Introduction: Power is the heart of information systems and electronic products. The quality of AC power determines whether information systems and electronic products can work normally. Therefore, understanding the quality of AC power can provide an effective solution. There are several quality problems with AC power.
First, the power quality problem
1. The range of voltage changes is too large, the power supply of the power grid is insufficient, the power supply department adopts step-down power supply, or is located in a remote area, and the loss is too much, resulting in a low voltage; the power supply of the power grid is too small, resulting in a high voltage. The voltage is too low, the load does not work properly; the voltage is too high, the load life is shortened, or the load is burned.
2. Waveform distortion (or harmonics) is caused by the use of switching power supplies in power electronics and electrical equipment such as rectifiers, UPS power supplies, electronic speed control equipment, fluorescent lighting systems, computers, microwave ovens, energy-saving lamps, and dimmers. The hazards of harmonics to the public power grid mainly include:
1) The components in the public power grid generate additional harmonic losses, which reduce the efficiency of power generation and transmission and transformation equipment. When a large number of 3rd harmonics flow through the neutral line, the line may be overheated or even fired;
2) Influencing the normal operation of various electrical equipment, in addition to causing additional losses, it can also cause mechanical vibration, noise and overvoltage of the motor, causing severe overheating of the transformer, causing overheating of capacitors, cables and other equipment, insulation aging, and shortening of service life. So that it is damaged;
3) It will cause local parallel resonance and series resonance in the public power grid, thereby amplifying the harmonics, greatly increasing the aforementioned hazards and even causing serious accidents;
4) It will cause relay protection and automatic device malfunction, and make the measurement of electrical measuring instruments inaccurate;
5) It will cause interference to neighboring communication systems, light noise will be generated, communication quality will be reduced, and information loss will be caused by heavy ones, which will make the communication system unable to work normally.
3. Surge (or surge, surge) means that the effective value of the output voltage is higher than the rated value of 110% in an instant (in milliseconds) and lasts for one or several cycles, which is the main culprit in destroying precision electronic equipment. . In addition to being caused by lightning strikes, the main reason is the high voltage generated by the sudden unloading of the power grid when the large electrical equipment connected to the power grid is turned off.
1) The effects of surges on sensitive electronic and electrical equipment are of the following types.
Destruction: voltage breakdown of semiconductor devices; destruction of metallized surface of components; destruction of printed circuit board printed circuits or contact points; destruction of three-terminal thyristor components / thyristors.
Interference: lockout, thyristor or triac eccentricity; data file partially corrupts data processing program; error: error and failure in receiving and transmitting data; unexplained failure.
Premature aging: parts are prematurely aged, electrical life is greatly shortened; output quality and picture quality are degraded.
2) Power surges will destroy electrical equipment. The electrical equipment containing the microprocessor is extremely vulnerable to power surges. This includes computers and auxiliary equipment, program controllers, PLCs, fax machines, telephones, and message machines. Program-controlled switches, Radio and television transmitters, video equipment, microwave relay equipment; products in the home appliance industry include televisions, stereos, microwave ovens, video recorders, washing machines, dryers, refrigerators, etc. According to the survey data, 63% of the electrical equipment that had problems during the warranty period was caused by a surge.
4. A sharp wave (or high voltage spike) refers to a voltage of up to 6000V with a duration of 10-4-10ms. This is mainly due to lightning strikes, arcing, static discharge or switching operations of large electrical equipment.
Its hazard is mainly: when the peak pulse amplitude is large, it will destroy the input filter, rectifier and even the main vibration tube of the industrial computer switching power supply. In addition, its spectrum is very wide, and it will also cause interference when it breaks into the computer.
5. Transient overvoltage and transient overvoltage refer to the pulse voltage with a peak voltage of up to 20000V but a duration of 10-6s-10-4s. The main cause and possible damage are similar to high-voltage spikes, mainly caused by lightning.
Its main hazards are: advanced electronic devices such as measurement, monitoring, protection, communication, computer networks, etc. with large-scale integrated circuits as the core components, and electronic devices such as large-scale CMOS integrated components. The shortcoming of current withstand capability is that the transient over-voltage will not only cause the electronic equipment to malfunction, or cause the electronic equipment to be interfered with, the data is lost, or temporarily paralyzed; in severe cases, the breakdown of the components and the burning of the circuit board may occur. The whole system is paralyzed.
6. Voltage sag/drop refers to the low voltage state where the rms voltage rms value is between 80-85% of the rated value and lasts for one to several cycles or even longer. Reasons for this include large equipment start-up and applications, large motor start-ups, or large power transformer access, main power line switching, line overload, and more.
The main hazard is that the impact on the computer is such that the interface device such as keyboard is suspended, and the data is lost and the file is destroyed. The sag of the voltage also destroys components in the computer, resulting in a shorter life. Voltage sags are the most common power problem, accounting for 87% of power problems.
