HOME NEWS Servo voltage regulator: types and selection of three-phase servo voltage regulator
Jun 09,2020

Servo voltage regulator: types and selection of three-phase servo voltage regulator

The working principle of servo voltage regulator: The servo motor type AVR uses a servo motor and a carbon brush to mechanically adjust the input voltage to the output voltage. The three-phase voltage stabilizer is a voltage stabilizing device installed in a three-phase circuit. Its function is to stabilize the power supply voltage that fluctuates greatly and fails to meet the requirements of electrical equipment within its set value range so that various circuits or electrical appliances The equipment can work normally under the rated working voltage. The three-phase AC voltage regulator is designed to stabilize the AC voltage. (Three-phase voltage regulator: function and working principle)When the external power supply network voltage fluctuations or load changes cause voltage fluctuations, it can automatically maintain the stability of the output voltage. It has the advantages of good efficiency, low energy consumption; excellent characteristics; small size, lightweight, easy to carry; easy to learn, easy to use in the actual operation process, convenient maintenance, and so on.


The scope of use of three-phase voltage regulator transportation, post and telecommunications, computer system injection molding, CNC machine tools, etc., can not only ensure the safety of the equipment but also extend the life of the equipment.


The voltage regulator is a device that can stabilize the output voltage, and it is composed of a voltage regulator circuit, a control circuit, and a servo motor. When the input voltage or load changes, the control circuit can sample, compare, and amplify the voltage. The position of the carbon brush of the compressor is changed, and the coil turns ratio is automatically adjusted to maintain a stable output voltage.


Compared with the relay type, the AVR type servo voltage regulator can provide more accurate voltage regulation, because it can be mechanically adjusted to ensure that your output voltage is always 220V, and has a faster response time: AVR type servo motor response is expected + /- 1% voltage deviation.

Servo motor Automatic Voltage Regulator SVC Series


However, because the cost of the servo motor itself is much higher than the relay-type electronic components, the price is higher. It is generally recommended for: sensitive electronic equipment, such as medical equipment, dental and laboratory equipment.

Rule of thumb: The more expensive the equipment the more sensitive the electronic components, so you may need to invest in an AVR servo motor to ensure safety.

 

Servo AC voltage regulator: It is characterized by an automatic regression circuit of the voltage regulator, which is composed of a sampling transformer, a rectifier circuit, a constant filter circuit, a voltage divider circuit, an op-amp, a drive circuit, a relay, and an energy storage circuit in turn. The mains is stepped down by the sampling transformer, rectified by the rectifier circuit, and sent to the constant filter circuit to obtain a DC signal whose output change is completely proportional to the input AC. The sampled voltage obtained by the signal after the voltage divider circuit is divided and sent to the op-amp The non-inverting end of the amplifier is connected to a reference power supply at the inverting end of the op-amp. The non-inverting end of the op-amp is compared with the inverting end potential through the drive circuit to control whether the relay is closed or not. The normally closed contact of the relay is connected to the voltage regulator The output end of the device, the normally open contact is connected to the negative power supply of the energy storage circuit, and the other end is connected to the motor.

 

When the input mains power is lower than 200V and shut down or power failure, the brush will return to the position near 260V on the line pack. When the input mains power is higher than 200V, the brush will stop in the state before shutdown regardless of shutdown or power failure. Due to the installation of this intelligent automatic return circuit, the problem of large current that occurs when starting up is completely solved, and the service life of the voltage regulator is extended. The core of the servo voltage regulator is an AC voltage regulator transformer (automatic voltage regulator). A servo motor is controlled by a control circuit to drive the voltage regulator to automatically adjust the voltage. (Keep the output voltage 220v).


According to the international division, automatic voltage regulators (AVR) are divided into the following 7 types:

RELAY jump type: Use electronic circuits to control RELAY jump between high and low voltage, control the output voltage to be within the set range, generally between ±3% or ±5%. The advantage is that the input range is large and the manufacturing cost Low and light. Its shortcomings are poor voltage regulation rate, short RELAY contact life, slow response, unable to do large capacity AVR.


TRICA jump type: its characteristics are similar to the RELAY type, the RELAY is changed to the TRIAC semiconductor, the contact switch is changed to an electronic contactless switch, the file jump speed is fast, the volume is small, and the weight is light. The full electronic type has no dynamic components.

Servo electronic type: use the electronic circuit to detect the high and low output voltage to control the forward and reverse rotation. When the voltage is low, the forward rotation is used to increase the output voltage. When the voltage is high, the output voltage is reversed to reduce the voltage to achieve the regulation effect. It can be set to ±1%~5% depending on the load requirements.

 

Magnetic resonance: its control is all designed in a transformer, no additional electronic circuit is needed for detection and control, and the voltage regulation completely uses an external set of capacitors and a set of harmonic coils of the transformer to generate LC resonance, and the resonance voltage is up to 600V or more, Use this resonance to use the frequency of 60Hz or 50Hz as the resonance point, that is, the FO control output is at the same voltage to achieve the effect of voltage stabilization, so the resonance type still needs to consume about 30% of the current on the resonance coil when it is no-load.


