How to wire the phase lock between synchronized devices?

Synchronous equipment between the phase lock how to wire the UPS power supply generally have three levels of protection, 1 is the utility power is normal, it regulates the voltage and frequency stabilization. 2 is the utility power interruptions or serious instability, by the battery power supply. 3 is the battery discharged after the bypass there is still a normal supply of electricity, it will be transferred to the bypass to power supply. There is also a situation where the inverter of the UPS itself fails or the inverter is overloaded, it will automatically go to the bypass to supply power. That is to say, the bypass power supply is the last protection of the UPS, in order to be able to safely transfer to the bypass power supply at such times and the back-end equipment does not affect, it is required that the UPS output frequency to synchronize with the bypass power supply frequency, which is the phase-locked, the specific principle is that there are two circuits within the UPS, one is sampled from the bypass, and the other is its own oscillation out of the standard sinusoidal waveforms, the UPS UPS in accordance with the standard sine wave inverter, but the frequency changes with the frequency of the bypass changes, but in order to protect the back-end loads, UPS have a synchronized range, generally plus or minus 3HZ, beyond this range or bypass power, UPS will only be according to the standard output of the internal machine.

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What is the principle of synchronous phase locking of UPS?

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What is the meaning of primary and secondary phase locking in UPS

To be precise, it should be Primary Phase Locked Loop (PLL) and Secondary Phase Locked Loop (SLL), right? ------------------------------------------- This paper introduces a high-power parallel-type UPS synchronization control scheme based on the composition of the TMS320C240DSP controller made by TT. Synchronization with the power grid, synchronization between the UPS in the parallel system has become the key to the control of the parallel UPS system. the core part of the UPS parallel system is a very high precision phase-locked loop, analog phase-locked loop is a mature technology, with its unique and excellent performance in many fields has been widely applied. However, with the development of digital technology, the full digital control of UPS is the trend, therefore, the phase-locked loop is also gradually transitioned to digital, digital DSP control phase-locked loop relative to the analog phase-locked loop is more convenient to implement, while using software instead of hardware to achieve, but also can be combined with the system's other functions of the unified design, cost savings. 1TMS320C240DSP controller introduction TMS320C240 is the U.S. TI company specializing in the use of digital motor control and the introduction of a 16-bit fixed-point arithmetic DSP for the control system application provides an ideal solution. It has the following main components: 3 general-purpose timer, can output 3-way comparison / PWM pulse, 3 full comparison unit, can output 3 pairs of comparison / PWM pulse with deadband control, 3 single comparison unit, can output 3-way comparison / PWM pulse, 4 capture pin CAP, for high-speed I / O management; two groups of 8 each 10-bit 10μs A/D converter, watchdog timer and timed interrupt timer; on-chip ROM or Flash memory, etc.. 2 Synchronization control scheme of UPS in parallel system 2.1 Phase-locked control principle of UPS The utility voltage waveform and UPS output voltage waveform are sinusoidal. Let the frequency of the UPS inverter voltage is f, and the frequency of the utility voltage is f1, the instantaneous value of the utility voltage waveform can be expressed as μ1=Um1sinω1t=Um1sin2πf1t The instantaneous value of the UPS inverter output voltage waveform can be expressed as μ=Umsin(ωt±θ)=Umsin(2πf1t±θ), of which +θ is the phase angle that the UPS output waveform exceeds the utility waveform. where +θ is the phase angle of the UPS output waveform ahead of the utility waveform; -θ is the phase angle of the UPS output waveform lagging behind the utility waveform. To realize the synchronization of UPS and utility must require: f = f1, θ = 0, the key is how to achieve 2πf1t = 2πft ± θ, can only be changed by changing the f so that θ gradually reduced, and ultimately, θ = 0, f = f1, when the UPS output waveform is ahead of the utility waveform, it is required to reduce the frequency of the output voltage of the UPS, i.e., f = f1 - θ / 2πt When the UPS output voltage waveform lags behind the utility waveform, it is required to reduce the frequency of the UPS output voltage, that is f = f1 - θ/2πt When the UPS output voltage waveform lags behind the utility waveform, the UPS