A multi-level dc-ac photonic power converter and its current conversion modulation method

Abstract

The application discloses a kind of multi-level DC-AC photon electric energy converters and its current conversion modulation method, for the topology complex, switch device multiple, bulky, the limited number of output level and the higher problem such as output waveform distortion degree generally existing in traditional switching inverter, a kind of multi-level DC-AC photon electric energy converter and its current conversion modulation method are proposed in the application, by topology structure design and current conversion modulation method, multi-level photon electric energy conversion from direct current input to alternating current output is realized, output N level, wherein N represents arbitrary positive odd number greater than 1, the only required number of switching tube is N-1, compared with the number of switching device used in traditional switching converter, reduce by half or more, the photon electric energy converter of the application shows the characteristics of simple structure, less switching device, small, wide application range, good electrical isolation, while having the advantages of low electromagnetic interference, small output ripple.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of electric energy conversion, in particular to a multi-level DC-AC photon electric energy converter and its current conversion modulation method. BACKGROUND

[0002] With the continuous development of photon electric energy converter in the field of power electronics, the photon electric energy converter has realized DC-DC, DC-AC, AC-DC and AC-AC electric energy conversion, and promoted the wide application of photon electric energy conversion. The traditional multi-level inverter has the problems of large number of opening devices, large volume, high output ripple, complex control strategy and electromagnetic interference, which is difficult to meet the demand for high quality output, especially in precision equipment and high reliability system.

[0003] The present application discloses a DC-AC multi-level photon electric energy converter and its current conversion modulation method, which realizes the energy conversion of direct current input and alternating current output by combining the characteristics of photoelectric material and the electrical output demand. Through the flexible configuration of the number of elements in the photovoltaic component, a multi-level output form is generated, which solves the problems of traditional multi-level inverters, such as large number of switching devices, large volume, limited output level, voltage distortion and electromagnetic interference. The photon electric energy converter has the advantages of small number of switching tubes, small volume, simple control strategy, low output ripple and low electromagnetic interference while realizing multi-level output, and is especially suitable for medical equipment, modern communication technology and other fields with high requirements for power quality. SUMMARY

[0004] The present application discloses a multi-level DC-AC photon electric energy converter and its current conversion modulation method, which utilizes the unique characteristics of photoelectric material and electrical output characteristics, so that the converter can adjust the number of output levels according to different numbers of photovoltaic elements. The converter realizes N-level output using only N-1 switching devices, which has the advantages of simple circuit structure, small number of switching devices, small volume, simple control strategy, good electrical isolation, low electromagnetic interference and small output ripple compared with traditional multi-level inverters, and expands the application field of photon electric energy converter, providing a new method for multi-level DC-AC photon electric energy conversion.

[0005] A multi-level DC-AC photon electric energy converter, comprising: an input side direct current power supply U DC , an input side LED-A, LED-B and LED-C light source, an output side photovoltaic element PV-A group, PV-B group, a control module and an output load Z.

[0006] The following N is the number of output levels, and N represents any positive odd number greater than 1;

[0007] The control module comprises switching tubes S1, S2, … S 2nPWM 1, PWM 2, …, PWM 2n, and a control unit;

[0008] the output side photovoltaic element PV-A group: photovoltaic elements PV-A1, PV-A2, …, PV-An, n=(N-1) / 2, N is the number of output levels;

[0009] the output side photovoltaic element PV-B group: photovoltaic elements PV-B1, PV-B2, …, PV-Bn; n=(N-1) / 2, N is the number of output levels;

[0010] the positive pole of the DC power supply U DC is connected with the positive pole of the input side LED-A, LED-B, LED-C light source;

[0011] the negative pole of the DC power supply U DC is connected with the negative pole of the input side LED-A, LED-B, LED-C light source;

[0012] the output side photovoltaic elements PV-A1, …, PV-An are connected in forward series;

[0013] the output side photovoltaic elements PV-B1, …, PV-Bn are connected in forward series;

[0014] the positive pole of the output side photovoltaic element PV-A1 and the negative pole of the output side photovoltaic element PV-B1 are connected with the positive pole of the output load Z;

[0015] the switching device is a full-controlled switching element, and the switching device port includes: a first port, a second port, and a gate;

[0016] the negative poles of the output side photovoltaic elements PV-A1, …, PV-An are respectively connected with the first ports of the switching tubes S1, …, S n ;

[0017] the positive poles of the output side photovoltaic elements PV-B1, …, PV-Bn are respectively connected with the first ports of the switching tubes S n+1 , …, S 2n ;

[0018] the positive pole of the output load Z is connected with the positive pole of the output side photovoltaic element PV-A1 and the negative pole of the output side photovoltaic element PV-B1;

[0019] the negative pole of the output load Z is connected with the second ports of the switching tubes S1, …, S 2n ;

[0020] Preferably, the emission wavelength of the input side LED-A, LED-B, LED-C light source matches the receiving wavelength of the output side photovoltaic element PV-A group and PV-B group, which is conducive to improving the transmission efficiency of photon energy.

