Small signal modeling method for digital phase-shift modulator on the basis of dynamic phasor method

Abstract

The invention discloses a small signal modeling method for a digital phase-shift modulator on the basis of a dynamic phasor method. The method comprises the following steps that: (1) determining the input and output signals of the digital phase-shift modulator; (2) utilizing the dynamic phasor method to carry out decomposition on the input and output signals, and deducing the general expression of arbitrary-time harmonic component of the dynamic phasor of the output signal under an input disturbance situation; (3) listing the time domain expression of the output signal, carrying out generalized dynamic phasor decomposition on the time domain expression of the output signal, keeping the leading harmonic wave ingredient of the time domain expression, and ignoring other harmonic wave components; and (4) carrying out small signal disturbance and first-order Taylor series expansion on the dynamic phasor of the output signal, and writing into a general expression form to obtain a small signal transfer function between a modulator instruction value and a phase-shift angle. The method discloses the small signal dynamic characteristics of the digital phase-shift modulator, is simple and easy in implementation, provides a relevant theoretical basis and effective technical support for the parameter design of a digital control system, and exhibits feasibility and practical values.

Description

technical field [0001] The invention belongs to the technical field of power electronics, in particular to a small-signal modeling method for a digital phase-shift modulator based on a dynamic phasor method. Background technique [0002] Power electronic converters have strong nonlinear characteristics and are extremely sensitive to frequency changes, so the design and implementation of control methods are very important. In the power electronic converter control system, the voltage closed-loop control is a common control method. The output voltage sampling value is compared with the reference value and then input to the voltage regulator. The voltage regulator generally uses a PI controller, and its output is used as the post- The command value of the level modulator. When phase-shift control is adopted, the phase-shift modulator adjusts the phase-shift angle of the drive signal of the switching tube of the main circuit according to the command value and a specific phase-s...

AI Technical Summary

Problems solved by technology

[0004] In the modern industry with the rapid development of power electronics technology, the application range of controllable devices is becoming wider and wider. In some cases where rapid switching is required, the dynamic characteristics of power electronic devices are mixed with some dynamic and discrete variables. This is the amount of change that time-domain analysis cannot reveal in detail, and, although time-domain analysis can accurately describe the change of the circuit, the nonlinear process of the switch tube when it is turned on and off will make the time-domain analysis more complicated, so it is necessary Introducing dynamic phasor method to analyze the dynamic process of power electronic system

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