Driving circuit, method, inverter and device capable of switching driving modes

Abstract

The present invention discloses a drive circuit, method, inverter and device with switchable drive modes. The circuit includes: a rectifier unit, including a first input end and an output end, the output end of the rectifier unit is connected to the input end of the inverter unit, and the line between the rectifier unit and the inverter unit is connected to the second input end of the rectifier unit; a first switch is arranged between the first input end of the rectifier unit and the output end of the inverter unit, and is used to control the drive circuit to switch between the series mode and the parallel mode by opening or closing; the inverter unit, the output end is connected to the load; the capacitor is connected in parallel between the rectifier unit and the inverter unit. Through the present invention, the switching of the series and parallel modes of the drive circuit is realized, so that the idle rectifier unit is transformed into a standby inverter unit and fully utilized.

Description

Technical Field

[0001] The present invention relates to the field of electronic power technology, and in particular to a drive circuit, method, inverter and device capable of switching drive modes. Background Art

[0002] With the development of power electronics technology and the rapid development of current conversion technology, DC power supply systems will become more and more common, such as Figure 1 As shown, a common DC-powered inverter is modified from an existing AC-input inverter. The AC inverter is divided into a rectifier unit and an inverter unit. The rectifier unit is responsible for converting the AC voltage into a DC voltage. DC can also be input from the front end of the rectifier unit, and the diode inside the module is turned on to prevent reverse connection, thereby realizing a DC-driven motor. However, this solution has the problem that the front-end rectifier unit is idle. After the voltage is converted from AC to DC, the rectifier unit actually has no practical effect on the DC-input motor, which is equivalent to being idle in the circuit and cannot be used.

[0003] With regard to the problem in the prior art that the rectifier unit is idle when the AC input inverter is changed to a DC input inverter, no effective solution has been proposed yet. Summary of the invention

[0004] The embodiments of the present invention provide a drive circuit, method, inverter and device with switchable drive modes to solve the problem in the prior art that the rectifier unit is idle when the AC input inverter is changed to a DC input inverter.

[0005] In order to solve the above technical problems, the present invention provides a driving circuit with switchable driving modes, wherein the circuit comprises:

[0006] A rectifier unit, comprising a first input end and an output end, wherein the output end of the rectifier unit is connected to the input end of the inverter unit, and a line between the rectifier unit and the inverter unit is connected to the second input end of the rectifier unit;

[0007] A first switch is provided between the first input terminal of the rectifier unit and the output terminal of the inverter unit, and is used to control the drive circuit to switch between the series mode and the parallel mode by opening or closing;

[0008] The inverter unit has an output end connected to a load;

[0009] The capacitor is connected in parallel between the rectifying unit and the inverter unit.

[0010] Furthermore, the circuit further includes: a second switch, one end of which is connected to a DC power supply, and the other end of which is alternatively connected to the first input end or the second input end of the rectifying unit.

[0011] Furthermore, the second switch is a double-pole double-throw switch.

[0012] Furthermore, the rectification unit comprises a three-phase rectification bridge circuit.

[0013] Furthermore, the inverter unit includes a three-phase inverter bridge circuit.

[0014] The present invention also provides a frequency converter, comprising the above-mentioned drive circuit.

[0015] The present invention also provides a device, comprising a motor and the above-mentioned frequency converter.

[0016] The present invention also provides a driving method capable of switching driving modes, wherein the method comprises:

[0017] In the series mode, the rectifier unit is controlled to charge the capacitor; wherein the capacitor is connected in parallel between the rectifier unit and the inverter unit;

[0018] After charging is completed, the second input terminal of the rectifier unit is controlled to be connected to the DC power supply;

[0019] The first input terminal of the rectifying unit is controlled to be conductive with the output terminal of the inverter unit, thereby controlling the driving circuit to switch to a parallel mode.

[0020] Further, in the series mode, controlling the rectifier unit to charge the capacitor includes:

[0021] The first input terminal of the rectifier unit is controlled to be conductive with the DC power supply, so as to charge the capacitor.

[0022] Further, controlling the first input terminal of the rectifier unit to be conductive with the DC power supply comprises:

[0023] Controlling two gates of the second switch to be thrown to two connecting ends of the first input end of the rectifier unit;

[0024] One end of the second switch is connected to a DC power supply, and the other end is alternatively connected to the first input end or the second input end of the rectifier unit.

