Pentagon theory

This is a theory aimed at operating and controlling a brushless motor, which has a salient-pole structure and a permanent magnet, with polyphase sinusoidal alternating current. The voltage relationship between the applied voltage of each phase and the elements inside the motor is described by the equation below. The relationship between the left and right-hand sides, which is composed of five elements, can be represented by a pentagon on a complex plane, as shown below.