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A PD-PWM Modulation Method Based on Dynamic Carrier Offset Allocation

A technology of PD-PWM and modulation method, which is applied to output power conversion devices, electrical components, and AC power input to DC power output. Improve stability, fast error correction ability, and have the effect of error tolerance mechanism

Active Publication Date: 2018-10-26
STATE GRID CORP OF CHINA +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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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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  • A PD-PWM Modulation Method Based on Dynamic Carrier Offset Allocation
  • A PD-PWM Modulation Method Based on Dynamic Carrier Offset Allocation
  • A PD-PWM Modulation Method Based on Dynamic Carrier Offset Allocation

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Experimental program
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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 Cycli...

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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 Patents(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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