Field weakening control of a PM vehicle drive

Abstract

This paper develops a new field weakening method for an integrated permanent magnet synchronous machine vehicle drive. This method adopts both the DC-link and the rotor speed as a feedback signals to generate the demagnetising current reference. This eliminates the effect of the rotor speed on the FW controller dynamics and ensures stable operation across the whole range of speeds. Mathematical analysis of the system is used to design the controller gains to achieve the desired dynamic response. A maximum torque per ampere (MTPA) strategy is included in the control design, with a linearised function to reduce the computational demand. Experimental results show stable and satisfactory operation at different speeds and load conditions. They also illustrate smooth transition between the MTPA operation and the FW operation when the rotor speed crosses base speed.

Keywords

• synchronous machines
• feedback
• torque control
• machine control
• synchronous motors
• rotors
• synchronous motor drives
• electric current control
• mathematical analysis
• dynamic response
• permanent magnet motors
• permanent magnet machines
• base speed
• FW operation
• MTPA operation
• load conditions
• different speeds
• control design
• ampere strategy
• desired dynamic response
• controller gains
• stable operation
• FW controller dynamics
• demagnetising current reference
• feedback signals
• rotor speed
• DC-link
• integrated permanent magnet synchronous machine vehicle drive
• field weakening method
• PM vehicle drive
• field weakening control