Optimization control method based on selective harmonic elimination pulse width modulation (SHEPWM)

An optimized control, fundamental wave technology, applied in output power conversion devices, irreversible DC power input conversion to AC power output, electrical components, etc., can solve the problem of high amplitude of residual harmonic components and lack of residual harmonic components. control, high harmonic content, etc.

Active Publication Date: 2013-03-20
GLOBAL ENERGY INTERCONNECTION RES INST CO LTD +1
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Problems solved by technology

However, the disadvantage of this PWM technology is that although the specified low-order harmonics are eliminated, the control of the unspecified high-order harmonics is lacking, so that the content of the first few unspecified high-order harmonics becomes very large, while Elimination of these harmonics requires the design of specific filter circuits
[0005] Although the traditional SHEPWM eliminates some harmonic components, i

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  • Optimization control method based on selective harmonic elimination pulse width modulation (SHEPWM)
  • Optimization control method based on selective harmonic elimination pulse width modulation (SHEPWM)
  • Optimization control method based on selective harmonic elimination pulse width modulation (SHEPWM)

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Embodiment Construction

[0047] The present invention will be further described in detail below in conjunction with the drawings.

[0048] Such as figure 1 , Provide an optimized control method based on SHEPWM, the method includes the following steps:

[0049] Step 1: List the amplitude expressions of the fundamental wave and each controlled harmonic;

[0050] Step 2: Determine the amplitude of the fundamental wave and each controlled harmonic;

[0051] Step 3: Obtain the switch angle.

[0052] In the step 1, the Fourier expression of the expected output square wave is:

[0053] F ( ωt ) = X i = 1 ∞ ( a i sin iωt + b i cos iωt ) - - - ( 1 )

[0054] The amplitude of each harmonic α i And b i , Because of symmetry

[0055] b i = 0 i = 1,2,3 , . . . a i = 0 i = 2,4,6 , . . . a i = 4 E iπ X k = 1 N ( - 1 ) k + 1 cos ( iα k ...

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Abstract

The invention provides an optimization control method based on selective harmonic elimination pulse width modulation (SHEPWM). The optimization control method based on the SHEPWM comprises the following steps: writing amplitude expressions of fundamental waves and controlled harmonic waves of all times in an arraying mode, confirming amplitude of the fundamental waves and the controlled harmonic waves of all times, and obtaining a switch angle. The optimization control method is combined with characteristics of amplitude frequency of a filter, obtains the most advantageous size value of the amplitude of the controlled harmonic waves by optimizing an objective function, improves the harmonic wave distribution condition of an SHEPWM wave form, reduces amplitude of surplus harmonic wave, enables a total harmonic content to reduce, and even removes the big surplus harmonic waves. Small amplitude changes of a controlled harmonic wave component can cause great influence on harmonic wave distribution of output voltage, and suitable changes can reduce amplitude of surplus harmonic wave components of a traditional SHEPWM method.

Description

Technical field [0001] The invention belongs to the technical field of flexible transmission and distribution of electric power systems, and specifically relates to an optimized control method based on SHEPWM. Background technique [0002] With the vigorous development of smart grids and new energy sources, pulse width modulation control power electronics technology has been vigorously developed. In high-voltage and high-power applications, the switching frequency of power devices cannot be very high due to the limitation of heat dissipation of the device itself. In these occasions, efficiency is especially valued, so the output harmonics cannot be too large. Therefore, on the one hand, the switching frequency of a single device must be reduced, and on the other hand, the harmonic content of the overall output must be reduced. There are two technologies that can help achieve the above goals: 1) multi-level technology; 2) SHEPWM (selective harmonic elimination pulse width modulat...

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Application Information

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IPC IPC(8): H02M7/48H02M1/12
Inventor 王志刚骆健侯凯赵晓冬何安然郑哲
Owner GLOBAL ENERGY INTERCONNECTION RES INST CO LTD
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