output voltage waveform will be reduced. When the UPS output waveform lags behind the utility waveform, the frequency of the UPS output voltage is required to increase, i.e., f=f1+θ/2πt 2.2 Realization of synchronous phase locking of parallel UPS system When the parallel UPS system switches between the utility and the inverter, the inconsistency of the output waveforms of the two in the switching instant will cause the interruption of power supply, and on the other hand, it may also cause the damage to the UPS due to the large circulating current between the two voltage sources. system utility and inverter in the switching time does not exist in the loop current, need to ensure that the utility waveform and inverter waveforms to maintain the phase close to. Therefore, a device is needed to detect the phase change of the utility, and used to control the phase and frequency of the inverter output voltage, so that the inverter and the utility to maintain synchronous operation. For phase locking of UPS in parallel system, a two-stage phase locking structure can be used. Among them, the first-level phase-locked loop, also known as external synchronization, refers to the parallel system UPS tracking utility phase and frequency and phase synchronization control between each other, that is, to achieve synchronization between the UPS and the bypass utility, and the second-level phase-locked loop, also known as internal synchronization, is based on the frequency of the output voltage of the various UPS and phase tracking and synchronization control, so as to achieve synchronization between the various UPS. Both levels of the phase-locked loop use PI regulators, of which the internal synchronization is faster and highly accurate (= within 10us), making it ensure that the parallel loop current between UPSs is minimized. The externally synchronized PI regulator is slower, making it ensure smooth switching between bypass and inverter. Each stage of the phase-locked loop includes phase error detection, and regulation of the regulator. The following describes how each stage of the phase-locked loop is realized. (1) external synchronization The input of the two UPS that is, the utility power shaped into a square wave by the comparator circuit, after the synchronization bus synthesis, the square wave signal will be sent to each UPS DSP capture cell element CAPI pin, set the rising edge or falling edge capture, then in the square wave signal occurs accordingly jumps in the burst of capture 1 interrupt to read the value of the counter T2CNT as a feedback signal of the PI regulator, by comparing with the set value, the phase difference can be derived, and then compared with the set value, the phase difference can be obtained. By comparing with the set value, the phase difference can be obtained, and then the operation of the PI regulator will form the regulation amount, which is used to change the value of T2PR, so that the inverter output can track the utility reference. (2) internal synchronization T2 counter as a UPS sinusoidal output phase and frequency reference, in order to ensure the synchronization between all UPS, all UPS use T2CNT generate a square wave, square wave synthesized by the synchronization bus, sent to the CAP2 port of all UPS, in the square wave signal occurs accordingly jump into the capture 2 interrupt on the T2CNT clear, to ensure that internal synchronization is synchronized. . The T2CNT value is read in the interrupt corresponding to the sinusoidal midpoint as a feedback quantity, compared with T2PR/2, and then the regulation quantity obtained after the operation of PI regulator is used to change the value of TIPR, so as to synchronize the inverter output sinusoidal waveform with the T2 counter, and thus the inverter output is kept in synchronization.

1 Like - 227 Views2018-09-27

Do UPS power supply internal circuits need phase-locked loop circuits?

The following answers from several brothers combined would be better, lol, offline UPS does not need it, online UPS does. On-line UPS in addition to the inverter output frequency to lock the bypass frequency (which is to ensure that the UPS from the utility inverter state into the bypass state, or bypass state to the utility inverter state phase to maintain the same) in addition to the process of UPS when the UPS parallel process of several machine input source for different phases and frequencies of the power grid, often need to designate the host in order to ensure that the slave of the utility inverter output voltage frequency and phase is locked to the master. Here the source is phase-locked does not need to be the exact 50 or 60Hz, China's Tyrell certification requirements are the frequency change range of plus or minus 4%, corresponding to the 50Hz system is plus or minus 2Hz

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How can ups keep pace with the world

