Power unit and power electronic converter using the same

Abstract

Provided in the invention is a power unit comprising a plurality of power conversion circuits, a local controller, and a plurality of drive circuits. A first output terminal of one of each two adjacent power conversion circuits among the plurality of power conversion circuits is connected with a second output terminal of the other power conversion circuit. The local controller is used for outputting a plurality of control signals. The plurality of drive circuits output drive signals based on the plurality of control signals to drive on or off of a plurality of power semiconductor switches; andcontrol signals corresponding to power semiconductor switches at the same positions in the plurality of power conversion circuits are identical with each other and the power semiconductor switches atthe same positions in the plurality of power conversion circuits are connected or disconnected simultaneously. According to the invention, the power unit is capable of sharing higher voltages, so that the numbers of fibers, auxiliary power supplies, and local controllers are reduced and thus the circuit structure is simplified and the system reliability is improved; the objective of reducing thepower unit number is achieved by using the low-voltage device, so that the cost is lowered; and only a voltage clamping circuit needs to be configured for each power conversion circuit, so that the number of the voltage clamping circuits is reduced, the cost is reduced, and the system reliability is improved.

Description

[0001] Cross References to Related Applications [0002] This application claims the priority of Chinese application No. 201611170857.3 filed on December 16, 2016, entitled "Power Unit and Power Electronic Conversion Device Using the Power Unit", the contents of which are incorporated herein by reference. technical field [0003] The present application relates to the technical field of power electronics, in particular to a power unit and a power electronic conversion device using the power unit. Background technique [0004] Limited by the withstand voltage level of current power electronic switching devices, in high-voltage and high-power applications, the cascaded topology in which power units are stacked in series is a better solution. The traditional cascading scheme needs to equip each power unit with a set of optical fiber, auxiliary power supply, and control board. As the voltage level increases, the number of power units that need to be cascaded also increases, res...

AI Technical Summary

Problems solved by technology

[0013] Disadvantages: Due to the low voltage of a single power device (such as a 1700V IGBT, the DC bus voltage at both ends of the bus capacitor C is about 1000V), so about 72 H-bridge circuits need to be cascaded in each phase circuit

[0016] Disadvantages: The cost of high-voltage IGBT is much higher than that of low-voltage IGBT (the cost of 6500V IGBT is much higher than the cost of 1700V IGBT 4 times), resulting in the cost of using high-voltage IGBT will be much higher than the cost saved by the control board and optical fiber, resulting in System cost increases substantially

[0019] Disadvantages: There is a problem of uneven voltage in the series application of low-voltage IGBTs. In order to solve this problem, each low-voltage IGBT needs to be equipped with clamping plates, resulting in a large number of clamping plates and reducing system reliability.

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