Hardware Block Diagram56
Uploaded by
kkkHardware Block Diagram56
Uploaded by
kkkIn this the regulated dc voltage from battery is provided to 555 timer which generates the pulses
according to the position of variable resistance.
The 12V regulated dc supply is provided to driver circuit so that it can able to drive the Power
Electronic switches of the proposed system as per the gate pulses generated from the timer.
VOLTAGE REGULATOR:
It is use to maintain a constant voltage level . I will be using voltage regulator to provide 12V
DC supply from 12V AC supply for driver circuit and 9V dc supply for the 555 timer.
555 TIMER:
In this PWM generater circuit, as we mentioned above we have used 555 Timer IC for
generating PWM signal. Here we have controlled the output frequency of the PWM signal by
selecting resistor RV1 and capacitor C1. We have used a variable resistor in place of fixed
resistor for changing duty cycle of the output signal. Capacitor Charging through D1 diode and
Discharge through D2 diode will generates PWM signal at 555 timer's output pin.
Below formula is used for deriving the frequency of the PWM signal:
T = 0.693*R1*C1
Pulse Width Modulation (PWM) is a digital signal which is most commonly used in control
circuitry. This signal is set high (5v) and low (0v) in a predefined time and speed. The time
during which the signal stays high is called the “on time” and the time during which the signal
stays low is called the “off time”. There are two important parameters for a PWM as discussed
below:
Duty cycle of the PWM:
The percentage of time in which the PWM signal remains HIGH (on time) is called as duty
cycle. If the signal is always ON it is in 100% duty cycle and if it is always off it is 0% duty
cycle.
Duty Cycle =Turn ON time/ (Turn ON time + Turn OFF time)
Frequency of a PWM:
The frequency of a PWM signal determines how fast a PWM completes one period. One Period
is complete ON and OFF of a PWM signal
DRIVER CIRCUIT:
TLP250 MOSFET driver is optically isolated. Its mean input and output of TLP250 mosfet
driver is isolated from each other. Its works like aoptocoupler. Input stage have a light emitting
diode and output stage have photo diode. Whenever input stage LED light falls on output stage
photo detector diode, output becomes high.
Buffer IC 4050: A buffer is a circuit that produces the same voltage output that is input into it.
The high input impedance allows the full voltage to fall across the buffer. It used between
controller and the driver circuit.
Driver Circuit:
TLP250:
The TOSHIBA TLP250 consists of a GaAlAs light emitting diode and a integrated
photodetector.
This unit is 8−lead DIP package.
TLP250 is suitable for gate driving circuit of IGBT or power MOS FET.
• Input threshold current: IF=5mA(max.)
• Supply current (ICC): 11mA(max.)
• Supply voltage (VCC): 10−35V
• Output current (IO): ±1.5A (max.)
• Switching time (tpLH/tpHL): 1.5μs(max.)
• Isolation voltage: 2500Vrms(min.)
• UL recognized: UL1577, file No.E67349
• Option (D4) type
VDE approved: DIN VDE0884/06.92,certificate No.76823
Maximum operating insulation voltage: 630VPK
Highest permissible over voltage: 4000VPK
Pin Configuration (top view):
1: N.C.
2: Anode
3: Cathode
4: N.C.
5: GND
6: VO (Output)
7: VO
8: VCC
TRANSFORMER:
A step up transformer is used . By using this,230V AC supply is provided from 12V AC voltage
output of the inverter is given to the load
The components used for the proposed system is provided below:
IRF740N - MOSFET 500v, 20A
Capacitor 1000µF, 25V
TRANSFORMER 12V, 1A
TRANSFORMER 12V, 3A
TLP 250 – DRIVER IC 12V, 1.5A
IN 4007 DIODE 700V, 1A
555 Timer 5-9V, 20mA
DC MOTOR:
For the wound-field DC machine, access is provided to the field terminals (F+, F-) so that the
machine model can be used as a shunt-connected or a series-connected DC machine. The torque
applied to the shaft is provided at the Simulink® input TL·
The armature circuit (A+, A-) consists of an inductor La and resistor Ra in series with a counter-
electromotive force (CEMF) E.
The CEMF is proportional to the machine speed.
KE is the voltage constant and w is the machine speed.
In a separately excited DC machine model, the voltage constant KE is proportional to the field
current 1/
KE= Larlr,
Lar is the field-armature mutual inductance.
The electromechanical torque developed by the DC machine is proportional to the armature
current Ia.
KT is the torque constant. The sign convention for Te and his:
Te,Ti > 0: Motor mode
Te,h < 0: Generator mode
The torque constant is equal to the voltage constant.
The armature circuit is connected between the A+ and A- ports of the DC Machine block. It is
represented by a series Ra La branch in series with a Controlled Voltage Source and a Current
Measurement block.
In the wound-field DC machine model, the field circuit is represented by an RL circuit. It is
connected between the F+ and F- ports of the DC Machine block.
In the permanent magnet DC machine model, there is no field current as the
excitation flux is established by the magnets. KE and Kr are constants.
The mechanical part computes the speed of the DC machine from the net torque
applied to the rotor. The speed is used to implement the CEMF voltage E of the
armature circuit.
The mechanical part implements this equation:
J dw = Te - TL - Bmw - Tr,
dt •
J = inertia, Bm = viscous friction coefficient, and Tr= Coulomb friction torque.