[0021] The output ports of the PWM 1, …, PWM 2n are connected with the gates of S1, …, S 2n , respectively.

[0022] A current conversion modulation method of a multi-level DC-AC photon electric energy converter comprises the following steps:

[0023] S1: the control unit outputs a modulation signal to the PWM 1, PWM 2, …, PWM n to control the on-off time sequence of S1, S2, …, S n , respectively, and the switching devices S1, S2, …, S n , …, S2, S1 are sequentially turned on, and only one switching device is turned on in each state to realize positive level output.

[0024] S2: the control unit outputs a modulation signal to the PWM n+1, PWM n+2, …, PWM 2n to control the on-off time sequence of S n+1 , S n+2 , …, S 2n , respectively, and the switching devices S n+1 , S n+2 , …, S 2n , …, S n+2 , S n+1 are sequentially turned on, and only one switching device is turned on in each state to realize negative level output.

[0025] As can be seen from the above technical method, the case embodiment of the present application has the following beneficial effects:

[0026] The multi-level DC-AC photon electric energy converter and the current conversion modulation method thereof disclosed by the present application realize DC input and AC N-level output by using N-1 switching devices, control the number of output PV photovoltaic elements by controlling the on-off time sequence of the switching devices, realize multi-level output, and are applied to DC-AC conversion occasions. Compared with the traditional switching converter, the multi-level DC-AC photon electric energy converter uses photons as the energy transmission medium, has the advantages of simple structure, few switching devices, small size, simple control strategy, low electromagnetic interference, etc., and expands the application field of the photon electric energy converter. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings needed to be used in the prior art and the embodiments, and the following drawings are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the premise of the drawings.

[0028] Figure 1A nine-level DC-AC photon electric energy converter topological structure diagram in an embodiment of the present application;

[0029] Figure 2 A nine-level DC-AC photon electric energy converter positive and negative half cycle output nine-level principle and output waveform diagram in an embodiment of the present application;

[0030] Figure 3 A nine-level DC-AC photon electric energy converter switch device working state diagram in a single cycle in an embodiment of the present application;

[0031] Figure 4 An input and output waveform diagram of a nine-level DC-AC photon electric energy converter in an embodiment of the present application;

[0032] Figure 5 An N-level DC-AC photon electric energy converter topological structure diagram in the present application;

[0033] Figure 6 An N-level DC-AC photon electric energy converter positive and negative half cycle output multi-level principle and waveform diagram in the present application;

[0034] Figure 7 An N-level DC-AC photon electric energy converter switch device working state diagram in a single cycle in the present application;

[0035] Figure 8 An input and output waveform diagram of an N-level DC-AC photon electric energy converter in the present application; DETAILED DESCRIPTION

[0036] In order to make the purpose, technical scheme and characteristics of the embodiments of the present application clearer, the technical scheme of the embodiments of the present application will be described clearly and completely below in combination with the drawings of the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of the present application.

[0037] Specifically, the multi-level DC-AC photon electric energy converter provided in the present application can output various levels. In actual application, a user can select the number of photovoltaic elements in a photovoltaic module according to actual demand to obtain various level numbers. In the present application, nine-level output is taken as an example, that is, photovoltaic element group PV-A and photovoltaic element group PV-B each contain 4 photovoltaic elements.

[0038] Please refer to Figure 1 , Figure 1A schematic diagram of a nine-level DC-AC photonic electric energy converter topology of the present application, comprising: an input side DC power supply U DC , an input side LED-A, LED-B light source, an output side photovoltaic element PV-A group, PV-B group, a control module, an output load Z, the output voltage U O (t) output nine levels;

[0039] The output side photovoltaic element PV-A group: photovoltaic element PV-A1, PV-A2, PV-A3, PV-A4;

[0040] The output side photovoltaic element PV-B group: photovoltaic element PV-B1, PV-B2, PV-B3, PV-B4;

[0041] The positive electrode of the DC power supply U DC is connected to the positive electrode of the input side LED-A and the positive electrode of the input side LED-B;

[0042] The negative electrode of the DC power supply U DC is connected to the negative electrode of the input side LED-A and the negative electrode of the input side LED-B;

[0043] The output side photovoltaic elements PV-A1, PV-A2, PV-A3, PV-A4 are connected in forward series;

[0044] The output side photovoltaic elements PV-B1, PV-B2, PV-B3, PV-B4 are connected in forward series;

[0045] The positive electrode of the output side photovoltaic element PV-A1 and the negative electrode of the output side photovoltaic element PV-B1 are connected to the positive electrode of the output load Z;

[0046] The control module comprises: switching devices S1, …, switching devices S8, PWM 1, PWM 2, …, PWM 8, and a control unit;

[0047] Optionally, the switching device is a full-controlled switching element, and the switching device port comprises: a first port, a second port, and a gate (signal input port).