[0025] Further, after charging is completed, controlling the second input terminal of the rectifier unit to be connected to the DC power supply includes:

[0026] Controlling two gates of the second switch to be thrown to two connecting ends of the second input end of the rectifier unit;

[0027] Among them, one end of the second switch is connected to the DC power supply, and the other end is selectively connected to the first input end or the second input end of the rectifier unit, and is a double-pole double-throw switch.

[0028] Further, controlling the first input end of the rectifier unit to be conductive with the output end of the inverter unit, thereby controlling the drive circuit to switch to a parallel mode, includes:

[0029] The first switch is controlled to be turned on, wherein the first switch is arranged between the input end of the rectifying unit and the output end of the inverting unit.

[0030] Furthermore, after controlling the first input end of the rectifier unit to be conductive with the output end of the inverter unit, thereby controlling the drive circuit to switch to the parallel mode, the method further includes:

[0031] Control the first switch to be disconnected,

[0032] The first input terminal of the first rectifying unit is controlled to be connected to the DC power supply, thereby controlling the driving circuit to switch to a series connection mode.

[0033] The present invention also provides a computer-readable storage medium on which a computer program is stored, and the program implements the above method when executed by a processor.

[0034] By applying the technical solution of the present invention, a second input end of the rectifier unit is led out between the output end of the existing rectifier unit and the input end of the inverter unit, and a first switch is set between the input end of the rectifier unit and the inverter unit. By controlling the conduction of the second input end or the second input end, the switching of the series and parallel modes of the drive circuit is realized, so that the idle rectifier unit is converted into a standby inverter unit and is fully utilized. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a structural diagram of a frequency converter in the prior art;

[0036] Figure 2 is a structural diagram of a driving circuit according to an embodiment of the present invention;

[0037] Figure 3 is a structural diagram of a driving circuit according to another embodiment of the present invention;

[0038] Figure 4 is a structural diagram of a driving circuit in a series mode according to an embodiment of the present invention;

[0039] Figure 5 is a structural diagram of a parallel mode driving circuit according to an embodiment of the present invention;

[0040] Figure 6 is a structural diagram of a driving circuit according to another embodiment of the present invention;

[0041] Figure 7 FIG. 4 is a flowchart of a driving method according to an embodiment of the present invention. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0043] The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. The singular forms "a", "said" and "the" used in the embodiments of the present invention and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings, and "multiple" generally includes at least two.

[0044] It should be understood that the term "and / or" used in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0045] It should be understood that although the terms first, second, etc. may be used to describe switches in the embodiments of the present invention, these switches should not be limited to these terms. These terms are only used to distinguish switches with different functions. For example, without departing from the scope of the embodiments of the present invention, the first switch may also be referred to as the second switch, and similarly, the second switch may also be referred to as the first switch.

[0046] As used herein, the words "if" and "if" may be interpreted as "at the time of" or "when" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrases "if it is determined" or "if (stated condition or event) is detected" may be interpreted as "when it is determined" or "in response to determining" or "when detecting (stated condition or event)" or "in response to detecting (stated condition or event)", depending on the context.

[0047] It should also be noted that the term "includes", "comprising" or any other variation thereof is intended to cover non-exclusive inclusion, so that a commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprising a ..." do not exclude the existence of other identical elements in the commodity or device including the elements.

[0048] The optional embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0049] Example 1

[0050] This embodiment provides a driving circuit capable of switching driving modes. Figure 2 is a structural diagram of a driving circuit according to an embodiment of the present invention, Figure 2 As shown, the drive circuit includes: a rectifier unit 11, including a first input end and an output end, the first input end includes a first connection terminal a1, a second connection terminal a2 and a third connection terminal a3, the output end of the rectifier unit 11 is connected to the input end of the inverter unit 12, the line between the rectifier unit 11 and the inverter unit 12 is connected to the second input end of the rectifier unit 11, and the second input end includes a third connection terminal b1 and a fourth connection terminal b2; a first switch K1 is arranged between the first input end of the rectifier unit 11 and the output end of the inverter unit 12, and is used to control the drive circuit to switch between a series mode and a parallel mode by opening or closing; the output end of the inverter unit 12 is connected to a load; a capacitor C is connected in parallel between the rectifier unit and the inverter unit, and the capacitor C is charged by the rectifier unit 11.

