Method for modulating single-phase cascade alternating-current high-frequency link bidirectional converters

A technology of bidirectional converter and modulation method, which is applied in the direction of reversible conversion equipment, output power conversion device, electrical components, etc., and can solve the problems of poor output waveform quality, poor scalability, and high system cost , to achieve the effects of offsetting low-order harmonic components, increasing system capacity, and improving output waveform quality

Inactive Publication Date: 2018-06-22
NANJING UNIV OF SCI & TECH
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Problems solved by technology

These modulation methods are widely used, and the research is relatively mature. However, at this stage, the research on the comprehensive modulation of combining these two circuit modulation methods to generate cascaded AC high-frequency chain circuits is still relatively lacking, and there are problems such as poor output waveform quality, poor scalability, high system cost

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  • Method for modulating single-phase cascade alternating-current high-frequency link bidirectional converters
  • Method for modulating single-phase cascade alternating-current high-frequency link bidirectional converters
  • Method for modulating single-phase cascade alternating-current high-frequency link bidirectional converters

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Embodiment 1

[0033] The experimental simulation model is built in Matlab. The system parameters are as follows: sine modulation wave frequency 50Hz, triangular carrier frequency 20kHz, DC power supply voltage 24V, transformer ratio 48:300, and the output voltage of a single AC high-frequency link unit is partially expanded. Figure 5 As shown, its amplitude is ±150V two-state SPWM wave. Fourier analysis of the output voltage as Figure 6 As shown, its harmonics are mainly distributed around the carrier frequency and its multiplier.

[0034] The cascading of four high-frequency chain units is realized by means of triangular carrier phase shift, and the phase difference of each unit triangular carrier is 1 / 4 of the carrier period from the adjacent unit. Figure 7 It is the output voltage waveform after cascading, and its voltage amplitude is 4 times the output voltage amplitude of a single high-frequency chain unit, and the number of levels increases at the same time. Figure 8 It is the F...

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Abstract

The invention discloses a method for modulating single-phase cascade alternating-current high-frequency link bidirectional converters. The method includes generating direct-current voltage signals with identical amplitudes by the aid of direct-current power supplies of various high-frequency link units; modulating the direct-current voltage signals by the aid of preceding-stage inverters and generating identical high-frequency square-wave voltage signals; carrying out voltage class transformation and electric isolation by the aid of high-frequency transformers; carrying out decoupling modulation by the aid of matrix converters, allowing the matrix converters to be equivalent to two groups of independent inverters and controlling the two groups of independent inverters; carrying out carrierphase-shift cascade modulation on the various high-frequency link units, carrying out cascade on voltages outputted by the various high-frequency link units, filtering the voltages and then generating stable sine waves. The method has the advantages that the method is flexible and reliable, high equivalent switching frequencies can be obtained under the condition of low device switching frequencies, output voltage waveforms can be improved, and output harmonic waves can be reduced.

Description

technical field [0001] The invention relates to micro-grid and energy storage technology, in particular to a single-phase cascaded AC high-frequency link bidirectional converter modulation method. Background technique [0002] Energy storage converter technology is developing towards large capacity, high conversion efficiency, high frequency isolation and low application cost. Single-phase cascaded AC high-frequency link topology. The AC side is composed of N high-frequency link units cascaded. By increasing the rated current of the AC high-frequency link power unit and the capacity of the single battery, the energy storage system can be increased in capacity. The cascaded AC high-frequency link structure can be directly connected to the 10kV power grid, avoiding the loss of power frequency transformers and filters, and improving efficiency; it can reduce the insulation design requirements for energy storage batteries through high-frequency isolation; in a certain AC high-fr...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02M7/72
CPCH02M7/72H02M1/0067H02M1/007
Inventor 潘梦姣刘钊葛晨阳王帅张越
Owner NANJING UNIV OF SCI & TECH
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