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Unipolar and bipolar hybrid modulation method for single-phase voltage type PWM rectifier

A technology of single-phase voltage and hybrid modulation, which is applied to electrical components, output power conversion devices, and AC power input to DC power output. The effect of current sine degree, improved efficiency, and small harmonic pollution

Inactive Publication Date: 2015-01-21
XIAN UNIV OF TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] The purpose of the present invention is to provide a unipolar and bipolar hybrid modulation method for a single-phase voltage-type PWM rectifier, while realizing unit power factor and high-quality sinusoidal current performance, on the one hand, it solves the problem of grid-side current overcurrent during unipolar modulation. The problem of zero point distortion, on the other hand, overcomes the defect of large switching loss during bipolar modulation

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Embodiment Construction

[0056] The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0057] The invention provides a unipolar and bipolar mixed modulation method for a single-phase voltage-type PWM rectifier, which divides the modulation interval on the sinusoidal current waveform of the power grid to achieve unity power factor and high quality, and uses bipolar near the zero-crossing commutation of the grid voltage Polar modulation, the rest of the grid voltage adopts unipolar modulation, such as figure 1 As shown, t0—is the starting point of the grid voltage power frequency cycle, that is, the time t0 is the positive zero-crossing point of the grid voltage, t1—is the positive voltage moment when the grid voltage is close to t0, t3—is the negative zero-crossing point of the grid voltage, and t2— is the positive voltage moment when the grid voltage is close to t3, t4 is the negative voltage moment when the grid voltage is clo...

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Abstract

The invention discloses a unipolar and bipolar hybrid modulation method for a single-phase voltage type PWM rectifier. By the adoption of the hybrid modulation manner with unipolar modulation and bipolar modulation combined, the problem that zero crossing point current distorts in the unipolar modulation process is solved, the sine degree of current is improved, and the problem of large switching losses in the bipolar modulation process is also solved. The purpose that harmonic pollution on a power grid from net-side unit power factors is low is achieved, and meanwhile the efficiency of the PWM rectifier can be improved.

Description

technical field [0001] The invention belongs to the technical field of PWM rectification, and is used for a PWM control method of a sinusoidal current waveform and a unit power factor on an AC input side of a single-phase voltage type PWM rectifier, and relates to a single-phase and bipolar mixed modulation method for a single-phase voltage type PWM rectifier. Background technique [0002] The development of rectifiers has gone through the development process of uncontrolled rectification, phase-controlled rectification, and PWM rectifier. Among them, PWM rectifier not only solves the problems of low power factor and serious grid-side current distortion in uncontrolled rectification and phase-controlled rectification, but also has energy bidirectional Due to the advantages of fast flow and dynamic response, it is widely used in systems such as uninterruptible power supplies, electric vehicle charging piles, and renewable energy. [0003] For single-phase voltage-type PWM rec...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02M7/217
Inventor 任碧莹孙向东张琦安少亮李佳
Owner XIAN UNIV OF TECH
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