SCR electronic: Use silicon controlled rectifier semiconductor (SCR for short). Do stepless phase control to achieve stable voltage with the magnitude of voltage conduction, voltage change from detection and detection. The calculation to the output control signal, adjust SCR. The flux starts to adjust within about half a week, and the adjustment is completed within about 5mSEC (about 80mSEC), the response speed is very fast, the accuracy is high, and the regulation rate is within ±1%. Advantages: No activity The wear-resistant component can filter out the noise generated by the electricity, the response speed is fast, the voltage regulation accuracy is high, and it is suitable for any load and precision equipment. Disadvantages: manufacturing is more complicated and the cost is higher.


Magnetic saturation type: The control principle is similar to the SCR electronic type, but the original control element is designed in the DC saturation coil of the transformer. The entire structure is also focused on the transformer. The transformer is wound with multiple sets of coils, including the main coil, the boost coil, and the buck Coil, DC coil and filter coil, (SCR type separates the various coils), the step-down coil is larger than the booster coil when the voltage is high, the DC saturation coil does not operate, and the step-down and booster coils are offset, the output voltage will be It will drop. When the voltage drops, the control circuit will send a direct current to the saturation coil to reduce the inductance of the step-down coil, then the step-down effect will be reduced, and the boost effect will remain unchanged. The size of the DC voltage will change according to the level of the output voltage, You can control the saturation of the step-down coil to achieve voltage stabilization. Advantages: no moving and easy-wear components, can filter out the noise generated by the mains, fast response, high voltage regulation accuracy, suitable for any load, high precision Equipment. Disadvantages: expensive.


Induction type (IVR): The principle is the same as the electronic servo type, except that the self-coupling transformer is changed to the axis induction. Its structure is similar to the structure of the motor, divided into the stator and the rotor, using the positive and negative rotation of the motor, rotating the angle of the rotor, so that The magnetic field of the rotor and stator changes. When the phase is induced in the forward direction, the voltage rises, and in the reverse direction, the voltage decreases, to make a voltage stabilizing effect.


How long can the AVR servo motor last forever: 


If voltage fluctuations frequently occur in your area, you may have to perform the following operations after a few years:

Replace carbon, because carbon wears out during all voltage regulation movements

Submit the servo motor for maintenance and calibration to readjust the voltage setting

Faster response time: The relay-type AVR will respond within 1 second of +/- 10% voltage deviation. Note: 1 second may make a huge difference for extremely sensitive electronic components, so for those types of equipment, the servo motor type will be better.

 

Servo motor automatic voltage regulator SVC series


Single-phase 500VA-10KVA servo motor type voltage regulator, the input voltage range is 140-260V, and the output voltage accuracy is 3%

Servo motor automatic voltage regulator SVC series products use large-scale linear and logic circuits to form a control system, control the servo motor to drive contact high-voltage automatic high voltage, apply industrial-grade high-precision servo voltage stabilization technology to civil power products, overcome The traditional transfer type instantaneous power loss realizes high-precision, uninterrupted voltage stabilization output. When the external power grid voltage is unstable, it can ensure the safety and normal use of high-end appliances, and can effectively extend the use of high-end appliances. life.

 

Three-phase servo motor AVR SVC33 series

3 Phase Servo Motor AVR SVC33 Series

Three-phase servo motor automatic voltage regulator: the use of linear and logic integrated circuits to form a control system. Complete functions and novel shapes. It can work uninterruptedly, the voltage regulation process is stable, and there is no instantaneous power loss. It can ensure the safe and normal use of various electrical appliances and home computers with memory function. Complete functions, with over-voltage, under-voltage indicators, and protection, long delay, short delay function, have good protection against overload or short circuit of the circuit. There is a mains/regulated voltage switching function, which can be directly connected to the mains when the user needs it.

Various indicators

Input

When the input voltage of the A.B&C phase is within the acceptable range, these LED lights.

Regardless of any phase over voltage, under-voltage, or phase loss, this LED will be off.

power

When the device is powered on, this LED indicator lights up; when the device is turned off, this LED indicator goes off.

delay

When the device enters the delay mode, this LED indicator lights up and turns off after the delay period is completed.

Output

When the device has an output voltage, the device enters the delay mode or protection occurs, the LED indicator will light.

 

The role that the voltage regulator can bring:


It plays a protective role in precision instruments with higher voltage requirements; laboratory equipment (laboratory equipment) in higher standard laboratories (laboratory) are equipped with voltage regulators to ensure the accuracy level (accuracy) of experimental (laboratory) data; Hospitals, national defense, factories, schools, finance, and other relevant agencies are equipped with voltage regulators to ensure the stability and safety of equipment operation.

 

Quickly select the appropriate three-phase servo voltage regulator method:


First look at your type of electrical equipment. In general, the load is not purely resistive, so in the actual selection, it is necessary to reasonably select the regulated power supply according to the specific conditions of the electrical equipment's rated power, power factor, and load type. The output power should have a proper margin, especially when the impact load is selected.

1. Pure resistive loads such as incandescent lamps, resistance wires, electric furnaces, etc., the power of the voltage regulator should be the power of the load equipment

1.5 times to 2 times. For example, your electric stove is about 250W, please choose a 500W regulator.

2. Inductive and capacitive loads such as fluorescent lamps, fans, motor pumps, air conditioners, refrigerators, etc. The power of the voltage regulator should be 3 times that of the load equipment. For example, if the motor is 1000W, please choose a 3000W regulator.

3. Under the environment of large inductive and capacitive loads, the starting current of the load should be considered to be particularly large (up to 5 to 8 times the rated current). Please select a power regulator with more than 3 times the power.