5.2 ADC Configuration

Each PWM channel on a 32-bit microcontroller is capable of independently triggering an ADC conversion on any of the analog input. Integrated PFC and sensorless FOC implementation requires to sense six analog inputs, as shown in Table 5-2. PFC-related analog input conversions are triggered simultaneously by PFC PWM Channel and sensorless FOC-related analog input conversions are triggered simultaneously by any one of the three FOC PWM Channels. Although DC Bus Voltage sensing is required for both PFC and FOC, its analog conversion is triggered by PFC PWM channel as PFC control loop runs at faster rate than FOC control loop.

Table 5-2. ADC Configuration for Integrated PFC and FOC Implementation On the PIC32MK PIM Using the MCHV-3
Analog InputApplicationADC ModuleADC TriggerSample Rate
AC Line VoltagePFCADC4PFC PWM Channel40 kHz
PFC Inductor CurrentPFCADC0PFC PWM Channel40 kHz
DC Bus VoltagePFC/FOCADC7 (Shared ADC)PFC PWM Channel40 kHz
Phase A Motor CurrentFOCADC3FOC PWM Channel20 kHz
Phase B Motor CurrentFOCADC1FOC PWM Channel20 kHz
Speed Reference PotentiometerFOCADC7(Shared ADC)FOC PWM Channel20 kHz