[0051] In a specific implementation, in the series mode, the first switch K1 is disconnected, the first connection terminal a1 and the second connection terminal a2 of the first input terminal of the rectifier unit 11 are connected to the DC power supply, the rectifier unit 11 and the inverter unit 12 are connected in series between the DC power supply and the load 13, the DC power first passes through the rectifier unit 11, and then passes through the inverter unit 12, is converted into AC power, and is output to the load 13; in the parallel mode, the first switch K1 is closed, the third connection terminal b1 and the fourth connection terminal b2 of the second input terminal of the rectifier unit 11 are connected to the DC power supply, the rectifier unit 11 and the inverter unit 12 are connected in parallel between the DC power supply and the load 13, one path of DC power passes through the inverter unit 12 to convert the DC power into AC power, and is output to the load 13; the other path of DC power passes through the second input terminal of the rectifier unit 11, and then passes through the first connection terminal a1 and the second connection terminal a2 of the first input terminal of the rectifier unit 11. Terminal a2 and the third connection terminal a3 are connected to the load 13. Since the second input terminal of the rectifier unit 11 is connected to the output terminal of the original rectifier unit 11, and the first input terminal is connected to the load 13 through the first switch K1, when the driving circuit is switched from the series mode to the parallel mode, the original output terminal of the rectifier unit 11 becomes the DC input terminal, and the original first input terminal becomes the DC output terminal. The initial function of the rectifier unit 11 is to convert AC power into DC power. After the input terminal and the output terminal are swapped, its function becomes to convert DC power into AC power, which is the same as the function of the inverter unit 12. Therefore, it can be used as a backup inverter unit. When the inverter unit 12 in the circuit fails and cannot be used normally, the output terminal of the rectifier unit 11 can be connected to the first input terminal, and the first input terminal of the rectifier unit 11 can be controlled to be connected to the load 13. The rectifier unit 11 is used to convert DC power into AC power to drive the load.

[0052] The driving circuit of this embodiment leads out a second input terminal of the rectifier unit between the existing output terminal of the rectifier unit and the input terminal of the inverter unit, and sets a first switch between the input terminal of the rectifier unit and the inverter unit. By controlling the conduction of the second input terminal or the second input terminal, the series mode and the parallel mode of the driving circuit are switched, so that the idle rectifier unit is converted into a standby inverter unit and is fully utilized.

[0053] Example 2

[0054] This embodiment provides another driving circuit capable of switching driving modes. Figure 3 FIG. 1 is a structural diagram of a driving circuit according to another embodiment of the present invention. In order to realize the switching between the series mode and the parallel mode using the same DC power supply, as shown in FIG. Figure 3As shown, on the basis of the above implementation, the circuit further includes: a second switch K2, one end of the second switch K2 is connected to the DC power supply, and the other end is selectively connected to the first input end or the second input end of the rectifier unit 11. When it is necessary to switch to the series mode, one end of the second switch K2 is controlled to be connected to the DC power supply, and the other end is controlled to be connected to the first input end of the rectifier unit 11, so that the DC power passes through the rectifier unit 11 and the inverter unit 12 in sequence, and then is output to the load 13. When it is necessary to switch to the parallel mode, one end of the second switch K2 is connected to the DC power supply, and the other end is connected to the second input end of the rectifier unit 11, so that the DC power passes through the rectifier unit 11 and the inverter unit 12 respectively, and then is output to the load.

[0055] In a specific implementation, in order to achieve simultaneous switching of two connection points, the second switch K2 is a double-pole double-throw switch. When it is necessary to switch to the series mode, one end of the second switch K2 is controlled to be connected to the DC power supply, and one of the gates at the other end is thrown to the first connection terminal a1 of the first input end of the rectifier unit 11, and the other gate is thrown to the second connection terminal a2 of the first input end of the rectifier unit 11. When it is necessary to switch to the parallel mode, one end of the second switch K2 is controlled to be connected to the DC power supply, and one of the gates at the other end is thrown to the third connection terminal b1 of the second input end of the rectifier unit 11, and the other gate is thrown to the fourth connection terminal b2 of the second input end of the rectifier unit 11.

[0056] It should be noted that the above is only a preferred embodiment of the present invention. In other embodiments, the second switch K2 may also include a first sub-switch, a second sub-switch, a third sub-switch and a fourth sub-switch, which are respectively arranged at the first connection terminal a1, the second connection terminal a2, the third connection terminal b1, the fourth connection terminal b2 and the DC power supply time. In the series mode, the first sub-switch and the second sub-switch are controlled to be turned on, and in the parallel mode, the third sub-switch and the fourth sub-switch are controlled to be turned on.

