CN219394715U - Inverter circuit and inverter system capable of switching modes - Google Patents

Abstract

The utility model discloses a switchable mode inverter circuit and an inverter system, wherein the inverter circuit comprises: the device comprises a direct current filtering unit, an energy charging switch unit, a follow current switch unit, an output filtering unit, a first output end, a second output end and a third output end; the direct current filtering unit comprises a first direct current end, a second direct current end and a third direct current end; the freewheel switch unit comprises a first freewheel end, a second freewheel end and a third freewheel end; the inverter circuit further comprises a first change-over switch and a second change-over switch; the third direct current end is electrically connected with the third follow current end through the first change-over switch; the third output end is electrically connected with the third follow current end through the second change-over switch. By adopting the technical scheme, the inverter circuit is compatible with a single-phase mode and a split-phase mode, an external device is not needed to be added, the reliability of the inverter circuit is improved, and unstable live wires and zero wires of the inverter circuit in the single-phase mode are avoided, and the circuit structure is damaged or potential safety hazards are caused.

Description

Inverter circuit and inverter system capable of switching modes

Technical Field

The utility model relates to the technical field of power conversion, in particular to a mode-switchable inverter circuit and an inverter system.

Background

The inverter is a converter for converting direct-current electric energy (a battery and an accumulator jar) into constant-frequency constant-voltage or frequency-modulated voltage-modulated alternating current (generally 220V,50Hz sine wave). The inverter comprises an inverter bridge, a controller and a filter circuit.

There are multiple modes of current global grid systems; the civil power grid system in China is single-phase (single-line) 220V/50HZ; the European civil power grid system is similar to China, but the voltage is changed from 220V/50HZ to 230V/50HZ, and most countries in Africa are similar to China and Europe, and only the voltages are slightly different; the system of the civil power grid in the Canadian area is single-phase (single-wire or double-wire) 120V/60HZ, wherein the single-wire connection method is fire wire and zero wire, and the system is 120V/60HZ; the two-wire connection method is a first live wire, a second live wire and a zero wire, and the voltage is 240V/60HZ; the japanese region is similar to the united states, canada region, except that the single-phase single-line voltage is changed from 120V to 100V, and the single-phase two-line voltage is changed from 240V to 200V. Such single-phase two-wire system power grids in the united states, canada, japan may be collectively referred to as split phase power grids.

Fig. 1 is a schematic diagram of a single-phase inverter circuit in the prior art, fig. 2 is a schematic diagram of a split-phase transformer in the prior art, and fig. 3 is a schematic diagram of a split-phase inverter circuit in the prior art. Currently, in the photovoltaic and energy storage inversion fields, HERIC topology is generally used for an inversion product of a single-phase power grid, as shown in fig. 1, an external split phase transformer scheme is additionally arranged at the rear stage of a single-phase inverter, as shown in fig. 2, or split phase topology is directly used, as shown in fig. 3. In order to enable the product to be compatible with the power grid system of each region and country worldwide, the compatible scheme aiming at single-phase and split-phase products at present is only to add an external split-phase transformer, but the scheme is high in cost, huge in volume, low in efficiency, heavy in weight and inconvenient to install due to the fact that the external split-phase transformer is needed to be added.

Disclosure of Invention

The utility model provides a switchable-mode inverter circuit and an inverter system, which solve various disadvantages of compatibility by using an external split-phase transformer.

