Push-pull inverter on resonant load

Discussion in 'The Projects Forum' started by alainp, Apr 15, 2009.

  1. alainp

    Thread Starter New Member

    Apr 15, 2009
    Hi all,
    I'm building a push-pull inverter for a resonant load. The schematic is shown on Schematic.jpg herewith. I am operating the inverter below the resonant frequency of the load which leads to the following problem (see sim1.jpg). At time t=0 transistor M1 is switched on; the current starts to oscillate, drops to zero and becomes negative, which means that it passes through the freewheel diode Drl1. At time t=6.25µs (the half of the period) transistor M2 is switched on. Due to the coupling between the two coils Drl1 is polarized negatively and then tends to switch off; but before that it will allow a very high reverse recovery current to flow, and the coupling will generate the same high current through M2. Sim2.jpg is a zoom of sim1.jpg which shows that this transient current is as high as 50A, while the load current is only in the range of 3A. This very high transient generates noise in the whole circuit and overheating of the components.
    Does anyone have a suggestion? Would you need any additional information, please just ask.
    Thanks for you help.