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Design Of Mechatronic Systems Assignment
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AC voltage controlling units are used for regulating the RMS units of an "alternating voltage" delivered towards a load resistance. The ac voltage controlling unit is a form of power system thyristor that converts a constant voltage, fixed frequencies alternating current necessary inputs towards a different voltage alternating current output. The "triggering angle" (a) is used for regulating the "RMS value" of the "ac output voltage" as well as the power supply delivery towards the load.
“AC voltage controller”
(Source: https://rmkcet.ac.in/eee/Notes/PowerElectronics/PowerElectronics.pdf)
The graphic below depicts a "single-phase full-wave ac voltage controller" having such a load resistance (Shahet al. 2018). Through altering the triggering angle (a), the ac output current towards the loads may be controlled across both half cycles. As a result, the "full wave ac voltage controller" is also known as a unidirectional regulator.
Circuit diagram of “AC voltage controller”
(Source: PSPICE)
Mode-1- From 0 to π
In the time of first +ve semi cycle of input unit of the voltage mains, there has been forward biasing for T1 thyristor. The T1 thyristor has been activated having an angle for delay (0 £a£p). When the thyristor is at ON state then it is being used as an ideally switching device, then inputs voltage level emerges throughout the "load resistance" RL as well as the "output voltage" Vo=Vs emerges throughout t to radians (Mokhtariet al. 2018). In the time of the absorption period of T1 between t to radians, the "load current" travels downwards via the ON thyristor T1 as well as the "load resistance" RL.
Mode-2- From 0 to π
Whenever the "input voltage" goes to 0 to pi state for omega, the transistors power decreases to null, therefore T1 switches off automatically. From alpha+pi and pi value for omega, no current is flowing inside the connection. There has been forward biasing for thyristor T2 in the time of the "negative cycle" of the input unit, as well as whenever activated at a delayed angle(p+a), the voltage output tracks the "negative half cycle" of the input through double pi value for alpha + omega.
Whenever T2 is turned on, its "load current" is flowing as in reverse way (rising) via T2 for w t =(p+a) to 2p radians. The durations among T1 as well as T2 gates trigger impulses is maintained constant atp radians or 1800. At w t =2p, its "inputs power supply" drops to zero, causing the "load current" decrease to zero as well, & the thyristor T2 switch off automatically.
A TRIAC could be utilized for input waveform ac voltage regulation for workloads up to 400Hz rather than two SCRs in parallel (Kimet al. 2018). Typically, pulse width modulation Thyristors, that are very affordable, and conversion grading Thyristors, that are weaker than rapid shifting converter level Thyristors, are utilized. Because of ac line synchronization or spontaneous commuting, no additional converter circuits or parts are required, as well as the circuitry for ac power regulators are relatively simple.
Waveforms
Waveform of “AC voltage controller” (Single phase)
(Source: https://rmkcet.ac.in/eee/Notes/PowerElectronics/PowerElectronics.pdf)
Waveform of I/p volt., load current, thyristor volt. as well as load volt.
(Source: https://rmkcet.ac.in/eee/Notes/PowerElectronics/PowerElectronics.pdf)
The "trigger angle" (a)can be used to change the RMS value of the O / p voltages as well as load conditions. Such circuit, known as an "AC RMS voltage regulator", could be utilized for managing the RMS voltage alongside the terminals of an alternating current motors (Jinget al. 2018). Through altering the RMS O/ P volt., this is possible on the way to adjust the temperatures of any furnaces. If the "load inductance" 'L is particularly big, the SCR can delay for commutating after being triggered, as well as the voltage level would become a complete "sine wave" as soon as the receiving impulses are supplied towards the thyristors T1 as well as T2. The "load signal" would look as a complete constant "sine wave", with the system "power factor" angle (f) causing it in the direction of lagging behind the generating "sine wave".
The "trigger angle" (a) could be changed via altering the RMS O/p volt. alongside the load. For a simply “resistive load” L =0, consequently the “load power factor angle” will be f= 0
Thyristor-based "ac voltage controllers" feature higher effectiveness, controlling versatility, as well as need less care. The development of harmonics inside the supplied flow as well as load voltages waves is a drawback of "ac voltage controllers", especially at "low output voltages”. Power factor management, often defined as power quality improvement, is the technique of minimizing "reactive power". The "reactive power" is at right angles (90°) towards the real electricity power triangles which is utilized for activating the magnetism. Despite the fact that "reactive power" has no practical use in electronic devices.
References
Journals
Jing, Y., Li, R., Xu, L. and Wang, Y., 2018. Enhanced AC voltage and frequency control of offshore MMC station for wind farm connection. IET Renewable Power Generation, 12(15), pp.1771-1777.
Kim, H.S., Jung, H.S. and Sul, S.K., 2018. Discrete-time voltage controller for voltage source converters with LC filter based on state-space models. IEEE Transactions on Industry Applications, 55(1), pp.529-540.
Mokhtari, M., Zouggar, S., M'Sirdi, N. and Elhafyani, M., 2018, June. Behavior Analysis Of Asynchronous Wind Turbine In Presence Of Static Synchronous Compensator Operating With Fuzzy Logic Voltage Controller. In ECRES 2018, 6th Eur. Conf. Ren. Energy Sys. 25-27 June 2018, Istanbul, Turkey.
Rakhmawati, R. and Murdianto, F.D., 2018. AC-AC Voltage Controller of Power Supply for Heater on Drying System. TELKOMNIKA, 16(3), pp.1061-1070.
Shah, R., Preece, R. and Barnes, M., 2018. The impact of voltage regulation of multiinfeed VSC-HVDC on power system stability. IEEE Transactions on Energy Conversion, 33(4), pp.1614-1627.