According to an aspect of the present utility model, there is provided a switchable mode inverter circuit comprising: the device comprises a direct current filtering unit, an energy charging switch unit, a follow current switch unit, an output filtering unit, a first output end, a second output end and a third output end;

the direct current filtering unit comprises a first direct current end, a second direct current end and a third direct current end; the charging switch unit comprises a first input end, a second input end, a first bidirectional end and a second bidirectional end; the freewheel switch unit comprises a first freewheel end, a second freewheel end and a third freewheel end; the output filter unit comprises a first output filter inductor and a second output filter inductor;

the first direct current end and the second direct current end are respectively and electrically connected with the positive electrode and the negative electrode of the direct current power supply; the first input end is electrically connected with the first direct-current end; the second input end is electrically connected with the second direct current end; the first bidirectional end is electrically connected with the first output end through the first output filter inductor; the second bidirectional end is electrically connected with the second output end through the second output filter inductor; the first follow current end is electrically connected with the first output end through the first output filter inductor; the second follow current end is electrically connected with the second output end through the second output filter inductor;

the inverter circuit further comprises a first change-over switch and a second change-over switch; the third direct current end is electrically connected with the third follow current end through the first change-over switch; the third output end is electrically connected with the third follow current end through the second change-over switch.

Optionally, the direct current filtering unit comprises a first direct current bus capacitor and a second direct current bus capacitor;

the first polar plate of the first direct current bus capacitor is electrically connected with the first direct current end; the second polar plate of the first direct current bus capacitor and the first polar plate of the second direct current bus capacitor are electrically connected with the third direct current end; and a second substrate of the second direct current bus capacitor is electrically connected with the second direct current end.

Optionally, the charging switch unit includes a first charging switch, a second charging switch, a third charging switch and a fourth charging switch;

the first end of the first charging switch and the first end of the third charging switch are electrically connected with the first input end, and the second end of the first charging switch and the first end of the second charging switch are electrically connected with the first bidirectional end; the second end of the third charging switch and the first end of the fourth charging switch are electrically connected with the second bidirectional end; and the second end of the second charging switch and the second end of the fourth charging switch are electrically connected with the second input end.

Optionally, the freewheel switch unit includes a first freewheel MOS transistor, a second freewheel MOS transistor, a third freewheel MOS transistor and a fourth freewheel MOS transistor;

the second pole of the first freewheel MOS transistor is electrically connected with the first freewheel end; the first electrode of the first follow current MOS tube is electrically connected with the first electrode of the second follow current MOS tube; the second pole of the second freewheel MOS transistor and the second pole of the third freewheel MOS transistor are electrically connected with the third freewheel end; the first electrode of the third follow current MOS tube is electrically connected with the first electrode of the fourth follow current MOS tube; and a second pole of the fourth follow current MOS tube is electrically connected with the second follow current end.

Optionally, the first switch comprises a first switch MOS tube and a second switch MOS tube; the second change-over switch comprises a third switch MOS tube and a fourth switch MOS tube;

the first electrode of the first switch MOS tube is electrically connected with the first electrode of the second switch MOS tube; the second pole of the first switch MOS tube is electrically connected with the first end of the first change-over switch; the second pole of the second switch MOS tube is electrically connected with the second end of the first change-over switch;

the first electrode of the third switch MOS tube is electrically connected with the first electrode of the fourth switch MOS tube; the second pole of the third switch MOS tube is electrically connected with the first end of the second change-over switch; and a second pole of the fourth switch MOS tube is electrically connected with a second end of the second change-over switch.

Optionally, the output filter unit further includes a first output filter capacitor and a second output filter capacitor;

the first polar plate of the first output filter capacitor is electrically connected with the first output end; the second polar plate of the first output filter capacitor and the first polar plate of the second output filter capacitor are electrically connected with the third output end; and a second polar plate of the second output filter capacitor is electrically connected with the second output end.

According to another aspect of the present utility model, there is provided a switchable mode inverter system including the above-described switchable mode inverter circuit and a controller;

the controller comprises a first control signal output end and a second control signal output end; the first control signal output end is electrically connected with the control end of the first change-over switch; the second control signal output end is electrically connected with the control end of the second change-over switch.

