Voltage minimization control of vector controlled interior permanent magnet motor

Abstract

Maximum Torque Per Voltage trajectory has been utilized only during field weakening operation of Interior Permanent Magnet (IPM) motor. In this paper, the voltage minimization control from zero-speed is proposed. Voltage minimization results in maximum torque per voltage control of IPM motor. The control implementation is also simple in comparison to current minimization, as the operation is always along the current-limit locus irrespective of operation in field-weakening. Voltage minimization technique minimizes the core losses whereas current minimization would minimize the copper losses. The mathematical model of IPM motor following voltage minimization is derived and the solution to the 4th order quartic equations is obtained using Ferrari’s method. The solution obtained is utilized to develop a look-up table for vector control of IPM motor. A comparative analysis of voltage minimization and current minimization is established which is supported by simulation results and demonstrated by detailed experimental results.