Smart Servo Stabilizer
The use of power supply in electronics equipment and gadgets has increased and it is still increasing. These power supplies are not stable as required by these electronics due to tremendous amount of gadgets damage or some technical fault. This arise the need for the power stabilization as to overcome this problem. There are multiple types of stabilizer in market but they are bulk and boost types and it have pre-define voltage level at output. They have lots of limitations, so this project handles this problem very well. The embedding of microprocessor chip technology and power electronic devices in the design of intelligent AC voltage stabilizers or automatic AC voltage regulators (AVR) to produce high-quality, stable electric power supply in the event of significant and continuous deviation of mains voltage. As advancement to use high performance digital control circuits and Autotransformer control using servo which gives pure sine wave output and allows the user to set voltage requirements through a keypad. It also provides over current protection due to short circuit. Is also protect from hazardous shock due to high voltage using Earth leakage circuit breaker. These stabilizers are low cost with higher Efficiency and better isolation in addition this can be adjusted with variable setting. This stabilizers used at CNC machines, domestic appliances medical equipment, tele-communication equipment’s, and so on.
Keywords - Servo voltage Stabilizer (SVS), Earth Leakage Circuit Breaker (ELCB), Triac,
I. INTRODUCTION
There is a huge amount of Servo Stabilizer but we have concluded and sorted out those latest versions of stabilizer work defined previously which can’t be neglected because these surveys are many much similar to the system, we are designing which are very helpful as well. But as usual there were some of the negative point, we have got through these surveys were some researches that they don’t consider earth leakage some has used complicated controllers can’t be able to set a particular value to the output.
The unstable power supply so produced has led to loss in industrial equipment’s. To combat the problems of power fluctuations, industries depend on servo voltage stabilizers to stabilize the power supply connected to their expensive machineries. The article focuses on the electrical hazards, consequences of electrical hazards, symptoms of electrical hazards, analysis of the situation in industries, types of stabilizers, servo voltage stabilizers, applications, advantages, history of servo voltage stabilizers and market potential. With the increasing growth of the consumer electronic/electrical products, the need for servo stabilizers is rising rapidly [1]
AC voltage sources is being used in many applications. The concept of conventional DC buck boost Converter is used. This project consists of three main units which are voltage and current sensing unit, control unit, and main circuit. These three units will work together to produce constant voltage. The voltage and current will sense the level of input voltage. Control unit in which 16-bit microcontroller is used will control the duty cycles of signal. This microcontroller has features like inbuilt ADC, JTAG, PWM generation etc. The PWM signal produced by this is given to main unit to drive the MOSFET. This circuit makes sure that at output we will get constant voltage. This circuit is implemented as a loop system but future development it can be implemented as a closed loop system.[2]
This is a stabilizer which constantly monitors the output voltage and controls the variations in the input voltage by movements of a motor. This motor in turn selects the proper output voltage on the variable transformer (variac). This is probably the cheapest power-conditioning product available. It gives reasonably good voltage regulation and is all right where voltage fluctuations are not considerable. Use of Servo Stabilizer is the only way to control erratic supply voltage conditions. Servo Stabilizer can control all types of loads i.e. inductive, resistive, capacitive loads. Other voltage stabilizers viz. Constant Voltage Transformers or Static Voltage Stabilizers cannot be used in such applications. Servo Stabilizers are available from 1 KVA 1 ph. to 250 KVA 1 ph and 3 KVA 3 ph. to 2000 KVA 3 ph. 3 ph. Servo Stabilizers can be for balanced or for unbalanced input voltages. [3]
The servo voltage stabilizer used in industries or for household the approved range of their operation is 150V,240V or 90V-280V. Servo Voltage Stabilizer are also manufactured and used widely in spite of the fact that they are obsolete and use outdated technology. The lately introduced technology which excludes this old-fangled, low voltage, high correction time, high maintenance issues of servo stabilizer are Static Voltage Stabilizer (SVS). Static Voltage Stabilizer doesn’t include any moving parts as in servo voltage stabilizer. The voltage in SVS is produced with the assistance of electronic circuits also it has absolute electronics to achieve correction in voltages and time. Therefore, it has extremely high voltage correction speed than servo voltage stabilizer. The paper deals with the static voltage stabilizer which is controlled by TMS320F28069 a DSP based controller and a voltage changes are accounted with the help of Buck- Boost Transformer.[4]
There is a summary of stabilizers from 2011 to 2018
II. LITERATURE REVIEW
Prof. Rutuja Bhat Warbhe, Shrivatsa Shandilya, Gaurav Kumar Tripathi, Ashish Kumar Rohit. [1] This is a stabilizer which constantly monitors the output voltage and controls the variations in the input voltage by movements of a motor. This motor in turn selects the proper output voltage on the variable transformer (variac) with fixed output voltage by manufacturer.
