fpga based motor controller
TRANSCRIPT
A
Seminar
On
“FPGA BASED MOTOR CONTROLLER”
Introduction
The recent advances in FPGA (Field
Programmable Gate Array) technology have made
it possible to implement digital control algorithms
in hardware solution with low costs.
FPGA In motor control
FPGA are being more popular in motor
control
Wide integration capabilities
Higher performance, reduce latency
Cost reduction
FPGA Principles
A Field-Programmable Gate Array
(FPGA) is an integrated circuit that can
be configured by the user to emulate
any digital circuit as long as there are
enough resources
An FPGA can be seen as an array of
Configurable Logic Blocks (CLBs)
connected through programmable
interconnect (Switch Boxes)
FPGA-Xilinx Spartan-3E Starter
Kit
FPGA
buttonsswitches
LEDs
FPGA structure
CLB SB
SB SB
CLB
SB
CLB SB CLBConfigurable Logic Blocks
Interconnection Network
I/O Signals (Pins)
Simplified CLB Structure
CLB SB
SB SB
CLB
SB
CLB SB CLBConfigurable Logic Blocks
Interconnection Network
I/O Signals (Pins)
Look-Up
Table
(LUT)
Q
QSET
CLR
D
MUXLook-Up
Table
(LUT)
Q
QSET
CLR
D
MUX
CLB SB
SB SB
CLB
SB
CLB SB CLBConfigurable Logic Blocks
Interconnection Network
I/O Signals (Pins)
Configuration
bits 1
0
0
0
00
Interconnection Network
Design Flow
Pulse Width Modulated
(PWM)
what is it?
Output signal alternates between on and
off within specified period
Controls power received by a device
The voltage seen by the load is directly
proportional to the source voltage
Definition
LOWHIAVG VDDVV )1(
Duty Cycle: on-time / period
Vlow is often zero
PWM signals of varying duty
cycles
Three Phase AC motors with PWM
3 different AC currents at different
phases
Phase: 120 degrees apart
Creates constant power transfer
Rotating magnetic field
Pulses substitute for AC current
Principles of PWM Motor
Drives
Phase A modulated pulse
Given to motor
Phase B modulated pulse
Given to motor
Average voltage
The net voltage across one motor
winding
Motor current
OPTOCOUPLER
An opto-isolator, also called an optocoupler,
photocoupler, or optical isolator, is a
component that transfers electrical signals
between two isolated circuits by using light.
Opto-isolators prevent high voltages from affecting the system receiving the signal.
Commercially available opto-isolators withstand input-to-output voltages up to 10 Kvand voltage transients with speeds up to 10 kV/μs.
Working of
OPTOCOUPLER
ADVANTAGES
High motor efficiency
Fast control response
Lower motor torque ripple
Close to ideal sinusoidal motor current
waveform
CONCLUSION
By controlling the amplitude and
frequency of the modulating waveforms,
the PWM drive can output to the motor a
three phase supply with the use of
optocoupler at the necessary voltage
and frequency to drive the motor at any
required speed.
