Automatic voltage regulators play a crucial role in power supply. So before discussing automatic voltage regulators, we must know what the role of the power supply is in designing the system? For example, in any working system such as smartphones, watches, computers, or laptops, the power supply is an important component of the power system as it provides consistent, reliable, and continuous power to the internal components of the system. In electronic devices, a stable and regulated power supply is provided to ensure the proper functioning of the circuit. There are two types of power sources, one is AC power obtained from a power outlet, and the other is DC power obtained from a battery.

A. What is an automatic voltage regulator:

Voltage regulators are used to regulate voltage levels. When stable and reliable voltage is required, automatic voltage regulators are the preferred equipment. It generates a fixed output voltage that remains constant under any changes in input voltage or load conditions. It acts as a buffer to protect components from damage. An automatic voltage regulator is a device with a simple feedforward design that uses a negative feedback control loop.

There are three main types of automatic voltage regulators:

1. Linear automatic voltage regulator and switch automatic voltage regulator; These are used for a wider range of applications.

2. Linear automatic voltage regulator is the simplest type of automatic voltage regulator. It has two types, compact, used for low-power, low-voltage systems.

3. Contactless automatic voltage regulator; It is currently the most advanced automatic voltage regulator, with high voltage stabilization accuracy, wide applicability, maintenance free, and long service life. Let's discuss different types of voltage regulators.

B. Structure and function of automatic voltage regulator:

Feedback circuit, stable reference voltage, and component control circuit. The voltage regulation process is very easy using the above three components. The first component of an automatic voltage regulator, such as a feedback circuit, is used to detect changes in the DC voltage output. Based on the reference voltage and feedback, a control signal can be generated and the voltage regulation circuit can be driven to compensate for changes.

Here, the path element is a solid-state semiconductor device similar to BJT transistors, PN junction diodes, or MOSFETs. Now, the DC output voltage can remain roughly stable.

C. Working principle of automatic voltage regulator:

Even when the input voltage or load conditions change, the voltage regulator circuit is used to generate and maintain a permanent output voltage. Automatic voltage regulators obtain voltage from the power supply and can maintain it within a range that is very suitable for other electrical components. The most common is that these automatic voltage regulators are used to convert DC/DC power, AC/AC, or AC/DC.

D. Types and working principles of automatic voltage regulators:

These regulators can be implemented through integrated circuits or discrete component circuits. Automatic voltage regulators are divided into two types, namely linear automatic voltage regulators and switch automatic voltage regulators. These automatic voltage regulators are mainly used to regulate the voltage of the system, but linear automatic voltage regulators have low efficiency, while switch automatic voltage regulators have high efficiency. In high-efficiency switch automatic voltage regulators, most of the i/p power can be transmitted to o/p without dissipation.

Basically, there are two types of automatic voltage regulators: linear automatic voltage regulators and switch automatic voltage regulators.

There are two types of linear automatic voltage regulators: series and parallel.

Switching automatic voltage regulators are divided into three types: boost type, buck type, and inverter automatic voltage regulators.

1. Linear automatic voltage regulator:

Linear automatic voltage regulator is used as a voltage divider. In the Ohmic region, it uses FET. The resistance of an automatic voltage regulator varies with the load, resulting in a constant output voltage. Linear automatic voltage regulator is the primitive type of automatic voltage regulator used to regulate power supply. In this type of automatic voltage regulator, the variable conductivity of active transmission elements (such as MOSFETs or BJTs) is responsible for changing the output voltage.

Once the load is connected, any input changes will cause a difference in current across the entire transistor to maintain a constant output. In order to change the current of the transistor, it should operate in an active ohmic region.

Throughout the process, this automatic voltage regulator consumes a significant amount of power as the net voltage inside the transistor decreases, dissipating like heat. Generally speaking, these regulatory agencies are classified into different categories.

Positive adjustable, negative adjustable, fixed output, tracking, floating, benefits.

