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A self-balancing method for input capacitors of five-level full-bridge grid-connected inverters

A technology of input capacitors and inverters, which is applied in the field of power electronic converter control, can solve problems such as increased circuit cost, uneven voltage of voltage dividing capacitors, complex control procedures and modulation methods, etc., and is easy to realize by DSP, modulation The method is simple and saves the effect of the capacitor voltage sampling circuit

Active Publication Date: 2017-09-15
HOHAI UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, since the input side adopts voltage dividing capacitors in series, within a certain modulation ratio range, the voltage of the input voltage dividing capacitors will be uneven.
[0004] Refer to the input capacitor voltage equalization method of the traditional single-phase half-bridge three-level inverter, such as figure 1 As shown, the five-level full-bridge grid-connected inverter can realize capacitor voltage equalization by adjusting the bias of the current reference signal according to the voltage difference of the input voltage-dividing capacitors, but this method needs to sample the voltages of two input capacitors at the same time, which increases the The circuit cost, control procedure and modulation method are all more complicated and need to be improved

Method used

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  • A self-balancing method for input capacitors of five-level full-bridge grid-connected inverters
  • A self-balancing method for input capacitors of five-level full-bridge grid-connected inverters
  • A self-balancing method for input capacitors of five-level full-bridge grid-connected inverters

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Embodiment 1

[0039] see figure 2 , the five-level full-bridge grid-connected inverter input capacitor self-balancing method of this embodiment, the full-bridge grid-connected inverter used includes a DC power supply U dc , input voltage dividing capacitor 1, five-level full-bridge inverter circuit 2, first output filter inductor L f1 , the second output filter inductor L f2 and output filter capacitor C f , the control circuit part of the full-bridge grid-connected inverter includes a control circuit 3 and a modulation circuit 4, wherein the control circuit 3 specifically includes a current sensor, a first subtractor, and an inductor current regulator, and the modulation circuit 4 includes a first comparator, The second comparator, the third comparator, the fourth comparator, the fifth comparator, the sixth comparator, the first drive circuit, the second drive circuit, the third drive circuit, the fourth drive circuit, the fifth drive circuit, A sixth drive circuit, a second subtractor...

Embodiment 2

[0060] see Figure 4 , the five-level full-bridge grid-connected inverter input capacitor self-balancing method of this embodiment, the full-bridge grid-connected inverter includes a DC power supply U dc , input voltage dividing capacitor 1, five-level full-bridge inverter circuit 2, first output filter inductor L f1 , the second output filter inductor L f2 and output filter capacitor C f , the control circuit part of the full-bridge grid-connected inverter includes a control circuit 3 and a modulation circuit 4, wherein the control circuit 3 includes a current sensor, a first subtractor, and an inductor current regulator, and the modulation circuit 4 includes a first comparator, The second comparator, the third comparator, the fourth comparator, the fifth comparator, the sixth comparator, the first drive circuit, the second drive circuit, the third drive circuit, the fourth drive circuit, the fifth drive circuit, A sixth driving circuit, a first adder, a second adder, a fi...

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Abstract

The invention discloses a method for self-equalizing voltage of an input capacitor of a five-level full-bridge grid-connected inverter, which belongs to the technical field of converter control. According to the change of the modulation ratio of the five-level full-bridge grid-connected inverter, the method changes the amplitude of the modulation wave signal or the triangular carrier signal to realize the natural equalization of the input capacitor voltage. The advantage is that it only needs to sample the total input voltage to realize the natural voltage equalization of the voltage dividing capacitor, which saves a set of capacitor voltage sampling circuits, and the control circuit cost is low; the control loop of capacitor voltage equalization is omitted, simplifying control program. This method is applicable to a variety of five-level full-bridge grid-connected inverter topologies, and has broad application prospects in the field of new energy grid-connected power generation.

Description

technical field [0001] The invention relates to a self-equalizing method for input capacitors of a five-level full-bridge grid-connected inverter, which belongs to the technical field of power electronic converter control. Background technique [0002] With the increasingly severe energy crisis and environmental pollution, new energy power generation technologies such as solar energy, wind energy, and fuel cells have become the focus of attention and research around the world. According to whether the new energy power generation system is connected to the public grid, it is divided into two modes: grid-connected operation and independent operation. Among them, grid-connected operation is the most common way for new energy power generation applications, and grid-connected inverters are used as new energy grid-connected systems. It is of great significance to improve its reliability, efficiency and power density. [0003] The dual-buck inverter has the advantages of high reli...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02M7/483
Inventor 张犁赵晋泉
Owner HOHAI UNIV