Having trouble with H-bridge inverter, can't get bottom half

[sdot88]

So I am doing unipolar switching in PSIM, and have an H bridge with an RL load in the center. When I measure the load voltage, I get only the top half of the "sine wave". Can someone take a look at my circuit and tell me where I am going wrong? Vtop and Vbottom are the outputs of the top and bottom comparators, respectively.

for links use the actual at sign Shift+2, i'm not sure why its not posting correctly

Heres the circuit, note the upside down Vsin at the bottom: https://www.flickr.com/photos/46483872@N04/4539389769/



Here are the two comparator outputs: https://www.flickr.com/photos/46483872@N04/4539389781/

The load voltage looks like only the blue part.

I think I am close, so I am just looking for a little help, but if I am way off please tell me. Thanks in advance.

 

[--jason--]

can you attach your designed circuit here? i cant access the links as you provided.

 

[sdot88]

Re: Having trouble with H-bridge inverter, can't get bottom

I actually figured out that I was doing it right and was using a single node voltage probe instead of node-to-node.