This single phase converter is achieved by using a pair of a thyristor controlled bridge (4 SCRs X 2) that enables the DC motor to get reversed polarity for either direction rotation and speed control also lowered in steps by Microcontroller triggering each bridge SCR bank of duly interfaced through Opto-isolators.
Full Answer
How to control speed and direction of rotation in DC motor?
Speed control and direction control in dc motors. A single phase dual converter can be used in controlling speed and direction of rotation interfacing with microcontroller, combination of four SCR‘s is placed either side of motor and motor is load.
How does a single phase converter work?
This single phase converter is achieved by using a pair of a thyristor controlled bridge (4 SCRs X 2) that enables the DC motor to get reversed polarity for either direction rotation and speed control also lowered in steps by Microcontroller triggering each bridge SCR bank of duly interfaced through Opto-isolators.
What is a dual converter in a DC drive?
Industrial variable speed DC drives. The dual converter is a power electronics control system to get either polarity DC from AC rectification by the forward converter and reverse converter. It can run a DC motors in either direction with speed control too.
What is the reverse motoring of a DC converter?
This operation is known as the reverse motoring. In reverse operation, the firing angle of converter-1 is less than 90˚ and firing angle of converter-2 is greater than 90˚. So, in this operation, the load current is negative but the average output voltage is positive. So, the converter-2 works in the second quadrant.
What is a three phase dual converter?
How does a single phase converter work?
How does a dual converter work?
What is dual converter?
What is converter 1?
What is the diode D1 and D2?
What voltage motor is used for polarity reverse?
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Which converter is used for speed control of dc motor?
DC Motor speed control is carried out by use of Four Quadrant Chopper drive. Insulated Gate Bipolar Transistors are used for speed control of the motor and the IGBT triggering is carried out by use of PWM converters under various loading conditions and by varying armature voltage and field voltage.
What is a dual converter explain the principle of operation of a dual converter in a circulating current mode how the same is used for speed control of DC drive?
In a dual converter, two converters are connected together back to back. One of the bridge works as a rectifier (converts AC to DC), another half bridge works as an inverter (converts DC to AC) and connected commonly to a DC load.
How does a dual converter work?
Dual Converter is an Electronic Device or Circuit made by the combination of two bridges. One of them works as Rectifier(Converts A.C. to D.C.) and other bridge works as Inverter(converts D.C. into A.C.). Thus an electronic circuit or device in which two processes take place at same time, is known as Dual Converter.
How do you reverse the polarity of a DC motor?
Are DC motors reversible? Yes! DC motors are capable of running in both clockwise and counterclockwise directions. This reversal of directions can be easily controlled by simply inverting the polarity of the applied voltage.
What is the major advantage of using dual converters?
Explanation: Dual converters provide four quadrent operation, which means voltage can be positive or negative and so can be the current.
What happens if there is no circulating current in dual converter?
1) Dual Converter Operation without Circulating Current In this type of dual converter, only one converter is in conduction and another converter is temporarily blocked. So, at a time one converter operates and the reactor is not required between the converters.
What is a single phase dual converter?
Single Phase Dual Converter The input is given to the converter 1 which converts the AC to DC by the method of rectification. It is then given to the load after filtering. Then, this DC is provided to the converter 2 as input. This converter performs as inverter and converts this DC to AC. Thus, we get AC as output.
What is the difference between full converter and dual converter?
Full wave rectifiers have three configurations - fully controlled, semi controlled and uncontrolled. Fully controlled config has 4 SCRs, semi controlled config has 2 SCRs and 2 diodes and uncontrolled config has 4 diodes. SCRs make the control over the output voltage possible (by controlling the firing angle).
What causes circulating current in dual converters?
What causes circulating current in dual converters? Explanation: In case of practical dual converters, the voltages from both the converter circuits though equal in magnitude is out of phase. This indifference in voltages causes circulating currents to flow.
How do you change the direction of rotation of a DC motor?
