rectifiers

1. rectifiers

3. Introductionsof rectifiers:
IN PARTICLE ACCELERATORS, ELECTRONS OR OTHER CHARGED PARTICLES ARE FORCED TO MOVE ALONG ORBITS OR
TRAJECTORIES BY MEANS OF MAGNETIC FIELDS. THE INTENSITY OF THE MAGNETIC FIELDS NEEDED TO OBTAIN THE
DESIRED EFFECTS IS RELATED TO THE ENERGY OF THE PARTICLES. ELECTROMAGNETS, CONVENTIONAL HOT ONES OR
SUPERCONDUCTING ONES, ARE NORMALLY USED. THE EXCITATION CURRENT IN THE MAGNETS CAN RANGE FROM SOME
AMPERES FOR SMALL ORBIT CORRECTION COILS TO SOME HUNDREDS OR THOUSANDS OF AMPERES (SEE, FOR EXAMPLE,
REFS. [1] AND [2]). THE POWER CONVERTERS NEEDED TO COVER SUCH A WIDE CURRENT RANGE HAVE WIDELY
DIFFERING STRUCTURES AND CHARACTERISTICS AND, FOR THE SAME POWER REQUIREMENT, SEVERAL SOLUTIONS ARE
OFTEN POSSIBLE.
IN THIS PAPER I SHOW THE TOPOLOGIES AND THE CHARACTERISTICS OF A PARTICULAR CLASS OF RECTIFIERS—THE
LINE COMMUTATED ONES—THAT WAS AND STILL IS WIDELY USED IN PARTICLE ACCELERATOR FACILITIES. EVEN TODAY,
IN THE ‘PWM ERA’, LINE COMMUTATED RECTIFIERS ARE OPERATING. MOREOVER, SWITCH MODE POWER SUPPLIES
(SMPS) VERY OFTEN INCLUDE IN THEIR STRUCTURE ‘CONVENTIONAL’ RECTIFIERS AS INPUT OR OUTPUT STAGES OR BOTH.
SINCE THE CURRENTS IN THE MAGNETS HAVE EITHER TO BE VARIED ACCORDING TO THE ENERGY (OR THE
REQUIRED CHANGES IN THE ORBIT) OF THE PARTICLES OR AT LEAST HAVE TO BE RAMPED FROM THE TURN ON VALUES TO
THEIR FINAL VALUES (THIS IS QUITE IMPORTANT IF THE TIME CONSTANT OF THE LOAD — A MAGNET STRING — IS HIGH),
THE RECTIFIERS USE THYRISTOR-BASED STRUCTURES OR MIXED ONES (DIODES AND THYRISTORS OR DIODES/THYRISTORS
AND TRANSISTORS).

4. Definitionofrectifiers
A RECTIFIER IS AN ELECTRICAL DEVICE COMPOSED OF ONE OR
MORE DIODES THAT CONVERTS ALTERNATING CURRENT (AC) TO
DIRECT CURRENT (DC). A DIODE IS LIKE A ONE-WAY VALVE THAT
ALLOWS AN ELECTRICAL CURRENT TO FLOW IN ONLY ONE
DIRECTION. THIS PROCESS IS CALLED RECTIFICATION.

5. Blockdiagramof powersupply

6. rectifier
• HALF WAVE RECTIFIER
• FULL WAVE RECTIFIER
• CENTRE TAPPED RECTIFIER.
• BRIDGE RECTIFIER.

7. Halfwaverectifier
AS THE NAME SUGGESTS, THE HALF WAVE RECTIFIER IS A TYPE OF RECTIFIER
WHICH CONVERTS HALF OF THE AC INPUT SIGNAL (POSITIVE HALF CYCLE)
INTO PULSATING DC OUTPUT SIGNAL AND THE REMAINING HALF SIGNAL
(NEGATIVE HALF CYCLE) IS BLOCKED OR LOST. IN HALF WAVE RECTIFIER
CIRCUIT, WE USE ONLY A SINGLE DIODE.

8. Operationof half waverectifier
OPERATION OF HALF-WAVE RECTIFIER. PN JUNCTION DIODE CONDUCTS ONLY DURING
THE FORWARD BIAS CONDITION. ... ALTERNATING CURRENT IS THE INPUT OF THE HALF
WAVE RECTIFIER. A STEP DOWN TRANSFORMER TAKES INPUT VOLTAGE AND THE
RESULTING OUTPUT OF THE TRANSFORMER IS GIVEN TO THE LOAD RESISTOR AND TO
THE DIODE.

10. Waveformshalfwaverectifier

11. Averagedc loadcurrent(IDC)

12. AVERAGEDC VOLTAGE(EDC)

13. IRMS ANDERMS

14. DCPOWERDELIVEREDTOTHELOAD

16. Rectifier efficiency

17. ADVANTAGESOFHALFWAVERECTIFIER
1)IT IS A SIMPLE CIRCUIT.
2)IT HAS LOW COST.
3)WE CAN EASILY TO CONSTRUCT.
4)IT HAS LOW NUMBER OF COMPONENTS THEREFORE, IT A
CHEAP APART FROM THIS,.