According to the technical scheme, the first change-over switch and the second change-over switch are arranged on the inverter circuit to switch the mode of the inverter circuit, so that the inverter circuit is compatible with a single-phase mode and a split-phase mode, an external device is not required to be added, the structure is simple, the size is small, and the installation is convenient; in addition, the first change-over switch and the second change-over switch enable the third direct current end to be completely turned off between the third follow current end and the third output end, so that current values in the first output filter inductor and the second output filter inductor can be always in a state with equal magnitudes, the reliability of the inverter circuit is improved, and unstable live wires and zero wires of the inverter circuit in a single-phase mode are avoided, a circuit structure is damaged, or potential safety hazards are caused.

It should be understood that the description in this section is not intended to identify key or critical features of the embodiments of the utility model or to delineate the scope of the utility model. Other features of the present utility model will become apparent from the description that follows.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the drawings required for the description of the embodiments will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present utility model, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic diagram of a single-phase inverter circuit in the prior art;

FIG. 2 is a schematic diagram of a split phase pressure vessel in the prior art;

FIG. 3 is a schematic diagram of a split phase inverter circuit in the prior art;

fig. 4 is a schematic structural diagram of an inverter circuit with a switchable mode according to an embodiment of the present utility model;

FIGS. 5-12 are schematic diagrams of current flow provided by embodiments of the present utility model;

fig. 13 is a schematic structural diagram of an inverter circuit with a switchable mode according to an embodiment of the present utility model;

fig. 14 is a schematic structural diagram of a switchable mode inverter system according to an embodiment of the present utility model.

Detailed Description

In order that those skilled in the art will better understand the present utility model, a technical solution in the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in which it is apparent that the described embodiments are only some embodiments of the present utility model, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the present utility model without making any inventive effort, shall fall within the scope of the present utility model.

It should be noted that the terms "first," "second," and the like in the description and the claims of the present utility model and the above figures are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate such that the embodiments of the utility model described herein may be implemented in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

Fig. 4 is a schematic structural diagram of an inverter circuit with switchable modes according to an embodiment of the present utility model. Referring to fig. 4, the inverter circuit 01 of the switchable mode includes: the device comprises a direct current filtering unit 10, a charging switch unit 20, a follow current switch unit 30, an output filtering unit 40, a first output end U, a second output end V and a third output end N. The dc filtering unit 10 includes a first dc terminal 11, a second dc terminal 12, and a third dc terminal 13; the charge switch unit 20 includes a first input terminal 21, a second input terminal 22, a first bidirectional terminal 23, and a second bidirectional terminal 24; the freewheel switch unit 30 includes a first freewheel terminal 31, a second freewheel terminal 32, and a third freewheel terminal 33; the output filter unit 40 includes a first output filter inductance L1 and a second output filter inductance L2.

The first direct current end 11 and the second direct current end 12 are respectively and electrically connected with the positive electrode and the negative electrode of the direct current power supply; the first input terminal 21 is electrically connected to the first dc terminal 11; the second input terminal 22 is electrically connected to the second dc terminal 12; the first bidirectional terminal 23 is electrically connected with the first output terminal U through a first output filter inductor L1; the second bidirectional terminal 24 is electrically connected to the second output terminal V through a second output filter inductor L2; the first freewheel end 31 is electrically connected to the first output end U through the first output filter inductor L1; the second freewheel terminal 32 is electrically connected to the second output terminal V through the second output filter inductance L2.

The inverter circuit 01 further comprises a first change-over switch S1 and a second change-over switch S2; the third direct current terminal 13 is electrically connected to the third freewheel terminal 33 through the first switching switch S1; the third output terminal N is electrically connected to the third freewheel terminal 33 through the second changeover switch S2.

The dc power supply provides a stable dc source for the inverter circuit 01, the first output terminal U, the second output terminal V and the third output terminal N are all connected with the load 50, the load 50 may be an electricity consumption unit or an electricity grid in a grid-connected scenario, for example, the load 50 may include a first resistor R1 and a second resistor R2, the first end of the first resistor R1 is electrically connected with the first output terminal U, the second end of the second resistor R2 is electrically connected with the second output terminal V, and the second end of the first resistor R1 and the first end of the second resistor R2 are electrically connected with the third output terminal N. The first and second switches S1 and S2 include, but are not limited to, relays, contactors, MOS transistors, tertiary transistors, and the like. When the inverter circuit 01 is in a single-phase mode, the first output end U can be connected with a live wire of a power grid or a power utilization unit, and the second output end V can be connected with a zero line of the power grid or the power utilization unit; when the inverter circuit 01 is in the split phase mode, the first output end U can be connected with a first live wire of the power grid or the power utilization unit, the second output end V can be connected with a second live wire of the power grid or the power utilization unit, and the third output end N can be connected with a zero line of the power grid or the power utilization unit.