DC motors, like AC motors, can be configured to turn in either direction. Their direction can be easily controlled by inverting the polarity of the applied armature voltage by reversing the armature leads. This works with shunt, series, and compound wound DC motors.
How do you make an electric motor go in reverse?
Remove power from the motor. Hook the battery positive wire to the negative terminal and hook the battery negative wire to the positive terminal for a simple DC motor. Install a double pole double throw changeover switch between the battery and the motor. The motor will now have a forward, reverse and an off position.
How do you reverse the direction of a DC shunt motor?
0:081:37Reversing a Shunt DC Motor - YouTubeYouTubeStart of suggested clipEnd of suggested clipIf I want to get this guy to go in the opposite direction all we have to do is just switch our a 1MoreIf I want to get this guy to go in the opposite direction all we have to do is just switch our a 1 and a 2 for armature.
What is circulating current in dual converter?
The circulating current helps in maintaining continuous conduction of both the converters irrespective of load and the time response to change the operation from one quadrant to other is faster. There are two functional modes: Non-circulating current mode and circulating mode. One converter will perform at a time.
What causes circulating current in dual converter?
3. What causes circulating current in dual converters? Explanation: In case of practical dual converters, the voltages from both the converter circuits though equal in magnitude is out of phase. This indifference in voltages causes circulating currents to flow.
What is dual converter controlled drive?
Dual converters are commonly used to operate the dc drives where the four-quadrant operation needed. Two back to back connected full controlled converters are called as dual converter. One of the converter works as a ac to dc converter and the other one works as a dc to ac converter.
What are the application of dual converter?
Application of Dual Converter Direction and speed control of DC motors. Applicable wherever the reversible DC is required. Industrial variable speed DC drives.
Single Phase Dual Converter | PDF | Direct Current | Rectifier - Scribd
A.D. PATEL INSTITUTE OF TECHNOLOGY. Subject :ELECTIRCAL DRIVES (2160910) Topic: SINGLE PHASE DUAL CONVERTER. Prepared by: KHICHADA BHAVIN(140013109005) Guided by: HARDIK SIR Contents Introduction Principle of Dual Converter Circuit Diagram Waveform Non-Circulating Current Mode of Operation Circulating Current Mode Of Operation Advantage Disadvantage Reference ...
Three phase dual converter drive - ECSTUFF4U
The schematic diagram of three phases dual converter d drive as shown in the figure. As per the circuit diagram converter, 1 allows motor control 1 and 4 quadrants whereas with converter 2 the operation in 2 and 3 quadrants obtained
Power Electronics - Dual Converters - tutorialspoint.com
Power Electronics - Dual Converters, Dual converters are mainly found in variable speed drives (VFDs). In a dual converter, two converters are linked together back to back. The operation of a dual
What is the nominal speed of a DC motor?
The nominal speed value of the DC motor (rpm). This value is used to convert motor speed from rpm to pu (per unit). Default is 1750.
What are the advantages of DC drives?
The main advantage of this drive, compared with other DC drives, is that it can operate in all four quadrants (forward motoring, reverse regeneration, reverse motoring, and forward regeneration). However, two anti-paralleled converters along with circulating current inductors are required, which increases the complexity of the drive system.
What is an average value converter?
The average-value converter represents the average behavior of a single-phase rectifier for continuous armature current in a dual-converter topology. This model is thus not suitable for simulating DC drives under discontinuous armature current conditions. The converter outputs a continuous voltage value equal to the average-value of the real-life rectified voltage. The armature voltage, armature current, and electromagnetic torque ripples are thus not represented. The input currents have the frequency and amplitude of the fundamental current component of the real-life input currents.
What is DC2 block?
