Multi-machine frequency converter

Abstract

Provided is a multi-machine frequency converter, which may comprise: a master control unit, and N1 execution units coupled in series by means of a communications port, said N1 execution unit sharing a common DC bus; the first communications port of the master control unit is connected to the second communications port of the first of the N1 execution units; the N1 execution units comprise N11 rectifier units and N12 inverter units; N11 is a positive integer, and N12 is a positive integer greater than 1; said first execution unit is an execution unit located at an edge position of said N1 execution units connected in series by means of a communications port. The technical solution provided by the embodiments of the present invention is conducive to reducing the complexity of frequency converter wiring configurations in the context of multiple machines, improving the stability and reliability in multi-machine operation of frequency converters.

Description

technical field [0001] The invention mainly relates to the technical field of power electronics, and in particular relates to a multi-machine frequency converter. Background technique [0002] At present, most inverters on the market are stand-alone inverters, which use a control unit to directly control an inverter unit. The control unit generally does not control the rectification unit. The specific structure can be as follows: Figure 1-a shown. [0003] The stand-alone inverters need to run in parallel synchronously (that is, the speed / torque of the load motors of at least two stand-alone inverters is the same or corresponding, or the outputs of at least two stand-alone inverters are connected in parallel with load motors or asynchronously to realize the factory macro) At the same time, at least two single-machine inverters form an inverter multi-machine system, and the communication between each inverter is based on the RS485 bus. The structure of the 485 bus communica...

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Problems solved by technology

This method of connecting multiple inverters to achieve parallel synchronous operation has problems in field applications, such as the high cost of parallel synchronous operation, complex wiring of various control lines, and too long serial bus wiring

[0004] In the process of research and practice, the inventor found that the existing inverter system has some defects in the application of dual-machine or multi-machine master-slave control: the communication mode of the 485 bus has weak anti-interference in the communication mode between the master and the slave machines. , the disadvantage of poor signal transmission stability

Due to the limitations of communication methods, it is difficult to carry out ultra-long-distance signal transmission

Moreover, the control structure of the master-slave system is complex, multiple signal lines work at the same time, and the installation and operation are cumbersome

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