Half-bridge cascade type multi-level inversion circuit capable of realizing three-phase four-wire system output

A multi-level inverter, three-phase four-wire system technology, applied in the output power conversion device, the conversion of AC power input to DC power output, electrical components and other directions, can solve the problem of low voltage utilization, mid-point potential floating, weight , large volume and other problems, to achieve the effect of improving voltage utilization, reducing switching loss, and reducing withstand voltage requirements

Inactive Publication Date: 2013-01-30
夏守行
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0002] Since the common three-phase inverter power supply may cause serious adverse consequences to the load when it is applied to an asymmetrical load, the circuit of the three-phase four-wire output inverter power supply applied to the three-phase asymmetric load is currently used to overcome the conventional three-phase Scholars at home and abroad have done a lot of research on the defects of inverter power supply
Solution 1 is to use two equal capacitors in series, and the load neutral line is connected to the connection point of the two capacitors in series. The disadvantage of this solution is that the voltage utilization is low. Under SPWM modulation, the maximum utilization rate of the phase voltage is only 0.5, and there is still the problem of midpoint potential floating; The second is to use three-phase four bridge arms, and the load neutral line is connected to the midpoint of the fourth bridge arm. The disadvantage is that the control scheme is complicated; the third option is to insert a △ / Y0 three-phase transformer; the fourth option is to use three-phase six bridge arms, every two The bridge arm constitutes a one-phase inverter, that is, a combined type, but the output requires a transformer. Both schemes 3 and 4 have power frequency transformers, and the three-phase four-wire output inverter power supply has problems such as weight and volume.

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  • Half-bridge cascade type multi-level inversion circuit capable of realizing three-phase four-wire system output
  • Half-bridge cascade type multi-level inversion circuit capable of realizing three-phase four-wire system output
  • Half-bridge cascade type multi-level inversion circuit capable of realizing three-phase four-wire system output

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Embodiment Construction

[0018] figure 1 and figure 2 These are the two types of N=2 of the basic inverter circuit of the present invention. by figure 1 For example, E is the input DC power supply, C21~C23 are its bootstrap energy storage capacitors, that is, power filter capacitors, SA1~SA4, SB1~SB4, SC1~SC4, S21~S23, etc. are power switching devices, S21, S22 and S23 are cascaded power switching devices. SA1 and SA2 are devices of the first-stage half-bridge cascaded inverter circuit, SA3 and SA4 are devices of the second-stage half-bridge cascaded inverter circuit, and so on. When working, the work of S21 and SA1 is synchronous, and the work of S22 and SB1 is also synchronous. Specific working principle: Take the A-phase inverter with N=2 as an example. When the upper and lower half bridges are under PWM modulation, each half bridge outputs the inverter fundamental wave and a DC potential with a value of 0.5E, and E is the input DC power supply. Therefore, the DC potential of the cascaded out...

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Abstract

The invention relates to the technical field of power conversion equipment for power electronics, in particular to a novel power electronic inversion technology of a half-bridge cascade type multi-level inversion structure. The invention particularly relates to a topological structure capable of realizing three-phase four-wire system output and adopting the multi-level inversion technology, and the topological structure is applicable to three-phase asymmetric load. The invention discloses a novel half-bridge cascade type three-phase four-wire system inversion circuit which is characterized in that conventional three-phase full-bridge inversion output ends are respectively in cascaded connection with half-bridge inversion circuits, the cascaded half-bridge inversion output ends are connected with three-phase asymmetric loads, a load middle wire is connected with an input direct current power end (an isolating capacitor is possibly needed), a bootstrap circuit can automatically generate a power supply for cascaded half-bridges when the inversion circuit operates, through a proper modulation method and reasonably distributing the modulation degree of upper and lower half-bridges, the peak current and inversion ripples of the inversion circuit can be reduced. Therefore, only one input direct current power can be adopted, the utilization rate of inversion voltage is improved, the inversion harmonic wave is reduced, the three-phase four-wire system output can be directly realized, and a power frequency transformer for outputting can be omitted.

Description

technical field [0001] The present invention relates to the technical field of power conversion equipment for power electronics, in particular to a power electronics technology of a multi-level cascaded inverter with a cascaded multi-level inverter structure, and specifically relates to a three-phase four-wire system output The topology structure of multi-level inverter technology can be applied to three-phase asymmetrical loads. Background technique [0002] Since the common three-phase inverter power supply may cause serious adverse consequences to the load when it is applied to an asymmetrical load, the circuit of the three-phase four-wire output inverter power supply applied to the three-phase asymmetric load is currently used to overcome the conventional three-phase Scholars at home and abroad have done a lot of research on the defects of inverter power supply. The first solution is to use two equal capacitors in series, and the load neutral line is connected to the co...

Claims

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Application Information

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Patent Type & AuthorityApplications(China)
IPC IPC(8): H02M7/483
Inventor夏守行
Owner夏守行