Half Bridge DC-AC Inverter with L Load and R-L Load

The DC-AC converter with inductive load is shown in Figure. For an inductive load, the load current cannot change immediately with the output voltage.

The working of the DC-AC inverter with inductive load is as follow is:

Case 1: In the time interval 0 £ t £ T1 the switch S1 is on and the current flows through the inductor from points a to b. When the switch S 1 is turned off (case 1) at t-T1, the load current would continue to flow through the capacitor C2 and diode D2 until the current falls to zero, as shown in Figure.

Case 2: Similarly, when S2 is turned off at t = T1 , the load current flows through the diode D1 and capacitor C1 until the current falls to zero, as shown in Figure.

When the diodes D1 and D2 conduct, energy is feedback to the dc source and these diodes are known as feedback diodes. These diodes are also known as freewheeling diodes. The current for purely inductive load is given by,

Similarly, for the R - L load. The instantaneous load current is obtained as

Where,

The instantaneous voltage ( vo ) across R - L load and the instantaneous current ( iL )

through it are shown in Figure .