Heric single-phase inverter circuit

Abstract

The utility model relates to a Helic single-phase inverter circuit, including: a Helic topology circuit, a capacitor branch, a filter branch, a main diode, a switch tube and a main inductor, the receiving side of the filter branch is connected with the alternating current side of the Helic topology circuit, the capacitor branch is connected between the two poles of the direct current side of the Helic topology circuit, the main diode is connected with the switch tube, and the main inductor is connected with the filter branch. The main diode is arranged between the midpoint of a follow current bridge arm in the Helic topology circuit and any pole of the direct current side of the Helic topology circuit, the switching tube is connected with the first end of the main inductor, and the second end of the switching tube is connected with the alternating current side of the Helic topology circuit. The second end of the main inductor is connected with the direct current end of the Heric topology circuit. According to the Helic single-phase inverter circuit provided by the invention, when peak voltage occurs, the main diode can clamp the peak voltage, so that the generation of the peak voltage is inhibited, and the peak voltage on a follow current tube in a Helic topology circuit is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of inverter circuits, in particular to a Heric single-phase inverter circuit. Background Art

[0002] At present, small-power single-phase inverters usually use non-isolated photovoltaic grid-connected inverters with the advantages of high conversion efficiency, high power density, and low cost. In addition, non-isolated photovoltaic grid-connected inverters usually use Heric topology circuits that have good performance in terms of device cost, conversion efficiency, and leakage current.

[0003] In the Heric topology circuit, both the high-frequency tube and the freewheeling tube operate in a hard switching state, that is, large voltage spikes will be generated on the high-frequency tube and the freewheeling tube, and the switching loss itself is high; especially when the Heric topology circuit operates under non-unit power factor conditions, the freewheeling tube therein will be damaged due to the excessive spike voltage stress.

[0004] Therefore, how to reduce the peak voltage on the freewheeling diode in the Heric topology circuit has become a problem that needs to be solved urgently. Utility Model Content

[0005] In view of this, the utility model provides a Heric single-phase inverter circuit.

[0006] Specifically, the utility model is realized by the following technical solutions:

[0007] According to the first aspect of the utility model, a Heric single-phase inverter circuit is provided, comprising: a Heric topology circuit, a capacitor branch, a filter branch, a main diode, a switch tube and a main inductor, wherein the receiving side of the filter branch is connected to the AC side of the Heric topology circuit, the capacitor branch is connected between the two poles of the DC side of the Heric topology circuit, the main diode is arranged between the midpoint of the freewheeling bridge arm in the Heric topology circuit and any pole of the DC side of the Heric topology circuit, the switch tube is connected to the first end of the main inductor, the second end of the switch tube is connected to the AC side of the Heric topology circuit, and the second end of the main inductor is connected to the DC end of the Heric topology circuit.

[0008] Optionally, the Heric topology circuit includes: a first inverter bridge arm, a second inverter bridge arm and a freewheeling bridge arm, wherein the first inverter bridge arm and the second inverter bridge arm are connected in parallel, and the freewheeling bridge arm is arranged between the midpoint of the first inverter bridge arm and the midpoint of the second inverter bridge arm.

[0009] Optionally, the first inverter bridge arm includes: a first switch tube and a fifth switch tube, the second inverter bridge arm includes: a second switch tube and a sixth switch tube, and the freewheeling bridge arm includes: a third switch tube and a fourth switch tube; wherein the drain of the first switch tube is connected to the positive electrode of the DC side of the Heric topology circuit, the source of the first switch tube is connected to the drain of the fifth switch tube, and the connection point serves as the midpoint of the first inverter bridge arm; the source of the fifth switch tube is connected to the negative electrode of the DC side of the Heric topology circuit; the The drain is connected to the positive electrode of the DC side of the Heric topology circuit; the source of the second switch tube is connected to the drain of the sixth switch tube, and the connection point serves as the midpoint of the second inverter bridge arm; the source of the sixth switch tube is connected to the negative electrode of the DC side of the Heric topology circuit; the emitter of the third switch tube is connected to the midpoint of the first inverter bridge arm; the collector of the third switch tube is connected to the collector of the fourth switch tube, and the connection point serves as the midpoint of the freewheeling bridge arm; the emitter of the fourth switch tube is connected to the midpoint of the second inverter bridge arm.

