What is the difference between single phase semi converter and single phase half wave converter?
Single Phase Half-Wave Thyristor Converter With R LoadFigure 1 below shows a single phase half-wave thyristor converter with a resistive load. For the positive half cycle of input voltage, the thyristor T1 is forward biased and when the thyristor is fired at wt = a it conducts and the input voltage appears across the load. When the input voltage goes negative at wt = p, the thyristor is reversed biased and it is turned off. The delay angle a, is defined as the time the input voltage starts to go positive to the time the thyristor is fired.Figure 1 - Single Phase Thyristor Converter With R LoadThe average output voltage Vdc is given byThe output voltage Vdc can be varied from Vm/p to zero as the firing angle a varies from zero to p.The rms output voltage is given bySingle Phase SemiconvertersFigure 2 shows a single phase semiconverter with a highly inductive load, such that the load current is assumed continuous and ripple free.Figure 2 Single-Phase SemiconverterDuring the positive half cycle of input voltage, thyristor T1 is forward biased and when this thyristor is fired at wt = a, the load is connected to the input supply via T1 and D2 for the period a£wt £p. For the period p£wt £ (p + a), the input voltage is negative and the thyristor T1 and diode D2 will be reversed biased. Under these conditions, freewheeling diode Dm is forward biased and provides a path for the flow of load current.During the negative half cycle of input voltage, thyristor T2 is forward biased and when a firing pulse occurs at wt = p+ a, diode Dm will be reversed biased and the load will be connected to the supply via thyristor T2 and diode D1.The average output voltage is found fromThe output voltage can be varied from a maximum of 2Vm/p to a minimum of zero as the firing angle a varies from zero to p.The rms output voltage is given by-It is a single quadrant converterIt has only one polarity of output voltage and current.Here two SCRs and two diodes are connected in bridge configuration.They can be arranged in two confg. namely symmetrically & asymmetrical.
What is the difference between single phase fully controlled converter and single phase semi converter?
I am limiting my answer to AC-DC converters, i.e. rectifiers. Further, the circuits I am considering have chokes (inductors) in the DC output circuits, which are common for high power rectifiers.The full controlled rectifier has four SCRs (thyristors), configured as in Figure 1. The control law equation shows that maximum output occurs when firing angle alpha is at 0 degrees, and zero output occurs when alpha is 90 degrees. The output voltage can go negative under certain load types and conditions, such as a DC motor regenerating in reverse. In this case it is no longer a rectifier, but an inverter regenerating back into the mains supply.Figure 1: Full controlled single phase bridge rectifierThe half (semi) controlled rectifier has two SCRs and 2 or 3 diodes. A typical example of a half controlled bridge rectifier is shown in Figure 2. This is called symmetrical and has a free-wheeling diode D5. There are other configurations possible, such as asymmetrical where T3 and D4 are interchanged and the free-wheeling diode is omitted. The control law equation is different from the full controlled rectifier - the output varies from maximum to zero as firing angle alpha varies between 0 and 180 degrees. Negative output is not possible with this circuit.Figure 2: Half controlled single phase bridge rectifierThe difference in output control laws for these two rectifier circuits is shown graphically in Figure 3.Figure 3: Characteristics of Rectifiers as Function of aFully controlled rectifiers are typically used for “active” loads such as DC motors. They can safely handle short circuited loads and can handle regeneration from the loads.Half controlled rectifiers are typically used in battery chargers and front end rectifiers in inverters and UPS. Short circuits are unusual and the output voltage will never need to be negative. A half controlled rectifier is cheaper (diodes are much cheaper than SCRs) and is simpler (only two SCR firing circuits are needed) than an equivalent rated full controlled rectifier.
What is the difference between a semi converter and a half wave rectifier (similarly a full converter and a full wave rectifier)?
Dont be confused by the names . LETS SEE :Full wave rectifier : Uses 4 diodes in specific configuration to convert an ac wave into dc .Full converter : In the same circuit as above uses 4 thyristors (which is like a diode which turns on only when an external signal is given by us) So that we can control the output voltage of the converter dc output.Semi converter : In the same circuit , 2 thyristors and 2 diodes are used. We can control the voltage during only one halfcycle when the thyristors are in forward bias state. The other half cycle it works like a normal full wave converter.Half wave rectifier : This is a different circuit where only one diode is connected in series with the ac source so that either the postive half or the negative half passes through making the output dc.
What is the maximum output voltage of a single-phase semi converter?
Thanks for A2A..The output voltage of a single phase semi converter circuit is DC in nature if semi converter device is bridge rectifier . If you have a controlled semi converter device just like controlled rectifier (take IGBT as electronic switches) then the output voltage will be variable DC …The formula of determining the peak value or maximum value of the variable DC output voltage is given as…Vdc= ( Vm/π)(1+cos(alpha))..Where Cos(alpha) be the cosine value of the firing angle.By controlling the firing angle we can regulate the amount of DC voltage takes place at the rectifier output terminal…
What is the difference between half controlled and half wave controlled converter?