Illustratively, when the inverter circuit 01 is in the single-phase mode, the first and second switches S1 and S2 are turned off.

In the single-phase positive half-cycle charging phase, the first bidirectional terminal 23 outputs a current, and the current sequentially passes through the first output filter inductor L1, the first output terminal U, the load 50, the second output terminal V, and the second output filter inductor L2 to reach the second bidirectional terminal 24, where the second bidirectional terminal 24 receives the current, as shown in fig. 5.

In the single-phase positive half-cycle freewheel phase, no current flows through the second bidirectional terminal 23 and the second bidirectional terminal 24, and at this time, the electric energy stored in the first output filter inductor L1 and the second output filter inductor L2 is output, and the current flows in the directions of the first output filter inductor L1, the first output terminal U, the load 50, the second output terminal V, the second output filter inductor L2, the second freewheel terminal 32, the first freewheel terminal 31 and the first output filter inductor L1, as shown in fig. 6.

In the single-phase negative half-cycle charging stage, the second bidirectional terminal 24 outputs a current, and the current sequentially passes through the second output filter inductor L2, the second output terminal V, the load 50, the first output terminal U, and the first output filter inductor L1 to reach the first bidirectional terminal 23, where the first bidirectional terminal 23 receives the current, as shown in fig. 7.

In the single-phase negative half-cycle freewheel phase, no current flows through the second bidirectional terminal 23 and the second bidirectional terminal 24, and at this time, the second output filter inductor L2 and the first output filter inductor L1 store electric energy for output, and the current flows in the directions of the second output filter inductor L2, the second output terminal V, the load 50, the first output terminal U, the first output filter inductor L1, the first freewheel terminal 31, the second freewheel terminal 32 and the second output filter inductor L2, as shown in fig. 8.

With continued reference to fig. 9, when the inverter circuit 01 is in the split phase mode, both the first switch S1 and the second switch S2 are turned on.

In the phase splitting positive half-cycle charging stage, the first bidirectional terminal 23 outputs current, the current sequentially passes through the first output filter inductor L1, the first output terminal U, the first resistor R1, the third output terminal N, the second switch S2, the first switch S1, and the third dc terminal 13 to reach the dc filter unit 11, the electric energy stored in the dc filter unit 11 is output, and the current can sequentially pass through the third dc terminal 13, the first switch S1, the second switch S2, the third output terminal N, the second resistor R2, the second output terminal V, and the second output filter inductor L2 to reach the second bidirectional terminal 24, where the second bidirectional terminal 24 receives the current, as shown in fig. 9.

In the positive half-cycle freewheel phase, no current flows through the second bidirectional terminal 23 and the second bidirectional terminal 24, and at this time, the electric energy stored in the first output filter inductor L1 and the second output filter inductor L2 is output, and the current of the first output filter inductor L1 flows in the directions of the first output filter inductor L1, the first output terminal U, the first resistor R1, the third output terminal N, the second switch S2, the third freewheel terminal 33, the first freewheel terminal 31, and the first output filter inductor L1, and the current of the second output filter inductor L2 flows in the directions of the second output filter inductor L2, the second freewheel terminal 32, the third freewheel terminal 33, the second switch S2, the third output terminal N, the second resistor R2, the second output terminal V, and the second output filter inductor L2, as shown in fig. 10.

