TORQUE MAXIMIZATION FOR PERMANENT-MAGNET SYNCHRONOUS MOTORS

This paper discusses the problem of maximizing the torque of permanent magnet synchronous motors in the presence of voltage and current cons traints. Formulas are given that are suitable to operation with voltag e and current source inverters and to real-time computation. Generally , the available torque is limited by current constraints at low speeds and by voltage constraints at high speeds, and there is often an inte rmediate range of speeds where both the voltage and the current constr aints are active, The paper specifies how optimal operation can be ach ieved in all three ranges, and at what speeds the optimal operation tr ansitions from one mode to another. An example is discussed to illustr ate the contributions of the paper and experimental results demonstrat e the usefulness of the formulas in a high-performance robotic applica tion.