Microchip Technology MA300015 Data Sheet
AN1208
DS01208A-page 2
© 2008 Microchip Technology Inc.
These peripherals offer the following major features:
• Multiple sources to trigger the ADC
• Input Conversion Capability up to 1 Msps rate
• Methods to simultaneous sample multiple analog
channels
• Fault detection and handling capability
• Comprehensive single-cycle DSP instructions
(e.g., MAC)
SYSTEM OVERVIEW
Figure 1 shows a block diagram of the integrated PFC
and Sensorless FOC system.
and Sensorless FOC system.
The first stage is a rectifier stage that converts the input
line voltage into a rectified AC voltage. The rectified AC
voltage is the input to the second stage, which is the
boost converter stage.
line voltage into a rectified AC voltage. The rectified AC
voltage is the input to the second stage, which is the
boost converter stage.
During the second stage, the boost converter boosts
the input voltage and shapes the inductor current
similar to that of the rectified AC voltage. This is
achieved by implementing digital power factor correc-
tion. The Average Current Mode Control method is
the input voltage and shapes the inductor current
similar to that of the rectified AC voltage. This is
achieved by implementing digital power factor correc-
tion. The Average Current Mode Control method is
used to implement PFC on a dsPIC DSC device. In this
control method, the output DC voltage is controlled by
varying the average value of the current amplitude sig-
nal. The current amplitude signal is calculated digitally.
control method, the output DC voltage is controlled by
varying the average value of the current amplitude sig-
nal. The current amplitude signal is calculated digitally.
The third and the final stage of the integrated system is
a three-phase inverter stage that converts the DC
voltage into a three-phase voltage. The converted
three-phase voltage is the input to the PMSM motor.
This stage is controlled by implementing the Sensor-
less FOC strategy on the dsPIC DSC device. The
Sensorless FOC controls the stator currents flowing
into the PMSM to meet the desired speed and torque
requirements of the system. The position and speed
information is estimated by executing mathematical
operations on the dsPIC DSC.
a three-phase inverter stage that converts the DC
voltage into a three-phase voltage. The converted
three-phase voltage is the input to the PMSM motor.
This stage is controlled by implementing the Sensor-
less FOC strategy on the dsPIC DSC device. The
Sensorless FOC controls the stator currents flowing
into the PMSM to meet the desired speed and torque
requirements of the system. The position and speed
information is estimated by executing mathematical
operations on the dsPIC DSC.
The integrated system uses five compensators to
implement PFC and Sensorless FOC technique. The
PFC technique uses two compensators to control the
voltage and current control loops, and the Sensorless
FOC technique uses three compensators to control the
speed control loop, torque control loop, and flux control
loop. All of the compensators are realized by
implementing Proportional-Integral (PI) controllers.
implement PFC and Sensorless FOC technique. The
PFC technique uses two compensators to control the
voltage and current control loops, and the Sensorless
FOC technique uses three compensators to control the
speed control loop, torque control loop, and flux control
loop. All of the compensators are realized by
implementing Proportional-Integral (PI) controllers.
FIGURE 1:
INTEGRATED PFC AND SENSORLESS FOC SYSTEM BLOCK DIAGRAM
K2
K1
K3
K4
K5
Analog-to-Digital Converter
Power Factor Correction
Sensorless Field Oriented Control
PWM Generator
PFC PWM Duty Cycle
Inverter PWM Duty Cycle
I
AC
V
AC
V
DC
Ia
Ib
Amplifier Gains
L
N
1
5
2
6
3
4
A
A
1
2
3
4
5
6
L
D
C
PMSM
PWM Generator