The principle of a PAM drive is simple, a carrier signal cuts through the supply signal to create pulses, the amplitude of these pulses can be controlled by controlling the amplitude of the supply signal. By applying a proper switching control it is possible to use this principle as a PMSM drive. As this is a low end technology PAM drives tend to be cheaper and more robust than PWM drives.
In this example, we introduce the case study that evaluate of IPM motor using PAM drive.
Fig. 1 shows the magnetic flux density distribution at the rotation speed of 1,800 r/min.
Fig. 2 and Fig. 3 show the torque and current characteristics at a single operation point 1,800 r/min when using the PAM drive.
Fig. 4 and Fig. 5 show the analysis for torque-speed and torque-current curves respectively, such an analysis is used to predict motor performance at various operating points. The IPM torque decreases as the rotation speed increases and increases as the current increases.