Parallel loop current control method and system based on direct-current magnetic loops and multiple converters

Abstract

The invention provides a parallel loop current control method and system based on direct-current magnetic loops and multiple converters. The system comprises the AC-DC-AC converters and the direct-current magnetic loops; the AC-DC-AC converters comprise the PWM rectifiers, the PWM inverters, the first filters and the second filters; alternative-current input ends of the PWM rectifiers are directlyelectrically connected through the first filters; alternative-current output ends of the PWM inverters are directly electrically connected through the second filters to form loop current passages; positive and negative bus bars of the AC-DC-AC converters are sleeved with the direct-current magnetic loops. According to the parallel loop current control method and system based on the direct-currentmagnetic loops and the converters, the arranged direct-current magnetic loops can provide high common mode impedance, so that loop current in a loop can be effectively suppressed. Simple and rapid parallel connection of the multiple converters is achieved, so that the system capacity is effectively expanded, modular production is facilitated at the same time, and the production efficiency is improved.

Description

technical field [0001] The invention belongs to the field of converter systems, and in particular relates to a method and system for controlling parallel circulation of multiple converters based on DC magnetic rings. Background technique [0002] Due to the development of semiconductor devices, a single large-capacity device has not come out, resulting in the high-power converters required in the market cannot be directly designed through large-capacity devices. The design of large-capacity converters on the market now has the following ideas: 1) Parallel connection of large-capacity devices through small-capacity semiconductor switching devices; 2) Design of small-capacity inverters through small-capacity semiconductor devices, Then it is formed by parallel connection of inverters with a common bus bar; 3) through small-capacity semiconductor devices passing through isolation transformers, they are connected in parallel or in series to form high-power converters. [0003] ...

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Problems solved by technology

[0003] In view of the ideas mentioned above, the first one is directly paralleled into a large-capacity device through a small-capacity semiconductor switching device, which cannot meet the capacity requirements due to the parallel structure, stray inductance, etc.; the second one is through the common bus of the inverter. In the parallel connection mode, it is difficult to control due to the short circulation loop of the inverter. Although it can be solved by sharing PWM, it increases the difficulty of parallel connection of the system. The cost of the device is high, and the complexity of the system increases after the isolation is increased

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