Synchronized switching controller and its control for parallel uninterrupted power supply

Abstract

The method includes following steps: 1) switch of synchro control signal transmission and modulation; 2) switch of modulated signal level; 3) arbitration and transmission of priority level of bus signal; 4) reception of bus signal, and inversion of level; 5) precise identification of synchro control signal; 6) executes operation of switching in each step according to synchro control signal.

Description

technical field [0001] The invention relates to the field of uninterruptible power supply systems, in particular to the control technology for parallel operation of uninterruptible power supply systems. Background technique [0002] With the continuous development of information technology, many electronic equipment systems need to provide continuous power supply without interruption, so inverter power supply and uninterruptible power supply have been widely used in many fields. However, in practical applications, various abnormalities may occur in the inverter power system itself, and AC power cannot be obtained through inverters. The usual way is to provide an AC power supply bypass to ensure that it switches to the standby bypass in these cases, so that The output of the system is uninterrupted, and it will switch back from the bypass when the inverter circuit resumes normal operation. Therefore, such a power system needs reliable switching between the inverter circuit an...

AI Technical Summary

Problems solved by technology

However, these parallel uninterruptible power supply systems must ensure the synchronization of actions when switching between inverter and bypass, and it is not allowed for each single unit to work in the bypass and inverter states at the same time, otherwise the bypass output and inverter output A short circuit between them may generate excessive current or even damage the power system, and the reliability cannot be guaranteed. Therefore, it is very important to control the synchronous switching of the parallel inverter power system

[0004] In the technical field of inverter power supply and uninterruptible power supply, there are some parallel power supply systems at home and abroad, such as the bus control parallel uninterruptible power supply (UPS) system disclosed in Chinese Patent No. 01130036. The switch between bypass and inverter realizes N+1 redundant parallel operation, basically meets the technical requirements of parallel operation, and proposes a kind of solution for UPS parallel operation, but the time for data transmission and processing is long, and the switching action The synchronization is poor, and there are disadvantages such as untimely switching and long output interruption time. If a data transmission error occurs in one of them, it may cause switching failure. It is only suitable for occasions with low power requirements.

In addition, there are some other types of inverters or uninterruptible power systems that can be paralleled and have backup bypasses. The synchronous switching between bypass and inverter states during parallel operation is mainly through two control signal buses. , one is to control the switching from bypass to inverter, and the other is to control the switching from inverter to bypass. Each signal is arbitrated by the priority level as the synchronous start of action execution, which can basically realize the switching function. The starting point of the switching control execution process of the intermittent power supply system is synchronous, but there is a problem of asynchrony in the various actions in the middle of the process. The system must allow a certain period of power output interruption to ensure that the bypass output and the inverter output are not short-circuited. , can only be used if the electrical equipment allows

[0005] In short, the uninterruptible power supply system in the prior art cannot overcome the requirements of electronic equipment on the reliability and high power of the power supply system at the same time, and is prone to defects such as output interruption and switching logic errors, and in order to avoid mutual interference between parallel power supplies , the cost of electrical isolation is higher

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