At the top is a schematic of an H-bridge that I built. Im conducting experiments where I attempt to use it as an inverter. I built a circuit that drives the mosfets with a modified sine wave waveform. The circuit consists of an astable multivibrator with the two outputs connected each to monostable multivibrators. The output signals look like this:
This picture is from earlier experiment. When I acctually use the signals to drive the mosfets, the amplitude is over 10V. The blue waveform is offset down for clarity.
The blue and the yellow waveforms are applied to mosfets as shown in the schematic above. The idea is to allow current flow through one pair of mosfets, pause, and then drive the other pair. Here is the output as measured by my oscilloscope:
The space between the pulses is longer than intended (the but that is not important for this experiment). This happened when I increased the voltage of the oscillator.
The output looks somewhat satisfactory except for the parts I've circled in red. They occur during the pause in the driving signal (on the edge of the driving pulse going zero). I understand that this is because the current now decreases, I get a voltage with the opposite polarity.
I would very much like to know how to possibly reduce or remove these unwanted opposite voltages. I have searched an answer to this problem but I have not been able to find a solution. I've been told that the diodes should be of help as they provide a path for the transformer primary current to discharge during the time when the driving signal is off. But they still ARE discharging and therefore producing an unwanted opposite voltage.
Any suggestions will be much appreciated!
EDIT: I did as Dave suggested and I reduced the dead time between pulses and added a load (a 100kohm resistor) across the secondary. This is the output:
The output looks the same with or without the load.