elec431lab 3dc ac

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Department of Electrical and Computer Engineering

Queens University

ELEC 431: Power Electronics

Fall, 2011

Group number: _______________________

Student names (ID): ____________________; ______________________; _________________

Lab date: _______________________

Lab #3: DC-to-AC Inverter

Objectives:

1. Using PSIM to simulate the operation of DC-to-AC Inverter2. Test the operation and performance of DC-to-AC InverterInstructions:There are two parts in this lab. The first part is computer simulation and the second part is circuitconnecting and lab testing. The lab report is at the end.

Please note, the first part (computer simulation) should be finished BEFORE the second part starts.

Part 1: Computer Simulation

Using schematic capture tool of PSIM, build a DC-to-AC inverter as shown in Fig.1. The input voltageis Vin = 140V. The output inductor value is L1 = 0.8H, the load resistor value is R1 = 300.

The following waveforms should be monitored: output voltage Vo, output current Io. Set the switchingfrequency at 100Hz. The duty cycle of the square wave should be set at 0.5. Please save the circuit as

Lab3_Inverter.sch.

(1)Simulate thesteady state operation of the circuit, plot the waveform of Vo and Io. First set the totaltime = 0.1(Second), print time = 0 to observe the transient waveform. Decide that in order to get

steady state waveform, what should be the value of total time and print time.(a)Measure the rms value of Vo and Io(b)Using FFT, measure the harmonic voltage and current value for Vo and Io (up to 13 th harmonics)and record the number at table 1. Please note, the harmonic voltage and current calculated by FFT

is peak value.(c)Calculate the total harmonic distortion for Vo and Io.(2)Set switching frequency = 200Hz(a)Measure the rms value of Vo and Io


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(b)Using FFT, measure the harmonic voltage and current value for Vo and Io (up to 13 th harmonics)and record the number at table 1. Please note, the harmonic voltage and current calculated by FFT

is peak value.(c)Calculate the total harmonic distortion for Vo and Io.(d)Fill in table 2. Compare the difference between 100Hz and 200Hz.

Fig.1 AC-to-DC Inverter

Part 2: Lab testing:

Connect the inverter according to Fig. 2. Use data acquisition system to monitor the following

waveforms: Vo and Io. Use E1 to monitor Vo and I1 to monitor Io. Set ch1 to E1, ch2 to I1. Adjust theswitching frequency to 100Hz by adjusting DC source 2. Apply the input voltage to 140V.

Adjust the duty cycle to 50% by adjusting DC source 1. It is noted that at D = 50%, the average value

of Vo is zero.(1)Plot the waveforms of Vo and Io. Measure the rms value of Vo and Io.(2)Using Harmonic Analyzer to measure the Total Harmonic Distortion (THD).


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(3)Using Spectrum Analyzer to measure the harmonic component of Vo and Io, (up to 13th harmonics)and fill in table 3.

(4)Calculate the Total Harmonic Distortion from measurement data in (3)

Fig.2 Test Circuit Connection


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Lab Report

Part 1: Computer simulation results:1. Print out the circuit schematic used to simulate the DC-to-AC inverter2. Print out the steady state waveforms of Vo and Io.3. For Fs = 100Hz, Vorms = , Iorms = .

Fill in the following table for simulation task (1)Table 1:

Harmonics number 1st 3rd 5th 7th 9th 11th 13th

Io

Vo

From the above number, using two methods to calculate the THD for Vo and Io

4. For Fs = 200Hz, Vorms = , Iorms = .Fill in the following table for simulation task (2)Table 2:


Io

Vo

From the above number, using two methods to calculate the THD for Vo and Io


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Part 2: Lab testing results:

(1)Print out the waveform of Vo and Io(2)THDV = , THDI = .(3)Record the measurement data from Spectrum Analyzer at Table 3

Table 3: Measured harmonic voltage and current


Io

Vo

The calculated THDV = , THDI = .

Compare the calculated and measured THD.

elec431lab 3dc ac

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