Simulation

The applet below can be run with the default parameters. To set any parameter, click on the arrow pointing downwards beside the Peak Source Voltage, a menu would appear. The default value of the parameter highlighted appears in the textfield for Set Value. To change the parameter, select the parameter and then click within the editable textfield for Set Value. In order to change this parameter, you must click on Set Value button. You can set the desired response to be one of three responses.

An example is presented now to explain how the per unit values can be set. Let a 3 phase, 415 V, 50 Hz source supply power to the converter. Then the maximum average voltage that can be obtained is presented in equation (10). Let the nominal rated dc link current be 100 A. Then the nominal load resistance or the base impedance for the system is assigned as shown by equation (11). Given that the current through the load is free of ripple, the rms line current is obtained according to equation (12) and this value includes both the fundamental component and the harmonic components. The fundamental rms component is obtained as illustrated by equation (13). Given that the dc link inductance is 10 mH, its p.u. value is obtained as shown by equation (14).

Given that the line inductance is 1 mH, its p.u. value is obtained as shown by equation (16). Usually the line inductance is called as the 4% reactor, implying that when the line current is at its rated value, the rms value of the fundamental component of voltage across the line reactor is 4% of the phase voltage. For example, if the rms phase voltage is 240 V, the drop across 4% reactor at rated current would be 9.6 V. When the line voltage is 415 V, the phase voltage is obtained as shown by equation (16). The drop across the line inductor can now be stated as a fraction of the phase voltage as given by equation (17). This means that if the drop across the line inductor is to be 4% of phase voltage, the inductance should be 0.4 mH and not 1 mH.

It is possible to set the load resistance to a value other than its nominal value. The nominal value of load resistance is 5.6 W. If the load resistance is to be 10 W, then set Load Fraction as shown by equation (18).

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