UPS power supply generally has three levels of protection, 1 is the utility power is normal when it is The UPS power supply generally has three levels of protection, 1 is when the utility power is normal, it stabilizes the voltage and frequency. 2 is when the utility power is interrupted or seriously unstable, it is powered by the battery. 3 is when there is still a normal supply of power in the bypass after the battery is discharged, it will be transferred to the bypass to supply power. There is also a situation where the inverter of the UPS itself fails or when the inverter is overloaded, it will automatically go to the bypass to supply power. That is to say, the bypass power supply is the last protection of the UPS, in order to be able to safely transfer to the bypass power supply at such times and the back-end equipment does not affect, it is required that the UPS output frequency to synchronize with the bypass power supply frequency, which is the phase-locked, the specific principle is that there are two circuits within the UPS, one is sampled from the bypass, and the other is its own oscillation out of the standard sinusoidal waveforms, the UPS UPS inverter according to the standard sine wave, but the frequency changes with the frequency of the bypass changes, but in order to protect the back-end loads, UPS have a synchronization range, generally plus or minus 3HZ, beyond this range or bypass power, UPS only according to the internal standard output of the machine.

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Briefly explain the working principle of UPS

, UPS and its working principle of UPS is the English abbreviation for Uninterruptible Power Supply, meaning "uninterruptible power supply", is a kind of energy storage device (commonly battery), with a battery to store energy. Common is the battery), with the inverter as the main component of the constant voltage and frequency of the uninterruptible power supply, it can solve the existing power outages, low voltage, high voltage, surge, noise and other phenomena, so that the computer system is more secure and reliable operation. Now has been widely used in computers, transportation, banking, securities, communications, medical, industrial control and other industries, and is rapidly coming into the family. Below, let us first briefly understand the working principle of UPS. When we do not use UPS, PCs, printers and other terminal equipment is directly connected to the utility use, with UPS, PCs, printers and other terminal equipment connected to the UPS to use, and UPS and then access to the utility. When the utility input is normal, the UPS will be stabilized utility voltage supplied to the terminal equipment (relative to the UPS, we will be these terminal equipment called loads) to use, at this time, the UPS is an AC utility voltage regulator, at the same time, it is also charging their own built-in batteries; when the utility interruptions (for example, blackouts), the UPS will be built-in battery power immediately, the inversion method to continue to supply the load through conversion 220V alternating current, so that the load to maintain normal operation and protect the load software and hardware systems from damage. Second, the impact of utility power on home PCs and their terminal equipment If our PCs, computer networks and other equipment do not use UPS, and what will be affected? Many people have a common misconception that we use the utility power, in addition to occasional power outages, are continuous and constant. This is not the case. The utility system as a public **** power grid, connected to thousands of various loads, some of the larger inductive, capacitive, switching power supply loads not only from the grid to obtain electricity, but also in turn on the grid itself, deterioration of the power grid or local grid power supply quality, resulting in utility voltage waveform distortion or frequency drift. In addition, accidental natural and man-made accidents, such as lightning strikes, transmission and transformation system disconnection or short-circuit, power plug ground wrong unplugging, etc., will jeopardize the normal supply of electricity, thus affecting the normal operation of the load. In particular, it should be especially pointed out that PCs, network equipment, communication systems, medical equipment, etc. are very sophisticated electronic equipment, the impact on them is particularly prominent. For PCs, normal power supply is required for both the monitor and the host to work. Memory, in particular, has higher requirements for power supply. It is a storage device that relies on electrical energy and requires constant refreshing action to maintain the stored content, and once the power is cut off, the saved content immediately disappears. If abnormal power failure results in the information in the memory not being saved to the hard disk and other storage devices in time, it will cause the information to lose its value because it is completely lost or becomes incomplete, thus wasting a lot of work energy and time; and operating systems like UNIX and Linux (nowadays, many computer enthusiasts use this kind of operating system), if they are not shut down normally, the system information in the memory is not written back to the hard disk, may also cause the system to crash, can not start again; In addition, the hard disk in the computer, although the application of magnetic storage media, will not be due to power outages and the loss of information, but a sudden power failure will make the hard disk is reading and writing the work of the physical head damage, or the system files in the maintenance of the file system, resulting in the file allocation table error, so as to make the hard disk to produce bad sectors, and in serious cases, will even cause the entire Hard disk scrap; In addition, most of the current operating system can set the virtual memory, due to a sudden power failure, so that the system can not cancel the virtual memory, resulting in hard disk "information fragmentation", not only a waste of hard disk storage space, but also lead to slow machine operation; computer power supply is a kind of rectifier power supply, too high a voltage may cause rectifier burnout. The computer power supply is a rectifier power supply, too high voltage may cause the rectifier burned. Voltage spike pulse and transient overvoltage, as well as power supply noise and other interference may enter the motherboard through the rectifier, affecting the normal operation of the machine, or even burn the host line. In general, the standard sine wave (220V, 50Hz) is an ideal state, but in practice, according to the test of power experts, the power grid often occurs and the computer or precision instruments to produce interference or damage to the following conditions: surge, high voltage spike, transient over-voltage, voltage sags, wire noise, frequency drift, sustained low voltage, utility interruptions. 