7. Three-phase voltage imbalance means that the phase voltages between the phases are not equal or the line voltages are not equal. It is caused by the imbalance of the load of each phase, that is, it is related to the load characteristics of the user, and also related to the planning and load distribution of the power system. The relevant standards stipulate that the allowable value of the unbalance degree in the normal operation mode of the common connection point of the power system shall be 2%, and the short time shall not exceed 4%. Hazard to the transformer: When the three-phase load is unbalanced, the transformer is in an asymmetrical operating state, resulting in increased transformer losses (including no-load loss and load loss). According to the transformer operating regulations, the neutral current of the transformer in operation shall not exceed 25% of the rated current of the low-voltage side of the transformer. In addition, the unbalanced operation of the three-phase load will cause the zero-sequence current of the transformer to be too large, and the temperature rise of the local metal parts may even cause the transformer to burn out. The impact on the electrical equipment: the occurrence of three-phase voltage imbalance will lead to the occurrence of several times the current imbalance, induce the increase of the reverse torque in the motor, so that the temperature of the motor rises, the efficiency decreases, the energy consumption increases, the vibration occurs, and the output Loss; the service life of the electrical equipment is shortened, the frequency of equipment parts replacement is accelerated, and the cost of equipment maintenance is increased; the excessive unbalanced current flowing into the neutral line causes the neutral line to be thickened. Impact on line loss: Increase line loss, where the load pattern has different effects. Taking the three-phase four-wire system as an example, when one phase load is heavy and the two-phase load is light, the line loss increment is small; when one phase load is heavy, one phase load is light, and the third phase load is In the case of average load, the line loss increment is large; when the phase load is light, and the two-phase load is heavy, the line loss increment is the largest. When the three-phase load is unbalanced, the current imbalance is greater and the line loss increment is larger regardless of the load distribution.
8. Noise interference (or noise) refers to radio frequency interference (RFI) and electromagnetic interference (EFI) and various other high frequency interferences, resulting from electromagnetic or high frequency wave induction. Motor operation, breaker operation, motor controller operation, broadcast emissions, microwave radiation, and electrical storms can cause noise. Its hazard is mainly: let the computer CPU produce a misjudgment action, in severe cases, it may burn out the CPU and other computer accessories, which may cause the radio transmission to be interrupted; the induction is transmitted to the surrounding environment, causing other electronic devices. Can not work normally; can make the civil aviation system The work is invalid, the communication is not smooth, the computer is running incorrectly, and the automatic device malfunctions.
The AC parameter regulated power supply designed by Aoqisi solves the above power problems due to the following special features.
1. Wide voltage regulation range and high output precision: The actual working range of input voltage can reach 120V∽300V for single phase, and 210V∽515V for three-phase can effectively solve the problem of excessive voltage change.
2. The total recovery time of 10-40ms effectively solves the voltage sags/drops.
3. Input and output isolation design and unique frequency selection parameter excitation oscillation function can realize input and output bidirectional anti-interference, effectively solve the problem of lightning lightning power quality such as noise interference, harmonics, glitch, sharp wave and transient overvoltage.
4. The unique magnetic circuit design achieves a three-phase flux balance complementary function, which can output a stable and balanced three-phase phase and line voltage when the input voltage and load impedance are fluctuating or severely unbalanced. Effectively solve the problem of three-phase phase and line voltage imbalance.
5. Magnetic saturation circuit magnetic circuit design, with output load short circuit automatic protection function, the voltage is reduced to zero by almost zero reaction time, effectively protecting the load and its own equipment from damage.
6. Circuit design without electronic components, no mechanical adjustment device, simple structure, reliable operation, low failure rate, can be regarded as semi-permanent equipment, will be free from worries.
The Auqis parameter regulated power supply consists of an isolation transformer, a lightning protection anti-interference filter, and a wide-range balanced fast regulator. It can automatically, quickly and steplessly stabilize the voltage, eliminate various power pollution, output high-quality electric energy, and effectively ensure the reliable operation of electrical equipment, so that its service life will also increase exponentially.
In the normal working state, the input energy is separated from each other by the regulator, and the initial and secondary electromagnetic coupling and the edge inductance parameter are changed by the frequency to realize energy transmission. The LC energy storage element absorbs system energy to generate excitation oscillations. The local magnetic circuit is brought into a non-linear working state. At the same time, its equivalent parameters are used to oscillate a narrow rectangular characteristic. The forced filter in the oscillating circuit and the large time constant are used to obtain good frequency selective anti-interference purification performance. When the input voltage or load changes, the compensating electromagnetic circuit that synchronously tracks the change immediately generates the reverse tracking compensation amount, and realizes fast, non-polar, and non-transition to the output terminal, thereby quickly maintaining the output voltage stable.
