ADC-PWM Synchronization for Motor Control Unit Development

Abstract

In the motor control unit, the precision and accuracy are everything. In this paper we propose an algorithm as a part of the implementation of field-oriented control (FOC) of the permanent magnet synchronous motor (PMSM). Though FOC is more computationally complex, it can drive more advantages like improved efficiency and full torque control. The proposed algorithm synchronizes the Analog to digital converter (ADC) and Flex timer module (FTM) such that the two-phase currents can be measured simultaneously in the middle of the Pulse-width modulator (PWM) pulse only when the bottom semiconductors of three-phase inverters are turned on. Regardless of ADC being able to measure precisely there is chance for obtaining wrong data. So, the instance for current sensing is more important. These timing implementations are supported by the micro controller peripherals. The Microcontroller (S32K144-EVB) is very versatile and supports the interconnectivity between different modules (ADC-PDB-TRGMUX-FTM). Their flexible interconnectivity helps in simplifying these complicated timing designs.