Extended multi-input multi-level conversion circuit and control method

A technology of converting circuits and multi-levels, which is applied in the direction of eliminating voltage/current interference, logic circuit connection/interface layout, reliability improvement and modification, etc. It can solve the problems of increased voltage stress at both ends of the switch tube, complex control strategies, etc., to achieve achieve self-balancing effect

CN111740734AActive Publication Date: 2020-10-02ZHENGZHOU UNIV
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2020-10-02

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Abstract

The invention provides an extended multi-input multi-level conversion circuit which comprises a preceding-stage converter X and a backward-stage full-bridge unit Y. The preceding-stage converter X comprises a direct-current input voltage source V0 and i switched capacitor basic modules. The relationship between the output level number N of the extended multi-input multi-level conversion circuit and the number i of the switched capacitor basic modules is as follows: N=4i+5; wherein the switched capacitor basic module comprises a switching tube S<i,1>, a switching tube S<i,2>, a switching tube S<i,3>, a switching tube S<i,4>, a diode D<i,1>, a diode D<i,2>, a diode D<i,3>, a capacitor Ci and a direct-current input voltage source Vi, and i belongs to N<*>; the rear-stage full-bridge unit Y comprises switching tubes Q1, Q2, Q3 and Q4; and the collector of the switching tube Q1 in the rear-stage full-bridge unit Y is connected with the emitters of the switching tube S<i,4> in the front-stage converter X. Cascading of basic modules of the switched capacitor is realized, and the problem of unbalanced capacitor voltage is solved.
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Description

technical field

[0001] The invention relates to the fields of power electronics and electric energy conversion, new energy power generation and medium and low voltage flexible power distribution, and specifically relates to an extended multi-input multi-level conversion circuit and a control method. Background technique

[0002] With the development of power electronics technology, multilevel inverters are widely used in new energy, electric vehicles and distributed power generation systems. Compared with traditional inverters, multilevel inverters output nearly sinusoidal step voltage waveforms, which can improve the quality of output waveforms and reduce total harmonic distortion and du / dt. At the same time, the multi-level inverter has the characteristics of low voltage stress and is suitable for high voltage and high power applications. In the application of kilowatt-level inverters, multi-level inverters also have higher efficiency and power density.

[0003] Traditio...

Examples

Embodiment 1

[0030] Such as figure 1As shown, the present invention provides an extended multi-input multi-level conversion circuit, the conversion circuit includes a front-stage converter X and a rear-stage full-bridge unit Y, the front-stage converter X is used to output voltage levels, so The rear-stage full-bridge unit Y is connected to the front-stage converter X for realizing polarity conversion of the voltage level;

[0031] The pre-converter X includes a DC input voltage source V 0 and i switched capacitor basic modules;

[0032] The switched capacitor basic module includes a switch tube S i，1 , switch tube S i，2 , switch tube S i，3 , switch tube S i，4 , Diode D i，1 , Diode D i，2 , Diode D i，3 , capacitance C i and DC input voltage source V i , i∈N * ;

[0033] The diode D i，1 of the cathode, the capacitor C i The positive poles of both and the switching tube S i，4 The emitter is connected; the switch tube S i，1 emitter with the diode D i，2 The anode is connected; ...

Embodiment 2

[0043] On the basis of the extended multi-input multi-level conversion circuit in Embodiment 1, the present invention also provides a control method for the extended multi-input multi-level conversion circuit.

[0044] The control method of the extended multi-input multi-level conversion circuit includes the following steps: generating a drive signal, controlling the aforementioned extended multi-input multi-level conversion circuit to work in 4i+5 working modes through the drive signal, Output 4i+5 levels.

[0045] Specifically, when generating the driving signal, execute: obtain a frequency f s , the amplitude is U s The sinusoidal modulation wave u s with 4 i +4 channels have the same frequency f c and the same amplitude U c The triangular carrier u c1 -u c(4i+4) ;

[0046] Among them, the modulation wave u s Can be expressed as: u s =U s sin(2πf s t);

[0047] The triangular carrier u c1 -u c(4i+4) Can be expressed as:

[0048]

[0049]

[0050] Amon...

Embodiment 3

[0109] The third aspect of the present invention provides an extended multi-input multi-level conversion system, including a controller and an extended multi-input multi-level conversion circuit, the extended multi-input multi-level conversion circuit is the extended Type multi-input multi-level conversion circuit.

[0110] When the controller controls the action of the switching tubes in the extended multi-input multi-level conversion circuit, the steps of the extended multi-input multi-level conversion method described in Embodiment 2 are executed.