An optimal current-control of permanent magnet synchronous motor by ILQ design method

摘要

This paper presents an optimal current-control of permanent magnet synchronous motor which is composed of a simple current controller without subjoining the estimating or lagging compensator, by analytical procedure of the inverse LQ (ILQ) design method. The ILQ design method is the strategy to find the optimal gains on a basis of pole assignment without solving the Riccati's equation, and is improved by adding an analytical optimal condition, by which the relations between the optimal solutions and their optimality are clarified. The ILQ current-controller has no armature resistance in its control law, so that we can achieve the robust current-control even at a transient against large variation of armature resistance. Comparing with conventional PI current-controller, it is confirmed that the ILQ design method leads to excellent current-control which is robust for variation of all the motor's parameters including non-linear feedback loop to linearize the coupling d- and q- systems.