EXTENDED CLARKE TRANSFORMATION FOR n-PHASE SYSTEMS

2016 ◽  
Vol 63 (0) ◽  
pp. 5-26
Author(s):  
Michał JANASZEK
Keyword(s):  
Coordinate System ◽  
Control Strategies ◽  
Multiphase System ◽  
Inverse Transformation ◽  
Phase System ◽  
Orthogonal Coordinate System ◽  
Three Phase ◽  
Clarke Transformation ◽  
Drive Systems ◽  
Orthogonal Coordinate Systems

The article describes how to convert space vectors written in a stationary multiphase system, consisting of a number of phases where n > 3, to the stationary alfa beta orthogonal coordinate system. The transformation of vectors from a stationary n-phase system to the stationary alfa beta orthogonal coordinate system is defined The inverse transformation of a vector written in the orthogonal coordinate system to a stationary n-phase system is also defined. The application of the extended Clarke transformation allows control calculations to be performed in both stationary alfa beta or rotating dq orthogonal coordinate systems. This gives the possibility of performing different control strategies. It has a practical application for drive systems with five-phase, six-phase or dual three-phase motors.

scholarly journals Structures of vector control of n-phase motor drives based on generalized Clarke transformation

2016 ◽  
Vol 64 (4) ◽  
pp. 865-872
Author(s):  
M. Janaszek
Keyword(s):  
Vector Control ◽  
Control Strategies ◽  
Open Loop ◽  
Current Control ◽  
Loop Current ◽  
Control Structures ◽  
Clarke Transformation ◽  
Drive Systems ◽  
Novel Concept ◽  
Multi Phase

Abstract The paper presents vector control structures for n-phase AC motors derived from generalized Clarke transformation. In contrast to known works, where authors operate on generalized formulas of the Clarke transformation, in this work, only a number of actually used phases, of mostly industrial purposes, are considered (n = 5, 6, 2×3). This allows to perform control calculations in stationary orthogonal coordinates aβ or rotating dq. There are implementations of different control strategies: ROC (rotor-oriented control) or FOC (field-oriented control). Next, the paper presents the novel concept of a voltage modulator designed for multi-phase drive systems. Operation of the modulator is based on the extended Clarke transformation for multiphase systems. A mathematical model of the multiphase voltage modulator, operating in open-loop and closed-loop current control has been presented. Some selected oscillograms of voltage and current waveform, which illustrate properties of proposed control structures have been presented.

scholarly journals SHUNT ACTIVE FILTER CONTROL OF A THREE-PHASE THREE-WIRE NETWORK IN THE COORDINATE SYSTEM OF THE TWO WATTMETERS METHOD

2021 ◽  
Vol 2021 (5) ◽  
pp. 11-20
Author(s):  
M.Yu. Artemenko ◽  
◽  
Y.V. Kutafin ◽  
V.M. Mykhalskyi ◽  
S.Y. Polishchuk ◽  
...  
Keyword(s):  
Coordinate System ◽  
Energy Saving ◽  
Active Filter ◽  
Phase System ◽  
Shunt Active Filter ◽  
Three Phase ◽  
Combined Control ◽  
Asymmetric Load ◽  
Saving Effect ◽  
Active Filtration

A combined control system for a shunt active filter in the coordinate system of the two-wattmeters method has been proposed, which, depending on the conditions of use, implements one of the four active filtration strategies, optimal according to a certain quality indicator. The most promising is the proposed integral strategy for active filtration control with the reference vector of line voltages of direct sequence, which provides symmetric sinusoidal currents of the network and the minimum pulsation of power consumption for the almost identical energy-saving effect as the concept of S. Fryze. New formulas for calculating the energy-saving effect and pulsations of the instantaneous power in a three-phase system of power in the case of the formation of an active current in the transmission line in the conditions of asymmetry of loading voltage and linear asymmetric load have been developed. Simulation studies have confirmed the adequacy of the proposed strategies and calculations. References 15, figures 5, tables 2.

scholarly journals A Visual Investigation of CO2 Convective Mixing in Water and Oil at the Pore Scale Using a Micromodel Apparatus at Reservoir Conditions

