Implementation of synchronousreferenceframe theorybased. Synchronous reference frame srf theory is coined long back. Active and reactive components of the threephase system are represented by direct and quadrature components respectively as given by. The next step is to transform the original stator and rotor abc frames of reference into a common. Control of the brushless doubly fed machine bdfm based on traditional multiple reference frames is complex. The wellknown srf method can be used for control of the apf and gci, and it also can be designed as in. Unit amplitude sine and cosine signals are output from the pll using the estimated phase. Providing a timeinvariant model of single phase inverters is the main feature of dq transformation.
The reference signal thus generated is transformed from the stationary abc frame to the rotating 0dq frame, using the reference frame transformation. Using these techniques, it is possible to transform the phase variable machine description to another reference frame. Inverter design and analysis using multiple reference frame theory by luke dale watson a dissertation presented to the faculty of the graduate school of the missouri university of science and technology in partial fulfillment of the requirements for the degree doctor of philosophy in electrical engineering 20 approved jonathan. Clarke transformation he transformed a change of variables associated with the stationary circuits to a variables associated with stationary reference frame. By judicious choice of the reference frame, it proves possible to simplify considerably the complexity of the mathematical machine model. Implementation of synchronousreferenceframe theory. The directquadraturezero dqz or dq0 or dqo, sometimes lowercase transformation or zerodirectquadrature 0dq or odq, sometimes lowercase transformation is a tensor that rotates the reference frame of a threeelement vector or a threebythree element matrix in an effort to simplify analysis. The dq0 transform is essentially an extension of the clake transform, applying an angle transformation to convert from a stationary reference frame to a synchronously rotating frame.
Roblescampos and others published a control scheme in the dq reference frame for hexverterbased systems. When the threephase stator current is transformed into the rotating reference frame, the current becomes a dc direct current. The dqz transform is the product of the clarke transform and the park transform, first proposed. In the name of god the most compassionate, the most. Stationary reference frame an overview sciencedirect. Most authors 24 use one or other of these reference frames without giving specific reasons for their choice. In particular, the performance of the srfpll in the threephase pv fed grid connected system is analyzed under the different power quality issues such as voltage sag and swell. Elimination of harmonics using active power filter based on dq reference frame theory. Mathematical model and control strategy on dq frame for.
As a result, the equivalent circuit of the power system in fig. Eliminates rotor position dependence inductances and capacitances. The stator voltage equations are transformed to the rotor, since rotor is already in dq domain. Synchronous reference frame phaselocked loop srfpll is a commonly used threephase pll in gridconnected power converters. Aalborg universitet a new synchronous reference frame. This paper presents a method for obtaining the desired reference current for voltage source converter vsc of the shunt active power filter sapf using synchronous reference frame theory. Threephase reference frame, in which i a, i b, and i c are coplanar threephase quantities at an angle of 120 degrees to each other. There are many methods to calculate the reference currents such as the instantaneous power theory pq 6, the synchronous reference frame srf 7, the abc reference frame 8, the synchronous detection sd 9 and the dq axis with fourier dqf 10. Theory of synchronous machines voltage equations and torque equation mechanical equation in abc domain voltage equations and torque equation mechanical equation in reference frame parks equation. Because these frames are used to specify positions of objects with respect. The position of the rotating frame is given by t where. How are 3phase to 2phase transformations in reference to. It performs the operation in steadystate or transient state as well as for generic voltage and current waveforms. In the stationary reference frame alpha, beta if pr controllers are used for current regulation, the complexity of the control becomes less compared to the structure implemented in the dq frame.
Elimination of harmonics using active power filter based on dq reference frame theory vn journal. We want to transform all the variables from the threephase abc system to the twophase stationary reference frame and. In addition, a detailed study on synchronous reference frame theory is presented. This discount cannot be combined with any other discount or promotional offer. Elimination of harmonics using active power filter based. In these notes, we provide a broader view of reference frame theory and then. Reference frames commonly used in the analysis of electric machines and power system components include arbitrary, stationary, rotor, and synchronous reference frames. In the name of god the most compassionate, the most merciful.