[0048] The negative electrodes of the output side photovoltaic elements PV-A1, …, PV-A4 are respectively connected to the first ports of the switching devices S1, …, S4;

[0049] The positive electrodes of the output side photovoltaic elements PV-B1, …, PV-B4 are respectively connected to the first ports of the switching devices S5, …, S8;

[0050] The control unit is respectively connected to the input ports of the PWM 1, …, PWM 8;

[0051] The output ports of the PWM 1, …, PWM 8 are connected with the gate of the switching devices S1, …, S8 respectively;

[0052] The positive pole of the output load Z is connected with the positive pole of the photovoltaic element PV-A1 and the negative pole of the PV-B1;

[0053] The negative pole of the output load Z is connected with the second port of the switching devices S1, …, S8;

[0054] Please refer to Figure 2 , a nine-level photonic electric energy converter modulation method and its output waveform diagram, the modulation method is:

[0055] S1: the control unit outputs the modulation signal to the PWM 1, PWM 2, …, PWM4, which controls the switching sequence of S1, S2, …, S4 respectively, and the switching devices S1, S2, S3, S4, S3, S2, S1 are turned on in turn, only one switching device is turned on in each state, to realize positive level output;

[0056] S2: the control unit outputs the modulation signal to the PWM 5, PWM 6, …, PWM 8, which controls the switching sequence of S5, S6, S7, S8 respectively, and the switching devices S5, S6, S7, S8, S7, S6, S5 are turned on in turn, only one switching device is turned on in each state, to realize negative level output;

[0057] Please refer to Figure 3 , Figure 3 is the working state diagram of each switching device in a single cycle, and the specific conduction sequence is as follows:

[0058] The modulation method for realizing positive half-cycle output is as follows:

[0059] T1: S1, S2, S3, S4, S5, S6, S7, S8 are turned off;

[0060] T2: S1 is turned on, and S2, S3, S4, S5, S6, S7, S8 are turned off;

[0061] T3: S2 is turned on, and S1, S3, S4, S5, S6, S7, S8 are turned off;

[0062] T4: S3 is turned on, and S1, S2, S4, S5, S6, S7, S8 are turned off;

[0063] T5: S4 is turned on, and S1, S2, S3, S5, S6, S7, S8 are turned off;

[0064] T6: S3 is on, S1, S2, S4, S5, S6, S7, S8 are off;

[0065] T7: S2 is on, S1, S3, S4, S5, S6, S7, S8 are off;

[0066] T8: S1 is on, S2, S3, S4, S5, S6, S7, S8 are off;

[0067] positive half-cycle output voltage U O1 (t) is:

[0068]

[0069] the time T of each state x is:

[0070]

[0071] where T is a single cycle time, and N is the number of levels;

[0072] The modulation mode for realizing the negative half-cycle output is as follows:

[0073] T9: S1, S2, S3, S4, S5, S6, S7, S8 are off;

[0074] T 10 : S5 is on, S1, S2, S3, S4, S6, S7, S8 are off;

[0075] T 11 : S6 is on, S1, S2, S3, S4, S5, S7, S8 are off;

[0076] T 12 : S7 is on, S1, S2, S3, S4, S5, S6, S8 are off;

[0077] T 13 : S8 is on, S1, S2, S3, S4, S5, S6, S7 are off;

[0078] T 14 : S7 is on, S1, S2, S3, S4, S5, S6, S8 are off;

[0079] T 15 : S6 is on, S1, S2, S3, S4, S5, S7, S8 are off;

[0080] T 16 : S5 is on, S1, S2, S3, S4, S6, S7, S8 are off;

[0081] negative half-cycle output voltage U O2(t) is:

[0082]

[0083] The time T of each state above x is:

[0084]

[0085] Wherein T is a single cycle time, and N is the number of levels;

[0086] Please refer to Figure 4 , Figure 4 is an input and output voltage waveform diagram of a nine-level DC-AC photon electric energy converter, and a single cycle output voltage U O (t) is:

[0087]

[0088] In summary, the application discloses a multi-level DC-AC photon electric energy converter and a current conversion modulation method thereof, combines the characteristics of photoelectric materials and electrical output characteristics, realizes the electric energy conversion of the DC-AC photon electric energy converter, uses N-1 switching devices to realize N-level output, and provides a method for realizing multi-level, which expands the application field of the photon electric energy converter.