[0010] Optionally, the direction of the main diode is from the midpoint of the freewheeling bridge arm to the positive pole of the DC side of the Heric topology circuit.

[0011] Optionally, the cathodes of the anti-parallel diodes of the two switch tubes in the freewheeling bridge arm are connected.

[0012] Optionally, the direction of the main diode is from the negative pole of the DC side of the Heric topology circuit to the midpoint of the freewheeling bridge arm.

[0013] Optionally, the anodes of the anti-parallel diodes of the two switch tubes in the freewheeling bridge arm are connected.

[0014] Optionally, the filter branch includes: a first output inductor branch, a second output inductor branch and an output capacitor branch, wherein the first end of the first output inductor branch is connected to the first end of the AC side of the Heric topology circuit, the first end of the second output inductor branch is connected to the second end of the AC side of the Heric topology circuit, and the output capacitor branch is arranged between the second end of the first output inductor branch and the second end of the second output inductor branch.

[0015] Optionally, each switch tube of the Heric topology circuit is a MOS transistor or an IGBT.

[0016] The technical solution provided by the utility model brings at least the following beneficial effects:

[0017] When a spike voltage occurs in a Heric single-phase inverter circuit provided by the present application, the main diode can clamp the spike voltage, thereby suppressing the generation of the spike voltage and reducing the spike voltage on the freewheeling tube in the Heric topology circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings herein are incorporated in and constitute a part of the specification, illustrate embodiments consistent with the present utility model, and together with the description, are used to explain the principles of the present utility model.

[0019] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or related technical descriptions are briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0020] Figure 1 A schematic diagram of a Heric inverter circuit provided in an embodiment of the utility model;

[0021] Figure 2 A schematic diagram of a Heric single-phase inverter circuit provided in an embodiment of the utility model. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solution and advantages of the embodiment of the utility model clearer, the technical solution in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is a part of the embodiment of the utility model, not all of the embodiments. Based on the embodiment of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0023] Figure 1 A Heric inverter circuit suitable for an embodiment of the utility model is schematically shown.

[0024] like Figure 1 As shown, the Heric inverter circuit specifically includes: a Heric topology circuit 10, an input capacitor Cbus, a first output inductor L1, a second output inductor L2 and an output capacitor Cg.

[0025] In the Heric inverter circuit, the DC side of the Heric topology circuit 10 serves as the DC side of the Heric inverter circuit; the first end of the AC side of the Heric topology circuit 10 is connected to the first end of the first output inductor L1, and the second end of the first output inductor L1 serves as the first end of the AC side of the Heric inverter circuit; the second end of the AC side of the Heric topology circuit 10 is connected to the first end of the second output inductor L2, and the second end of the second output inductor L2 serves as the second end of the AC side of the Heric inverter circuit. The input capacitor Cbus is connected between the two poles of the DC side of the Heric topology circuit 10, and the output capacitor Cg is connected between the second end of the first output inductor L1 and the second end of the second output inductor L2.

[0026] Specifically, the Heric topology circuit 10 specifically includes: a first inverter bridge arm 11, a second inverter bridge arm 12 and a freewheeling bridge arm 13. In the Heric topology circuit 10, the first inverter bridge arm 11 and the second inverter bridge arm 12 are connected in parallel, one end of the parallel connection serves as the DC positive pole of the Heric topology circuit 10, and the other end of the parallel connection serves as the DC negative pole of the Heric topology circuit 10; the freewheeling bridge arm 13 is arranged between the midpoint of the first inverter bridge arm 11 and the midpoint of the second inverter bridge arm 12; the midpoint of the first inverter bridge arm 11 and the midpoint of the second inverter bridge arm 12 serve as the two ends of the AC side of the Heric topology circuit 10 respectively. Among them, the first inverter bridge arm 11 is composed of a first switch tube Q1 and a fifth switch tube Q5.

[0027] Specifically, if the first switch tube Q1 and the fifth switch tube Q5 are both MOS transistors with body diodes, at this time, the drain of the first switch tube Q1 serves as the first end of the first inverter bridge arm 11, and is connected to the positive electrode of the DC side of the Heric topology circuit 10; the source of the first switch tube Q1 is connected to the drain of the fifth switch tube Q5, and the connection point serves as the midpoint of the first inverter bridge arm 11; the source of the fifth switch tube Q5 serves as the second end of the first inverter bridge arm 11, and is connected to the negative electrode of the DC side of the Heric topology circuit 10.

