How to connect two Three phase bridge rectifiers in parallel and get 12 pulse per cycle

I build a simple circuit of two three phase source one of them is Va,Vb,Vc with 220v as a value and (0,-120,120) phase shift, and the other three voltage source is 220v as a value and (30,-90,150), so the phase shift between the two sources 30 degree , the two bridges are connected for each one of them ,and the output voltage for each bridge is six pulse , but when I connect the two bridges in parallel the output voltage is 6 pulse too, what is the problem or what is the explaination for this issue