Control method of three-phase multi-level inverter and inverter system

A technology of multi-level inverters and control methods, applied to electrical components, output power conversion devices, and conversion of AC power input to DC power output, etc., which can solve the problems of increased cost of inverters, increased ripple current, etc.

Active Publication Date: 2021-10-26
HUAWEI DIGITAL POWER TECH CO LTD
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Compared with the SPWM modulation method, although the above-mentioned advantages can be obtained by using the DPWM modulation method to control the inverter, it increases the ripple current in the bus capacitor on the DC side of the inverter.
In order to suppress this increased ripple current, it is usually necessary to increase the size of the bus capacitor or use more bus capacitors to share the ripple current, which leads to an increase in the cost of the inverter

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  • Control method of three-phase multi-level inverter and inverter system
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  • Control method of three-phase multi-level inverter and inverter system

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Embodiment Construction

[0040] Embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although certain embodiments of the present disclosure are shown in the drawings, it should be understood that the disclosure may be embodied in various forms and should not be construed as limited to the embodiments set forth herein; A more thorough and complete understanding of the present disclosure. It should be understood that the drawings and embodiments of the present disclosure are for exemplary purposes only, and are not intended to limit the protection scope of the present disclosure.

[0041] In the description of the embodiments of the present disclosure, the term "comprising" and its similar expressions should be interpreted as an open inclusion, that is, "including but not limited to". The term "based on" should be understood as "based at least in part on". The term "one embodiment" or "the embodiment" should be read as "at least one ...

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Abstract

The embodiment of the invention provides a control method of a three-phase multi-level inverter and an inverter system. The control method of the three-phase multi-level inverter comprises the following steps: determining a modulation ratio based on the output of the three-phase multi-level inverter, wherein the modulation ratio represents the ratio of the amplitude of a sinusoidal modulation wave to the amplitude of a carrier wave in pulse width modulation; on the basis of the modulation ratio and a modulation ratio threshold value, generating a common-mode voltage adjusting signal used for adjusting common-mode voltage in the phase voltage of the three-phase multi-level inverter; adding the common-mode voltage regulation signal and a differential-mode voltage regulation signal for regulating a differential-mode voltage in each phase voltage of the three-phase multi-level inverter to obtain a composite regulation signal, the composite regulation signal presenting a discontinuous pulse width modulation wave; and generating a driving signal for controlling a switch of each phase of the three-phase multi-level inverter based on the composite adjustment signal. According to the invention, the switching loss can be reduced and the ripple current of the bus capacitor can be suppressed at the same time, so that the efficiency of the inverter is improved and the cost is reduced.

Description

technical field [0001] The present disclosure generally relates to the field of power electronics. More specifically, the present disclosure relates to methods and inverter systems for controlling three-phase multilevel inverters. Background technique [0002] Three-phase multilevel inverters can convert DC power to AC power, and are widely used in power systems. For example, the photovoltaic three-phase multi-level inverter can convert the direct current generated by the photovoltaic string into alternating current, so as to input electric energy into the grid or off-grid system. [0003] Generally, a sinusoidal pulse width modulation (SPWM) technique may be used to control the three-phase multilevel inverter to obtain a high-quality sinusoidal AC output voltage. SPWM technology utilizes the impulse equivalent principle in the sampling control theory, that is, when narrow pulse variables with different sizes and waveforms act on the inertial system, as long as their impul...

Claims

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Application Information

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IPC IPC(8): H02M7/487H02M1/14
CPCH02M7/487H02M1/14Y02E10/56H02M1/15H02M7/5395Y02B70/10H02M1/123H02M7/527H02M7/797
Inventor季林辛凯郭海滨
OwnerHUAWEI DIGITAL POWER TECH CO LTD