IGBT based pwm inverter
10:10:00
AIM
Obtain output voltage from single phase PWM inverter.
APPARATUS
1. IGBT single phase PWM kit
2. CRO
3. Connecting probes
PRINCIPLE
IGBT has been developed by combining th best qualities of both BJT and PMOSFET. So IGBT have high input impedence and low on-state power loss. PWM inverters are used in industrial purposes. This PWM techniques are characterized by constant amplitude pulses. The width of these pulsses are varied to control output voltage.
TRIGGERRING CIRCUIT
Microcontroller based trigger circuit uses 1419C55 with LCD display from 15V AC input to ach section.
Control circuit consists of rectifiers, filters, regulators, optocoupler, and a buffer. Switches to control are
1. SET – To select modulation technique.
2. INC – T o increment the parametrs.
3. DEC- To decrement the parameter.
MODULATION TECHNIQUES
• Trapezoidal PWM
• Sinusoidal PWM
• Staircase PWM
• Single pulse PWM
• Multiple pulse PWM
In trapezoidal PWM, the pulse width follows a t rapezoidal wave manner ie, its width first increases then decreases.
In sinusoidal PWM , the width of pulse will be maximum at peak of sine wave.
There will be constant increase as decrease in the width of the pulse.
In staircase PWM , the distance between pulses will increase step by step which seems like a staircase.The distance between each pulse is greater than the width of the pulse.
In single pulse PWM , there will be a single pulse in positive half cycle and another single pulse in the negative haf cycle. By changing the duty ratio we can increase or decrease he width of this pulse.
In multiple pulse PWM, each half cycle will contain atlest 7 or 8 single pulses with small deviation. The width of pulses can be controlled by controlling the duty ratio of the sigal triggering.
• FREQ/ DUTY – To select the parameter
• RUN/ TOP – To stop or start output signal
PROCEDURE
Switch on the kit after connecting the probes at proper slots. Select which type of modulation required using SET and INC or DEC , after pressing RUN/STOP button. Obtain the waveform at CRO, observe and plot it.
RESULT
Output voltage waveforms are obtained and plotted from single phase PWM inverter.
Obtain output voltage from single phase PWM inverter.
APPARATUS
1. IGBT single phase PWM kit
2. CRO
3. Connecting probes
PRINCIPLE
IGBT has been developed by combining th best qualities of both BJT and PMOSFET. So IGBT have high input impedence and low on-state power loss. PWM inverters are used in industrial purposes. This PWM techniques are characterized by constant amplitude pulses. The width of these pulsses are varied to control output voltage.
TRIGGERRING CIRCUIT
Microcontroller based trigger circuit uses 1419C55 with LCD display from 15V AC input to ach section.
Control circuit consists of rectifiers, filters, regulators, optocoupler, and a buffer. Switches to control are
1. SET – To select modulation technique.
2. INC – T o increment the parametrs.
3. DEC- To decrement the parameter.
MODULATION TECHNIQUES
• Trapezoidal PWM
• Sinusoidal PWM
• Staircase PWM
• Single pulse PWM
• Multiple pulse PWM
In trapezoidal PWM, the pulse width follows a t rapezoidal wave manner ie, its width first increases then decreases.
In sinusoidal PWM , the width of pulse will be maximum at peak of sine wave.
There will be constant increase as decrease in the width of the pulse.
In staircase PWM , the distance between pulses will increase step by step which seems like a staircase.The distance between each pulse is greater than the width of the pulse.
In single pulse PWM , there will be a single pulse in positive half cycle and another single pulse in the negative haf cycle. By changing the duty ratio we can increase or decrease he width of this pulse.
In multiple pulse PWM, each half cycle will contain atlest 7 or 8 single pulses with small deviation. The width of pulses can be controlled by controlling the duty ratio of the sigal triggering.
• FREQ/ DUTY – To select the parameter
• RUN/ TOP – To stop or start output signal
PROCEDURE
Switch on the kit after connecting the probes at proper slots. Select which type of modulation required using SET and INC or DEC , after pressing RUN/STOP button. Obtain the waveform at CRO, observe and plot it.
RESULT
Output voltage waveforms are obtained and plotted from single phase PWM inverter.
 |
| output waveform-1 |
 |
| output-2 |
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| output-3 |
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