First, the power quality problem
1. The range of voltage changes is too large, the power supply of the power grid is insufficient, the power supply department adopts step-down power supply, or is located in a remote area, and the loss is too much, resulting in a low voltage; the power supply of the power grid is too small, resulting in a high voltage. The voltage is too low, the load does not work properly; the voltage is too high, the load life is shortened, or the load is burned.
2. Waveform distortion (or harmonics) is caused by the use of switching power supplies in power electronics and electrical equipment such as rectifiers, UPS power supplies, electronic speed control equipment, fluorescent lighting systems, computers, microwave ovens, energy-saving lamps, and dimmers. The hazards of harmonics to the public power grid mainly include:
1) The components in the public power grid generate additional harmonic losses, which reduce the efficiency of power generation and transmission and transformation equipment. When a large number of 3rd harmonics flow through the neutral line, the line may be overheated or even fired;
2) Influencing the normal operation of various electrical equipment, in addition to causing additional losses, it can also cause mechanical vibration, noise and overvoltage of the motor, causing severe overheating of the transformer, causing overheating of capacitors, cables and other equipment, insulation aging, and shortening of service life. So that it is damaged;
3) It will cause local parallel resonance and series resonance in the public power grid, thereby amplifying the harmonics, greatly increasing the aforementioned hazards and even causing serious accidents;
4) It will cause relay protection and automatic device malfunction, and make the measurement of electrical measuring instruments inaccurate;
5) It will cause interference to neighboring communication systems, light noise will be generated, communication quality will be reduced, and information loss will be caused by heavy ones, which will make the communication system unable to work normally.
3. Surge (or surge, surge) means that the effective value of the output voltage is higher than the rated value of 110% in an instant (in milliseconds) and lasts for one or several cycles, which is the main culprit in destroying precision electronic equipment. . In addition to being caused by lightning strikes, the main reason is the high voltage generated by the sudden unloading of the power grid when the large electrical equipment connected to the power grid is turned off.
1) The effects of surges on sensitive electronic and electrical equipment are of the following types.
Destruction: voltage breakdown of semiconductor devices; destruction of metallized surface of components; destruction of printed circuit board printed circuits or contact points; destruction of three-terminal thyristor components / thyristors.
Interference: lockout, thyristor or triac eccentricity; data file partially corrupts data processing program; error: error and failure in receiving and transmitting data; unexplained failure.
Premature aging: parts are prematurely aged, electrical life is greatly shortened; output quality and picture quality are degraded.
2) Power surges will destroy electrical equipment. The electrical equipment containing the microprocessor is extremely vulnerable to power surges. This includes computers and auxiliary equipment, program controllers, PLCs, fax machines, telephones, and message machines. Program-controlled switches, Radio and television transmitters, video equipment, microwave relay equipment; products in the home appliance industry include televisions, stereos, microwave ovens, video recorders, washing machines, dryers, refrigerators, etc. According to the survey data, 63% of the electrical equipment that had problems during the warranty period was caused by a surge.
4. A sharp wave (or high voltage spike) refers to a voltage of up to 6000V with a duration of 10-4-10ms. This is mainly due to lightning strikes, arcing, static discharge or switching operations of large electrical equipment.
Its hazard is mainly: when the peak pulse amplitude is large, it will destroy the input filter, rectifier and even the main vibration tube of the industrial computer switching power supply. In addition, its spectrum is very wide, and it will also cause interference when it breaks into the computer.
5. Transient overvoltage and transient overvoltage refer to the pulse voltage with a peak voltage of up to 20000V but a duration of 10-6s-10-4s. The main cause and possible damage are similar to high-voltage spikes, mainly caused by lightning.
Its main hazards are: advanced electronic devices such as measurement, monitoring, protection, communication, computer networks, etc. with large-scale integrated circuits as the core components, and electronic devices such as large-scale CMOS integrated components. The shortcoming of current withstand capability is that the transient over-voltage will not only cause the electronic equipment to malfunction, or cause the electronic equipment to be interfered with, the data is lost, or temporarily paralyzed; in severe cases, the breakdown of the components and the burning of the circuit board may occur. The whole system is paralyzed.
6. Voltage sag/drop refers to the low voltage state where the rms voltage rms value is between 80-85% of the rated value and lasts for one to several cycles or even longer. Reasons for this include large equipment start-up and applications, large motor start-ups, or large power transformer access, main power line switching, line overload, and more.
The main hazard is that the impact on the computer is such that the interface device such as keyboard is suspended, and the data is lost and the file is destroyed. The sag of the voltage also destroys components in the computer, resulting in a shorter life. Voltage sags are the most common power problem, accounting for 87% of power problems.