The Four-Quadrant Single-Phase Rectifier DC Drive (DC2) block represents a four-quadrant, single-phase, thyristor-based (or phase controlled) drive for DC motors. This drive features closed-loop speed control with two anti-paralleled single-phase thyristor rectifiers. The anti-parallel rectifiers operate in circulating current mode with the help of circulating current inductors. The speed control loop outputs the reference armature current of the machine. Using a PI current controller, the thyristor firing angles (for the two rectifiers) corresponding to the commanded armature current are derived. These firing angles are then used to obtain the required gate signals for the rectifiers through a thyristor bridge firing unit.
How many PI regulators are used to control armature voltage?
The armature voltage is provided by two single-phase antiparallel-connected converters controlled by two PI regulators. The circulating current produced by the instantaneous voltage difference at the terminal of both converters is limited by inductors connected between these terminals. Armature current oscillations are reduced by a smoothing inductance connected in series with the armature circuit.
What is the default input for torque?
Select between the load torque, the motor speed and the mechanical rotational port as mechanical input. Default is Torque Tm.
What is the RMS voltage?
RMS voltage of the single-phase voltage source connected to the A+,A− terminals of the drive (V). This parameter is not used when using the detailed rectifier. Default is 460.
How many three phase converters are connected back to back?
The circuit diagram of the three-phase dual converter is as shown in the below figure. Here, two three-phase converters are connected back to back. The principle of operation is the same as a single-phase dual converter.
How does a first converter work?
Out of these two converters, the first converter works in two quadrants depending upon the value of firing angle α. This converter works as a rectifier when the value of α is less than 90˚. In this operation, the converter produces a positive average load voltage and load current, and operates in the first quadrant.
What is the firing angle of a converter?
The firing angle of converter-1 is α1 and α1 is less than 90˚. Hence, the converter-1 act as a rectifier. For positive half cycle (0 < t < π), thyristor S1 and S2 will conduct and for a negative half cycle (π < t < 2π), thyristor S3 and S4 will conduct. In this operation, output voltage and current both are positive. So, this operation is known as forward motoring operation and the converter works in the first quadrant.
What happens when load current is reversed?
If the load current is reversed, the converter which is operated as a rectifier is now operating as an inverter, while the converter which is operated as an inverter is now operating as a rectifier. In this scheme, both converters conduct at the same time. So, it requires two firing angle generator unit.
What is a positive group converter?
The converter operating as a rectifier is called a positive group converter and the other converter working as an inverter is called a negative group converter.
What is the advantage of the inversion scheme?
The advantage of this scheme is that we can get smooth operation of the converter at the time of inversion. Time response of the scheme is very fast. The normal delay period is 10 to 20 msec in the case of circulating current free operation is eliminated.
What type of converter is used for load?
According to the type of load, single-phase and three-phase dual converters are used.
What is a single phase dual converter?
A single phase dual converter can be used in controlling speed and direction of rotation interfacing with microcontroller, combination of four SCR‘s is placed either side of motor and motor is load. These thyristors can be triggered through an optocoupler which is connected to a port of microcontroller.
What is dual converter?
Dual converter is a combination of a rectifier and inverter in which the conversion of A.C to D.C happens and followed by D.C to A.C where load lies in between. A dual converter can be of a single phase or a three phase. A dual converter consists of two bridges consisting of thyristors in which one for rectifying purpose where alternating current is converted to direct current which can be given to load. Other bridge of thyristors is used for converting D.C to A.C.
What input is given to converter 1 for rectification?
A.C input given to converter 1 for rectification in this process positive cycle of input is given to first set of forward biased thyristors which gives a rectified D.C on positive cycle, as well negative cycle is given to set of reverse biased thyristors which gives a D.C on negative cycle completing full wave rectified output can be given to load. During this process converter 2 is blocked using an inductor. As thyristor only start conducting when current pulse is given to gate and continuous conducting until supply of current is stopped. Output of Thyristor Bridge can be as follows when it is given to different loads.
How many legs does a single phase AC/AC converter have?