[0057] Figure 4 FIG. 4 is a structural diagram of a driving circuit in a series mode according to an embodiment of the present invention. Figure 4As shown, the rectifier unit 11 includes a three-phase rectifier bridge circuit, which includes a first rectifier bridge, a second rectifier bridge and a third rectifier bridge. The first rectifier bridge includes a first transistor Q1 with an internal reverse parallel diode and a second transistor Q2 with the same structure. The line between the first transistor Q1 and the second transistor Q2 is connected to a first connection terminal a1. The second rectifier bridge includes a third transistor Q3 and a fourth transistor Q4 with the same structure as the first transistor Q1. The line between the third transistor Q3 and the fourth transistor Q4 is connected to a second connection terminal a2. The third rectifier bridge includes a fifth transistor Q5 and a sixth transistor Q6 with the same structure as the first transistor Q1. The line between the fifth transistor Q5 and the sixth transistor Q6 is connected to a third connection terminal a3. In the series mode, the first connection terminal a1 and the second connection terminal a2 are connected to the positive and negative poles of the DC power supply, and the third connection terminal a3 is suspended.

[0058] like Figure 4 As shown, the inverter unit includes a three-phase inverter bridge circuit, and the three-phase inverter bridge circuit includes a first inverter bridge, a second inverter bridge and a third inverter bridge. The first inverter bridge includes a seventh transistor Q7 with an internal reverse parallel diode and an eighth transistor Q8 with the same structure. The line between the seventh transistor Q7 and the eighth transistor Q8 is connected to the first phase line U. The second inverter bridge includes a ninth transistor Q9 and a tenth transistor Q10 with the same structure as the seventh transistor Q7. The line between the ninth transistor Q9 and the tenth transistor Q10 is connected to the second phase line V. The third inverter bridge includes an eleventh transistor Q11 and a twelfth transistor Q12 with the same structure as the seventh transistor Q7. The line between the eleventh transistor Q11 and the twelfth transistor Q12 is connected to the third phase line W. In the series mode, the first phase line U, the second phase line V and the third phase line W output three-phase alternating current to the load.

[0059] Figure 5 FIG. 4 is a structural diagram of a parallel mode driving circuit according to an embodiment of the present invention. Figure 5 As shown, in the parallel mode, the input end of the rectifier unit 11 is connected to a DC power supply. After the DC power passes through the three-phase rectifier bridge, the three-phase AC power is output to the load through the first phase line U, the second phase line V and the third phase line W. The first phase line U, the second phase line V and the third phase line W of the rectifier unit 11 are respectively three lines connected to the first connection terminal a1, the second connection terminal a2 and the third connection terminal a3 of the first input end of the rectifier unit 11 in the series mode.

[0060] Example 3

[0061] This embodiment provides another driving circuit capable of switching driving modes. Figure 6FIG. 4 is a structural diagram of a driving circuit according to another embodiment of the present invention. Figure 6 As shown, the driving circuit includes:

[0062] The rectifier module 51 (i.e., the rectifier unit 11 in the above embodiment), the inverter module 52 (i.e., the inverter unit 12 in the above embodiment), the motor load 53 (i.e., the load 13 in the above embodiment), the mode switching switch K3 (and the first switch K1 in the above embodiment), the selection switch K4 (i.e., the second switch K2 in the above embodiment) and the capacitor C1, wherein the rectifier module 51 includes a first input end and an output end, the output end of the rectifier module 51 is connected to the input end of the inverter module 52, and the line between the rectifier module 51 and the inverter module 52 is connected to the rectifier module 51. The second input end of the block 51; the output end of the inverter module 52 is connected to the load; the mode switching switch K3 is arranged between the first input end of the rectifier module 51 and the output end of the inverter module 52, and is used to control the drive circuit to switch between the series mode and the parallel mode by opening or closing; the selection switch K4 is used to realize the DC power supply and the first DC input end or the second DC input end of the rectifier module 51 to be selectively connected; the capacitor C1 is connected in parallel between the rectifier unit and the inverter unit, and the capacitor C1 is charged through the rectifier module 51.

