MEDI’s Static Voltage Stabilizer is an IGBT based PWM type buck-boost voltage stabilizer which has tight regulation and fast correction speed which is impossible to obtain using conventional methods such as servo voltage stabilizers, SCR / triac type stabilizer, relay type stabilizer etc.

This is an SMPS type voltage stabilizer for mains voltage (AC input and AC output). This is a new switching topology where PWM is made directly in AC-to-AC switching, without any harmonic distortion. In this topology there is no need to convert the AC input to DC and again convert it back to regulated AC output. This simplifies the design, reduces the component count and improves the efficiency and reliability. The power stage is an IGBT chopper control. The chopping frequency is around 20KHz which ensures absolutely silent operation and pure sine wave output (no waveform distortion).

The control section is based on dsPIC controller which ensures quick correction of output which is not possible in conventional relay type stabilizer or servo controlled stabilizers. The circuit is having LCD display which will show all parameters like: input voltage, output voltage, connected load, your company name (We will program your company name in the dsPIC at the time of technology transfer) etc.

Since the circuit is fully solid state (no mechanical or moving parts) there will not be any wear and tear like the brush tear in servo stabilizer or relay degrading in relay based stabilizer.

This is specially useful in places where we need very fast correction speed, constant output voltage, overload current limiting and short circuit protection, soft start, high voltage cut-off and low voltage cut-off, automatic bypass, no wear and tear, long life and maintenance free which is impossible with other conventional relay type or servo control stabilizers.

WORKING

Let me explain what it is in brief – In this IGBT based PWM type static voltage stabilizer only the difference voltage is switched through IGBT and will be added or subtracted from the mains. This is done electronically without any step changing in voltage which occurs when the system regulates. This is achieved by a feedback control system using digital signal processor (DSP). The output voltage is sensed by the DSP and corrections are made by varying the duty cycle of the PWM.

This stabilizer boosts up the voltage if it is low and bucks the voltage if it is high.

For example - If the AC input is 200V and the AC output is set for 220V, only 20V will be regulated through the IGBT and will be added to the original mains source which is 200V. If the AC input is 195V, then 25V will be added....

So the power and current in the IGBT will be very less

Material cost (BOM) of 10KVA single phase -  approx. Rs.7,000  (includes control PCB + IGBT power PCB + heat sink +transformer + LCD + cabinet )

(Click to Download Write Up)