1. power surge (Power Surges): refers to the output voltage RMS value is higher than the rated value of 110%, and the duration of one or more cycles. Power surge is mainly due to the connection of large electrical equipment on the grid shutdown (such as common household air conditioner shutdown), the grid due to the sudden unloading of high voltage (we will have such a personal experience: in the evening from 6:00 to 9:00 or so of the time period, is the peak of the power supply, the utility voltage is generally low, the lighting at home is darker, the peak of the power supply, such as in the evening at 10:00 or so, you will find that the lighting at home is not very good, but it will be a lot more than the power surge. (After the peak period, for example, at 10:00 p.m., you will find that the lighting at home suddenly flickers and is much brighter, which is a kind of surge phenomenon most commonly seen in our daily life). 2. High Voltage Spikes (High Voltage Spikes): refers to voltages with a peak value of up to 6,000v and a duration ranging from one ten-thousandth of a second to one-half of a cycle (10ms). This is mainly due to lightning strikes, arc discharges, static discharges, or switching operations of large electrical equipment. 3. Transient overvoltage (Switching Transients): refers to the peak voltage of up to 20,000V, but the duration of the impulse voltage bounded by millionths of a second to ten thousandths of a second. Its main cause and the damage it may cause is similar to the high-voltage spike pulse, but there will be differences in the solution. 4. Voltage sag (Power Sags): refers to a low voltage condition where the rms value of the mains voltage is between 80% and 85% of the rated value, and lasts for one to several cycles. This problem can be caused by the start-up of large equipment, the start-up of large motors, or the connection of large power transformers. 5. Electrical Line Noise: This refers to radio frequency interference (RFI) and electromagnetic interference (EFI), as well as a variety of other high frequency interference. Motor operation, relay operation, motor controller operation, radio transmission, microwave radiation, as well as electrical storms, etc., will cause line noise interference. 6. 6. Frequency Variation (Frequency Variation): refers to the change in utility frequency of more than 3Hz. This is mainly due to the unstable operation of emergency generators, or by the frequency of unstable power supply. 7. sustained low voltage (Brownout): refers to the utility voltage RMS value is lower than the rated value, and continue for a long time. Its causes include: large equipment startup and application, main power line switching, startup of large electric motors, line overload (this problem exists in many areas of our country). 8. Power Fail: This is the type of power outage that we commonly experience. The causes are: tripping of circuit breakers on the line, interruption of utility supply, grid failure. III. Classification of UPS UPS has evolved from a rotating generator in the 1960s to today's static fully electronic circuits with a degree of intelligence, and continues to evolve. At present, UPS generally refers to stationary UPS, according to its mode of operation can be divided into three categories: backup, online interactive and online. 1. Backup UPS: in the normal utility power supply directly from the utility to the load, when the utility power beyond its operating range or power outage, through the conversion switch to the battery inverter power supply. Its characteristics are: simple structure, small size, low cost, but the input voltage range is narrow, the output voltage stabilization accuracy is poor, there is a switching time, and the output waveform is generally a square wave. The schematic diagram is as follows: 2. online interactive UPS: when the utility power is normal, directly from the utility power to the load power supply, when the utility power is low or high, through the UPS internal voltage regulator line voltage regulator output, when the utility power is abnormal or blackout, through the conversion switch to the battery inverter power supply. It is characterized by: a wide range of input voltage, low noise, small size and other characteristics, but there is the same switching time, but compared with the general backup UPS, this model has a stronger protection function, the inverter output voltage waveform is better, generally sinusoidal. The schematic diagram is as follows: 3. online UPS in the utility power normal, rectified by the utility power to provide DC voltage to the inverter work, the inverter to provide AC power to the load, in the utility power abnormal, the inverter from the battery to provide energy, the inverter is always in the working state, to ensure that there is no interruption to the output. It is characterized by an extremely wide input voltage range, no switching time and high accuracy of output voltage stabilization, which is especially suitable for occasions with high power requirements, but at a higher cost. At present, the power greater than 3KVA UPS is almost always on-line UPS. schematic diagram as follows: UPS according to the size of the output capacity is divided into small capacity below 3KVA, small and medium-capacity 3KVA ~ 10KVA, medium and large-capacity 10KVA or more. UPS can be divided into three categories according to the input / output method: single-phase input / single-phase output (referred to as single in single out), three-phase input / single-phase output (referred to as three in single out), three-phase input / three-phase output (referred to as three in three out). For the user, three-phase power supply and load distribution of utility power distribution is easy, each phase is responsible for a portion of the load current, and thus the medium and high power UPS more than three-phase input/single-phase output or three-phase input/three-phase output power supply mode. Backup UPS is mainly used to provide power protection to a single PC with small size, low price and simple operation, which is very suitable for home use, so when you buy a UPS for your home computer, please buy a backup one. On-line UPS can solve almost all common power problems, when there is utility power, the function is to stabilize the voltage and prevent power fluctuation interference, because of its better function, so its cost also rises with the enhancement of the performance, the price is much more expensive than the backup UPS. On-line UPS is mainly used for some computer equipment, medical equipment, etc. with very strict power requirements, generally used in series with multiple external batteries to extend the power supply time, mostly for the unit configuration. Intelligent UPS is a major development trend of today's UPS, with the UPS in the network system applications, network managers emphasize the entire network system for the protection of the object, I hope that the entire network system in the power supply system failure, can still continue to work without interruption. Therefore, the UPS internal configuration microprocessor to make it intelligent is the new trend of the UPS, UPS internal hardware and software combination, greatly improving the function of the UPS, you can monitor the operation of the UPS work status, such as: UPS output voltage frequency, grid voltage frequency, battery status and fault records. Can also be detected through the software on the battery, automatic discharge charging, as well as remote control switching and so on. Network managers can analyze the quality of power supply according to the information, according to the actual situation to take appropriate measures. When the UPS detects an interruption in the power supply grid, the UPS automatically switches to the battery power supply, and immediately notifies the server to make preparations for shutdown when the battery power supply capacity is insufficient, and shuts down itself before the battery runs out. Intelligent UPS through the interface to communicate with the computer, so that network administrators can monitor the UPS, so the function of its management software is extremely important. What is backup UPS Normally in the battery charging state, in the event of a power outage inverter emergency switching to the working state, and will be provided by the battery DC power into a stable alternating current output, backup UPS is also known as offline UPS. Backup UPS exists in the time switching of 2 to 10 milliseconds, and is not suitable for critical power supply sites. In addition, backup UPSs generally only provide continuous power for a few minutes to ten minutes. The advantages of backup UPS power supply are: high operating efficiency, low noise, relatively inexpensive, mainly applicable to the utility power fluctuation is not high, the power supply quality requirements are not high occasions. What is online UPS online UPS: online UPS in the work, first of all, the utility converted to DC power to the UPS battery charging, at the same time the inverter (see Tips) will be the DC inverter for the AC power for the load power supply, due to the utility has been through the AC to DC, and then to the conversion process of the AC, the utility of the original interference and impulse voltage components have been filtered very cleanly, so the voltage converted out by the online UPS is very low. Therefore, the voltage inverted by the online UPS is very stable. Because the inverter circuit is always working, so when the power outage, the UPS can immediately through the inverter stored power into AC power supply to the load, so as to achieve the output voltage zero interruption of the switching target. Double conversion also refers to the UPS output voltage after two AC and DC mutual conversion process. And high frequency means that the UPS internal work in a high-frequency environment. The advantages of high frequency UPS are small size, light weight, high efficiency, and its disadvantage is poor overload and shock resistance. What is online interactive UPS Online interactive UPS: This is an intelligent UPS, the so-called online interactive UPS, is that when the input utility power is normal, the inverter of the UPS is in reverse operation (i.e., rectifier operating state), charging the battery pack; in the utility power abnormality inverter immediately turned to invert the operating state, converting the battery pack electrical energy into AC output, so online interactive UPS also has a conversion time. Therefore, online interactive UPS also has conversion time. Compared with the backup UPS, online interactive UPS has stronger protection function, the inverter output voltage waveform is better, generally sine wave, and its biggest advantage is that it has strong software function, which can be conveniently connected to the Internet for remote control and intelligent management of UPS. It can automatically detect whether the external input voltage is within the normal range, and if there is any deviation it can be boosted or bucked by the voltage regulator circuit to provide a more stable sine wave output voltage. And it can communicate with the computer through the data interface (such as RS-232 serial port), through the monitoring software, the user can directly from the computer screen to monitor the power supply and UPS status, simplify and facilitate the management of the work, and can improve the reliability of the computer system. This UPS centralized backup UPS high efficiency and on-line UPS power supply quality advantages, but its frequency stabilization characteristics are not ideal, not suitable for UPS power supply to do constant delay.

