UNIT II PHASE CONTROLLED CONVERTERS PhaseControl Converters SinglePhase

Phase-Control Converters Single-Phase Three-Phase Semiconverter Full converter Dual converter www. Vidyarthiplus. com

Semiconverter. . is a one-quadrant converter and it has one polarity Full converter. .

Average Output Voltage Maximum Output Voltage Normalizing Output Voltage RMS Output Voltage www. Vidyarthiplus.

If the converter has a purely resistive load of R and the delay angle

Single-Phase Semiconverter www. Vidyarthiplus. com

Single-Phase Semiconverter (RL-load( Mode 1 Mode 2 www. Vidyarthiplus. com

Single-Phase Semiconverter (RL-load( RMS Current for Thyristor RMS Output Current AVG Output Current www.

The single-phase semiconverter has an RL load of L = 6. 5 m. H,

Rectification Mode Inversion Mode Single-Phase Full Converter www. Vidyarthiplus. com

Single-Phase Full Converter www. Vidyarthiplus. com

Single-Phase Full Converter (RL-load( Mode 1 = Mode 2 www. Vidyarthiplus. com

Single-Phase Full Converter (RL-load( RMS Current for Thyristor RMS Output Current AVG Output Current

Single-Phase Dual Converter High-Power Variable-Speed Drives www. Vidyarthiplus. com

Three-Phase Semiconverter www. Vidyarthiplus. com

3 Phase Controlled Rectifiers • • • Operate from 3 phase ac supply voltage.

• Extensively used in high power variable speed industrial dc drives. • Three

3 -Phase Half Wave Converter (3 -Pulse Converter) with RL Load Continuous & Constant

Vector Diagram of 3 Phase Supply Voltages www. Vidyarthiplus. com

3 Phase Supply Voltage Equations www. Vidyarthiplus. com

Each thyristor conducts for 2 /3 (1200) Constant Load Current io=Ia Ia Ia www.

To Derive an Expression for the Average Output Voltage of a 3 -Phase Half

3 Phase Half Wave Controlled Rectifier Output Voltage Waveforms For RL Load at Different

3 Phase Half Wave Controlled Rectifier With R Load and RL Load with FWD

3 Phase Half Wave Controlled Rectifier Output Voltage Waveforms For R Load or RL

To Derive An Expression For The Average Or Dc Output Voltage Of A 3

Three Phase Semiconverters • 3 Phase semiconverters are used in Industrial dc drive applications

3 Phase Half Controlled Bridge Converter (Semi Converter) with Highly Inductive Load & Continuous

Wave forms of 3 Phase Semiconverter for > 600 www. Vidyarthiplus. com

To derive an Expression for the Average Output Voltage of 3 Phase Semiconverter for

Three Phase Dual Converters • For four quadrant operation in many industrial variable speed

Outputs of Converters 1 & 2 • During the interval ( /6 + 1)

To obtain an Expression for the Circulating Current If v. O 1 and v.

Four Quadrant Operation www. Vidyarthiplus. com

• There are two different modes of operation. § Circulating current free (non

Non Circulating Current Mode Of Operation • In this mode of operation only one

• When the converter 1 is on, For 1 > 900 the converter

• When the converter 2 is switched on, For 2 < 900 the

Circulating Current Mode Of Operation • Both the converters are switched on at the

When 1 < 900, converter 1 operates as a controlled rectifier. 2 is made

• When 2 < 900, converter 2 operates as a controlled rectifier. 1

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UNIT II PHASE CONTROLLED CONVERTERS

Phase-Control Converters Single-Phase Three-Phase Semiconverter Full converter Dual converter www. Vidyarthiplus. com

Semiconverter. . is a one-quadrant converter and it has one polarity Full converter. . is a two-quadrant converter and the polarity of its output can be either positive or negative. However the output current of full converter has one polarity only Dual converter. . can operate in four quadrants ; both the output voltage and current can be either positive or negative www. Vidyarthiplus. com

www. Vidyarthiplus. com

Average Output Voltage Maximum Output Voltage Normalizing Output Voltage RMS Output Voltage www. Vidyarthiplus. com

