In order to complete the active switching between the mains power supply and the inverter power supply, the EPS power supply is backup, so the active switching device is an indispensable component in the EPS power supply, but also affects the reliability of the EPS power supply.One of the important components
According to the output capacity and load requirements of the EPS power supply, the active switching device can be made of power relay, communication contactor, mutual punctuation, solid state switch (thyristor), and the like.For the switching time of EPS, it requires diversity, for example, general fire emergency lighting requires switching time less than 5 s, but the fire emergency lighting in high hazardous areas is required to switch time less than 0.25 s. When the high-pressure gas discharge lamp is not turned off, thenThe switching time is required to be several milliseconds, which is a fan, pump, rolling door, and elevator, and other load, depending on the application requirements, the switching time will also be in several milliseconds.
The EPS power supply and the UPS power supply differ in that most applications are not very demanding on the switching moment, and the requirements in the switching time are not shorter, the better, under the premise of satisfaction with the demand, it can be switched at a point Other aspects benefit, to degrade loss, reduce transient impact, improve reliability, etc., avoiding the load may cause operation due to instantaneous power failure. When the main electricity is normal, the inverter of the EPS power is basically in the backup state, and there is two ways to work with hot backup and thermal backup. In the cold backup, the inverter is only in the operating state, and the power portion is in the power-on standby state, but does not start; the heat standby, the entire inverter is in normal operation, but does not assume the load. When the inverter is hot backup, the short switching time is basically determined at the action time of the switching device used; and when the inverter is cold backup, the short switching time is also subject to the constraints of the inverter. In particular, the capacity of EPS power supply, if the start is too fast, the inverter transformer and low pass filter produces a large transient impact, and even may damage the IGBT power device, so the inverter generally has soft start characteristics, and The larger the power, the slower the start, the start time of the large capacity EPS inverter can reach the number of seconds. If you need a faster switching time, you can only adopt a hot backup job method. At this moment, the standby loss of EPS naturally adds a lot, and the whole machine power will be lower.
As for which switching device is used, this is mainly based on the requirements of the switching time. If you want millisecondary switching moments, you can only use a solid state switch (thyristor) to switch, and the inverter is in a hot statter. Compared with the same capacity mechanical switching switch, the solid-state switch (thyristor) switching is much higher, and there is relatively relatively relatively relatively relatively relatively much. In the case where the switching time is not demanding, the mechanical switching switch is generally selected, and the EPS power supply with a smaller capacity is generally selected by the power relay. EPS with large power is generally used interlocking communication contactor or active interplacing switch. Compared with the communication contactor, the active intermitting switch is slow, but since the mutually switched switch has mechanical self-holding characteristics, for unvermissive switches, there is more advantages in the reliability of long-term operation.
The fast switching technology between the main switch (thyristor) is used to complete the rapid switching technology between the output of the UPS power supply in the UPS power supply, but the UPS power relay (or contactor) is combined with solid state switch (thyristor). A bypass (BYPASS) switching device, solid state switch (thyristor) is mainly to do instant overload bypass switching, relying on it to make the inverter with the power grid with a short parallel transport, then get an instantone without switching moment Power supply (compensate for the transfer of power relays or contacts). The key is to complete the phase locked operation of the inverter and fast detection and tail to the mainstream instant voltage. It is not really power-off, because this method is "online" UPS, the solid state switch (thyristor) is not in the homework when it is true. When it is used for the EPS power supply, it is really a solid-state switch (thyristor), and the EPS power supply is a backup is no bypass contactor. It is in the case where the market is normal, the inverter is also working properly, even if it is uninterrupted, it can be done in technology, but the practice is that the switching demand is suddenly suspended or wrong in the city electricity. Performing, due to the random and non-predictive time of the epithelial stop or the occurrence of malfunction, the detection of the maintenance needs of the city’s electrical corruption, the switching time at this moment does not perhaps less than the detection, recognizing the time of the maintenance requirements of the city.
In order to avoid malfunction, the test is not too short to detect a variety of power agitation. Practice has proved that when the detection time is less than 2 ms, the detection reliability will decrease significantly. Therefore, the switching time of less than 2 ms is not available. In the various types of loads in the EPS power supply, the demanding required to switch time should be high pressure gas discharge lamps. Although this luminaire is not allowed to be used in fire emergency lighting, because of its high strength, high power features, there is use in many large venues. But there is such a problem, that is, once the lamp is turned off, the demand cooling can restart, to ensure that the lighting does not discontinue, the EPS power must have fast switching capabilities. According to the test of a variety of high-pressure gas discharge lamp products, if there is no proper continuation method, 5MS power stops may cause flameout, and single products or even 3ms electric power will be quite. For some elevator loads, the switching of milliseconds is clearly unnecessary, but the power supply in the moment when switching is the same, may result in an elevator manipulation system to enter the protection state. This situation is required to ensure that the elevator continues to function properly after the EPS power control system delay is properly added. In some applications, in order to complete zero switching, the EPS is required to be online operation method, then the EPS power practice has become a dedicated UPS, and the inverter is a long-band load job. Shenzhen Yinglang Optoelectronics Co., Ltd. specializes in lighting emergency power supply for 18 years. The company is located in Shenzhen and is a high-tech enterprise, and the company has 18 patented technology. The company is committed to letting the lighting of 365 days not afraid of power outage. With independent technology and manufacturing strength, all the year round serve the Ocean King, Skyworth Lighting, Sun Optoelectronics, Tongfang Shares, State Shares, Huarong Shares, China Oil, Japan Senfa and other enterprises. Get unanimous recognition and full trust of customers, is a stable product supplier in the LED lighting emergency power industry.
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