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Jun 06,2020

Constant voltage regulator:ac voltage stabilizer characteristics & installation environmental condit

The constant voltage regulator consists of a high-voltage resonant winding and a capacitor storage circuit to produce an almost constant average output with a constant input. The constant voltage regulator method is attractive due to the lack of active components. It relies on the square loop saturation characteristic of the oscillation circuit to absorb changes in the average input voltage. The key to judging the quality of a voltage regulator is to see whether its short-term dynamic stability is good. The regulator generates a fixed output voltage of a preset size, which remains constant regardless of changes in input voltage or load conditions.

Basic structural characteristics of commonly used voltage regulators:

Constant voltage regulator:ac voltage stabilizer characteristics & installation environmental condit

Fully-automatic compensation type power regulator:

the motor drives the carbon brush to slide between the windings of the self-coupling transformer to directly adjust the output voltage or adjust the output voltage through the compensation transformer. It has a strong load capacity, high working efficiency, small wave shape distortion, The power supply has a strong anti-interference ability. However, the response time is slow (≥1s), there is mechanical wear, regular maintenance is required, and the AC contactor and motor generate large noise during the voltage stabilization process. When the grid voltage is unstable or the load changes, the automatic control circuit drives the servo motor according to the change in output voltage, adjusts the position of the carbon brush on the contact auto-coupler regulator, and adjusts the output voltage to the rated value and reaches a stable state. It is generally used in large-scale electromechanical equipment such as industry, agriculture, transportation, post and telecommunications, military, and railways.

Purified AC voltage regulator:

 A method of combining sine wave energy distribution with a filter to adjust the output voltage by adjusting the conduction angle of the thyristor of the primary circuit. The voltage regulation accuracy is s±1%, the response time is ≤40ms, and it has good isolation, which can eliminate spike interference from the power grid. There is a phase shift between the output and input voltage, there is a little wave-shaped distortion (additional ≤3.5%) with some special loads (such as thyristor load) is not ideal. Generally used in precision electronic equipment, medical equipment, computer rooms, laboratories, product aging, and testing.

Ferromagnetic resonance AC voltage regulator

It is composed of a saturated choke coil and a corresponding capacitor, and has a constant voltage volt-ampere characteristic.

Magnetic amplifier type AC voltage regulator:

 A magnetic amplifier and an autotransformer are connected in series, and the impedance of the magnetic amplifier is changed by an electronic circuit to stabilize the output voltage. High voltage regulation accuracy and fast response time, generally used in precision electronic equipment, medical equipment, computer room, laboratory, product aging, and testing.

Non-contact AC voltage regulator

the principle of induction is used for voltage adjustment, and no contact is linearly adjusted in the load. In the voltage adjustment, no noise coupling and voltage drop will occur, resulting in the same load power quality as the input terminal The voltage regulator is equipped with an independent detection of output voltage under voltage and output voltage high voltage circuit. The upper and lower limits can be set by the load characteristics of the equipment. When the output voltage is under voltage or high voltage. The voltage regulator will automatically cut off the output power to protect the load and give an early warning. Switching one or more sets of thyristors when the voltage or current crosses zero, so that the compensation winding of one or more transformers in the compensation transformer set is boosted, stepped down, primary shorted, or switched from the tap of the lotus transformer To adjust the output voltage. Strong load capacity, high working efficiency, small waveform distortion, fast response time, low noise. Used in all places where voltage regulation is required.

Sliding AC voltage stabilizer

stabilize the output voltage by changing the position of the sliding contact of the transformer.

Inductive AC voltage regulator

By changing the phase difference between the transformer secondary and primary voltage, the output AC voltage is stabilized. Analyze the sampled circuit detection model. When the output voltage is too high, send a control signal to reduce the voltage to the drive device, adjust the drive voltage adjustment device to lower the output voltage, and when the output voltage is low, send the control device Send a control signal to increase the voltage, and drive the voltage regulator to increase the output voltage so that the output voltage is stable to achieve the purpose of stable output.

Thyristor AC regulator:

 Use thyristor as a power adjustment element. High stability, fast response, and no noise. But it causes interference to communication equipment and electronic equipment.

Modulated AC voltage regulator

stepless smooth adjustment; fast transient response, which can be called synchronous response; high precision voltage regulator: theoretical accuracy can reach more than 1%, currently adjustable from 1 to 3%; energy saving, low carbon and environmental protection; Wide voltage regulation range; Strong protection function: It has multiple protection functions such as over- and under-voltage, overload, over-current, short circuit, etc.; strong load capacity; input and output in the same phase, no waveform distortion; low failure rate, relatively thyristor products Reliability is improved by about 3 times. But the technical difficulty is higher and the price is higher.

Parameter voltage regulator

Use the saturation characteristics of the iron core material to show that the output voltage is stable. Advantages: reliable operation, strong overload capacity, automatic protection when the output is a short circuit, simple structure, large voltage range. Strong anti-interference ability. Generally used in computer-related products, medical monitoring systems, program control systems, and other environments.