There are many existing technologies in single phase AC/AC converters; they are single phase – two legs, three legs and four legs. The single phase – two and four legs converters have some demerits like – they need large number of power devices, large control circuitry, more switching and losses are reduced only half to control the 50% ...
How to make a thyristor conduct?
To make thyristors conduct, a trigger pulse must be given to its gate simultaneously along with line voltage. A separate gate drive circuit must be added to a dual converter thyristor bridges Gate drive circuit must be equally synchronized with source voltage, any delay causes zero cross jitter and zero frequency fluctuates. To prevent these circuits must be included with phase lock loops and comparators.
How to initialize rotation of motor?
Rotation of motor can be initialized using optocoupler by setting a set of thyristor to trigger which is placed at one side and change in direction of motor can be achieved by triggering another set of thyristor Variation in speed of motor can be achieved by delayed firing angle of SCR.
What is mode selection?
Mode selection and speed selection are microcontroller interfaced switches using these switches speed and rotation can be selected.
What is a single phase converter?
Single-Phase Full Converter: Single-Phase Full Converter converts the AC signal to DC signal and utilizes thyristor only. The utilization of thyristor only for the conversion process makes it fully controllable and provides wider control over the level of DC output voltage.
How many SCRs are in a single phase bridge converter?
A single-phase full-wave bridge converter utilizes four SCRs or thyristors. The load is of RLE type where R is the resistor, L is the inductor and E is the load circuit emf which may be due to a battery connected in the load circuit or due to the back emf of a DC motor.
What is EMF in a load circuit?
In the load circuit, emf E is reversed such that it will supply power back to the source and the operation of a single-phase full converter for α>90 o is termed as inverter mode of operation. In other words, it is also known as a line-commutated inverter.
How many thyristor pairs are triggered in a full converter?
In the full converter circuit, a thyristor pair is triggered at once . Here T 1 and T 2 are simultaneously triggered and after a time interval of π radian thyristor pair, T 3 and T 4 are triggered. The cycle is continuous.
What is the maximum reverse voltage that appears across the thyristors?
The maximum reverse voltage that appears across the thyristors = V m
What is the RMS value of output voltage?
Here, the RMS value of output voltage is equal to the supply voltage (V S ).
Which thyristors conduct load currents?
During this period T 1 and T 2 are forward biased whereas for the continuous load currents the thyristors T 3 and T 4 are already conducting.
What is a three phase dual converter?
In three phase dual converter, we make use of three phase rectifier which converts 3 phase AC supply to DC. The structure of the converter is same as single phase dual converter.
How does a single phase converter work?
This single phase converter is achieved by using a pair of a thyristor controlled bridge (4 SCRs X 2) that enables the DC motor to get reversed polarity for either direction rotation and speed control also lowered in steps by Microcontroller triggering each bridge SCR bank of duly interfaced through Opto-isolators.
How does a dual converter work?
One of the bridge works as a rectifier (converts AC to DC), another half bridge works as an inverter (converts DC to AC) and connected commonly to a DC load. Here two conversion processes take place simultaneously, so it is called as a dual converter. The dual converter can provide four quadrant operations. The four quadrant operation is shown below.
What is dual converter?
The dual converter is a power electronics control system to get either polarity DC from AC rectification by the forward converter and reverse converter. It can run a DC motors in either direction with speed control too.
What is converter 1?
The Converter 1 consists of Rectifier. Then the rectified DC fed to a filter which removes pulses from rectified DC and converts it to a pure DC by filtering.
What is the diode D1 and D2?
Here Diode D1 and D2 represent the unidirectional current flow characteristics of the converters. However, the direction of current can be in any way. Let us assume, the average output voltage of the converter 1 is V01 and converter 2 is V02. To make the output voltage of the two converters in same polarity and magnitude, the firing angles of the thyristors have to be controlled.
What voltage motor is used for polarity reverse?
This project uses 12-volt ac at the input and a 12 volt DC motor to verify either direction rotation as the polarity gets reversed.