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• CIRCUIT DIAGRAM
• OPERATION
• WAVEFORMS

• CIRCUIT DIAGRAM
• OPERATION
• WAVEFORMS

• CIRCUIT DIAGRAM
• OPERATION
• WAVEFORMS

• CIRCUIT DIAGRAM
• OPERATION
• WAVEFORMS

• CIRCUIT DIAGRAM
• OPERATION

• Inverter circuit
• Modes of OPERATION- equivalent CIRCUITS
• Waveforms of ic, vo , IO, iT1, iT2, vT1, vT2
• EXPRESSION for VC, vL , vo , io, tc

• Inverter circuit
• MODES of operation- equivalent circuits
• WAVEFORMS of ic, vc , io
• EXPRESSION for TC, vc, vL

• Inverter CIRCUIT
• OPERATION- equivalent CIRCUITS
• Waveforms of PHASE and line voltage

• Inverter circuit
• OPERATION- EQUIVALENT circuits
• Waveforms of phase and LINE VOLTAGE

• External CONTROL of ac output voltage
• External control of dc input voltage
• Internal control of INVERTER

PWM inverter

• SINGLE pulse modulation
• MULTIPLE pulse modulation
• Sinusoidal pulse modulation

PWM inverter

• series inverter circuit
• CURRENT & voltage WAVEFORMS
• OPERATION
• Expression for output frequency, VL, VC

• chopper circuit
• Modes of OPERATION- equivalent circuit diagrams
• Current & voltage waveforms
• Design of C & L

• CHOPPER circuit
• MODES of operation- EQUIVALENT circuit diagrams
• Current & voltage WAVEFORMS
• DESIGN

• CHOPPER CIRCUIT
• OPERATION

• CHOPPER circuit
• OUTPUT voltage & current waveforms
• AVERAGE load voltage EXPRESSION

• CHOPPER circuit
• output voltage & current waveforms
• AVERAGE LOAD voltage expression

• 3Φ? dual converter bridge circuit
• waveforms of vo , io , vo1 , vo2 , i1, I2 , VS , ic
• Operation for with CIRCULATING current and WITHOUT circulating current
• LOAD voltage expression, peak value icp

• 3?Φ semi CONVERTER bridge CIRCUIT
• waveforms of vo , io , iA, vs
• Operation
• AVERAGE output VOLTAGE expression.

• 3?Φ FULL converter BRIDGE circuit
• WAVEFORMS of vo , io , iA, VS
• Operation
• Average OUTPUT voltage expression.

• 1?Φ FULL converter BRIDGE circuit
• waveforms of vo , io , IFD, is, VT1, VT2
• Operation for α? < 900, α? &GT; 900
• AVERAGE output voltage, rms value of output voltage expression.

• 1?Φ semiconverter bridge circuit
• WAVEFORMS of vo , IO , ifd, is, VT1, VT2
• Operation
• Average output voltage, rms value of output voltage expression

• BASIC STRUCTURE, SYMBOL
• Operation
• V-I CHARACTERISTICS, Switching characteristics

• BASIC STRUCTURE, symbol
• OPERATION
• V-I CHARACTERISTICS, Switching characteristics

• FORWARD VOLTAGE triggering
• The dv/dt triggering
• GATE triggering
• TEMPERATURE triggering
• Light triggering

• EQUIVALENT CIRCUIT
• V-I CHARACTERISTICS
• SWITCHING characteristics

• Schematic DIAGRAM (2M)
• TWO transistor model diagram (2M)
• OPERATION (4M)

The part of the cyclo-CONVERTER circuit that permits the flow of CURRENT during NEGATIVE half CYCLE of output current is called negative converter group.

The part of the cyclo-converter circuit that permits the flow of current during negative half cycle of output current is called negative converter group.

The PART of the cyclo-converter circuit that PERMITS the FLOW of CURRENT during positive half cycle of output current is CALLED positive converter group.

The part of the cyclo-converter circuit that permits the flow of current during positive half cycle of output current is called positive converter group.