In the phase splitting negative half-cycle charging stage, the second bidirectional terminal 24 outputs current, the current sequentially passes through the second output filter inductor L2, the second output terminal V, the second resistor R2, the third output terminal N, the second switch S2, the first switch S1, and the third dc terminal 13 to reach the dc filter unit 11, the electric energy stored in the dc filter unit 11 is output, and the current can sequentially pass through the third dc terminal 13, the first switch S1, the second switch S2, the third output terminal N, the first resistor R1, the first output terminal U, and the first output filter inductor L1 to reach the first bidirectional terminal 23, and the first bidirectional terminal 23 receives the current, as shown in fig. 11.

In the phase splitting negative half-cycle freewheel phase, no current flows through the second bidirectional terminal 23 and the second bidirectional terminal 24, at this time, the electric energy stored in the first output filter inductor L1 and the second output filter inductor L2 is output, and the current of the first output filter inductor L1 flows in the directions of the first output filter inductor L1, the first freewheel terminal 31, the third freewheel terminal 33, the second switch S2, the third output terminal N, the first resistor R1, the first output terminal U, and the first output filter inductor L1, and the current of the second output filter inductor L2 flows in the directions of the second output filter inductor L2, the second output terminal V, the second resistor R2, the third output terminal N, the second switch S2, the third freewheel terminal 33, the second freewheel terminal 32, and the second output filter inductor L2, as shown in fig. 12.

Specifically, by controlling the states of the first switch S1 and the second switch S2, the mode of the inverter circuit 01 can be switched. When both the first switch S1 and the second switch S2 are turned on, the inverter circuit 01 of fig. 4 may implement two current loops, so that the first output terminal U and the second output terminal V both have power output, and at this time, the potentials of the first output terminal U and the second output terminal V are opposite, and the potential at the third output terminal V is zero. When the first switch S1 and the second switch S2 are turned off, a single current loop can be realized in both the single-phase positive/negative half-cycle charging stage and the single-phase positive/negative half-cycle freewheeling stage, no current flows between the third output terminal V and the second switch S2, and the current of the single current loop is not shunted, so that the current values in the first output filter inductor L1 and the second output filter inductor L2 are always in the equal state, that is, the current value in the first resistor R1 and the current value in the second resistor R2 are always in the equal state, thereby improving the stability of a power grid or a power consumption unit connected with the inverter circuit 01, and further improving the reliability of the inverter circuit 01. If the first switch S1 or the second switch S2 is turned on in the single-phase mode, the third direct current terminal 13 is turned on with the third flywheel terminal 33 or the third flywheel terminal 33 is turned on with the third output terminal N, the current of the single current loop in the single-phase mode is split, the current values in the first output filter inductor L1 and the second output filter inductor L2 cannot be guaranteed to be completely equal, the inverter circuit 01 cannot be completely converted into the single-phase mode, and the current value in the first resistor R1 and the current value in the second resistor R2 cannot be guaranteed to be completely equal, so that the reliability of the inverter circuit 01 is not good, and therefore, in the single-phase mode, the first switch S1 and the second switch S2 must be turned off.

According to the embodiment of the utility model, the mode of the inverter circuit is switched by arranging the first change-over switch and the second change-over switch on the inverter circuit, so that the inverter circuit is compatible with a single-phase mode and a split-phase mode, an external device is not required to be added, and the inverter circuit has a simple structure, a small volume and convenient installation; in addition, the first change-over switch and the second change-over switch enable the third direct current end to be completely turned off between the third follow current end and the third output end, so that current values in the first output filter inductor and the second output filter inductor can be always in a state with equal magnitudes, the reliability of the inverter circuit is improved, and unstable live wires and zero wires of the inverter circuit in a single-phase mode are avoided, a circuit structure is damaged, or potential safety hazards are caused.

Optionally, with continued reference to fig. 4, the output filter unit 40 further includes a first output filter capacitor C3 and a second output filter capacitor C4; the first polar plate of the first output filter capacitor C3 is electrically connected with the first output end U; the second polar plate of the first output filter capacitor C3 and the first polar plate of the second output filter capacitor C4 are electrically connected with the third output end N; the second polar plate of the second output filter capacitor C4 is electrically connected to the second output terminal V.

