An-Najah National UniversityAn-Najah National UniversityFaculty Of EngineeringFaculty Of Engineering

Electrical Engineering DepartmentElectrical Engineering Department

THE MOTOR WE USED

A run-type capacitor permanently connected in series with the start (Aux.) winding.

It provides the 90 degree phase shift between main & aux.

This 90 degree will be done by programming.

Measured motor Measured motor SpecificationsSpecifications

Unfortunately, all of these components increase the cost of the system for basic ON and OFF control in two directions.

Constant V/F resulting the motors to produce their rated torque over the widest possible speed range.

DESIGN DESCRIPTION DESIGN DESCRIPTION

FULL CIRCUIT FULL CIRCUIT PREVIEWPREVIEW

HardwareHardwareDesignDesign

PIC MICROCONTROLLER PIC MICROCONTROLLER BASIC CCTBASIC CCT

KEYPAD + LCD KEYPAD + LCD CONNECTION CONNECTION

Dead Band Time CCTDead Band Time CCT

GATEGATE DRIVER DRIVER

AC inverters are used to convert DC voltage to AC voltage to feed the motor under control.It is used to vary the frequency.Also it will be the main element in direction control of the motor.

The winding voltages, Va, Vb, and Vc, should be controlled to achieve the phase difference between the effective voltages across the main and starting windings, in order to have a 90-degree phase shift to each other.

SoftwareSoftwareDesignDesign

To achieve 90º between main & aux:

* Semi sinusoidal waveforms.

* Nearly high frequency (around 7 KHz was used).

*R-C (low pass) filter used to see the wave*R-C (low pass) filter used to see the wave**PWM2 signal is the same but with 90º phase shift PWM2 signal is the same but with 90º phase shift (±0x4000, according to the direction of rotation)(±0x4000, according to the direction of rotation)

YES

3

NO

2

Splitting grounds of low&high Splitting grounds of low&high sidessides

Auxiliary power supplyAuxiliary power supplyNot enough to trigger the gate.Not enough to trigger the gate.

Switching FrequencySwitching Frequency