Dr.Rajendra Sawant, Kshitija Sawant, Laxmi Kanojia, Priyanka Samgiskar, Vishakha Nevarekar [2] The research consists of three main units which are voltage and current sensing unit, control unit, and main circuit and it will work together to produce constant voltage. Control unit will control the duty cycles of signal.
Sudha Venkatesh, Krishnaveni Muthiah [3] The article focuses on the electrical hazards, consequences of electrical hazards, symptoms of electrical hazards, analysis of the situation in industries.
Kapil Mulchandani, Shubham Bannore, Shilpa Lambor, Vrinda Parkhi [4] The paper deals with the static voltage stabilizer which is controlled by a controller and a voltage changes are accounted with the help of Buck- Boost Transformer.
III. METHODOLOGY
Here we are regulating the 230v AC power supply by using autotransformer. Because it has feature to stepping up and stepping down AC voltage using it variable arm. Its arm will move rotary clockwise or anti clockwise direction. The ATmega328P microcontroller is the heart of the smart servo stabilizer because the microcontroller will decide when voltage is to step up or step down the voltage level with monitor the input and output voltage continuously. Input voltage will sense through ADC via voltage divider circuit continuously and converted into a digital value. The driver is driving the servo motor clockwise or anti clockwise by using microcontroller signal. Basically, the microcontroller will give the signal to opto- coupler then this two TRIAC one for forward and another for reverse. AC servo motor which have 3 wire system first wire is for reverse, second wire is ground or common and third is for reverse. When signal is getting from first TRIAC then Forward coil will energize and motor will rotate anticlockwise, this motor shaft will connect to gear system it will reduces the speed and gives opposite direction arm movement and it will step up the voltageThe current transformer (CT) will used to sense the load current for cut-off the over current as second is used to sense the Earth leakage current for act asana earth leakage circuit breaker. This both current transformers will decide the relay cut-off condition when large current will draw or earth leakage will happen otherwise it will remain in on condition. 16x2 LCD display which is used to monitor purposed. This LCD display is used to display the input voltage and output voltage with current value continuously. This display is also showing the status of delay timer as well as low and high voltage limit status. Keypad is setting up the stabilizer parameters
IV. MODEL DESIGN AND IMPLEMENTATION
Here auto transformer is the main part of the stabilizer. This auto transformer act as step down as well as step up transformer so when voltage is below the set point then it acts as step up transformer. So, when voltage is over the set point then it acts as step down transformer. AC servomotor is used to rotate the knob of auto-transformer by using microcontroller and driver (Triac). There are two Triac U1 and U2, here U1 is used to rotate motor forward and U2 is used as rotate motor as reverse. This U1 and U2 are connected using Opto-isolator U4 and U5 respectively this opto-isolator diac is used to trigger the triac when input signal getting from the microcontroller. But here input voltage is sense by using ADC which is 8 bits, then this digital data is compare with reference value which is already store in EEPROM by using keypad. Voltage sensing is done through voltage divide resistor R7 and R8.
Here is CT 1 coil is sense load current using r1 r2 and r3. Here r3 and r2 are used as current divider circuit. R2 is act as pull up resistor and r3 as a pull-down resistor. R1 is used as coupling resistor from higher voltage spikes. Microcontroller is comparing with reference value and actual CT output current if current is below reference value then relay will be kept in ON position and if it will rise the reference value then relay will turn off with in 500 milliseconds
CT 2 coil is sense load current using r4 r5 and r6. Here r5 and r4 are used as current divider circuit. R4 is act as pull up resistor and r5 as a pull-down resistor. R6 is used as coupling resistor from higher voltage spikes. Microcontroller is comparing both phase and neutral current if this current is below 30mA then relay will be kept in ON position and if it will rise the current over 30mA then relay will turn off with in 500 milliseconds
Here both conditions will satisfy for on the Relay then Port PD.7 will high then transistor BC547 will turn on the relay and AC Supply passes to the load. This relay will turn on when voltage in a range, lower load current and earth leakage is less than 30 mA.Here 16x2 LCD Display is used to display the Input voltage, Output voltage and load current.