Specifically, the first output filter capacitor C3 and the second output filter capacitor C4 can play roles in filtering and energy storage, and the current cannot be suddenly changed in the positive and negative half-cycle freewheeling stages. The first switch S1 and the second switch S2 enable the third dc terminal to be completely turned off from the third freewheel terminal and the third freewheel terminal to be completely turned off from the third output terminal, and in the single-phase mode, the consistency of the first output filter capacitor C3 and the second output filter capacitor C4 is better, so that the reliability of the inverter circuit 01 is better.

Alternatively, fig. 13 is a schematic structural diagram of an inverter circuit 01 with a switchable mode according to an embodiment of the present utility model. Referring to fig. 13, a first switching switch S1 includes a first switching MOS transistor T1 and a second switching MOS transistor T2; the second switch S2 includes a third switch MOS transistor T3 and a fourth switch MOS transistor T4. The first pole of the first switch MOS tube T1 is electrically connected with the first pole of the second switch MOS tube T2, the second pole of the first switch MOS tube T1 is electrically connected with the first end of the first switch S1, and the second pole of the second switch MOS tube T2 is electrically connected with the second end of the first switch S1; the first pole of the third switching MOS tube T3 is electrically connected with the first pole of the fourth switching MOS tube T4; the second pole of the third switch MOS tube T3 is electrically connected with the first end of the second change-over switch S2; the second pole of the fourth switch MOS tube T4 is electrically connected with the second end of the second change-over switch S2.

So, first change over switch S1 and second change over switch S2 all include the MOS pipe of back-to-back, and the switching speed is very fast, and can avoid receiving the influence of the body diode of single MOS pipe, leads to the unidirectional conduction of electric current, has improved inverter circuit 01' S reliability.

Optionally, with continued reference to fig. 13, the dc filtering unit 10 includes a first dc bus capacitor C1 and a second dc bus capacitor C2; the first polar plate of the first direct current bus capacitor C1 is electrically connected with the first direct current end 11; the C1 second polar plate of the first direct current bus capacitor and the first polar plate of the second direct current bus capacitor C2 are electrically connected with the third direct current end 13; the second substrate of the second dc bus capacitor C2 is electrically connected to the second dc terminal 12. The first dc bus capacitor C1 and the second dc bus capacitor C2 may play roles of filtering and energy storage.

Optionally, with continued reference to fig. 13, the charging switch unit 20 includes a first charging switch Q1, a second charging switch Q2, a third charging switch Q3, and a fourth charging switch Q4; the first end of the first charge switch Q1 and the first end of the third charge switch Q3 are electrically connected to the first input end 21, and the second end of the first charge switch Q1 and the first end of the second charge switch Q2 are electrically connected to the first bidirectional end 23; the second end of the third charge switch Q3 and the first end of the fourth charge switch Q4 are both electrically connected to the second bidirectional terminal 24; the second terminal of the second charge switch Q3 and the second terminal of the fourth charge switch Q4 are electrically connected to the second input terminal 22.

Illustratively, in the single-phase or split-phase positive half-cycle charging phase, the first charging switch Q1 and the fourth charging switch Q4 are turned on, and the second charging switch Q2 and the third charging switch Q3 are turned off; in the single-phase or split-phase negative half-cycle energy charging stage, the second energy charging switch Q2 and the third energy charging switch Q3 are turned on, and the first energy charging switch Q1 and the fourth energy charging switch Q4 are turned on and off; in the single-phase or split-phase positive and negative half-cycle freewheeling stage, the first charge switch Q1, the second charge switch Q2, the third charge switch Q3 and the fourth charge switch Q4 are all turned off. The first charge switch Q1, the second charge switch Q2, the third charge switch Q3, and the fourth charge switch Q4 include, but are not limited to, MOS transistors.

