SVPWM (Space Vector Pulse Width Modulation) synchronous modulation/overmodulation method of high-power AC transmission system

An AC drive, synchronous modulation technology, applied in the direction of AC motor control, control system, electrical components, etc., can solve the problems of harmonic distortion, limitation, unsuitable for high-power inverter occasions, etc., to reduce harmonics, the method is simple workable effect

Inactive Publication Date: 2017-01-04
DALIAN UNIV OF TECH
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Problems solved by technology

[0004] However, since this method is limited to the asynchronous modulation over-modulation algorithm, however, the asynchronous modulation will produce serious harmonic distortion when working at low switching frequency, so this method is limited to low-power conditions and is not suitable for high-power inverters

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  • SVPWM (Space Vector Pulse Width Modulation) synchronous modulation/overmodulation method of high-power AC transmission system
  • SVPWM (Space Vector Pulse Width Modulation) synchronous modulation/overmodulation method of high-power AC transmission system
  • SVPWM (Space Vector Pulse Width Modulation) synchronous modulation/overmodulation method of high-power AC transmission system

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[0045] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments It is a part of embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

[0046] figure 1 It is a flow chart of the SVPWM synchronous modulation and over-modulation method of the high-power AC drive system of the present invention, as figure 1 As shown, the method of this embodiment may include:

[0047] Step 101, according to the modulation ratio, the modulation area is divided into a linear modulation area, an over-...

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Abstract

The invention provides a SVPWM (Space Vector Pulse Width Modulation) synchronous modulation / overmodulation method of a high-power AC transmission system. The SVPWM synchronous modulation / overmodulation method comprises the following steps of dividing a modulation region to a linear modulation region, an overmodulation region I and an overmodulation region II according to a modulation ratio; calculating a first modulation ratio corresponding to a boundary of the linear modulation region and the overmodulation region I, a second modulation ratio corresponding to a boundary of the overmodulation region I and the overmodulation region II and maximum modulation ratio corresponding to an upper limit of the overmodulation region II by using a basic bus clamping strategy according to number and positions of sampling points in a fan-shaped region; determining a modulation coefficient according to the modulation ratios, determining a weighting coefficient of synthesis compensation voltage vector according to the modulation coefficient, and synthesizing compensation voltage vectors of the overmodulation region I and the overmodulation region II; and calculating action time of two effective voltage vectors and a zero vector required by the synthesis compensation voltage vector for PWM (Pulse Width Modulation) by using a volt-second balance pricinple. By the SVPWM synchronous modulation / overmodulation method, a high-power inverter can be smoothly transitioned to a six-beat wave working state from linear modulation.

Description

technical field [0001] The invention relates to the field of high-power AC drive control, in particular to a SVPWM synchronous modulation and over-modulation method for a high-power AC drive system. Background technique [0002] Medium and high voltage high-power inverters based on high-power power electronic switching devices have been widely used in metal rolling, mine hoisting, ship propulsion, locomotive traction and other fields. However, when power electronic switching devices work under high voltage and high current conditions, switching loss and device heat dissipation cannot be ignored, and the highest allowed switching frequency is usually less than 1kHz. At such a low switching frequency, a synchronous modulation strategy is usually used to maintain a high degree of symmetry in the output PWM waveform, thereby effectively reducing harmonics. [0003] When the bus voltage on the DC side of the inverter decreases or the AC drive system enters the field-weakening re...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02P27/12
CPCH02P27/12
Inventor 郭源博李泽张晓华张铭
Owner DALIAN UNIV OF TECH
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