Basic introduction
Voltage regulator: Ouyang Huasi power supply is a power supply circuit or power supply equipment that can automatically adjust the output voltage. Its function is to stabilize the power supply voltage that fluctuates greatly and cannot meet the requirements of electrical equipment within its set value, so that all kinds of circuits or electrical equipment can work normally under the rated working voltage.
Voltage regulators include: tens to thousands of kilowatts of large-scale AC voltage regulators, which are the working power supply for large-scale experimental, industrial and medical equipment. There are also small AC voltage regulators of several watts to several kilowatts to provide high-quality power for small laboratories or household appliances.
The original power regulator is to stabilize the voltage through the jump of relay. When the grid voltage fluctuates, the automatic correction circuit of the power regulator is started to make the internal relay act. Forcing the output voltage to stay near the set value, this circuit has the advantages of simple circuit, but the disadvantage is that the voltage stabilization accuracy is not high, and the power will be cut off instantly every time the relay jumps and shifts, resulting in spark interference.
This greatly interferes with the reading and writing work of computer equipment, which is easy to cause computer error signals and even damage the hard disk in serious cases.
At present, most of the high-quality small voltage regulators adopt the way of motor dragging carbon brush to stabilize the voltage, which has little interference to electrical equipment and relatively high voltage stabilization accuracy.
principle of operation
Because some electrical appliances contain coil elements, eddy current will be generated at the initial stage of power-on, which will not only weaken the instantaneous voltage when the electrical appliance is started, resulting in slow start-up, but also strengthen the instantaneous voltage generated after the circuit is disconnected, which may cause sparks to damage the circuit. At this time, a voltage regulator is needed to protect the normal operation of the circuit.
The voltage regulator consists of voltage regulating circuit, control circuit and servo motor. When the input voltage or load changes, the control circuit samples, compares and amplifies, and then drives the servo motor to rotate, so that the position of the carbon brush of the voltage regulator changes, and the output voltage is kept stable by automatically adjusting the coil turns ratio. The large-capacity voltage regulator also works according to the voltage compensation principle.
Regulator
function
With the rapid development of society, electrical equipment is increasing day by day. The aging and lagging development of transmission and distribution facilities, as well as poor design and insufficient power supply, cause the end-user voltage to be too low, while the end-user voltage is often very high, which is like an untimely bomb for electrical equipment, especially for high-tech and precision equipment with strict voltage requirements. As a public power grid, commercial power system is connected with thousands of loads, some of which are inductive, capacitive and switching power supplies. They not only get electric energy from the power grid, but also adversely affect the power grid itself, worsen the power supply quality of the power grid or local power grid, and cause waveform distortion or frequency drift of commercial power supply voltage. In addition, unexpected natural and man-made accidents, such as earthquake, lightning strike, open circuit or short circuit of power transmission and transformation system, will endanger the normal power supply, thus affecting the normal work of the load.
Unstable voltage will cause fatal injury or misoperation of equipment, affect production, delay delivery, unstable quality and other losses. At the same time, it will accelerate the aging of equipment, affect the service life and even burn the accessories, which will make the owners face the trouble of maintaining or updating the equipment in a short time and waste resources; In serious cases, even safety accidents occur, causing immeasurable losses.
According to the test of electric power experts, the problems that often occur in the power grid that cause interference or damage to computers and precision instruments mainly include the following:
1. Power surge: the effective value of the output voltage is higher than the rated value 1 10% for one or several cycles. Surge is mainly due to the high voltage caused by the sudden unloading of large electrical equipment connected to the power grid when it is turned off.
2. High voltage spike: refers to the voltage with a peak value of 6000V and a duration from one ten thousandth of a second to half a cycle (10 ms). This is mainly caused by lightning strike, arc discharge, electrostatic discharge or switching operation of large electrical equipment.
3. Switching transient: refers to the pulse voltage whose peak voltage is as high as 20000V, but its duration is between one millionth of a second and one ten thousandth of a second. The main causes and possible damages are similar to those of high-voltage sharp pulses, but the solutions are different.
2. Power sag: refers to the low voltage state where the effective value of the mains voltage is between 80% and 85% of the rated value and lasts for one to several cycles. Large equipment startup, large motor startup or large power transformer connection may cause this problem.
5. Electrical line noise refers to high-frequency interference such as radio frequency interference (RFI) and electromagnetic interference (EFI). The operation of motor, the action of relay, the work of motor controller, broadcast emission, microwave radiation and electric storm will all cause line noise interference.
6. Frequency change: refers to the power supply frequency change exceeding 3Hz. This is mainly caused by unstable operation of emergency generator or unstable power frequency.
Therefore, it is essential to use voltage regulator for electrical equipment, especially for high-tech and precision equipment with strict voltage requirements.