Abstract of this energy paper-presentations :
The H-bridge works by asymmetric unipolar modulation. The high side of the asymmetric H-bridge should be driven by 50Hz half-wave dependent on the polarity of the mains while the opposite low side is PWM modulated to form the mains sinusoidal shape.
The 10nF ceramic capacitor (C5) should be placed close to the gate-emitter pins of the high side transistors to eliminate cross through conduction due to fast switching of the low side transistors. A negative gate turn off voltage on the high side gate may also improve switching performance. The low side gate drive resistor should be selected to adjust the speed of MOSFET switching.
