A method for enhancing the phase-locking performance of ups when the oil-engine bypass is running

Abstract

The invention discloses a method for enhancing the phase-lock performance of a UPS during oil-engine bypass operation. The method comprises the following steps that whether a UPS parallel operation system is in an inverted operation state or a bypass operation state is monitored; when the UPS parallel operation system is in the inverted operation state, an inverter operates at a first phase-lock speed; and when the UPS parallel operation system is in the bypass operation state, the inverter operates at a second phase-lock speed which is higher than the first phase-lock speed. The method helps lock the bypass phase in a severe condition, and avoids influence on stability of a current sharing ring.

Description

technical field [0001] The invention relates to an uninterruptible power supply (UPS), in particular to a method for enhancing the phase-locking performance of the UPS when the oil generator bypasses the operation. Background technique [0002] For UPS parallel system, such as figure 1 and figure 2 As shown, the general system power distribution connection method can be divided into two types: main road bypass different source and main road bypass same source connection. Regardless of the connection method, the mains power failure may occur, and the load is powered by the bypass of the oil generator. If the capacity of the oil generator is not large enough, or the quality of the oil engine is not good, or the load pollutes the oil engine relatively heavily. When supplying power to the load, the output voltage amplitude and frequency of the diesel engine will change greatly, which will cause the inverter to fail to track the bypass voltage and fail to complete the action o...

AI Technical Summary

Problems solved by technology

The first-level phase-locking module should ensure that the output command changes slowly, and the second-level phase-locking module should ensure the rapidity of tracking the output of the first-level phase-locking module, so the tracking speed is required to be fast, but due to the influence of parallel current sharing, too fast The rate will affect the stability of the current sharing loop, so the tracking rate of the secondary phase-locked module will also be slowed down

[0006] Due to the influence of the current sharing loop, the speed of the phase-locked loop cannot be made very fast, which leads to the problem that the inverter cannot lock the phase of the bypass when the bypass is relatively poor.

That is, UPS bypass operation, if the oil generator load is heavy, the change rate of bypass frequency and THDU will be very large, making the system phase unable to lock

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