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9.3 LC Filter Activated

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Please note that the exercises proposed here are without neutral connection.

9.3.1 Changing PWM Frequency

This exercise is intended to change the PWM frequency and observe its impact on the waveforms, THD, and the power flow.
For that, keep all the parameters unchanged except for the slider: PWM Frequency (Hz).



Figure 31: Changing PWM Frequency

Apply the PWM frequency values of the first column of table 20, observe the waveforms, read the displays, and fill out below:

PWM Frequency (Hz)

Power1 / Display1

Power2 / Display2

Power3 / Display3

900




1500




1800




2400




3000




Table 20: Changing PWM Frequency with LC Filter ON

Disable the Connect Filter button and repeat the same exercise

PWM Frequency (Hz)

Power1 / Display1

Power2 / Display2

Power3 / Display3

900




1500




1800




2400




3000




Table 21: Changing PWM Frequency with LC Filter OFF

How does the change of PWM Frequency impact the THD of load and inverter currents?
     Hint: Please observe the values of Display6 and Display7.

9.3.2 Changing AC-source Amplitude

This exercise is intended to show the impact of changing the amplitude of the AC Source and to observe the source current and the power flow.
Using the slider Amplitude (V), do the following:

Increase the value of the amplitude to 75 V and observe the waveforms and the power flow.

Figure 32: Changing AC-source Amplitude to 75 V

Increase the value of the amplitude to 82 V and redo the same observations.

Figure 33: Changing AC-source Amplitude to 82 V

Determine the amplitude at which the power flow vanishes.

9.3.2 Changing AC-source Phase-shift

This exercise is a repetition of exercise 9.2.3 except that the LC filter is ON. Repeat the same steps as before.

Figure 34: Changing AC-source Phase-Shift; Load More Inductive and LC Filter On

Figure 35: Changing AC-source Phase-Shift; Load More Capacitive and LC Filter On

What difference do you observe in terms of power flow between Phase-Shift of 60 and -75?

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