If the converter has a purely resistive load of R and the delay angle is , determine )a) the rectification efficiency )b) the form factor FF )c) the ripple factor RF and (d) the peak inverse voltage PIV of thyristor T 1 www. Vidyarthiplus. com

www. Vidyarthiplus. com

Semiconverterwww. Vidyarthiplus. com

Single-Phase Semiconverter www. Vidyarthiplus. com

Single-Phase Semiconverter (RL-load( Mode 1 Mode 2 www. Vidyarthiplus. com

Single-Phase Semiconverter (RL-load( RMS Current for Thyristor RMS Output Current AVG Output Current www. Vidyarthiplus. com

The single-phase semiconverter has an RL load of L = 6. 5 m. H, R = 2. 5 Ohm, and E = 10 V. The input voltage is VS = 120 V(rms) at 60 Hz. Determine )a) the load current IL 0 at , and the load current IL 1 at, )b) the average thyristor current IA )c) the rms thyristor current IR )d) the rms output current Irms and (e) the average output current Idc www. Vidyarthiplus. com

Rectification Mode Inversion Mode Single-Phase Full Converter www. Vidyarthiplus. com

Single-Phase Full Converter www. Vidyarthiplus. com

Single-Phase Full Converter (RL-load( Mode 1 = Mode 2 www. Vidyarthiplus. com

Single-Phase Full Converter (RL-load( RMS Current for Thyristor RMS Output Current AVG Output Current www. Vidyarthiplus. com

Dual www. Vidyarthiplus. com Converter

Single-Phase Dual Converter High-Power Variable-Speed Drives www. Vidyarthiplus. com

Three-Phase Semiconverter www. Vidyarthiplus. com

3 Phase Controlled Rectifiers • • • Operate from 3 phase ac supply voltage. They provide higher dc output voltage. Higher dc output power. Higher output voltage ripple frequency. Filtering requirements are simplified for smoothing out load voltage and load current. www. Vidyarthiplus. com

• Extensively used in high power variable speed industrial dc drives. • Three single phase half-wave converters can be connected together to form a three phase half-wave converter. www. Vidyarthiplus. com

3 -Phase Half Wave Converter (3 -Pulse Converter) with RL Load Continuous & Constant Load Current Operation www. Vidyarthiplus. com

www. Vidyarthiplus. com

Vector Diagram of 3 Phase Supply Voltages www. Vidyarthiplus. com

3 Phase Supply Voltage Equations www. Vidyarthiplus. com

www. Vidyarthiplus. com

van vbn vcn www. Vidyarthiplus. com van

Each thyristor conducts for 2 /3 (1200) Constant Load Current io=Ia Ia Ia www. Vidyarthiplus. com

To Derive an Expression for the Average Output Voltage of a 3 -Phase Half Wave Converter with RL Load for Continuous Load Current www. Vidyarthiplus. com

www. Vidyarthiplus. com

3 Phase Half Wave Controlled Rectifier Output Voltage Waveforms For RL Load at Different Trigger Angles www. Vidyarthiplus. com

=300 =600 www. Vidyarthiplus. com

=900 www. Vidyarthiplus. com

3 Phase Half Wave Controlled Rectifier With R Load and RL Load with FWD www. Vidyarthiplus. com

www. Vidyarthiplus. com

3 Phase Half Wave Controlled Rectifier Output Voltage Waveforms For R Load or RL Load with FWD at Different Trigger Angles www. Vidyarthiplus. com

