THIS IS ALSO A TORQUE CONTROLLER!! Compare the measured current with the desired current and generate an error signal Amplify the error signal to generate a correction voltage 4. Current Controller Measure the current of the motor NOTE. Freescale Semiconductor, Incġ4 Control Current On A Brush DC Motor Desired Current Command - PID Controller v Armature Motorola Dave s Control Center M 1. Modulate the correction voltage onto the motor terminals owners.
THIS DOES NOT LIMIT CURRENT!! Compare the measured speed with the desired speed and generate an error signal Amplify the error signal to generate a correction voltage 4. Measure speed of the motor Speed Controller BUT. Freescale Semiconductor, Incġ3 Simple Speed Control On A Brush DC Motor Desired Speed Command - PID Controller v Armature Motorola Dave s Control Center M Encoder 1.
steady state error) Derivative - determines the reaction to the rate at which the error has been changing The weighted sum of these three actions is used to adjust the process via a control element such as the position of a control valve or the power supply of a heating element or the voltage to a motor A fast response may require rapid calculation of the PID output and this can force the use of a higher performing CPU core (i.e. Freescale Semiconductor, Incġ2 Proportional Integral Derivative (PID) Controller The PID controller corrects the error between a measured variable and a desired set-point The PID controller calculation involves 3 separate parameters Proportional - determines the reaction to the current error Integral - determines the reaction based on the sum of recent errors (i.e. Freescale Semiconductor, IncĨ Choosing Your MCU Therefore Depends Upon The same application may have different performance if implemented on different MCUs The peripheral features can significantly impact performance of target application, not CPU only Application Features should be considered Type of motor Type of load Operational mode Minimal speed Maximal speed Current control Speed control and/or position control Number of PID controllers Fault control System Cost! owners. Freescale Semiconductor, IncĦ Typical Motor Control MCU Peripherals Function Timer: PWM signals < 20Khz Dead time insertion Commutation (mask-out) ADC triggering Fault control ADC Measure current Delay block Set ADC measurement at specific times Position decoder Quadrature decoder inputs if not sensorless Position decoder 6 ch PWM timer Fault inputs Prog delay 12 bit ADC owners. Freescale Semiconductor, Incĥ Global Motor Control Markets and Applications Appliance Typical Motor Type Washing machine/dishwasher/dryer ACIM, PMSM Refrigerator/Freezer BLDC Shaver DC Drills DC Vacuum Cleaner SR Industrial Factory automation Stepper Robotic systems Universal, BLDC Compressors ACIM, PMSM Fans BLDC Air conditioning ACIM, BLDC, PMSM Elevators ACIM Shutters BLDC Gates DC Surveillance platforms DC owners. 4 Many Different Motor Types DC Motor Brushless DC Motor (BLDC) Stepper Motor (half step) Stepper Motor (full step) AC Induction Motor (ACIM) Permanent Magnet Synchronous Motor (PMSM) Switched Reluctance Motor owners.
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