18. Disadvantages of half wave rectifier
THE HALF WAVE RECTIFIER HAS MORE NUMBER OF DISADVANTAGES AS COMPARED TO THE
ADVANTAGES. SOME OF THEM ARE:
1. SINCE, POWER IS DELIVERED ONLY DURING ONE HALF OF THE CYCLE OF THE INPUT
ALTERNATING VOLTAGE, THEREFORE, ITS POWER OUTPUT AND RECTIFICATION FREQUENCY IS
LOW.
2. TRANSFORMER UTILIZATION FACTOR IS ALSO LOW.
3. THE DC OUTPUT POWER PRODUCED FROM THE HALF WAVE RECTIFIER IS NOT SATISFACTORY
TO MAKE A GENERAL POWER SUPPLY.

19. Fullwaverectifier
A FULL WAVE RECTIFIER IS A CIRCUIT, WHICH CONVERTS AN AC VOLTAGE INTO
A PULSATING DC VOLTAGE USING BOTH HALF CYCLES OF THE APPLIED AC
VOLTAGE. IT USES TWO DIODES OF WHICH ONE CONDUCTS DURING ONE HALF
CYCLE WHILE THE OTHER CONDUCTS DURING THE OTHER HALF CYCLE OF THE
APPLIED AC VOLTAGE.

20. Classificationsof fullwaverectifiers
IT IS DIVIDED IN TO TWO TYPES:
1.CENTER TAPPED FULL WAVE RECTIFIER.
2.FULL WAVE BRIDGE RECTIFIER.

21. Centretappedfullwaverectifier
IN THE CASE OF CENTRE-TAP FULL WAVE
RECTIFIER, ONLY TWO DIODES ARE
USED, AND ARE CONNECTED TO THE
OPPOSITE ENDS OF A CENTRE-TAPPED
SECONDARY TRANSFORMER AS
SHOWN IN THE FIGURE BELOW. THE
CENTRE-TAP IS USUALLY CONSIDERED
AS THE GROUND POINT OR THE ZERO
VOLTAGE REFERENCE POINT.

22. Fullwavebridgerectifier
A BRIDGE RECTIFIER IS AN ALTERNATING CURRENT (AC) TO DIRECT
CURRENT (DC) CONVERTER THAT RECTIFIES MAINS AC INPUT TO DC
OUTPUT. BRIDGE RECTIFIERS ARE WIDELY USED IN POWER SUPPLIES
THAT PROVIDE NECESSARY DC VOLTAGE FOR THE ELECTRONIC
COMPONENTS OR DEVICES.

23. Fullwaverectifiertheory:
THEORY : A FULL WAVE
RECTIFIER IS A CIRCUIT, WHICH
CONVERTS AN AC VOLTAGE
INTO A PULSATING DC
VOLTAGE USING BOTH HALF
CYCLES OF THE APPLIED AC
VOLTAGE. IT USES TWO DIODES
OF WHICH ONE CONDUCTS
DURING ONE HALF CYCLE
WHILE THE OTHER CONDUCTS
DURING THE OTHER HALF
CYCLE OF THE APPLIED AC
VOLTAGE.

24. Advantages
RIPPLE FREQUENCY IS TWO TIMES THE INPUT FREQUENCY.
THE OUTPUT AND EFFICIENCY OF CENTRE TAP FULL WAVE
RECTIFIER ARE HIGH BECAUSE AC SUPPLY DELIVERS POWER
DURING BOTH THE HALVES.
FOR THE SAME SECONDARY VOLTAGE BRIDGE RECTIFIER
HAS DOUBLE OUTPUT.

25. Disadvantages
IT IS DIFFICULT TO LOCATE THE CENTRE TAP ON THE SECONDARY
WINDING.
THE DC OUTPUT IS SMALL AS EACH DIODE UTILIZES ONLY ONE
HALF OF THE TRANSFORMER'S SECONDARY VOLTAGES.
THE DIODES USED HAVE HIGH PEAK INVERSE VOLTAGE.
FULL WAVE RECTIFIER REQUIRES MORE DIODES TWO FOR CENTRE
TAP RECTIFIER AND FOUR FOR BRIDGE RECTIFIER.
WHEN A SMALL VOLTAGE IS REQUIRED TO BE RECTIFIED THIS FULL
WAVE RECTIFIER CIRCUIT IS NOT SUITABLE.

26. parameter Half wave rectifier Centre tapped full
wave rectifier
Full wave bridge
rectifier
DC OR AVERAGE LOAD
CURRENT(ILDC)
𝐼 𝑚
𝜋
2𝐼𝑚
𝜋
2𝐼𝑚
𝜋
Dc or average load voltage
𝑣𝑚
𝜋 2𝑣𝑚
𝜋
2𝑣𝑚
𝜋
Rms load current
(Ilrms)
Im
2
Im
2
Im
2
Rms load voltage
(vlrms)
𝑣𝑚
2
𝑣𝑚
2
𝑣𝑚
2
Dc load power (pdc) 𝐼 𝑚
2
𝜋2
𝑅 𝐿
4
𝐼 𝑚
2
𝜋2 𝑅 𝐿 4
𝐼 𝑚
2
𝜋2 𝑅 𝐿
Max. rectification efficiency 40% 01.2% 81.2%
Ripple factor 121% 48% 48%
COMPERISIONOF RECTIFIERCIRCUIT