=00 =150 www. Vidyarthiplus. com

=300 =600 www. Vidyarthiplus. com

To Derive An Expression For The Average Or Dc Output Voltage Of A 3 Phase Half Wave Converter With Resistive Load Or RL Load With FWD www. Vidyarthiplus. com

www. Vidyarthiplus. com

Three Phase Semiconverters • 3 Phase semiconverters are used in Industrial dc drive applications upto 120 k. W power output. • Single quadrant operation is possible. • Power factor decreases as the delay angle increases. • Power factor is better than that of 3 phase half wave converter. www. Vidyarthiplus. com

3 Phase Half Controlled Bridge Converter (Semi Converter) with Highly Inductive Load & Continuous Ripple free Load Current www. Vidyarthiplus. com

www. Vidyarthiplus. com

Wave forms of 3 Phase Semiconverter for > 600 www. Vidyarthiplus. com

www. Vidyarthiplus. com

Wave forms of 3 Phase Semiconverter for 600 www. Vidyarthiplus. com

www. Vidyarthiplus. com

To derive an Expression for the Average Output Voltage of 3 Phase Semiconverter for > / 3 and Discontinuous Output Voltage www. Vidyarthiplus. com

www. Vidyarthiplus. com

Three Phase Dual Converters • For four quadrant operation in many industrial variable speed dc drives , 3 phase dual converters are used. • Used for applications up to 2 mega watt output power level. • Dual converter consists of two 3 phase full converters which are connected in parallel & in opposite directions across a common load. www. Vidyarthiplus. com

www. Vidyarthiplus. com

Outputs of Converters 1 & 2 • During the interval ( /6 + 1) to ( /2 + 1), the line to line voltage vab appears across the output of converter 1 and vbc appears across the output of converter 2 www. Vidyarthiplus. com

www. Vidyarthiplus. com

To obtain an Expression for the Circulating Current If v. O 1 and v. O 2 are the output voltages of converters 1 and 2 respectively, the instantaneous voltage across the current limiting inductor during the interval ( /6 + 1) t ( /2 + 1) is given by www. Vidyarthiplus. com

www. Vidyarthiplus. com

Four Quadrant Operation www. Vidyarthiplus. com

• There are two different modes of operation. § Circulating current free (non circulating) mode of operation § Circulating current mode of operation www. Vidyarthiplus. com

Non Circulating Current Mode Of Operation • In this mode of operation only one converter is switched on at a time • When the converter 1 is switched on, For 1 < 900 the converter 1 operates in the Rectification mode Vdc is positive, Idc is positive and hence the average load power Pdc is positive. • Power flows from ac source to the load www. Vidyarthiplus. com

• When the converter 1 is on, For 1 > 900 the converter 1 operates in the Inversion mode Vdc is negative, Idc is positive and the average load power Pdc is negative. • Power flows from load circuit to ac source. www. Vidyarthiplus. com

• When the converter 2 is switched on, For 2 < 900 the converter 2 operates in the Rectification mode Vdc is negative, Idc is negative and the average load power Pdc is positive. • The output load voltage & load current reverse when converter 2 is on. • Power flows from ac source to the load www. Vidyarthiplus. com

• When the converter 2 is switched on, For 2 > 900 the converter 2 operates in the Inversion mode Vdc is positive, Idc is negative and the average load power Pdc is negative. • Power flows from load to the ac source. • Energy is supplied from the load circuit to the ac supply. www. Vidyarthiplus. com

Circulating Current Mode Of Operation • Both the converters are switched on at the same time. • One converter operates in the rectification mode while the other operates in the inversion mode. • Trigger angles 1 & 2 are adjusted such that ( 1 + 2) = 1800 www. Vidyarthiplus. com

When 1 < 900, converter 1 operates as a controlled rectifier. 2 is made greater than 900 and converter 2 operates as an Inverter. • Vdc is positive & Idc is positive and Pdc is positive. www. Vidyarthiplus. com

• When 2 < 900, converter 2 operates as a controlled rectifier. 1 is made greater than 900 and converter 1 operates as an Inverter. • Vdc is negative & Idc is negative and Pdc is positive. www. Vidyarthiplus. com