Control method of back-to-back current source converter

Abstract

The invention discloses a control method of a back-to-back current source converter, belongs to the field of electrical systems, and aims at a frequency converter scheme adopting back-to-back series current source converter topology and the like, and adopts a method of a central controller to carry out coordination control on current source converters on a rectification side and an inversion side. Stability of the system is improved, the utilization rate of direct-current bus current is improved, and loss of direct-current side reactance is reduced; besides, when space vector modulation is adopted, five-segment SVM modulation for cutting small vectors is completed by optimizing zero vectors, the maximum value of the common-mode voltage on each side is kept to be half of the original value, and according to the relation between the working sectors of the current source converters on the two sides, vector sorting during driving signal wave sending is switched. The method can suppress the common-mode voltage of the system, and the common-mode voltage is reduced by more than half of that of a traditional method; and meanwhile, the insulation requirement on a load side common-mode loop can be reduced, and power density is improved while the size of the direct-current side common-mode reactor is reduced.

Description

technical field [0001] The invention belongs to the field of electrical systems, and more specifically relates to a control method for a back-to-back current source converter. Background technique [0002] With the rapid development of power electronics technology, not only the voltage source converter (VSC) has been popularized, but the current source converter (CSC) is also used in photovoltaic grid-connected power generation because of its better life and boosting capability. , HVDC transmission, wind power and many other fields have high application potential. But it is the same as the voltage source converter, due to the action of the switching device, there is also a problem of common mode voltage (CMV) in the process of operation. Excessive common-mode voltage will threaten the insulation of the system, damage the bearings of the motor load, and interfere with the reliable operation of the system. [0003] In order to solve this problem, isolation transformers, inte...

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Problems solved by technology

However, this common-mode voltage suppression method based on the traditional three-phase system can only bring a suppression effect of 50% at most in principle, and will increase the number of continuous switching of a single device, resulting in uneven power distribution and heat dissipation failure. question

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