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Fusion of Neural Networks, Fuzzy Systems and Genetic Algorithms: Industrial Applications
by Lakhmi C. Jain; N.M. Martin CRC Press, CRC Press LLC ISBN: 0849398045 Pub Date: 11/01/98 |
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The filters design parameters are shown in Table IV. Finally, the converter state is selected applying the set of rules from the expert knowledge based SVM technique. These are shown below.
where,
The previous sections of this chapter have described the modeling, operation, and control of the presented XDFC. However, the advantages of the proposed converter have yet to be shown. In this section, results of the converter operation are given. For this purpose computer simulations were performed to validate the control algorithm presented.
The XDFC is evaluated in an Adjustable Speed Drive (ASD) like the one shown in Figure 4. The converter is controlled to produce a constant V/f characteristic up to 50 Hz, and constant power in the field weakening region. The loads current distortion is set to a maximum of 6%, and the input current harmonic distortion is reduced. The load considered is a 20 kVA squirrel cage induction machine. The test circuit parameters are shown in Table V.
Parameters | Values |
---|---|
Input rms phase voltage | 120 V |
Input frequency | 50 Hz |
Power rating | 20 KVA |
Squirrel cage induction machine phase parameters | X=2.4 Ω/phase |
R=6 Ω /phase | |
Input capacitive filter (Wye connected, ungrounded) | 86 μF/phase |
Computer simulations of the XDFC were performed using Matlab under Windows environment. Although Matlab is a computer language and not a circuit simulator, it offers multiple advantages due to its graphics interface and matrix-like functions which are proper for circuit representations. The converters transfer function can be extensively employed when simulating under these conditions, being a powerful tool for modeling static power converters.
Example-Computer simulation using Matlab
As an example for simulating under Matlab environment, the rectifying system depicted in Figure 2 will be analyzed, but with a resistive-inductive (R-L) load instead of the current source. In order to simulate any circuit, all its equations must be written in the time domain. The equations for the circuit in Figure 2 are the following.
Now, if a time step of Δt is used to discretize the time variable t, Equation (34) can be rewritten as shown in (36) using a first order approximation for the current derivative.
The load current io may be determined at time instant t.
Finally, to simulate the circuit the following steps are required:
Figure 11a) shows the input phase voltage va and input line current ia, and Figure 11b) shows the output voltage vo and load current io. The simulations results were obtained using the following load parameters.
Figure 11 Simulation results of rectifying-system shown in Figure 2 using an R-L load instead of a current source.
Figure 12 Input phase voltage Vr, input line current Ir, output line voltage Vab, and output line current Ia of the XDFC operating at 70 Hz.
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