Recent content by Dave in NZ

Hi John, This is a commerical product. The work is interesting and challenging. We have just "released" just under 10% of our staff globally so chances of a job are low but you are welcome to apply:- LOCAL SITE http://www.powerware.co.nz/New_Zealand/careers/default.asp GLOBAL SITE...

The inputs (U) are sinewaves as are the feedback waveforms (V). when locked the feedback waves should lag the input waves by 90 degrees. the three axis are 120 degrees apart. I was calling these the basis vectors. let me know if I'm deluded :-) Thanks

to clarify would the answer for 120 degrees between unit vectors be:- u.v = (u1)(v1)+(u2)(v2)+(u3)(v3)-(0.5)[(u1)(v2)+(u1)(v3)+(u2)(v1)+(u2)(v3)+(u3)(v1)+(u3)(v2)] then can I assume that this is equal to:- (u)(v)cos(angle between them) I need the polar form to be representive as I...

The phase comparator in a three phase phase-locked-loop. i.e. I've calculated the dot product of the incoming mains samples with the feedback waveform samples without doing a Clark tranform to the incoming mains samples first. The aim is to reduce computation time and keep all information, the...

Thank you John. Your explanations have been very useful. Cheers Dave

Hi John, I'm rusty on notation. Please would you expand "cos (bi,bj)"? am I correct to assume from the special case for orthogonal unit vectors that the inner product for the non-orthgonal unit vector case is not simply R1R2cos(angle between vectors). Where R1 and R2 are the magnitudes of...

Thanks for the help, I have a follow up question:- Does the following still apply? (V1)(U1)+(V2)(U2)+(V3)(U3) = (R1)(R2)cos [(w1-w2)] where V and U are the input vectors referenced to the 2D 120degree separated 3-axis co-ordinate system. R1 is the magnitude of vector V and R2 is the...

Is the result of a dot product of two vectors valid if the frame of reference unit vectors are not orthgonal? i.e. 2D 3 axis co-ordinate system as commonly used in power systems where the axis are 120 degrees apart in 2D space?