The transformation to a dq coordinate system rotating at the speed is performed using the rotating matrix where. Pdf elimination of harmonics using active power filter. Elimination of harmonics using active power filter based on dq reference frame theory m. Among them, the synchronous reference frame srf or dq theory, which is widely applied to three phase systems, is believed to be one of the simplest and most attractive techniques.
In addition to that, control design of the inverter in dq frame becomes similar to those of dcdc and three phase converters making it easier to achieve superior performance under different operation conditions while achieving a robust controller. Elimination of harmonics using active power filter based on dq reference frame theory and svm. The synchronous reference frame can be aligned to rotate with the voltage e. It is quite simple but you have to be clear whether you want an orthogonal power variant or nonorthogonal power invariant transform. A dq rotating frame controller for single phase full. Park transformation dq transformation implemented in dsp 3 phase to dq transformation dq transformation pmsm park transformation implemented in dsp permanent magnet synchronous machine park transformation implemented in digital inverse clarke transformation adsp21990 text. Pmsm fieldoriented control it has became a standard to position the dq, clarke transformation.
To generate the reference compensating current for singlephase shunt apfs, different techniques can be applied 5. Fall 2005 ee595s electric drive systems 2 reference frame theory power of reference frame theory. Transforms nonlinear systems to linear systems for certain cases. Inverter design and analysis using multiple reference. Elimination of harmonics using active power filter based on dq reference frame. A local reference frame is constituted when the reference point i. Transformation is used to decouple variables with timevarying coefficients and refer all variables to a common reference frame transformation to decouple abc phase variables f 012t 012f abc where the symmetrical transformation is applicable to steadystate vectors or instantaneous quantities a a t a a 1 1 2 1 1 1.
This represents the theory of srf with the equations obtained by park. The method relies on the performance of the proportionalintegral pi controller for obtaining the best control performance of the sapf. Field oriented control foc transformations in the case of foc of electric machines, control methods are performed in a twophase reference frame fixed to the rotor qrdr or fixed to the excitation reference frame qede. To simplify the control scheme, a new and simpler derivation of the dq model of the bdfm is proposed, leading to a unifiedreferenceframe model. The main concept as the name suggests is to have a frame which rotates at a synchronous speed. This common reference frame is also called arbitrary reference frame. Dq frame finally, using 6, the cable section can be transformed into dq frame 21. Extending the material presented in this chapter to the analysis of ac machines is straightforward, involving a minimum of trigonometric manipulations. The stationary twophase variables of clarkes transformation are denoted as. Now the question comes that with what speed this reference frame should rotate and how do.
An improved synchronous reference frame current control. The dq representation of the cable is then combined with the controlled rectifier as shown in fig. Modeling of threephase controlled rectifier using a dq. A control scheme in the dq reference frame for hexverter. The first part gives a mathematical introduction to the threephase vectors the more general timedependent quantities and the less general spacedependent spacephasors. Specifically, in terms of space vectors and rotating matrix. In the former all physical units in abc are the same inmath \alpha\betamath and dq reference frames wher. The synchronous reference frame theory or dq theory is based on timedomain reference signal estimation techniques.
Then perform an 0 to dq0 transformation in a rotating reference frame, that is. Clarke and park transforms in the field orientated control foc the foc consists of controlling the components of the motor stator currents, represented by a vector, in a rotating reference frame d,q aligned with the rotor flux. What is the concept of synchronous reference frame theory. Reference frame theoryinduction machines there are some additional topics that are appropriate to include in a course on power systems dynamics, and i do so here because they are highly relevant to what might be called current events. Elimination of harmonics using active power filter. This way, a simple dq model can be established, which could be an interesting tool for controlsynthesis tasks. This method uses a reference frame transformation module, abcdq. Certain controllers, namely, the pi controllers, are implemented in the dq frame also called the srf to adjust the grid currents in the dqsynchronous frame. The pid controller controls the reference signal in 0dq rotating frame to obtain the reference signal as required for the pulse width modulation. The transformation is the same for the case of a threephase current. D, q reference frames for the simulation of induction motors.
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