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A dpwm modulation method for three-level inverter with neutral point balance function

A three-level inverter, DPWM technology, applied in the direction of output power conversion device, AC power input conversion to DC power output, electrical components, etc., can solve problems such as midpoint imbalance, reduce loss, realize The process is easy to operate and the effect of flexible control of the midpoint potential

Active Publication Date: 2021-08-03
SHANDONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] In order to solve the deficiencies of the prior art, the present disclosure provides a DPWM modulation method for a three-level inverter with a midpoint balance function, which solves the problem of midpoint imbalance when the three-level inverter uses DPWM modulation, and realizes Midpoint Balance Control for Loss Reduction

Method used

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  • A dpwm modulation method for three-level inverter with neutral point balance function
  • A dpwm modulation method for three-level inverter with neutral point balance function
  • A dpwm modulation method for three-level inverter with neutral point balance function

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Embodiment 1

[0039] The present disclosure provides a three-level inverter DPWM modulation method having a midpoint balancing function. It is implemented in the form of an initial modulation wavelee plus co-modem wave, which is a mixed modulation strategy of DPWM and SVPWM. DPWM reduction loss and SVPWM have the advantage of adjustment in the midpoint potential adjustment;

[0040] The absolute value of the voltage is absolutely valued, resulting in a common mode modulation wave of 60 ° clamping, based on the median potential to become SVPWM and control a pair of redundant small vectors in SVPWM, resulting The corrected common mode modulation wave, superimposes the corrected common mode wave with the initial modulation wave, obtains the output modulation wave, drives the switch tube.

[0041] The specific content is as follows:

[0042] The control target of this embodiment is a non-separated tripartic inverter system, such as figure 1 As shown, including the grid E a , E b , E c , Inverter, D...

Embodiment 2

[0072] Embodiment 2 of the present disclosure provides a three-level inverter DPWM modulation system having a midpoint balance function, including:

[0073] The data acquisition module is configured to obtain the operating status data of the three-level inverter to obtain three-phase initial modulation waves;

[0074] The clamp control module is configured to: a plurality of voltage absolute values ​​to obtain a common mode modulation wave after clamping;

[0075] The common mode correction module is configured to: adjust the midpoint potential difference of the inverter by PI control, and use the PI control output to fix the correction wave;

[0076] The overlay output module is configured to superimpose the corrected common mode wave with the initial modulation wave to obtain the output modulation wave, drive the switch tube.

[0077] The working method of the system is the same as the three-level inverter DPWM modulation method having the midpoint balance function provided in E...

Embodiment 3

[0079] The present disclosure provides a medium that stores a program, which is implemented when executed by the processor, implemented, a three-level inverter DPWM modulation method of the midpoint balance function as described in Example 1 of the present disclosure. The steps are:

[0080] Get the running status data of the three-level inverter to obtain three-phase initial modulation wave;

[0081] A common mode modulation wave after the absolute value is maximized.

[0082] The midpoint potential difference of the inverter is adjusted by PI control, and the amount of common mode modification is used to use PI control.

[0083] The corrected common mode waves are superimposed with the initial modulation wave, obtain the output modulation wave, drive the switching tube.

[0084] The detailed steps are the same as the three-level inverter DPWM modulation method having the midpoint balance function provided in Example 1, and details are not described herein again.

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Abstract

This disclosure provides a three-level inverter DPWM modulation method with a midpoint balance function, which is realized by superimposing the initial modulation wave with a common-mode modulation wave. It is a mixed modulation strategy of DPWM and SVPWM, taking into account the reduction of DPWM Loss and SVPWM adjust the advantage of the midpoint balance according to the midpoint potential. The method includes the following steps: obtaining the operating state data of the three-level inverter to obtain the three-phase initial modulation wave; clamping the phase with the largest absolute voltage value to obtain the clamped common-mode modulation wave; adopting PI control to control the inverter The midpoint potential difference of the device is adjusted, and the output of the PI control is used to correct the common-mode modulation wave; the modified common-mode modulation wave is superimposed on the initial modulation wave to obtain the output modulation wave, which drives the switch tube to work; the disclosure The method can reduce the system loss while ensuring the balance of the midpoint potential, adopts the method of common mode injection, the realization process is simple and easy to operate, without the complicated calculation process of the traditional SVPWM, and has strong application value.

Description

Technical field [0001] The present disclosure relates to the field of three-level inverter modulation techniques, and in particular, to a three-level inverter DPWM modulation method having a midpoint balance function. Background technique [0002] The statement of this section is merely the background technology related to the present disclosure, and it is not necessarily constituting the prior art. [0003] In the case where the energy equipment is vigorously developed, the inverter is used as a wide concern between the network between the new energy and the grid. It changes the direct current energy to AC energy, which is widely used in uninterruptible power supplies, electric vehicles, wind power , Solar power generation, power active filters and other fields. Japanese scholar A.NABAE proposed a medium-point clamp three-level inverter (NPC) in 1980, compared to two level inverters, smaller harmonic content, now It is widely used in high voltage high power fields. [0004] Whet...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02M7/487
CPCH02M7/487
Inventor 张承慧张博学邢相洋李晓艳王志祯
Owner SHANDONG UNIV