Three-level SVG midpoint potential control method

A potential control and three-level technology, which is applied in the direction of electrical components, circuit devices, AC network circuits, etc., can solve the potential fluctuation of the midpoint of the DC capacitor, the decrease of the output performance of the three-level converter, and the increase of output voltage and current harmonics and other problems, to achieve the effect of high precision, simple and effective control method

Pending Publication Date: 2021-01-29
NANCHANG HANGKONG UNIVERSITY
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Problems solved by technology

However, the three-level also has some disadvantages, that is, the midpoint potential of its DC capacitor will fluctuate during operation, resulting in unbalanced midpoint potential, a large increase in output voltage and current harmonics, and greatly improving the output performance of the three-level converter. reduce, and even damage the power switching devices of the three-level converter due to overvoltage

Method used

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  • Three-level SVG midpoint potential control method
  • Three-level SVG midpoint potential control method

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Embodiment Construction

[0021] In order to understand the above-mentioned purpose, features and advantages of the present invention more clearly, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. In the following description, many specific details are set forth in order to fully understand the present invention, but the present invention can also be implemented in other ways different from those described here, therefore, the present invention is not limited to the specific embodiments disclosed below limit.

[0022] Such as figure 2 As shown, a three-level SVG midpoint potential control method includes the following steps:

[0023] Step 101: Sampling the DC side BUS capacitor voltage, subtracting the positive BUS voltage value from the negative BUS voltage value to obtain an error value ΔU;

[0024] Step 103: Use ΔU as the input of the voltage equalizing loop controller and the voltage stabilizing loop controlle...

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Abstract

The invention discloses a three-level SVG midpoint potential control method, which comprises the steps of: sampling three voltages, comparing absolute values of the voltages, and acquiring correctionvalues delta ia, delta ib and delta ic of currents; and sending the current correction value of each phase, an extraction quantity of a reactive current and an output quantity of a voltage stabilizingring into a current loop controller for control, performing sinusoidal pulse width modulation (SPWM) through the output of the controller, and driving a switching tube to act, thereby realizing bus voltage stabilization, voltage equalization and reactive current compensation. Compared with a traditional control method of superimposing common-mode voltage components, the three-level SVG midpoint potential control method has the advantage that the neutral-point potential of the input bus of the three-level three-phase three-wire system SVG system can be simply and effectively controlled.

Description

technical field [0001] The invention relates to a method for controlling the midpoint potential balance of a three-level converter, in particular to a method for controlling the midpoint potential of a three-level SVG. Background technique [0002] Compared with the traditional two-level converter, the three-level converter has the advantages of small voltage stress on power devices, small voltage change rate, good output waveform characteristics, low switching frequency and high efficiency, and is especially suitable for high-voltage large-capacity power conversion. Occasionally, in addition, under the same DC voltage, the change rate and common mode interference of the three-level converter are smaller than those of the two-level converter, which greatly reduces the electromagnetic interference and the spike voltage on the motor winding, which is conducive to the safe operation of the motor. Therefore, it has been widely used in high-voltage and high-power occasions such a...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02J3/18H02M7/487
CPCH02J3/1842H02M7/487Y02E40/10
Inventor 杨谊华刘斌邱敏徐可心
Owner NANCHANG HANGKONG UNIVERSITY
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