Diesel generators are very important electrical equipment when used on construction sites or in enterprises. They are crucial tools in emergencies and can provide reliable power in the absence of electricity. However, many people need to be aware of the necessity of diesel generators, especially automatic voltage regulators. Let’s take a look at what an automatic voltage regulator is, its importance, its functions and how it works?

    What is an automatic voltage regulator?

    An automatic voltage regulator (commonly known as an AVR) is essentially a solid-state electronic device used in diesel generators. The design purpose of the AVR is to facilitate the automatic maintenance of the output terminal voltage of the diesel generator at the preset value, especially when the load of the diesel generator changes or the operating temperature of the diesel generator changes. Simply put, the AVR can be regarded as a component of the excitation system of a diesel generator.

    The AVR is essentially a part of the alternator. Here, the AVR model that comes with the alternator largely depends on the type of alternator and the accessories installed.

    It can stabilize the output of generators with irregular loads frequently, and can distribute reactive loads among numerous parallel generators (referred to as voltage drop), and provide assistance to diesel generators when overloaded.

    Generally speaking, automatic voltage regulators can be found anywhere below

    In the main control box of the diesel generator

    In the junction box of the alternator

    Various types of automatic voltage regulators (AVRs) control and regulate power systems. Some of the most common types include:

    Automatic voltage regulator

    Electromechanical AVR

    These are the oldest types of AVR, which rely on mechanical components such as rotors and stators to regulate voltage. Their designs are relatively simple and can handle various voltage and   power levels.

    Static AVR

    They use solid-state components such as transistors and thyristors to control the voltage output of diesel generators. They are more reliable and efficient than electromechanical AVRs, but may not be very robust under extreme conditions.

    Microprocessor-based AVR is the most advanced type of AVR and uses a digital controller (usually a microprocessor) to regulate the voltage output. They offer the highest level of accuracy and can be programmed to adapt to different operating conditions.

    Digital AVR

    Similar to the microprocessor-based AVR, it does not use a microprocessor as a digital controller but instead employs a digital signal processor specifically designed for high-speed mathematical operations.

    Servo motor AVR

    This type of AVR uses a servo motor to adjust the excitation of the diesel generator according to the changes in power load and voltage. It uses control loops to enhance accuracy and performance.

    Computer-controlled regulator

    As the name suggests, it mainly depends on the total system load current transmitted to the power generation computer. The engine computer ensures that the magnetic field circuit is connected and disconnected on time as per the specified values, enabling the electrical system to operate normally.

    These are not a broad list. There are also other types of AVR on the market, such as IC-based AVR, etc.

    An automatic voltage regulator (AVR) is a device that automatically maintains a stable voltage level in the power system.

    What is the function of the automatic voltage regulator (AVR)?

    It regulates and stabilizes the voltage of diesel generators.

    It serves as a machine for maintaining the stability of voltage steady-state.

    It reduces high voltage by distributing reactive power loads on parallel AC diesel generators.

    AVR regulates overvoltage caused by a sudden drop in the load.

    Enhance the incentive of the system in case of failure.

    Ensure that the synchronous power supply still exists after the fault situation is eliminated.

    The AVR adjusts the load of the excitation system when the load changes to maintain a constant voltage.

    It is used in the field of exciter. In addition, it also modifies the excitation current and the output voltage of the exciter.

    During violent oscillations, it remains calm and does not respond, which keeps the voltage stable and continuous.

    How does the diesel generator AVR work?

    The AVR mainly functions by controlling the output voltage of the diesel generator. It accomplishes this task by first sensing the voltage from the terminals of the diesel generator and then comparing it with a preset stable reference value to check for any error signals (if any). If there is a difference between the two, the AVR adjusts the excitation current by increasing or decreasing the current flowing to the stator of the exciter, which in turn ensures that there are lower or higher voltages at the main stator terminals respectively.

    You may now understand that the AVR is used as a regulating device to ensure that the voltage output of the diesel generator remains within the predetermined range. Therefore, it ensures that the voltage of the diesel generator will never drop to a level that would cause any connected electrical equipment or electrical installations to malfunction. It also helps prevent the diesel generator battery from running out of power.

    When the speed of a diesel generator changes, the adjustment of its output becomes crucial – this mainly occurs when the speed of the diesel generator engine changes, as the transmission ratio between the diesel generator and the engine is fixed. During this period, a stable voltage can ensure the safe operation of the electrical equipment for power supply and the diesel generator battery.

    At Yaokai, with our extensive understanding of the market and our expertise in the design, research and development, and manufacturing of diesel generator set components, we can help you select the ideal diesel generator replacement parts that meet your requirements. At the same time, we can also provide high-quality diesel generators for industrial buildings, data centers, hospitals, commercial facilities, etc.! If you still have any questions related to diesel generators, please contact Yaokai. Our professionals are always ready to help you solve any doubts about diesel generator sets and their components, and assist you in finding the best choice.