V. RESULTS
When we set the following Setting Parameters
Output Set voltage = 230 V
Output vtg variation = ±1V
Output voltage =210 to 250.
Input voltage =190 to 270
Load current= 10 A
Delay Time for Relay= 5 Sec
Here we analysis that is when we set the upper parameters to the stabilizer we got as following changes as shown in table. Here we observe input voltage load status stabilizer action and motor action. That when input voltage 190 to 270 it will try to maintain between 229 to 331v. For below 229v servo motor will rotate clockwise and auto transformer act as step up transformer. As well as for below 231v then servo motor rotate Anticlockwise and auto transformer act as step down transformer
In this both graph Blue level show input voltage and orange level shows output voltage. Here we analysis that is when input voltage will increment after 190 voltage stabilizer maintain 230 V upto 270 V. Same as input voltage will decrement after 270 voltage stabilizer again maintain 230 V and upto 190 V. That is in both graph we result that 190v to 270 it will maintain output as 230v and load remain turn on.
But below 190v and above 270v load get automatically turn off. Here Gray line shows the loads is in ON or Off Conditions using higher and lower level. Here we analysis for wide voltage range from 150 v to 320 v over this limit it may have chance to burn the auto-transformer
VI. CONCLUSION
The project mainly focuses on the stabilization of industrial equipments which has the fluctuating voltage or current rating this can be stabilized by this project very easily the report specifies all the in depth details of the overall activity done to complete the project which mainly consist of circuit diagram through all information is been brightened. Block diagram which helps us to understand the project much easily. Through which anyone can get help by that information.
VII. FUTURE WORK
In the future work, we would like to plan to use more advanced stabilizer that will be helpful for three phase power supply and also maintain the power factor at 0.99
REFERENCES
[1] Prof. Rutuja Bhat Warbhe, Shrivatsa Shandilya, Gaurav Kumar Tripathi, Ashish Kumar Rohit “Servo Controlled Automatic Voltage Stabilizer with Automatic High & Low Cut-Off Provision” Dr. D.Y Patil Institute of Engineering and Technology Vol.4(2017), Issue No:5 ISSN No:2348-4845
[2] Dr.Rajendra Sawant, Kshitija Sawant, Laxmi Kanojia, Priyanka Samgiskar, Vishakha Nevarekar “Static Voltage Regulator Using Thyristor with Transient Protection Implementation” K.K. Wagh Institute of Engineering Education and Research, Nashik, India, August 2017| IJIRT | Volume 4 Issue 3 | ISSN: 2349-6002
[3] Sudha Venkatesh, Krishnaveni Muthiah “A study on the determinants of growth for SMEs – with reference to Servo Stabilizer manufacturing units” Computer Training Centre, Coimbatore, India, ISSN 2229 – 3795
[4] Kapil Mulchandani, Shubham Bannore, Shilpa Lambor, Vrinda Parkhi ”Static Voltage Stabilizer” Electronics, Vishwakarma Institute of Technology, Pune, India, Volume: 05 Issue: 01 | Jan-2018, e-ISSN: 2395-0056 ,p-ISSN: 2395-0072
[5] Tang Hou-jun1 Liu Wei1 Nan1, 2 and Ye Peng-sheng1, "Analysis and control of buck-boost chopper type ac voltage regulator", Power Electronics and Motion Control Conference, IPEMC '09. IEEE 6th International, pp.1019-1023,2009. (references)
[6] Akiteru Ueda, Shinichiro Fujikura and Akihiro Torii, "Analysis of a three-phase buck boost ac chopper controlled in two phases, "Power Conversion Conference, pp.824-830, 2007..
[7] M. Naden and S.M. Hietpas, "Voltage regulator using an ac voltage-voltage converter", IEEE Transaction on Industry Application, Vol.36, No.1, pp.33-38, 2000..
[8] Hunyar M Veszpremi K. "New application fields of the PWM IGBT ac chopper", Eighth International Conference of Power Electronics and Variable Speed Drives, Vol.11, pp. 46-51, 2000.