[0089] The above examples are only used to illustrate the technical solutions of the application, rather than limit them; the description of the disclosed embodiments enables those skilled in the art to use or implement the application, and the technical solutions recorded in the foregoing embodiments can still be modified or some technical features can be replaced by equivalents; and these replacements or modifications do not make the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the application.

Claims

1. A multi-level DC-AC photon power converter, characterized in that: include: Input DC power supply U DC , input side LED-A, LED-B, LED-C light sources, output side photovoltaic elements PV-A group, PV-B group, control module, output load Z; The control module includes: switch devices S1, S2, ..., switch devices S 2n , PWM1, PWM2, ..., PWM 2n, and a control unit; The output-side photovoltaic element PV-A group includes photovoltaic elements PV-A1, PV-A2, ..., PV-An, where n=(N-1) / 2, where N is the number of output levels and represents any positive odd number greater than 1; The output-side photovoltaic element PV-B group includes photovoltaic elements PV-B1, PV-B2, ..., PV-Bn, where n=(N-1) / 2; The DC power supply U DC The positive electrode is connected to the positive electrodes of the input side LED-A, LED-B, and LED-C light sources; The DC power supply U DC The cathode of is connected to the cathode of the input side LED-A, LED-B, and LED-C light sources; The output-side photovoltaic elements PV-A1, ..., PV-An are connected in series in the forward direction; The output-side photovoltaic elements PV-B1, ..., PV-Bn are connected in series in the forward direction; The positive electrode of the output-side photovoltaic element PV-A1 and the negative electrode of PV-B1 are connected to the positive electrode of the output load Z; The switch device is a fully controlled switch element, and the switch device ports include: a first port, a second port, and a gate; The negative electrodes of the output-side photovoltaic elements PV-A1, ..., PV-An are connected to the switching devices S1, ..., S n The first port is connected; The positive electrodes of the output-side photovoltaic elements PV-B1, ..., PV-Bn are connected to the switching devices S n+1 ,…,S 2n The first port is connected; The positive electrode of the output load Z is connected to the positive electrode of PV-A1 and the negative electrode of PV-B1; The negative electrode of the output load Z is connected to the switching devices S1, ..., S 2n The second port is connected; The control units are connected to the input ports of PWM 1, ...PWM 2n respectively; The output ports of PWM 1, ... PWM 2n are connected to S1, ..., S 2n Gate connection.

2. A current conversion modulation method for a multi-level DC-AC photonic power converter, characterized in that: The multi-level DC-AC photonic power converter described in claim 1 is adopted, and its specific current conversion modulation method is: S1: The control unit outputs modulation signals to PWM 1, PWM 2, ..., PWM n, respectively. n The conduction timing of the switching devices S1, S2, ..., S n , ..., S2, S1 are turned on in sequence, and only one switch device is turned on in each state to achieve positive level output; S2: The control unit outputs modulation signals to PWM n+1, PWM n+2, ..., PWM 2n respectively. n+1 、S n+2 ,…,S 2n The switching timing is controlled, the switching device S n+1 、S n+2 ,…,S 2n ,…,S n+2 、S n+1 They are turned on in sequence, with only one switching device turned on in each state to achieve negative level output.

3. The current conversion and modulation method of a multi-level DC-AC photonic power converter according to claim 2, characterized in that: The control unit controls the switching devices S1, S2, ..., S n The PWM modulation of S1 is: The output side photovoltaic element PV-A group works and outputs a multi-level positive half cycle, wherein the number of multi-levels is determined according to the number of PV photovoltaic elements that are turned on in the output side photovoltaic element PV-A group. The positive half cycle outputs a multi-level voltage U O1 (t) Formula: in is the voltage of the corresponding photovoltaic element PV, and the voltage of each photovoltaic element is equal.

4. The current conversion and modulation method of a multi-level DC-AC photonic power converter according to claim 2, characterized in that: The control unit controls the switching device S n+1 、S n+2 ,…,S 2n The PWM modulation of S2 is: The output side photovoltaic element PV-B group works and outputs a negative half-cycle multi-level, wherein the number of multi-levels is determined according to the number of photovoltaic elements in the output side photovoltaic element PV-B group that are turned on. The negative half-cycle output multi-level voltage U O2 (t) Formula: in is the voltage of the corresponding photovoltaic element PV, and the voltage of each photovoltaic element is equal.

5. A current conversion modulation method for a multi-level DC-AC photonic power converter according to claim 3 or 4, wherein the output voltage U of a single cycle is O (t) is: The working hours for each status are: Where T is the single cycle time and N is the number of levels.

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