High Performance Low Cost Low Lost Wireless DC Motor Speed Control Jing Guo & Yu Qiao TA: Jim Kolodziej Professor: Paul Carney Powerpoint Templates

Product Features Wirelessly controlled Five basic operations: start, stop, accelerate, decelerate, reset 90% efficiency with normal load High tolerance in overload conditions Low cost (under $12)

Main Components Control signal generating logic Wireless transceiver with encoder and decoder Microcontroller for PWM generation and overload detection Low side gate driver Buck converter

Operation of the Product

Control Signal Generator Five push buttons for five commands with a 3-input NAND gate A 3-LED array is used to test the output of the circuit. Commands Codes Start 110 Stop 111 Accelerate 100 Decelerate 010 Reset 001

Encoder & Decoder Forward and backward parallel to serial transformation Testing: Connect the signal generator, encoder and decoder in cascade and test if the output from LED is consistent.

Wireless Transmitter & Receiver Operating frequency: 315 MHz Serial data output from decoder directly feed into TX module Digital modulate and send to antenna RX module demodulates and amplifies the signal picked up by antenna Serial data output to decoder

Testing Test with 1kHz square wave from function generator (waveform got duplicated at RX end) Test with the designed circuit (the LED array at RX gives correct combination)

Micro-controller Unit MSP430G2152 PWM Generation Feedback Unit

PWM Generation MSP430G2152

Testing Connect the Control Signal Generator to the selected input and the generated waveform has the correct the frequency and changes according to the command signals

Low Side Gate Driver The low side gate driver take the PWM signal as its input and then boost the voltage to 10V Testing: Connect the 3V PWM signal to the input and check if the output waveform has the same shape but swings between 0 and 10V

Buck Converter

Testing Connect the PWM signal from the function generator to the gate of the MOSFET. Changing the duty ratio of the PWM will change the speed of the motor correspondingly.

Feedback Unit Voltage Detector Numerical Integral Approximation Overload Signal Generation (detect signal and shut down signal)

Control Unit Structure

Numerical Integral Approximation The average detect voltage over 100 time periods is over V_normal, then overload is detected. If overload for 192000 time periods, output an OFF signal to PWM generator until the RESET signal is sent by the user

Overload Circuit Protection Function Two frequency modes High (160 kHz): for normal operation Low (1.6 kHz): for overload protection Note: Switching from Low to High requires RESET command from the user

Normal Load Setup

Normal Load Efficiency Temperature Around 34 ℃ Input Power = 12.1V *12.41A = 150.04 W Output Power = 10.4V * 14.0A = 145.6 W Efficiency = 145.6W /150.04W = 97%

250W Overloading Setup

250W Overloading without Protection Temperature Around 91 ℃ Input Power = 11.97V *21.3A = 254.96W Output Power = 10.1V * 22.9A = 231.29 W Efficiency = 231.29W /254.96W = 90.7%

250W Overloading with Protection Temperature Around 31 ℃ Input Power = 11.97V *21.5A = 257.35 W Output Power = 12.8V * 16.8A = 215.04 W Efficiency = 215.04W /257.35W = 83.5%

Cost Total cost for the motor speed control parts = $10.602 Total cost for the wireless connection parts = $55.44 Total cost for the entire project = $66.442

Challenge Properly detect and respond to overloading Handle high current test cases (up to 50 A) Cost limitation ($12 per unit)

Success Transmitting and receiving control signals wirelessly Successfully protecting the circuit by lowering frequency Properly setup shut down point to protect the motor Keeping the cost low

Future Applications - Shopping cart - Golf bag carrier Solid competitiveness on markets

Credits Professor Philip T. Krein Power lab administrator: Kevin James Colravy TA: James Kolodziej