Optionally, with continued reference to fig. 13, the freewheel switch unit 30 includes a first freewheel MOS transistor M1, a second freewheel MOS transistor M2, a third freewheel MOS transistor M3 and a fourth freewheel MOS transistor M4; the second pole of the first freewheel MOS transistor M1 is electrically connected with the first freewheel end 31; the first electrode of the first freewheel MOS transistor M1 is electrically connected with the first electrode of the second freewheel MOS transistor M2; the second pole of the second freewheel MOS transistor M2 and the second pole of the third freewheel MOS transistor M3 are electrically connected with the third freewheel end 33; the first electrode of the third freewheel MOS transistor M3 is electrically connected with the first electrode of the fourth freewheel MOS transistor M4; the second pole of the fourth freewheel MOS transistor M4 is electrically connected to the second freewheel end 32.

For example, in the single-phase or split-phase positive and negative half-cycle charging stage, the first freewheel MOS transistor M1, the second freewheel MOS transistor M2, the third freewheel MOS transistor M3 and the fourth freewheel MOS transistor M4 are all turned off; in the single-phase or split-phase positive and negative half-cycle freewheeling stages, the first freewheeling MOS tube M1, the second freewheeling MOS tube M2, the third freewheeling MOS tube M3 and the fourth freewheeling MOS tube M4 are all conducted.

Based on the same inventive concept, the embodiment of the present utility model further provides a switchable mode inverter system, and fig. 14 is a schematic structural diagram of the switchable mode inverter system provided by the embodiment of the present utility model, as shown in fig. 14, where the inverter system includes an inverter circuit 01 and a controller 02 provided by any embodiment of the present utility model; the controller 02 includes a first control signal output 021 and a second control signal output 022; the first control signal output end 021 is electrically connected with the control end of the first switch S1; the second control signal output terminal 022 is electrically connected to the control terminal of the second changeover switch S2.

For example, when the inverter circuit 01 is set to the single-phase mode, the controller 02 may output a first control signal to the first switch S1 and a second control signal to the second switch S2, such that the first switch S1 and the second switch S2 are turned off, and the inverter circuit 01 enters the single-phase mode; when the inverter circuit 01 is set to the split phase mode, the controller 02 may output a first control signal to the first switch S1 and a second control signal to the second switch S2, so that the first switch S1 and the second switch S2 are turned on, and the inverter circuit 01 enters the split phase mode. The mode of the inverter circuit 01 is switched by arranging the first change-over switch S1 and the second change-over switch S2 on the inverter circuit 01, so that the inverter circuit 01 is compatible with a single-phase mode and a split-phase mode, an external device is not required to be added, and the inverter circuit is simple in structure, small in size and convenient to install; in addition, the first switch S1 and the second switch S2 enable the third dc terminal 13 and the third freewheel terminal 33 and the third output terminal N to be completely turned off, so that the current values in the first output filter inductor L1 and the second output filter inductor L1 can be always in the state of equal magnitudes, reliability of the inverter circuit 01 is improved, and unstable live wire and zero wire of the inverter circuit 01 in a single-phase mode are avoided, and circuit structures are damaged or potential safety hazards are caused.

Note that the above is only a preferred embodiment of the present utility model and the technical principle applied. It will be understood by those skilled in the art that the present utility model is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the utility model. Therefore, while the utility model has been described in connection with the above embodiments, the utility model is not limited to the embodiments, but may be embodied in many other equivalent forms without departing from the spirit or scope of the utility model, which is set forth in the following claims.