[0028] Among them, the second inverter bridge arm 12 is composed of a second switch tube Q2 and a sixth switch tube Q6. Specifically, if the second switch tube Q2 and the sixth switch tube Q6 are both MOS transistors with body diodes, at this time, the drain of the second switch tube Q2 serves as the first end of the second inverter bridge arm 12, and is connected to the positive electrode of the DC side of the Heric topology circuit 10; the source of the second switch tube Q2 is connected to the drain of the sixth switch tube Q6, and the connection point serves as the midpoint of the second inverter bridge arm 12; the source of the sixth switch tube Q6 serves as the second end of the second inverter bridge arm 12, and is connected to the negative electrode of the DC side of the Heric topology circuit 10.

[0029] The freewheeling bridge arm 13 is composed of a third switch tube Q3 and a fourth switch tube Q4. Specifically, if the third switch tube Q3 and the fourth switch tube Q4 are both MOS transistors with body diodes, then the internal structure of the freewheeling bridge arm 13 is as follows: Figure 1 As shown: the emitter of the third switch tube Q3 serves as the first end of the freewheeling bridge arm 13, connected to the midpoint of the first inverter bridge arm 11; the collector of the third switch tube Q3 is connected to the collector of the fourth switch tube Q4, and the connection point serves as the midpoint of the freewheeling bridge arm 13; the emitter of the fourth switch tube Q4 serves as the second end of the freewheeling bridge arm 13, connected to the midpoint of the second inverter bridge arm 12.

[0030] In addition, each switch tube in the Heric topology circuit 10 can also be an IGBT with an anti-parallel diode, or other controllable switch tubes with an anti-parallel diode. Even the implementation forms of each switch tube do not have to be the same, and various mixed combinations can be formed. For example, Q1, Q2, Q5 and Q6 are MOS transistors with body diodes, while Q3 and Q4 are IGBTs with anti-parallel diodes (as shown in the various structural schematic diagrams).

[0031] like Figure 2 As shown, the present application also provides an improved Heric single-phase inverter, which adds a switch tube and two main inductors on the basis of the Heric topology circuit, wherein the switch tube is connected to the first end of the main inductor, the second end of the switch tube is connected to the AC side of the Heric topology circuit, and the second end of the main inductor is connected to the DC end of the Heric topology circuit. When the load current is switched from the high-frequency path to the freewheeling path, the added main inductor is much higher than the parasitic inductance in the original loop, so the current change speed during the commutation process can be greatly reduced. Therefore, at the initial moment of commutation, that is, the moment when the switch tube is switched on, the on-current of the switched tube is almost zero, thereby significantly reducing the switching loss of the switch tube, or the on-current of the diode that is forced to be turned on is also almost zero, thereby significantly reducing the reverse recovery loss of the diode.

[0032] However, the main inductor is directly connected in series with the switch tube, and the direction of the inductor current must be ensured when the switch tube is turned off, otherwise there will be a risk of damage to the switch tube. When the circuit operates at a non-unit power factor, this risk is almost unavoidable, so there are strict restrictions on the application of this circuit. In addition, the added switch tube is connected to the midpoint of the DC bus, so additional midpoint potential control is required.

[0033] When a spike voltage occurs in a Heric single-phase inverter circuit provided by the present application, the main diode can clamp the spike voltage, thereby suppressing the generation of the spike voltage and reducing the spike voltage on the freewheeling tube in the Heric topology circuit.

[0034] It should be noted that, in the present application, the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inner", "outer", "vertical", "horizontal", "lateral", "longitudinal" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings. These terms are mainly used to better describe the present application and its embodiments, and are not used to limit the indicated devices, elements or components to have a specific orientation, or to be constructed and operated in a specific orientation.

[0035] In addition, some of the above terms may be used to express other meanings in addition to indicating orientation or positional relationship. For example, the term "on" may also be used to express a certain dependency or connection relationship in some cases. For those of ordinary skill in the art, the specific meanings of these terms in this application can be understood according to specific circumstances.

