1-Phase Full  Bridge  inverter will RL Load

For a  resistive load R the load  current  wave form  will be  identical with load  voltage wave form  and feedback  diodes will not  come into  conduction. In  the case of RL -Load  the wave form  of output current is  shown in the  circuit of 1-? full bridge  inverter with R_l load  is shown .

Before t =0  thyristors T₃ and T₄ are conducting and load  current is flowing in  negative direction. After  T₃ and T₄  are turned of at t=0  load current  io can not change its direction immediately due to the existence of inductance in the load. Therefore  after t= 0 diodes D₁ and D₂ start conducting and  allow the  load  current  to flow  against  the source voltage. Load voltage becomes  V_dc.

At t=0  thyristor  T₁ and T₂  are gated but these  thyristors will not  turn on because these are reverse biased by voltage drops across  D₁ and D2. After the  load  current  becomes equal to zero T₁ and  T₂  start concocting up to  the period t = T/2  now  load  current  start flowing in positive direction ( as we  assumed in circuit) at  t= T/2 T₁ and   T₂ are  commutated and T₃  and T₄  are gated but tagging  the current can not change its direction immediately. As  a result diodes D₃ and D4 starts conducting to allow the current to flow in positive direction. Thyristors T₃ and T4 will not  start conduction until the  load current through diodes D₃ and D₄ falls  to zero because these thyristors will not turn  on as these  are reverse  biased by the voltage drops in the D₃ and