1. Induction HEATING
2. Speed CONTROL of high power ac DRIVES
3. Static VAR generator
4. Power supply in AIRCRAFT or ship BOARDS

In these CONVERTERS, the OUTPUT FREQUENCY is more than the SUPPLY frequency.

In these converters, the output frequency is more than the supply frequency.

In these CONVERTERS, the OUTPUT FREQUENCY is LESS than the SUPPLY frequency.

In these converters, the output frequency is less than the supply frequency.

1. Step-up cyclo-converters
2. Step-down cyclo-converters

1. SYSTEM power FACTOR is IMPROVED.
2. Harmonics are reduced in the source current and the load VOLTAGE.

It means that the stages of voltage CONTROLLERS in parallel triggered in a proper sequence ONE after the other so as to OBTAIN a variable output with LOW harmonic content.

It means that the stages of voltage controllers in parallel triggered in a proper sequence one after the other so as to obtain a variable output with low harmonic content.

<P>Thyristor is turned on by using a TRAIN of PULSES from a to p. This type of SIGNAL is called as high frequency carrier gating.

Thyristor is turned on by using a train of pulses from a to p. This type of signal is called as high frequency carrier gating.

1. More HEATING of the SCR GATE.
2. Increases the SIZE of pulse TRANSFORMER.

HIGH frequency carrier GATING signal is used for single PHASE ac voltage CONTROLLER with RL LOAD.

High frequency carrier gating signal is used for single phase ac voltage controller with RL load.

The control RANGE is Φ < α <180°,

where Φ = load POWER FACTOR ANGLE.

The control range is Φ < α <180°,

where Φ = load power factor angle.

Here the power FLOW is CONTROLLED during both cycles of the input VOLTAGE.

Here the power flow is controlled during both cycles of the input voltage.

1. Due to the presence of diode on the circuit, the CONTROL RANGE is limited and the EFFECTIVE RMS output voltage can be VARIED between 70.7% and 100%.
2. The INPUT current and output voltage are asymmetrical and contain a dc component.If there is an input transformer, saturation problem will occur
3. It is only used for low power resistive load.

Here the POWER flow is CONTROLLED only during the positive half-cycle of the input VOLTAGE.

Here the power flow is controlled only during the positive half-cycle of the input voltage.

Answer : Duty CYCLE K = N/ (n + m),

where n = NUMBER of ON cycles,
m = number of OFF cycles.

where n = number of ON cycles,
m = number of OFF cycles.

This type of CONTROL is APPLICABLE in systems that have high mechanical inertia and high thermal TIME constant.

This type of control is applicable in systems that have high mechanical inertia and high thermal time constant.

Due to ZERO-voltage and zero CURRENT SWITCHING of thyristors, the HARMONICS generated by the switching action are reduced.

Due to zero-voltage and zero current switching of thyristors, the harmonics generated by the switching action are reduced.

ON-OFF control: In this method, the THYRISTORS are employed as switches to connect the LOAD circuit to the source for a few CYCLES of the load voltage and disconnect it for another few cycles. PHASE control: In this method, thyristor switches connect the load to the ac source for a portion of each half cycle of INPUT voltage.

ON-OFF control: In this method, the thyristors are employed as switches to connect the load circuit to the source for a few cycles of the load voltage and disconnect it for another few cycles. Phase control: In this method, thyristor switches connect the load to the ac source for a portion of each half cycle of input voltage.

1. ON-OFF CONTROL
2. PHASE control

The main draw back is the introduction of HARMONICS in the supply current and the load voltage waveforms PARTICULARLY at LOW output voltages.

The main draw back is the introduction of harmonics in the supply current and the load voltage waveforms particularly at low output voltages.

1. HIGH efficiency
2. Flexibility in CONTROL
3. Less MAINTENANCE

1. Domestic and industrial HEATING
2. Lighting CONTROL
3. Speed control of single phase and three phase AC motors
4. Transformer TAP changing

It is DEVICE which CONVERTS FIXED alternating voltage into a VARIABLE voltage without change in FREQUENCY.

It is device which converts fixed alternating voltage into a variable voltage without change in frequency.