[0036] In addition, the terms "installed", "set", "provided with", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection, or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be an internal connection between two devices, elements, or components. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0037] In addition, the terms "first", "second", etc. are mainly used to distinguish different devices, elements or components (the specific types and structures may be the same or different), and are not used to indicate or imply the relative importance and quantity of the indicated devices, elements or components. Unless otherwise specified, "plurality" means two or more.

[0038] The above description is only a specific embodiment of the present invention, so that those skilled in the art can understand or implement the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but should conform to the widest scope consistent with the principles and novel features applied herein.

Claims

1. A Heric single-phase inverter circuit, characterized in that: include: A Heric topology circuit, a capacitor branch, a filter branch, a main diode, a switch tube and a main inductor, wherein the receiving side of the filter branch is connected to the AC side of the Heric topology circuit, the capacitor branch is connected between the two poles of the DC side of the Heric topology circuit, the main diode is arranged between the midpoint of the freewheeling bridge arm in the Heric topology circuit and any pole of the DC side of the Heric topology circuit, the switch tube is connected to the first end of the main inductor, the second end of the switch tube is connected to the AC side of the Heric topology circuit, and the second end of the main inductor is connected to the DC end of the Heric topology circuit.

2. The Heric single-phase inverter circuit according to claim 1, characterized in that: The Heric topology circuit includes: a first inverter bridge arm, a second inverter bridge arm and a freewheeling bridge arm, wherein the first inverter bridge arm and the second inverter bridge arm are connected in parallel, and the freewheeling bridge arm is arranged between the midpoint of the first inverter bridge arm and the midpoint of the second inverter bridge arm.

3. The Heric single-phase inverter circuit according to claim 2, characterized in that: The first inverter bridge arm includes: a first switch tube and a fifth switch tube, the second inverter bridge arm includes: a second switch tube and a sixth switch tube, and the freewheeling bridge arm includes: a third switch tube and a fourth switch tube; wherein the drain of the first switch tube is connected to the positive electrode of the DC side of the Heric topology circuit, the source of the first switch tube is connected to the drain of the fifth switch tube, and the connection point serves as the midpoint of the first inverter bridge arm; the source of the fifth switch tube is connected to the negative electrode of the DC side of the Heric topology circuit; the drain of the second switch tube is connected to the negative electrode of the DC side of the Heric topology circuit; The second switching tube is connected to the positive electrode of the DC side of the Heric topology circuit; the source of the second switching tube is connected to the drain of the sixth switching tube, and the connection point serves as the midpoint of the second inverter bridge arm; the source of the sixth switching tube is connected to the negative electrode of the DC side of the Heric topology circuit; the emitter of the third switching tube is connected to the midpoint of the first inverter bridge arm; the collector of the third switching tube is connected to the collector of the fourth switching tube, and the connection point serves as the midpoint of the freewheeling bridge arm; the emitter of the fourth switching tube is connected to the midpoint of the second inverter bridge arm.

4. The Heric single-phase inverter circuit according to claim 1, characterized in that: The direction of the main diode is from the midpoint of the freewheeling bridge arm to the positive pole of the DC side of the Heric topology circuit.

5. The Heric single-phase inverter circuit according to claim 4, characterized in that: The cathodes of the anti-parallel diodes of the two switch tubes in the freewheeling bridge arm are connected.

6. The Heric single-phase inverter circuit according to claim 1, characterized in that: The direction of the main diode is from the negative pole of the DC side of the Heric topology circuit to the midpoint of the freewheeling bridge arm.

7. The Heric single-phase inverter circuit according to claim 6, characterized in that: The anodes of the anti-parallel diodes of the two switch tubes in the freewheeling bridge arm are connected.

8. The Heric single-phase inverter circuit according to claim 1, characterized in that: The filter branch includes: a first output inductor branch, a second output inductor branch and an output capacitor branch, wherein the first end of the first output inductor branch is connected to the first end of the AC side of the Heric topology circuit, the first end of the second output inductor branch is connected to the second end of the AC side of the Heric topology circuit, and the output capacitor branch is arranged between the second end of the first output inductor branch and the second end of the second output inductor branch.

9. The Heric single-phase inverter circuit according to claim 1, characterized in that: Each switch tube of the Heric topology circuit is a MOS transistor or an IGBT.

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