[0063] This embodiment can utilize the idle rectifier module after the DC input of the general frequency converter to form a spare inverter module or a parallel power voltage module to drive the motor load 53, realize redundant backup or power sharing between modules, drive the motor load 53, and form a drive circuit that supports parallel operation or has redundant inverter units. The working principle of this embodiment is as follows:

[0064] First, the intermediate capacitor is charged using the original structure of the frequency converter, and the structural transformation must be performed after the intermediate capacitor is charged; specifically, the control selection switch K4 is turned to the first DC input terminal, and the capacitor C1 is charged through the DC module 51. After the charging is completed, a voltage is generated at both ends of the capacitor C1;

[0065] Then, after the capacitor C1 generates a voltage, the selection switch K4 is switched from the first DC input terminal to the second DC input terminal, and the mode switching switch K3 is closed to switch the drive circuit to the parallel mode.

[0066] After the mode switching is completed, the output end of the rectifier module 51 (i.e., the first input end in the above embodiment) is connected to the motor load 53; the rectifier module 51 and the inverter module constitute a parallel drive system or a redundant backup drive system;

[0067] By switching the system drive mode, the frequency converter with AC input can be quickly changed to the frequency converter with DC input without wasting the rectifier module. The present invention is suitable for variable frequency centrifuges and air conditioners with AC input, as well as all occasions where the DC input needs to be converted into AC input by a frequency converter; the function of the rectifier modules running in parallel is the same as that of the inverter modules, and a part of the power of the inverter modules can be evenly distributed. The motor load is powered by the redundant inverter modules, that is, when one of the inverter modules fails, the other inverter module can immediately serve as a backup inverter module to power the motor load, thereby realizing the backup of the redundant inverter modules.

[0068] Example 4

[0069] This embodiment provides a driving method with switchable driving modes. Figure 7 is a flow chart of a driving method according to an embodiment of the present invention. Figure 7 As shown, the method includes:

[0070] S101, in series mode, controlling a rectifier unit to charge a capacitor; wherein the capacitor is connected in parallel between the rectifier unit and the inverter unit;

[0071] S102, after charging is completed, controlling the second input terminal of the rectifier unit to be connected to the DC power supply;

[0072] S103, controlling the first input end of the rectifier unit to be conductive with the output end of the inverter unit, thereby controlling the drive circuit to switch to a parallel mode.

[0073] In order to realize charging of the capacitor, in the specific implementation, step S101 includes: controlling the first input end of the rectifier unit to be connected with the DC power supply, so as to charge the capacitor. Specifically, controlling the first input end of the rectifier unit to be connected with the DC power supply includes: controlling two gates of the second switch to be thrown at the first connection terminal a1 and the second connection terminal a2 of the first input end of the rectifier unit, so as to control the first input end of the rectifier unit to be connected with the DC power supply, and then controlling the DC power to be input into the rectifier unit through the first input end, and charging the capacitor C through the rectifier unit, and at the same time, the DC power is also output to the inverter unit through the output end of the rectifier unit, and is converted into AC power after passing through the inverter unit and output to the load; wherein, one end of the second switch is connected to the DC power supply, and the other end is selectively connected to the first input end or the second input end of the rectifier unit.

[0074] In a specific implementation, in order to realize the switching of the two DC input terminals, the first input terminal and the second input terminal, step S102 includes:

[0075] The two gates of the second switch are controlled to be thrown at the third connection terminal b1 and the fourth connection terminal b2 of the second input terminal of the rectifier unit to control the second input terminal of the rectifier unit to be connected to the DC power supply, thereby controlling the DC power to be input into the rectifier unit through the second input terminal, output from the rectifier unit through the first input terminal, converted into AC power by the rectifier unit, and transmitted to the load; wherein one end of the second switch is connected to the DC power supply, and the other end is selectively connected to the first input terminal or the second input terminal of the rectifier unit.

[0076] In a specific implementation, in order to control the switching between the series mode and the parallel mode, step S103 includes: controlling the first switch to be turned on, wherein the first switch is arranged between the input end of the rectifier unit and the output end of the inverter unit for control.

[0077] In a specific implementation, in order to switch the drive circuit back to the series mode, after controlling the first input end of the rectifier unit to be conductive with the output end of the inverter unit, and then controlling the drive circuit to switch to the parallel mode, the method further includes: controlling the first switch to be disconnected; controlling the first input end of the rectifier unit to be conductive with the DC power supply, and then controlling the drive circuit to switch to the series mode. Thus, the parallel mode is switched to the series mode.