Claims (7)

1. A switchable mode inverter circuit comprising: the device comprises a direct current filtering unit, an energy charging switch unit, a follow current switch unit, an output filtering unit, a first output end, a second output end and a third output end;

the direct current filtering unit comprises a first direct current end, a second direct current end and a third direct current end; the charging switch unit comprises a first input end, a second input end, a first bidirectional end and a second bidirectional end; the freewheel switch unit comprises a first freewheel end, a second freewheel end and a third freewheel end; the output filter unit comprises a first output filter inductor and a second output filter inductor;

the first direct current end and the second direct current end are respectively and electrically connected with the positive electrode and the negative electrode of the direct current power supply; the first input end is electrically connected with the first direct-current end; the second input end is electrically connected with the second direct current end; the first bidirectional end is electrically connected with the first output end through the first output filter inductor; the second bidirectional end is electrically connected with the second output end through the second output filter inductor; the first follow current end is electrically connected with the first output end through the first output filter inductor; the second follow current end is electrically connected with the second output end through the second output filter inductor;

the inverter circuit further comprises a first change-over switch and a second change-over switch; the third direct current end is electrically connected with the third follow current end through the first change-over switch; the third output end is electrically connected with the third follow current end through the second change-over switch.

2. The switchable mode inverter circuit of claim 1 wherein the dc filtering unit comprises a first dc bus capacitor and a second dc bus capacitor;

the first polar plate of the first direct current bus capacitor is electrically connected with the first direct current end; the second polar plate of the first direct current bus capacitor and the first polar plate of the second direct current bus capacitor are electrically connected with the third direct current end; and a second substrate of the second direct current bus capacitor is electrically connected with the second direct current end.

3. The switchable mode inverter circuit of claim 1, wherein the charge switch unit comprises a first charge switch, a second charge switch, a third charge switch, and a fourth charge switch;

the first end of the first charging switch and the first end of the third charging switch are electrically connected with the first input end, and the second end of the first charging switch and the first end of the second charging switch are electrically connected with the first bidirectional end; the second end of the third charging switch and the first end of the fourth charging switch are electrically connected with the second bidirectional end; and the second end of the second charging switch and the second end of the fourth charging switch are electrically connected with the second input end.

4. The inverter circuit of claim 1, wherein the freewheel switch unit includes a first freewheel MOS transistor, a second freewheel MOS transistor, a third freewheel MOS transistor, and a fourth freewheel MOS transistor;

the second pole of the first freewheel MOS transistor is electrically connected with the first freewheel end; the first electrode of the first follow current MOS tube is electrically connected with the first electrode of the second follow current MOS tube; the second pole of the second freewheel MOS transistor and the second pole of the third freewheel MOS transistor are electrically connected with the third freewheel end; the first electrode of the third follow current MOS tube is electrically connected with the first electrode of the fourth follow current MOS tube; and a second pole of the fourth follow current MOS tube is electrically connected with the second follow current end.

5. The switchable mode inverter circuit of claim 1, wherein the first switching switch comprises a first switching MOS transistor and a second switching MOS transistor; the second change-over switch comprises a third switch MOS tube and a fourth switch MOS tube;

the first electrode of the first switch MOS tube is electrically connected with the first electrode of the second switch MOS tube; the second pole of the first switch MOS tube is electrically connected with the first end of the first change-over switch; the second pole of the second switch MOS tube is electrically connected with the second end of the first change-over switch;

the first electrode of the third switch MOS tube is electrically connected with the first electrode of the fourth switch MOS tube; the second pole of the third switch MOS tube is electrically connected with the first end of the second change-over switch; and a second pole of the fourth switch MOS tube is electrically connected with a second end of the second change-over switch.

6. The switchable mode inverter circuit of claim 1 wherein the output filter unit further comprises a first output filter capacitor and a second output filter capacitor;

the first polar plate of the first output filter capacitor is electrically connected with the first output end; the second polar plate of the first output filter capacitor and the first polar plate of the second output filter capacitor are electrically connected with the third output end; and a second polar plate of the second output filter capacitor is electrically connected with the second output end.

7. A switchable mode inverter system comprising the switchable mode inverter circuit of any one of claims 1 to 6 and a controller;

the controller comprises a first control signal output end and a second control signal output end; the first control signal output end is electrically connected with the control end of the first change-over switch; the second control signal output end is electrically connected with the control end of the second change-over switch.