Advantages of linear automatic voltage regulator:

Provide low output ripple voltage; Quickly respond to load or line changes; Low electromagnetic interference, low noise;

Disadvantages of linear automatic voltage regulators:

The efficiency is very low; Requires large space - requires a radiator; Cannot increase the voltage above the input

2. Series automatic voltage regulator:

The series automatic voltage regulator uses variable elements connected in series with the load. By changing the resistance of the series component, the voltage drop at both ends can be altered. And the voltage across the load remains constant.

The amount of current effectively used by the load; This is the main advantage of a series automatic voltage regulator. Even if the load does not require any current, the series automatic voltage regulator will not draw all the current. Therefore, series automatic voltage regulators are much more efficient than parallel automatic voltage regulators.

3. Parallel automatic voltage regulator:

The working principle of a shunt automatic voltage regulator is to provide a path from the power supply voltage to ground through a variable resistor. The current flowing through the parallel automatic voltage regulator has been transferred from the load and is useless to the ground, which makes the efficiency of this form usually lower than that of the series automatic voltage regulator. However, it is simpler, sometimes consisting only of a voltage reference diode, and is used in very low-power circuits where the wasted current is too small to worry about. This form is very common in voltage reference circuits. Parallel automatic voltage regulators typically can only absorb (absorb) current.

Application of Parallel Automatic Voltage Regulator:

Parallel automatic voltage regulator is used for: low output voltage switching power supply; Current source and current supply circuit; Error amplifier; Adjustable voltage or current linear and switching power supply; Voltage monitoring; Analog and digital circuits that require precise benchmarks; Precision current limiter.

4. Automatic voltage regulator switch:

The switch automatic voltage regulator can quickly open and close series devices. The duty cycle of the switch determines the amount of charge transferred to the load. This is controlled by a feedback mechanism similar to a linear regulator. Switching automatic voltage regulators are efficient because the series components are either fully conductive or closed, as they consume almost no power. Unlike linear automatic voltage regulators, switch automatic voltage regulators can generate output voltages that are higher than the input voltage or have opposite polarity.

The switch automatic voltage regulator quickly opens and closes to change the output. It requires a control oscillator to charge the storage components.

In a pulse rate modulated switch automatic voltage regulator, the constant duty cycle and noise spectrum applied by PRM will change; Filtering out this kind of noise is even more difficult.

A switch automatic voltage regulator with pulse width modulation, constant frequency, and variable duty cycle is efficient and easy to filter out noise.

In a switch automatic voltage regulator, the continuous mode current through the inductor never drops to zero. It allows for the highest output power. It provides better performance.

In a switch automatic voltage regulator, the discontinuous mode current through the inductor drops to zero. When the output current is low, it provides better performance.

5. Contactless automatic voltage regulator:

The contactless automatic voltage regulator uses integrated circuits to control the zero crossing and breaking of several thyristors in a specific order to change the magnitude and polarity of the compensation voltage. It is a perfect combination of thyristor AC switching technology and transformer technology.

Using high-power thyristors (thyristors) instead of mechanical and carbon brushes to control voltage regulation, the capacity can reach over 3000KVA, the compensation range can reach ± 60%, and the efficiency can reach over 99%. It is an advanced product in the development direction of high-power power automatic voltage regulators, an energy-saving and environmentally friendly product, with all protection functions, reliable operation, and strong adaptability.

It has achieved contactless voltage regulation, with the advantages of good stability and high efficiency, no pollution to the power grid, and can reliably work continuously under various harsh power grids and complex loads. It has a long service life and can operate continuously without faults for more than 100000 hours, achieving long-term maintenance free operation of the automatic voltage regulator.

Working principle: Using a microcomputer (DSP) for intelligent detection, output commands to control the fast switching of electronic modules (IGBT or SCR), and maintain stable output voltage through transformer frequency synchronization, phase locking, and sine wave superposition compensation. Fast response speed, no carbon brushes, no contacts, no machinery, automatic balancing of three-phase voltage.

Scope of application: Various CNC machining centers, medical equipment, microwave communication unmanned stations, industrial equipment matching, elevator matching printing machinery equipment, environmental testing equipment, electronic detection equipment, communication equipment, etc., especially suitable for harsh power supply environments such as large fluctuations in the power grid and sudden voltage changes.