7. Three-phase voltage imbalance means that the phase voltages between the phases are not equal or the line voltages are not equal. It is caused by the imbalance of the load of each phase, that is, it is related to the load characteristics of the user, and also related to the planning and load distribution of the power system. The relevant standards stipulate that the allowable value of the unbalance degree in the normal operation mode of the common connection point of the power system shall be 2%, and the short time shall not exceed 4%. Hazard to the transformer: When the three-phase load is unbalanced, the transformer is in an asymmetrical operating state, resulting in increased transformer losses (including no-load loss and load loss). According to the transformer operating regulations, the neutral current of the transformer in operation shall not exceed 25% of the rated current of the low-voltage side of the transformer. In addition, the unbalanced operation of the three-phase load will cause the zero-sequence current of the transformer to be too large, and the temperature rise of the local metal parts may even cause the transformer to burn out. The impact on the electrical equipment: the occurrence of three-phase voltage imbalance will lead to the occurrence of several times the current imbalance, induce the increase of the reverse torque in the motor, so that the temperature of the motor rises, the efficiency decreases, the energy consumption increases, the vibration occurs, and the output Loss; the service life of the electrical equipment is shortened, the frequency of equipment parts replacement is accelerated, and the cost of equipment maintenance is increased; the excessive unbalanced current flowing into the neutral line causes the neutral line to be thickened. Impact on line loss: Increase line loss, where the load pattern has different effects. Taking the three-phase four-wire system as an example, when one phase load is heavy and the two-phase load is light, the line loss increment is small; when one phase load is heavy, one phase load is light, and the third phase load is In the case of average load, the line loss increment is large; when the phase load is light, and the two-phase load is heavy, the line loss increment is the largest. When the three-phase load is unbalanced, the current imbalance is greater and the line loss increment is larger regardless of the load distribution.
8. Noise interference (or noise) refers to radio frequency interference (RFI) and electromagnetic interference (EFI) and various other high frequency interferences, resulting from electromagnetic or high frequency wave induction. Motor operation, breaker operation, motor controller operation, broadcast emissions, microwave radiation, and electrical storms can cause noise. Its hazard is mainly: let the computer CPU produce a misjudgment action, in severe cases, it may burn out the CPU and other computer accessories, which may cause the radio transmission to be interrupted; the induction is transmitted to the surrounding environment, causing other electronic devices. Can not work normally; can make the civil aviation system The work is invalid, the communication is not smooth, the computer is running incorrectly, and the automatic device malfunctions.
The AC parameter regulated power supply designed by Aoqisi solves the above power problems due to the following special features.
1. Wide voltage regulation range and high output precision: The actual working range of input voltage can reach 120V∽300V for single phase, and 210V∽515V for three-phase can effectively solve the problem of excessive voltage change.
2. The total recovery time of 10-40ms effectively solves the voltage sags/drops.
3. Input and output isolation design and unique frequency selection parameter excitation oscillation function can realize input and output bidirectional anti-interference, effectively solve the problem of lightning lightning power quality such as noise interference, harmonics, glitch, sharp wave and transient overvoltage.
4. The unique magnetic circuit design achieves a three-phase flux balance complementary function, which can output a stable and balanced three-phase phase and line voltage when the input voltage and load impedance are fluctuating or severely unbalanced. Effectively solve the problem of three-phase phase and line voltage imbalance.
5. Magnetic saturation circuit magnetic circuit design, with output load short circuit automatic protection function, the voltage is reduced to zero by almost zero reaction time, effectively protecting the load and its own equipment from damage.
6. Circuit design without electronic components, no mechanical adjustment device, simple structure, reliable operation, low failure rate, can be regarded as semi-permanent equipment, will be free from worries.
The Auqis parameter regulated power supply consists of an isolation transformer, a lightning protection anti-interference filter, and a wide-range balanced fast regulator. It can automatically, quickly and steplessly stabilize the voltage, eliminate various power pollution, output high-quality electric energy, and effectively ensure the reliable operation of electrical equipment, so that its service life will also increase exponentially.
In the normal working state, the input energy is separated from each other by the regulator, and the initial and secondary electromagnetic coupling and the edge inductance parameter are changed by the frequency to realize energy transmission. The LC energy storage element absorbs system energy to generate excitation oscillations. The local magnetic circuit is brought into a non-linear working state. At the same time, its equivalent parameters are used to oscillate a narrow rectangular characteristic. The forced filter in the oscillating circuit and the large time constant are used to obtain good frequency selective anti-interference purification performance. When the input voltage or load changes, the compensating electromagnetic circuit that synchronously tracks the change immediately generates the reverse tracking compensation amount, and realizes fast, non-polar, and non-transition to the output terminal, thereby quickly maintaining the output voltage stable.
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