A half controlled converter consists of only half of the total no. of switching devices as controlled devices (SCR’s) while the other half are uncontrolled devices (diodes).Whereas a half wave controlled rectifier is a half wave rectifier (works for positive half cycle of input ac voltage) which consists of a controlled device (SCR).
What is the difference between converter and inverter?
There seems to be three terms used in this area, converter, inverter, and adaptor. In general, a converter is a trasformer to "convert" the voltage from one value to another. The voltage may typically convert from 120 VAC to 220 VAC or vice versa. An inverter is normally used to change direct current to alternating current. Like an inverter for your car would invert 12 VDC to 120VAC. Last would be the term dc adaptor - this is usually used to change an alternating current to direct current with a trasformation, such as 120VAC to 9VDC.
Power electronic (difference between the three-phase 3-pulse and 6-pulse rectifiers?
3 pulse uses the part of the sine wave from 30 to 150 degrees, 3 of these pulses per cycle of power line frequency. 6 pulse uses the part of the sine wave from 60 to 120 degrees, 6 of these pulses per cycle of power line frequency. There is less ripple in the 6 pulse and higher average voltage. Ripple frequency is also higher making it easier to filter with smaller capacitors and inductors.
Is single phase half controlled bridge converter possible?
A fully-controlled rectifier circuit contains only controlled-rectifiers, whereas a semi-controlled rectifier circuit is made up of both controlled and uncontrolled rectifiers. Due to presence of diodes, free-wheeling operation takes place without allowing the bridge output voltage to become negative. In a semi-controlled rectifier, control is effected only for positve output voltage, and no control is possible when its output voltage tends to become negative since it is clamped at zero volt. A semi-controlled full-wave bridge rectifier can be configured in a few ways. They are shown below.The circuit in Configuration 1 contains two SCRs and two diodes. When source Vin is positive, SCR S1 can be triggered at a firing angle called a and then current flows out of the source through SCR S1 first, then through the load and returns via diode D3. Ifthen SCR S1 and diode D3 conduct during a< wt < p. When p < wt < 2p, Vin is negative and SCR S2 is normally triggered when wt = p + a. During p < wt < (p + a) , the output of the bridge circuit would have been negative if we had used a fully-controlled bridge rectifer and if the current flow was continuous. But here we have two diodes D3 and D4 instead of two SCRs. When the output of the bridge tends to becomes negative just after wt exceeds p, diode D4tends to get forward-biased and it starts conducting. Then diode D3 is reverse-biased and it stops conducting. During p < wt < (p + a) , the devices in conduction are SCR S1 and diode D4 and the output of the bridge is clamped at zero, assuming that the on-state drops across devices in conduction is zero. During ( p + a) < wt < 2p, the devices in conduction are SCR S2 and diode D4. SCR S2 and diode D3 would conduct during 0 < wt < a .The circuit in configuration 1 has SCRs as the devices in the top-half and diodes as the devices in the bottom-half. Instead, it it is possible to use SCRs as the devices in the bottom-half and diodes as the devices in the top-half.It is also possible to build a semi-controlled full-wave bridge rectifier as shown by the circuit in configuration 2. The behaviour of the circuit is the same as described earlier. In this circuit, SCR S1and diode D3 conduct during a < wt < p . During p < wt < (p + a) , the devices in conduction are diodes D3 and D4 and the output of the bridge is clamped at zero. During (p + a) < wt < 2p , the devices in conduction are SCR S2 and diode D4. Diodes D3 and D4 would conduct during 0 < wt < a .
What is the need of a single-phase half-controlled bridge converter?
I have used this circuit in battery chargers of output capacity between about 100W to 5kW. These battery chargers are typically in a UPS configuration, either running an inverter or a critical DC load. So as well as charging the battery, they are running a standing load.The characteristics of this circuit that are beneficial for this application are:The output voltage is stable and well regulated. This is important for the application float charging a battery.The circuit is rugged and the devices can be protected against short circuits with simple fuses.By using a L-C output filter, the DC output is smooth and is OK to supply the load with the battery disconnected.The circuit is economical on power rectifier devices - two SCRs and two or 3 diodes.The charger is reasonably efficient. The power losses (rectifier, transformer and choke) are reasonable, especially for higher output voltages.Mains current harmonic content is quite low and can be mitigated with simple inductors. Also radio frequency interference is low.The only downside is the size and weight. Mains transformers and chokes are heavy things and a high-frequency switch-mode equivalent will be smaller and lighter. However RFI for a higher powered SMPS can be a problem, and harmonic mitigation is much more complicated.