Three-phase ac motors have been the workhorse of industry since the earliest days of electrical engineering. They are reliable, efficient, cost-effective and need little or no maintenance. In addition, ac motors such as induction and reluctance motors need no electrical connection to the rotor, so can easily be made flameproof for use in hazardous environments such as in mines. In order to provide proper speed control of an ac motor, it is necessary to supply the motor with a three phase supply of which both the voltage and the frequency can be varied. Such a supply will create a variable speed rotating field in the stator that will allow the rotor to rotate at the required speed with low slip. This ac motor drive can efficiently provide full torque from zero speed to full speed, can overspeed if necessary, and can, by changing phase rotation, easily provide bi-directional operation of the motor. A drive with these characteristics is known as a PWM (Pulse Width Modulated) motor drive. Drives and motors are an integral part of industrial equipment from packaging,robotics, computer numerical control (CNC), machine tools, industrial pumps,and fans. Designing next-generation drive systems to lower operating costs requires complex control algorithms at very low latencies as well as a flexibleplatform to support changing needs and the ability to design multiple-axis systems. Traditional drive systems based on ASICs, digital signal processors (DSPs), and microcontroller units lack the performance and flexibility to address these needs. Altera’s family of FPGAs provides a scalable platform that can be used to offload control algorithm elements in hardware. You may also integrate the whole drive system with industry-proven processor architectures while supporting multipletypes of encoders and industrial Ethernet protocols. This “drive on a chip” system reduces cost and simplifies development.

1. A
Seminar
On
“FPGA BASED MOTOR
CONTROLLER”

2. 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.

3. FPGA In motor control
 FPGA are being more popular in motor
control
 Wide integration capabilities
 Higher performance, reduce latency
 Cost reduction

4. 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)

5. FPGA-Xilinx Spartan-3E Starter
Kit
FPGA
buttons
switches
LEDs

6. FPGA structure
CLB SB
SB SB
CLB
SB
CLB SB CLB
Configurable Logic Blocks
Interconnection Network
I/O Signals (Pins)

7. Simplified CLB Structure
CLB SB
SB SB
CLB
SB
CLB SB CLB
Configurable Logic Blocks
Interconnection Network
I/O Signals (Pins)
Look-Up
Table
(LUT)
Q
Q
SET
CLR
D
MUX
Look-Up
Table
(LUT)
Q
Q
SET
CLR
D
MUX

8. CLB SB
SB SB
CLB
SB
CLB SB CLB
Configurable Logic Blocks
Interconnection Network
I/O Signals (Pins)
Configuration
bits 1
0
0
0
0
0
Interconnection Network

9. Design Flow

10. 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

11. Definition
LOWHIAVG VDDVV )1( 
 Duty Cycle: on-time / period
 Vlow is often zero

12. PWM signals of varying duty
cycles

13. 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

14. Principles of PWM Motor
Drives
Phase A modulated pulse
Given to motor
Phase B modulated pulse
Given to motor

15. Average voltage
 The net voltage across one motor
winding

16. Motor current

17. 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 Kv
and voltage transients with speeds up to 10
kV/μs.

18. Working of
OPTOCOUPLER

19. ADVANTAGES
 High motor efficiency
 Fast control response
 Lower motor torque ripple
 Close to ideal sinusoidal motor current
waveform

20. 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.