58 Likes-5,017 Views2017-09-24

UPS power supply working principle

UPS uninterruptible power supply immediately transferred to the battery inverter state; in order to prevent utility switching back and forth, only when the utility power is restored to 170 ~ 270V, the UPS will be transferred to the utility inverter state. Detection and control of utility frequency detection of utility frequency as the basis for inverter phase lock, inverter phase adjustment by adjusting the inverter over zero point, so that the utility state of the inverter output and utility input is basically the same frequency, the same phase. When the utility power is turned on, the UPS detects the frequency of the input utility power as the frequency of the inverter output; when the power is turned on under the battery state, the frequency of the inverter output is set as the frequency of the previous output. When the utility power is normal, phase locking will be executed, the inverter frequency will chase the utility frequency first, and then track the phase after the frequency is the same, and the inverter and utility will be in phase by changing the inverter frequency. After phase locking, the phase difference between inverter and utility is less than 3 degrees, and the frequency error is less than 0.01 Hz. When the utility frequency exceeds the range of 47-53 Hz, the UPS does not perform phase locking, and immediately transfers to the battery inverter state, and only when the utility frequency is returned to 48-52 Hz, the UPS performs phase locking again and transfers to the utility inverter state. Triangle wave generator CPU sends out 38.4kHz square wave, through the operational amplifier composed of two frequency division circuit, into a 19.2kHz square wave, and then integrated by the integrator into a triangle wave. The standard sine wave generator CPU sends out an imitation sine wave divided by 128 points equally, which is filtered by a second-order low-pass filter to generate a standard sine wave.The standard sine wave of the PWM signal is compared with the sinusoidal feedback signal of the inverter output voltage, and the result is cut by the triangular wave to generate the PWM signal. The inverter voltage adjustment CPU reads the inverter voltage value every 16ms and compares it with the set voltage value. When the difference is higher than 10V, the CPU immediately adjusts the standard sine wave, and thus adjusts the PWM signal, so that the output voltage is correspondingly added or subtracted by 5V to narrow the difference; when the difference is lower than 10V, the CPU accumulates the difference, and when the accumulative value reaches 30V, the CPU adjusts the standard sinusoidal wave, so that the output voltage is correspondingly added or subtracted by 2V. CPU's A/D reading CPU reads the battery voltage, positive and negative BUS voltage and internal temperature every half-cycle, and reads the mains voltage, inverter voltage and inverter current every 8 standard sine wave points (at the beginning of each cycle, CPU changes the initial position of the reading point, so that it reads every 8 standard sine wave points, and achieves the scanning effect through 128 A/D reading points), and the read values are stored in the scanner. The read values are stored in RAM).

8 Likes-30,156 Views2019-09-22

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