Since it's not so easy to incorporate single phase to three phase conversion quickly we find this particular implementation difficult to acquire and enforce. The proposed circuit enables the above discussed well calculated spaced and positioned sine waves outputs to be generated from a single master input source.
The above buffered master signal gets once again inverted and buffered by the next unity gain op amp A2 creating an output with zero degree initial phase across the points "Phase1"
Simultaneously, the master signal from A1 output is phase shifted by 60 degrees via the RC network R1, C1, and fed to the input of A4.
A4 is set up as a non-inverting opamp with a gain of 2 in order to make up for the signal-loss in the RC configuration.
The circuit is intentionally wired up to work with a fixed frequency in order to yield better accuracy.
Fixed values are used for R1 and C1 for rendering the intended, accurate 60 degree phase shifts.
For specific customized frequencies, you may use the following formula
R1 = (1.732 x 106) / (6.28 x F x C1)
R1 is in kohms
C1 is in uf
A1---A4 = LM324
Supply = +/- 12vdc
|Frequency (hz)||R1 (kohms)||C1 (nf)|
I needed a 15VAC 3-phase supply to test 3-phase rectifiers. I simulated
this circuit the other day but failed to get proper results. Today, I
made it work.
IC A2 and resistors connected to pin 6 could be
eliminated. The resistor between pin 7 and 9 could be connected between
the main input and pin 9. Phase-1 output can be collected from the
original AC input. Phase 2 and 3 can be collected as indicated in the
However, my actual requirement could not be fulfilled. When these 3
phases are connected to a 3-phase rectifier, the wave form of phase 2
and 3 gets disturbed. I tried with the original circuit, in that case
all three phases gets disturbed
Finally got a solution! A 100nF capacitor connected in series with each phase and the rectifier solved the problem to a great extent.
Though the rectified output is not consistent but, it is quite acceptable