reports on a new method for compensation of machine tool thermal errors that is based on system of thermal transfer functions. Due to their relative simplicity they enable real-time calculations which make them suitable for compensation algorithms of thermal displacements at tool centre point. The applicability and robustness of the thermal transfer function compensation model have been experimentally verified on a real machine tool. Tested compensation algorithms proved its ability to significantly reduce thermal errors. The thermal error minimization of more than 85 % of the standard compensation technique based on linear regression model was achieved in particular machine tool coordinate direction.

Compensation of Additional Mass Effect in Frequency Response Function Measurement

The acceleration sensors are generally attached to the structure to measure the response in FRF (frequency response function) measurement. The mass of the sensor often have some effect on dynamic characteristics of the structure. This paper proposes a new method for compensation of sensor's mass effect in FRF measurements. In the method, inertial force of the sensor's mass is regarded as external force acting on the structure;FRF is corrected so as to remove the external force effect. The compensated FRFs of an accuracy are evaluated by a Reliability Factor which it is installed in this paper. The compensation method for the use of multiple sensors is also presented. The method is validated by applying it to a brass plate structure. The usability of the method is demonstrated via measuring FRFs of a car body.

High-speed FM demodulator of a homodyne laser interferometer for measuring mechanical vibration

A high-speed FM demodulation method for measuring mechanical vibration using a homodyne laser interferometer is presented. The Doppler frequency, which represents the surface velocity of a vibrating object, is obtained by using the homodyne laser interferometer, and converted to a voltage signal by using the proposed analogue FM demodulation circuit. The dc offsets of the interference signals obtained from the homodyne laser interferometer are eliminated by using simple subtraction. The new method for compensation of the asymmetry of each interference signal is presented. The laser power variation of the interferometer is normalized by using an auto-gain controller (AGC). The performance of the proposed FM demodulation algorithm is proved by using theoretical methods, and validated by using experimental results. In the experiments, the proposed FM demodulation algorithm is compared with a conventional demodulation method.

Compensating for the mutual coupling effect in a normal-mode helical antenna array for adaptive nulling

A practical normal-mode helical antenna array together with a new method for the compensation of the mutual coupling effect is proposed for the efficient adaptive nulling of interferences in a mobile communication environment. The helical antenna array is shown to be able to generate deeper nulls than an equivalent monopole antenna array in the presence of the mutual coupling effect. The helical antenna elements are smaller in size and less susceptible to the mutual coupling effect than monopole antenna elements. The new method for compensation of the mutual coupling effect is shown to have a greater ability and flexibility than previous methods. A new definition of mutual impedance is introduced and used to find the coupling-free signal voltages across the antenna terminal loads. Numerical examples demonstrate the superior performance of the proposed adaptive array and the new compensation method.

Small Angle Bending Using Shear Deformation with Negative Punch-die Clearance

In sheet metal bending, bending die is designed in prospect of spring back after unloading. Although accuracy of spring back analysis has been improved, slight variation of thickness or material properties depending on production lot of sheet metal causes scatter of bend angle in mass production, which is a serious problem especially in bending high strength steels or low priced sheets. As a countermeasure, a new method for compensation of bend angle is proposed in this paper. When sheet metal is partially sheared with negative punch-die clearance, it is slightly bent by the gradient of plastic strain normal to bend axis developed in the sheared zone. By controlling this deformation, accurate and adjustable bending was studied. Change of bend angle depending on punch penetration, clearance, tool edge condition and lubrication was investigated experimentally for two kinds of pure aluminum sheets 0.8 mm in thickness. Among test parameters, punch penetration was found to be most influential one and to have linear relationship with bend angle, which suggests good angle-controllability of this method. Strength of bent portion was tested and sufficient strength was assured up to 20% punch penetration against sheet thickness under the optimum condition. Moreover, spring back was little observed since plastic strain is much higher than that by moment bending. These results were studied with strain distribution estimated by elastoplastic finite element analysis.

A simple method for thecompensation of the nonlinearity in the heterodyne interferometer

The accuracy of a heterodyne interferometer is oftenlimited by the periodic nonlinearity that arises mainly fromimperfect separation of the two optical frequencies. Thispaper describes a new method for compensation of thenonlinearity in the heterodyne laser interferometer using thequadrature mixing technique for the phase measurement. Thecompensation technique is based on the elliptical fitting oftwo phase-quadrature signals obtained by a lock-in amplifier.The brief analysis and compensation scheme of the nonlinearityin the heterodyne interferometer, and the experimental result using a Zeeman stabilized He-Ne laser, have been presented. Theresults show that the suggested method can compensate for thenonlinearity of the heterodyne interferometer with sub-nanometre accuracy.

A new method for compensation of losses in electronic power switches using bipolar power transistors

The contribution proposes a novel method for reduction of voltage drop across Darlington circuits when used as power switches and reports preliminary experimental results. The compensation leads to at least an effective doubling of the energy efficiency of the switch while no detrimental effects on current fall time have been found. The scheme is easily realisable in modern electronic technology.