Low-cost high-gain three-level inverter and space vector modulation method thereof

A three-level inverter and space vector modulation technology, which is applied in the field of power electronics and power transmission, can solve the application occasions where it is difficult to meet the wide range of input voltage of the new energy power generation system, and the SNPC three-level inverter cannot realize the upgrade Voltage operation, failure to produce the output state of the vector, etc., to avoid output voltage waveform distortion, reduce the number, and restore the effect of the neutral point voltage balance

Active Publication Date: 2021-12-10
SHANDONG JIANZHU UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] Restricted by the characteristics of the topology itself, the SNPC three-level inverter can only output two level states at most, which makes it impossible to generate the output state of the vector
Therefore, the modulation methods used in traditional diode-clamped and T-type three-level inverters cannot be directly applied to SNPC three-level inverter systems
[0006] The inventors found that the traditional SNPC three-level inverter cannot achieve boost operation, that is, the output AC voltage is lower than the input DC voltage, which is difficult to meet the wide range of input voltage applications of new energy power generation systems

Method used

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  • Low-cost high-gain three-level inverter and space vector modulation method thereof
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  • Low-cost high-gain three-level inverter and space vector modulation method thereof

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Embodiment 1

[0057] This embodiment invents a low-cost high-gain three-level inverter, see the attached figure 1 As shown, the whole system is composed of DC power supply, DC input side capacitor, boost network, low-cost three-level inverter and resistive inductive load. Among them, V in is the DC supply voltage, C 1 and C 2 is the capacitor on the DC input side. The boost network is used to boost the DC input voltage, which consists of two inductors (L 1 and L 2 ), two capacitors (C 3 and C 4 ), two diodes (D 1 and D 2 ). The low-cost three-level inverter is used to convert the DC output of the step-up network into AC, which contains ten power switches (S 1 , S 2 ,...,S 10 ), where, S 1 , S 2 , S 3 , S 4 Four power switch tubes are connected in series to form a public switch unit, S 5 , S 6 The first group of independent switching units is formed by series connection, S 7 , S 8 The second group of independent switching units is formed by series connection, S 9 , S 10...

Embodiment 2

[0060] This embodiment invents a space vector modulation method for a low-cost high-gain three-level inverter, figure 2 is the space vector diagram of the method of the present invention.

[0061] The switching states of the low-cost high-gain three-level inverter include two types: non-through state and direct state. Among them, the non-through state includes three kinds: [P], [O] and [N]. Among them, when the switch state is [P], the bridge arm output voltage is V dc / 2; when the switch state is [O], the output voltage of the bridge arm is 0; when the switch state is [N], the output voltage of the bridge arm is -V dc / 2. There are two types of shoot-through states: Upper Shoot-Through (UST) state and Lower Shoot-through (LST) state, which are marked as [U] and [L] respectively. Further, the straight-through state is realized by controlling the on-off of the power switch tube in the public switch unit. Table 1 shows the switching states and turned-on power switches of t...

Embodiment 3

[0123] The purpose of this embodiment is to provide a computer-readable storage medium.

[0124] A computer-readable storage medium, on which a computer program is stored, and when the program is executed by a processor, the steps of the above method are performed.

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Abstract

The invention provides a low-cost high-gain three-level inverter and a space vector modulation method thereof. The inverter circuit topology provided by the invention comprises a direct current input side capacitor, a boost network and a low-cost three-level inverter, can realize boost and buck operation in a single-stage power conversion mode, and can remarkably reduce the number of power switch tubes and passive devices at the same time. The novel space vector modulation method provided by the invention comprises the steps of sector judgment, basic voltage vector selection and duty ratio calculation, neutral point balance active control, direct connection state injection and duty ratio updating, switching sequence design and the like. According to the method, the direct connection state is injected into the small vector, the boost function is achieved, normal alternating current output voltage is not affected, neutral-point voltage deviation caused by non-ideal factors can be effectively restrained through the neutral-point balance active control strategy, and then the operation reliability of the system is guaranteed.

Description

technical field [0001] The invention belongs to the technical field of power electronics and electric transmission, and in particular relates to a low-cost high-gain three-level inverter and a space vector modulation method thereof. Background technique [0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art. [0003] The three-level inverter has obvious advantages such as low voltage stress of the power switch tube, good output waveform quality, and small filter size, and has been widely used in new energy power generation, energy storage systems, and power quality control. The diode-clamped three-level inverter and the T-type three-level inverter are the two most commonly used three-level inverter topologies. However, the traditional three-level inverter circuit topology contains a large number of power switch tubes, which increases the system cost and control complexity. ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02M7/487H02M7/5387H02M1/088
CPCH02M7/487H02M7/53875H02M7/5395
Inventor 秦昌伟邢相洋姜英
Owner SHANDONG JIANZHU UNIV
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