Gases ◽  
2021 ◽  
Vol 1 (1) ◽  
pp. 53-67
Author(s):  
Widuramina Amarasinghe ◽  
Seyed Farzaneh ◽  
Ingebret Fjelde ◽  
Mehran Sohrabi ◽  
Ying Guo
Keyword(s):  
Water Saturation ◽  
Multiphase System ◽  
Phase System ◽  
Pore Scale ◽  
Convective Mixing ◽  
Co2 Transport ◽  
Dead End ◽  
Three Phase ◽  
Reservoir Conditions ◽  
First Time

CO2 convective mixing in water has been visualized in Hele-Shaw and PVT cell experiments but not at the pore scale. Furthermore, CO2 convective mixing in a three-phase system (i.e., CO2 in the presence of both water and oil) has not been visually investigated. A vertically placed micromodel setup was used to visualize CO2 convective mixing at 100 bar and 50 °C, representative of reservoir conditions. To the best of our knowledge, for the first time, we have visually investigated CO2 convective mixing in water at the pore scale and also CO2 convective mixing in a multiphase system (water and oil). CO2 mixing in water governed by both diffusion and convection mechanisms was observed. The vertical CO2 transport velocity was calculated to be 0.3 mm/min in both a 100% water saturation system and a residual oil-saturated system. First, CO2 always found the easiest path through the connected pores, and then CO2 was transported into less connected pores and dead-end pores. CO2 transport into dead-end pores was slower than through the preferential path. CO2 transport into water-filled ganglia with trapped oil was observed and was slower than in water.

scholarly journals Impedance Matching-Based Power Flow Analysis for UPQC in Three-Phase Four-Wire Systems

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2702
Author(s):  
Xiaojun Zhao ◽  
Xiuhui Chai ◽  
Xiaoqiang Guo ◽  
Ahmad Waseem ◽  
Xiaohuan Wang ◽  
...  
Keyword(s):  
Power Flow ◽  
Control Strategies ◽  
Impedance Matching ◽  
Flow Analysis ◽  
Point Of View ◽  
Impedance Model ◽  
Power Flow Analysis ◽  
Three Phase ◽  
System Node ◽  
Power Quality Conditioner

Different from the extant power flow analysis methods, this paper discusses the power flows for the unified power quality conditioner (UPQC) in three-phase four-wire systems from the point of view of impedance matching. To this end, combined with the designed control strategies, the establishing method of the UPQC impedance model is presented, and on this basis, the UPQC system can be equivalent to an adjustable impedance model. After that, a concept of impedance matching is introduced into this impedance model to study the operation principle for the UPQC system, i.e., how the system changes its operation states and power flow under the grid voltage variations through discussing the matching relationships among node impedances. In this way, the nodes of the series and parallel converter are matched into two sets of impedances in opposite directions, which mean that one converter operates in rectifier state to draw the energy and the other one operates in inverter state to transmit the energy. Consequently, no matter what grid voltages change, the system node impedances are dynamically matched to ensure that output equivalent impedances are always equal to load impedances, so as to realize impedance and power balances of the UPQC system. Finally, the correctness of the impedance matching-based power flow analysis is validated by the experimental results.

Three‐component sonde orientation in a deviated well

Geophysics ◽  
1990 ◽  
Vol 55 (10) ◽  
pp. 1386-1388 ◽  
Author(s):  
M. Becquey ◽  
M. Dubesset
Keyword(s):  
Hydraulic Fracturing ◽  
Coordinate System ◽  
Vertical Plane ◽  
Vertical Axis ◽  
Horizontal Axis ◽  
Orthogonal Coordinate System ◽  
Coordinate Rotation ◽  
Orthogonal Components ◽  
Particle Velocities

In well seismics, when operating with a three‐component tool, particle velocities are measured in the sonde coordinate system but are often needed in other systems (e.g., source‐bound or geographic). When the well is vertical, a change from the three orthogonal components of the sonde to another orthogonal coordinate system can be performed through one rotation around the vertical axis and, if necessary, another one around a horizontal axis (Hardage, 1983). If the well is deviated, the change of coordinate system remains easy in the case when the source is located at the vertical of the sonde, or in the case when the source stands in the vertical plane defined by the local well axis. In the general case (offset VSPs or walkaways) or when looking for unknown sources (such as microseismic emissions induced by hydraulic fracturing), coordinate rotation may still be performed, provided that we first get back to a situation in which one of the axes is vertical.

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