Linear regulator

Active (BJT or MOSFET) adjustment device (series or parallel) controlled by a high-gain differential amplifier. It compares the output voltage with an accurate reference voltage and adjusts and adjusts the device to maintain a constant output voltage. A feedback loop is used, which automatically changes the resistance in the system to counteract the effects of load impedance and input voltage changes, all of which ensure that the output voltage remains constant. The voltage at the input of the linear regulator must be greater than the voltage at the output by a minimum value called dropout. As a workaround, use a linear regulator called an LDO (Low Dropout) regulator because their design has the ability to operate with a difference between input and output voltages as low as 100mV.

Switching regulator

Converts the DC input voltage to the switching voltage applied to the power MOSFET or BJT switch. The filtered power switch output voltage is fed back to the circuit that controls the power switch on and off time, so that no matter how the input voltage or load current changes, the output voltage remains constant. The basic implementation of the switching regulator is to use the "pass transistor" in the off state or saturation state as the switching element. When the transfer transistor is in the off state, no current flows, so no power is consumed, but in the saturated state, the voltage drop across the transistor is negligible, with a small amount of power consumption, the maximum current is forwarded to the load. The efficiency of the switching regulator is usually 70% north due to the energy saved during the switching action and off state.

Application scenarios of linear and switching regulators:

For a given input and output voltage, the power consumption of the linear regulator is proportional to the output current, so the typical efficiency can reach 50% or even lower. Using the best components, the switching regulator can achieve 90% efficiency. However, the noise output from a linear regulator is much lower than a switching regulator with the same output voltage and current requirements. Generally, switching regulators can drive higher current loads than linear regulators.


The unstable voltage will cause fatal injury or malfunction to the equipment, affect production, and result in delays in delivery and unstable quality. At the same time, it accelerates the aging of equipment, affects the service life and even burns accessories, which makes the owner face the trouble of needing to repair or update the equipment in a short period of time, wasting resources; in serious cases, even a safety accident occurs, causing inestimable losses.

In addition to the most basic voltage stabilization function, the voltage regulator should also have overvoltage protection (over +10% of the output voltage), under voltage protection (less than -10% of the output voltage), phase loss protection, and short-circuit overload protection. Basic protection functions.

When the grid voltage or load fluctuates instantaneously, the regulated power supply will compensate for the voltage amplitude with a response speed of 10-30ms to make it stable within ±2%.



Among them, the digitally stabilized power supply samples at the output end of the equipment through the observation area, and compares and checks the current-voltage with the rated voltage. If the comparison is negative, the data is sent to the central processing unit (CPU), and the central processing unit makes the voltage plus command. At the same time, the detection area detects whether the semiconductor has been turned on or off. After confirming that it is correct, the central processor makes a voltage plus command to control the semiconductor work, so as to reach the standard of the rated voltage. If it is positive, the central processor makes a command to reduce the voltage, and the entire process takes only 0.048 seconds to digitize. This device stabilizes the voltage that changes instantaneously through the digital control loop to ensure that the output voltage is always the rated voltage.


Circuit debugging process of constant voltage regulator:

When debugging, first adjust the moving contacts of RP and R to the middle position, connect a manual voltage regulator to the input terminal of the AC regulator, connect a voltmeter to the output terminal, adjust the voltage regulator to make the input AC The voltage is 220V, and then adjust the resistance of the R Tuo, so that M stops when the output voltage is 220V.

Disconnect the lead of M (the sliding contact should be connected at -220V), adjust RPl so that when the input voltage is adjusted to 230V, K can be pulled in immediately.


Conditions required for the installation environment of the voltage regulator:

The regulated power supply should be used in a ventilated and dry place indoors, and its use conditions are strict. The installation site should be free of gases, steam, chemical deposits, dust, greasy dirt, and other explosive and corrosive media that seriously affect the insulation performance of the regulator. There should be no severe vibration or bumps.

When the stabilized power supply reaches the installation site, it should be installed lightly and gently, and the voltage stabilizer should always be in a vertical upward state, and must not withstand wind, snow, ice, hail.

In order to prevent magnetic leakage interference, the distance between the voltage regulator and the equipment used should not be less than 2 meters. Various magnetic records, discs, cards, etc. should be 2 meters away from the machine to prevent accidental magnetization.

Before the commissioning and installation of the stabilized power supply, you must first check that all parts of the equipment should be intact and that the fixing parts should be firm and reliable. Confirm again that the voltage of the use occasion is consistent with the voltage of the voltage regulator. This equipment is a three-phase four-wire system with phase adjustment In this way, the reliability of the system neutral (neutral) connection is high, and the contact resistance of the neutral (neutral) connection should be reduced as much as possible. This equipment must be well connected to the ground, and the ground wire cannot be used together with the repeated ground wire of the power system (the neutral wire and the side of the ground wire) to ensure safety and improve anti-interference performance.

Voltage regulators generally include input terminals (A, B, C), output terminals (a, b, c, n), shielding, and iron core-shell ground terminals. These terminals are correctly connected to the voltage stabilizing system.

When the load equipment has a short circuit, the user needs to shut down to check, and then turn on again after eliminating the short circuit fault.

If the load imbalance exceeds 20%, a resistive load is connected in parallel with one phase of the light load to balance it. Similarly, if the imbalance of the line voltage at the input terminal is greater than 10%, it will also affect the voltage regulation performance of the machine. It should also be set from the input terminal to a single-phase voltage regulator to make the line voltage at the input terminal basically balanced. The two balances of input voltage and load do not exceed the above range, and the output line voltage imbalance is ≤5%.