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PD-PWM modulation method based on dynamic carrier offset distribution

A technology of PD-PWM and modulation method, which is applied in the direction of output power conversion device, electrical components, AC power input conversion to DC power output, etc. It can solve the problems of low carrier frequency and inability to effectively balance the capacitor voltage of subunits, etc., to achieve Improve stability, fast error correction ability, and have the effect of error tolerance mechanism

Active Publication Date: 2017-01-04
STATE GRID CORP OF CHINA +2
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  • Abstract
  • Description
  • Claims
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Problems solved by technology

However, when the initial state of the subunit capacitance is different, or the carrier frequency is too low, this method cannot effectively balance the voltage of the subunit capacitance

Method used

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  • PD-PWM modulation method based on dynamic carrier offset distribution
  • PD-PWM modulation method based on dynamic carrier offset distribution
  • PD-PWM modulation method based on dynamic carrier offset distribution

Examples

Experimental program
Comparison scheme
Effect test

Embodiment

[0058] The present invention builds a single-phase inverter model of the CHB grid-connected model in the electromagnetic transient simulation software PSIM, and the simulation parameters are shown in Table 4.

[0059] Table 4 Simulation parameters

[0060] parameter name parameter value Subunit capacitor voltage 100V

[0061] rated value Number of subunits 5 Subunit Capacitance 10mF Grid-connected inductance 10mH AC voltage frequency 50Hz

[0062] 1. Compared with the traditional cyclic carrier offset distribution type PD-PWM

[0063] In order to test the dynamic voltage equalization characteristics of the method of the present invention, and compare it with the traditional cyclic conversion carrier bias type PD-PWM, the present invention has carried out the following simulation: the system first selects the DC bus capacitance parameters of the subunits to be consistent, and adopts Cyclic carrier bias PD-PWM mo...

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Abstract

The invention relates to a PD-PWM modulation method based on dynamic carrier offset distribution, comprising the steps of getting a double-modulated wave signal, distributing carrier signals corresponding to H-bridge subunits, and comparing the double-modulated wave signal with the carrier signals corresponding to the H-bridge subunits to get control signals of the H-bridge subunits. According to the novel CHB structure modulation method provided by the invention, while the multi-level degree of freedom and low harmonic output voltage advantages of full-bridge subunits are brought into a maximum play, the capacitive voltages of the subunits can be balanced effectively, and engineering implementation is easy. Simulation and experiment results verify that the modulation strategy is feasible and effective.

Description

technical field [0001] The invention relates to a modulation method in the field of power electronics, in particular to a PD-PWM modulation method based on dynamic carrier offset distribution. Background technique [0002] Cascaded H-bridge has become a research hotspot in recent years because of its modular structure, simple control, and multi-level output, and is widely used in various medium-voltage and high-power power electronic equipment. Compared with the traditional multilevel converter, its main control difficulty lies in the voltage balance of the floating capacitors of the DC bus of each sub-unit. When it is used as a rectifier with multiple different DC loads, it is more difficult to control the DC output voltage of each channel, and it may even cause system stability problems when the load difference is too large. Therefore, the subunit capacitor voltage equalization strategy has always been the research focus of this type of topology. [0003] At present, the...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02M7/501H02M7/5395H02M1/12
Inventor 燕翚王轩付永生訾振宁王宇红
Owner STATE GRID CORP OF CHINA
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