The static stabilizer offers a reasonable improvement on slow servo controlled stabilizer as well as other static tap changing stabilizers. This technology does not cause di/dt problems as it does not switch the power path. The basic topology is with buck-boost transformer with high primary to secondary ratio for voltage correction of ± 25%. The control voltage is imposed on the primary of this buck-boost transformer. The voltage regulation with help of buck and boost topology is achieved electronically without the step changes in voltage that occur when the system regulates. This task is accomplished through a feedback and a control system implemented by using a microcontroller. 
The system uses IGBTs as power switches. Direct AC-AC converter circuit improve the overall system response and fast voltage correction. No storage capacitor increase life of the system. 20Khz PWM control operation using high end dsPIC controller to achieve correction time of 1 to 1.5 cycle. Excellent performance in voltage sensitive application.

What is Static Voltage Regulator? 

    What are the advantages of Static Voltage Regulator? 

WM Controlled Static Voltage Stabilizer V/s Tapchanging or Servo Mechanical Stabilizer

PWM Controlled IGBT based technology

Other Conventional Electromechanical Stabilizer

Designed with fully solid state components to govern regulation, no moving part or tapchanging mechanism (relay / static device)

This conventional method is designed with moving part (motor) or tap changing mechanism (Relay / static device) to govern regulation

No maintenance required

Periodic preventive maintenance required

Due to the fully solid state drive and power circuitry which uses no mechanical parts in the regulation circuitry, operation is highly reliable, precise, noiseless, interruption-free and fast and the units are absolutely free from wear and malfunctions.

The motor driven mechanical system, motor commutators, and the moving brushes on the variable transformer need

Exceptionally high speed of voltage correction to meet modern voltage sensitive equipment

Slow speed of voltage correction to meet modern equipment

Because the series of Static Automatic Voltage Stabilizers function only through static electronic components, the speed of the line and load regulation is exceptionally high (of the order of 360 v/sec. line and 500 v/sec. load regulation) Ideal for modern voltage sensitive equipment.

Because of the inertia of electro-mechanical regulation gear, Motor Driven Voltage Stabilizers can only respond to regulate the voltage fluctuations at a speed of 40 v/sec. in general and 70 v/sec. maximum.

Inbuilt auto-bypass with no transition time

In conventional stabilizer auto bypass is not there or with limitations

PWM controlled IGBT based technology has advantage of providing auto bypass. System will get bypass if any electronics part will get failed with no transition time.

In conventional method to achieve auto bypass feature excessive switch gear is required which add cost to the system as well this solution will provide power interrupt during bypass

Same correction speed in all power range

Correction range vary according to power range

Static Voltage Stabilizer are manufactured through the power range from 2 KVA single phase to 600 KVA tri-phase with the same design and operation principal. Only different driver PCB's (printed circuit boards) are used all through the standard power range, so the compactness and reliability is unchanged.

The Motor-Driven Voltage Stabilizers require excessive switch gear and additional buck-boost transformers when the nominal power is increased above a certain level.