[0078] Example 5

[0079] This embodiment provides a frequency converter, including the above-mentioned driving circuit.

[0080] Example 6

[0081] This embodiment also provides a device, including a motor and the inverter in Embodiment 5.

[0082] Example 7

[0083] The present invention also provides a computer-readable storage medium on which a computer program is stored, and the program implements the above method when executed by a processor.

[0084] The circuit embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place, or may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0085] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0086] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A driving circuit, characterized in that: The circuit comprises: A rectifier unit, comprising a first input end and an output end, wherein the output end of the rectifier unit is connected to the input end of the inverter unit, and a line between the rectifier unit and the inverter unit is connected to the second input end of the rectifier unit; A first switch is provided between the first input end of the rectifier unit and the output end of the inverter unit, and is used to control the drive circuit to switch between the series mode and the parallel mode by opening or closing; including: in the series mode, the first switch is controlled to be opened, the first input end of the rectifier unit is controlled to be connected to the DC power supply, and the rectifier unit is controlled to charge the capacitor; after charging is completed, the first switch is controlled to be closed, the second input end of the rectifier unit is controlled to be connected to the DC power supply; the first input end of the rectifier unit is controlled to be connected to the output end of the inverter unit, and then the drive circuit is controlled to switch to the parallel mode; The inverter unit has an output end connected to a load; The capacitor is connected in parallel between the rectifying unit and the inverter unit.

2. The circuit according to claim 1, characterized in that The circuit further includes: a second switch, one end of which is connected to a DC power supply, and the other end of which is selectively connected to the first input end or the second input end of the rectifying unit.

3. The circuit according to claim 2, characterized in that The second switch is a double-pole double-throw switch.

4. The circuit according to claim 1, characterized in that The rectifying unit comprises a three-phase rectifying bridge circuit.

5. The circuit according to claim 1, characterized in that The inverter unit includes a three-phase inverter bridge circuit.

6. A frequency converter, characterized in that: The driving circuit comprises the driving circuit according to any one of claims 1 to 5.

7. An electrical device, comprising a motor, characterized in that: The electrical equipment also includes the frequency converter as claimed in claim 6.

8. A driving method, applied to the driving circuit according to any one of claims 1 to 5, characterized in that: The method comprises: In the series mode, the rectifier unit is controlled to charge the capacitor; wherein the capacitor is connected in parallel between the rectifier unit and the inverter unit; After charging is completed, the second input terminal of the rectifier unit is controlled to be connected to the DC power supply; The first input terminal of the rectifying unit is controlled to be conductive with the output terminal of the inverter unit, thereby controlling the driving circuit to switch to a parallel mode.

9. The driving method according to claim 8, characterized in that: In series mode, the rectifier unit is controlled to charge the capacitor, including: The first input terminal of the rectifier unit is controlled to be conductive with the DC power supply, so as to charge the capacitor.

10. The driving method according to claim 9, characterized in that: Controlling conduction between the first input terminal of the rectifier unit and the DC power supply, comprising: Controlling two gates of the second switch to be thrown to two connecting ends of the first input end of the rectifier unit; One end of the second switch is connected to a DC power supply, and the other end is alternatively connected to the first input end or the second input end of the rectifier unit.

11. The driving method according to claim 8, characterized in that: After charging is completed, controlling the second input terminal of the rectifier unit to be connected to the DC power supply includes: Controlling two gates of the second switch to be thrown to two connecting ends of the second input end of the rectifier unit; One end of the second switch is connected to a DC power supply, and the other end is alternatively connected to the first input end or the second input end of the rectifier unit.

12. The driving method according to claim 8, characterized in that: Controlling the conduction between the first input end of the rectifier unit and the output end of the inverter unit, thereby controlling the drive circuit to switch to a parallel mode, includes: The first switch is controlled to be turned on, wherein the first switch is arranged between the input end of the rectifying unit and the output end of the inverting unit.

13. The driving method according to claim 12, characterized in that: After controlling the first input end of the rectifier unit to be conductive with the output end of the inverter unit, thereby controlling the drive circuit to switch to a parallel mode, the method further includes: Control the first switch to be disconnected, The first input terminal of the rectifying unit is controlled to be connected to the DC power supply, thereby controlling the driving circuit to switch to a series connection mode.

14. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the method according to any one of claims 8 to 13 is implemented.

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