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Hi, this is the circuit as it is now. RL of value 0.2 is the load with a LC filter before it on the output of the bridge. I thought this was a synchronous design? Q1 and Q4 switch the pulse train whilst Q2 and Q3 are off then they switch the signal whilst Q1 and Q4 are off or have I got the...
Hi, thanks, I saw these on google too but they don't describe if the sine wave is offset.
The sine wave from my inverter I'm simulating is offset toward negative and my calculations seem off. I was wondering if they were incorrect because of the offset below zero. My peak to peak is 65V but...
Quick question, concerning a sine wave, is peak voltage just half the peak to peak or is it the peak voltage above zero?
i.e, if the sine wave had a negative offset and only a third of it was above zero, would it be the amplitude above zero or half the p-p?
Regards,
Dale
Hi thanks, The switching frequency in the last image is 15.6KHz. I've changed the circuit so that ground is connected to the source's of the low side switches and rolled back the switching freq to 3.9KHz (4MHz clock).
I'm getting the target results, 0-100A but the waveform is a bit deformed...
Ye but I found in the simulation that if I dont use bipolar and tie to ground instead I get something like this,
**broken link removed**
Thats at 4MHz clock with filter, if I try at 16MHz I just get groups of pulses about 1uS long? Any Ideas how I can round this??
- - - Updated - - -
I think...
Hi, I'm simulating my inverter but finding a efficiency of 35% across the switching circuit. I calculated the switching voltage as 35V but this produces a Vpeak of 18.5V and 65A at the output.
I bypassed the filter and connected the oscilloscope as shown above and this is the output,
The peak...
Hi, it repeats the shown waveform every cycle, I've tried changing the end/beginning values to 1, 5 or 10 and still gives the same error.
/*
Project: Pure Sine Wave SPWM
Version: 7.1
Target: Re-arrange code, comment and tidy
Sub-Target:
Revisions: 7 - Set for 16MHz selection
Coded by: Dale...
I've found that this problem seems to be with the placement of the TMR2IF_bit (interrupt) reset. If I have the reset within the else statement as before the output seems fine (therefore missing the last reset when the counter is reset),
void interrupt() //Interrupt Function
{...
I've managed to get the code to produced the SPWM as before (minus the pulse at the end), I reverted back to an earlier version and added the rest bit by bit. This problem started when I introduced a new bit of code to dynamically change the values of duty cycle and I'm thinking I probably...
Hi,
Thanks for that. I changed those bits but its still the same, I tried taking di down to 36 which then replaced that area with a flat spot which suggests that it something with the loading of values to CCPR1L? I thought it might have something to do with it having 0's at each end but tried...
So, I thought I'd finished this part of the project and was just tidying up when the above PWM output starting happening. The PWM signal is a half sine wave and was working fine but now has a pulse for about 2 periods at the start/finish of each cycle. This therefore messes up my output sine...
Hi,
I multiplied both my clock and carrier frequency by four to 16MHz and 15.6KHz. The result is the same but at the new frequency so I reckon its a simulation error, I'll find out when I build it. Thanks,
Thank you for your replies,
my carrier freq is 3922Hz, fundamental is 50Hz (60Hz max), so I chose a resonant freq of 10 times the fundamental and tried values in a table in excel (now realizing I forgot to square Z). I set the capacitance at 1500uF and then the inductance matching the impedance...
https://ww1.microchip.com/downloads/en/devicedoc/39582b.pdf
page 65 onward,
what are you wanting to do with it, Ive used the PWM
PR2 = 255; //Timer2 Period Register - Period of PWM (MAX 255)
CCP1CON = 0b00111100; //<5:4> DC LSBs, <3:2> PWM Mode
T2CON = 0b00000100...
Id work it this way,
Carrier signal=31.25kHz = 32uS = period
Half wave @ 50Hz=20ms/2=10mS
10mS/32uS= 312.5 divisions/half cycle
312.5/4=78 values of sine repeated four times
180 degrees/78 divisions = 2.304 degrees/division
use excel to make a table with 1-78 in column a, column b =...
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