Zero Current Switching Limitations
- Switching losses at tum-OFF can be eliminated and those at turnON can be reduced in a ZCS converter.
- During resonance, converter operation is insensitive to diode’s junction capacitance as a relatively large capacitor is connected across the output diode.
- Energy stored in the capacitance of the device will dissipate when power MOSFETs are switched ON by zero current methods. This capacitive tum-ON loss is proportional to the switching frequency.
- A considerable rate of change of voltage can be ‘ coupled to the gate drive through Miller Capacitor, thereby increasing the switching losses as well as noise during the tum-ON condition.
- Moreover, ZCS switches are under high current stress so the conduction loss shoots up high. However, ZCS is particularly effective in reducing switching loss for power devices (such as IGBT) with the large tail current in the tum-OF F process.