Z-source Inverter
  Z-source inverter is a symmetrical impedance network. The symmetrical impedance network consists of two identical inductors and two identical capacitors connected in a specific manner to achieve the desired properties. The impedance network changes the circuit configuration from that of a voltage source to an impedance source (i.e., Z-source). It allows the VSI to be operated in a new state called the shoot-through state in which the two switching devices in the same inverter leg are simultaneously switched-on to effect a short circuit to the dc link. As the capacitors may be charged to higher voltages than the input source voltage, the diode is necessary to prevent discharging of them through the input source.

Block Diagram of the Z-source Inverter