Not sure if anyone has a better reference to explain something like PWM/SPWM being done in SPICE. LTSpice Directive. WAVE statement Attach the cursor in the Waveform Viewer window to a. R1, R2 1.2kohm - Include your screenshots of netlist and output trace in. Construct a voltage divider and probe input and output. Amplitude + /5 V - Square Wave Voltage Signal. V1 1 0 PWL FILE SquareWave.txt - Frequency 100kHz. An allowed negative tdelay equating to -120 deg would sure have been easier.)īy the way, my copy of "SPICE for Power Electronics and Electric Power", 3rd Edition by Muhammad Rashid (Chpt. LTspice tips n tricks page, with examples on how to: Add a model to a symbol. Transcribed image text: - Open LtSPICE, load SquareWave.txt using following code. the reversal of zeros and ones was effectively a 180 degree shift then shifted 60 degrees to result in 240, but without the blank spot to start off the pulse train. I ended up creating dependent variables from 0,1 to 1,0 and then put in a tdelay of 1/6 of the overriding output frequency period (i.e. A big blank spot started off the third square wave phase shifted by 240 degrees inside my SPWM subcircuit (that compares to its internal triangle wave operating at a higher frequency by the pulse number to an input sinusoid and then the comparators output is compared with both this square wave and its inverse to create the two output PWM pulse trains). I am trying to set up a three-phase PWM motor drive with three different sinusoidal pulse train drivers, one for each leg. Not being able to use a negative tdelay in a pulse train seems limiting.
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