1. Microchip Technology Inc.
Motor Types

2. Common Motor Control Elements
Measure
Calculate
Control
Rotation
Position
Temperature
Pulse Width Modulation
Power Drivers
Timing
Math Functions

3. Primary Motor Types DC Brush Motor DC Brushless Motor Stepper Motor
AC Induction
Switched Reluctance
The four types of motors that we will discuss are the DC Brush Motor, the Stepper Motor, the DC Brushless Motor, and the Switched Reluctance Motor.
For each motor we will discuss construction, operating principles, and important concepts related to control electronics that may utilize PICmicro devices.
It will be evident that common principles are shared by each motor type. We will spend most of our time on the DC brush motor and the stepper motor, since the other two motors can easily be understood with reference to these.

4. DC Brush Motor Common Control Implementations PICmicro® MCU solutions
Simple power stage control
May use position feedback sensors for closed loop control
PICmicro® MCU solutions
4Kw 28-pin to 32Kbyte 64-pin
Ex. include PIC16F876 and PIC17C766
The two basic control methodologies for the SR are closed-loop and sensorless
Closed-loop control is realized with the use of incremental encoders. Rotor position information is required for synchronized phase switching patterns.
The sensorless control strategies eliminate the rotor position sensor. One technique applies short pulses to the non-excited stator coils. The difference in current at two different instances is obtained so that the stator inductance can be calculated. This is sometimes referred to as inductance signatures. The stator inductance is a function of the instantaneous rotor position.
For the ACIM, BLDC and SR motor types the sensorless control approach seems to be gaining popularity. Being able to eliminate the rotor positioning feedback sensors is a plus and reduces system costs. The issue with this approach is that increased computational horsepower is typically required along with additional program memory and a fast ADC.
Typical Customer PICmicro implementations from design wins information.

5. DC Brushless Motor Common Control Implementations
Closed-loop control
Sensor and sensorless control
PICmicro® MCU solutions
TC6XX Fan Controller Family
4Kw 28-pin to 16Kw 64-pin
Ex. include: PIC16C73 and PIC18C658
The various types of motors listed here and on the next few slides are those which we should support. Each motor type has its own pros and cons for an application. Various control strategies exist for each of the motor types, each with its own pros and cons.
The three basic control methodologies for the ACIM are open-loop, closed-loop and sensorless. These three control methodologies can be further divided into:
V/F control (scalar control)
Slip frequency control
Vector control (Field orientated control)
Sensorless vector control (Kalman observer) strategies are used to predict the rotor position based on the characteristics of the motor and the measured phase currents.
The two basic control methodologies for the BLDC are closed-loop and sensorless. Closed loop control relates to the use of rotor feedback information provided by Hall sensors for motor commutation states. It is noted here that rotor positioning information can also be derived from incremental encoders as well. Sensorless control does not implement Hall sensors but rather rotor positioning information is derived for sensing back EMF on a non-energized motor winding.

6. Stepper Motor Common Control Implementations PICmicro® MCU solutions
Open Loop Control
Simple and inexpensive control
PICmicro® MCU solutions
2Kw 8-pin to 16Kw 40-pin
Ex. include: PIC12C509A and PIC18C452
The various types of motors listed here and on the next few slides are those which we should support. Each motor type has its own pros and cons for an application. Various control strategies exist for each of the motor types, each with its own pros and cons.
The three basic control methodologies for the ACIM are open-loop, closed-loop and sensorless. These three control methodologies can be further divided into:
V/F control (scalar control)
Slip frequency control
Vector control (Field orientated control)
Sensorless vector control (Kalman observer) strategies are used to predict the rotor position based on the characteristics of the motor and the measured phase currents.
The two basic control methodologies for the BLDC are closed-loop and sensorless. Closed loop control relates to the use of rotor feedback information provided by Hall sensors for motor commutation states. It is noted here that rotor positioning information can also be derived from incremental encoders as well. Sensorless control does not implement Hall sensors but rather rotor positioning information is derived for sensing back EMF on a non-energized motor winding.

7. AC Induction Motor Common Control Implementations
Open-loop control
Closed-loop sensor and sensorless control
PICmicro® MCU solutions
4Kw and 8Kw, 28 and 40 pins
Ex. include: PIC16C773, PIC16C774, PIC16F873, PIC16F874
The various types of motors listed here and on the next few slides are those which we should support. Each motor type has its own pros and cons for an application. Various control strategies exist for each of the motor types, each with its own pros and cons.
The three basic control methodologies for the ACIM are open-loop, closed-loop and sensorless. These three control methodologies can be further divided into:
V/F control (scalar control)
Slip frequency control
Vector control (Field orientated control)
Sensorless vector control (Kalman observer) strategies are used to predict the rotor position based on the characteristics of the motor and the measured phase currents.
The two basic control methodologies for the BLDC are closed-loop and sensorless. Closed loop control relates to the use of rotor feedback information provided by Hall sensors for motor commutation states. It is noted here that rotor positioning information can also be derived from incremental encoders as well. Sensorless control does not implement Hall sensors but rather rotor positioning information is derived for sensing back EMF on a non-energized motor winding.

8. Switched Reluctance (SR) Motor
Common Control Implementations
Closed-loop sensor and sensorless control
PICmicro® MCU solutions
2Kw/4Kw 18/28 pins
Ex. Include: PIC16C622, PIC16C73, PIC16F873
Trend moving to higher memory PIC18FXXX and dsPIC™ families
The two basic control methodologies for the SR are closed-loop sensor and sensorless control.
Closed-loop control is realized with the use of incremental encoders. Rotor position information is required for synchronized phase switching patterns.
The sensorless control strategies eliminate the rotor position sensor. One technique applies short pulses to the non-excited stator coils. The difference in current at two different instances is obtained so that the stator inductance can be calculated. This is sometimes referred to as inductance signatures. The stator inductance is a function of the instantaneous rotor position.
For the ACIM, BLDC and SR motor types the sensorless control approach seems to be gaining popularity. Being able to eliminate the rotor positioning feedback sensors is a plus and reduces system costs. The issue with this approach is that increased computational horsepower is typically required along with additional program memory and a fast ADC.