Power supply circuit

Abstract

The utility model provides a power supply circuit which is coupled with a motor, and the power supply circuit comprises a rectification circuit which is coupled with a power supply and rectifies the power supply to form a first voltage in a DC form; the inverter circuit is coupled between the rectifying circuit and the motor and is used for inverting the first voltage to form a second voltage in an alternating current form; the frequency converter is coupled between the inverter circuit and the motor and is used for changing the parameter of the second voltage and generating a third voltage; and the first filter circuit is coupled between the frequency converter and the motor and is used for filtering the third voltage, the filtering parameter of the first filter circuit is variable, and the filtering parameter represents the harmonic wave processing capability of the first filter circuit. By adopting the technical scheme, the working stability of the motor can be improved.

Description

Technical Field

[0001] The utility model relates to the technical field of circuits, in particular to a power supply circuit. Background Art

[0002] A frequency converter (VFD) is a power electronic device that controls a motor's speed and torque by adjusting the frequency and voltage of its power supply. In recent years, with the increasing demand for industrial automation and energy conservation and emission reduction, VFDs have become increasingly important in various motor applications. The use of VFDs not only improves motor efficiency but also reduces energy consumption and maintenance costs.

[0003] In actual power supply, the use of frequency converters generates a large amount of harmonics in the power grid, which affects the stability of the motor. Therefore, how to provide a technical solution to improve the working stability of the motor has become an urgent problem to be solved. Utility Model Content

[0004] In view of this, the present disclosure provides a power supply circuit capable of improving the working stability of a motor.

[0005] The utility model provides a power supply circuit coupled to a motor, the power supply circuit comprising:

[0006] A rectifier circuit coupled to a power source to rectify the power source to form a first voltage in a direct current form;

[0007] an inverter circuit coupled between the rectifier circuit and the motor, and inverting the first voltage to form a second voltage in an alternating current form;

[0008] a frequency converter coupled between the inverter circuit and the motor, configured to change parameters of the second voltage to generate a third voltage;

[0009] A first filter circuit is coupled between the inverter and the motor and performs filtering on the third voltage, wherein the filtering parameters of the first filter component are variable, and the filtering parameters represent the processing capability of the first filter component for harmonics.

[0010] Optionally, the number of the first filtering circuit is at least one, and each of the first filtering circuits includes three filtering branches, wherein each filtering branch includes a first switch, a first capacitor, and a first inductor coupled to each other;

[0011] The first end of the first switch is coupled to the inverter, the second end of the first switch is coupled to the first end of the first capacitor; the second end of the first capacitor is coupled to the first end of the first inductor; and the second end of the first inductor is coupled to the motor.

[0012] Optionally, the number of the first filtering circuit is one, and the capacitance value of the first capacitor and / or the inductance value of the first inductor on each filtering branch is variable.

[0013] Optionally, there are multiple first filter circuits, and the capacitance values ​​of the first capacitors and the inductance values ​​of the first inductors of different first filter circuits are not completely different;

[0014] At any time, only one of the first filtering circuits is enabled, wherein the filtering parameters of the first filtering circuit in the enabled state are used as current filtering parameters.

[0015] Optionally, the capacitance value of the first capacitor and the inductance value of the first inductor on each filter branch in the same first filter circuit are the same.

[0016] Optionally, any filtering branch includes at least one of the following items coupled to the first switch, the first capacitor, and the first inductor:

[0017] a second inductor, and the first capacitor is located between the first inductor and the second inductor;

[0018] First resistor.

[0019] Optionally, the rectifier circuit includes: a first diode, a second diode, a third diode, a fourth diode, a fifth diode and a sixth diode, wherein:

[0020] The first end of the first diode is connected to the second end of the fourth diode and connected to the power supply, and the second end of the first diode is coupled to the second end of the second diode, the second end of the third diode and the inverter circuit respectively;

[0021] The first end of the second diode is connected to the second end of the fifth diode and is connected to the power supply;

[0022] The first end of the third diode is connected to the second end of the sixth diode and is connected to the power supply;

[0023] The first end of the fourth diode is coupled to the first end of the fifth diode, the first end of the sixth diode, and the inverter circuit respectively.

[0024] Optionally, the inverter circuit includes: a first transistor, a second transistor, a third transistor, a fourth transistor, a fifth transistor and a sixth transistor, wherein:

[0025] The control terminals of the first transistor, the second transistor, the third transistor, the fourth transistor, the fifth transistor, and the sixth transistor are adapted to input a bias voltage, the first terminal of the first transistor being coupled to the first terminal of the third transistor, the first terminal of the fifth transistor, the rectifier circuit, and the inverter, respectively, the second terminal of the first transistor being connected to the first terminal of the second transistor and coupled to the inverter as a first output terminal;

[0026] The second end of the second transistor is respectively coupled to the second end of the fourth transistor, the second end of the sixth transistor, the rectifier circuit and the inverter;

[0027] The second end of the third transistor is connected to the first end of the fourth transistor and coupled to the frequency converter as a second output end;

[0028] The second end of the fifth transistor is connected to the first end of the sixth transistor and is coupled to the frequency converter as a third output end.

[0029] Optionally, the power supply circuit further includes:

[0030] A second filter circuit is coupled between the rectifier circuit and the inverter circuit.

[0031] Optionally, the power supply circuit further includes:

[0032] A fuse is coupled between the rectifier circuit and the power supply.

[0033] Compared with the prior art, the technical solution of the embodiment of the utility model has the following advantages:

[0034] With the power supply circuit provided by the present invention, the first filter circuit is coupled between the frequency converter and the motor. During the operation of the motor, when the frequency converter generates harmonics, the first filter circuit can filter the third voltage generated by the frequency converter to reduce the interference of the harmonics on the motor; and the filter parameters of the first filter circuit are made variable, which can change the first filter circuit's harmonic processing capability, so that the third voltage output to the motor at any time has smaller harmonics, thereby improving the working stability of the motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments of the present invention or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0036] Figure 1 It is a structural schematic diagram of a power supply circuit;

[0037] Figure 2 This is a schematic structural diagram of a power supply circuit in the first embodiment of the utility model;

[0038] Figure 3 This is a structural diagram of a power supply circuit in the second embodiment of the utility model. DETAILED DESCRIPTION

[0039] As described in the background art, the harmonics in the power grid will affect the operating stability of the motor.

[0040] For easier understanding, see Figure 1 A schematic diagram of a power supply circuit is shown in FIG. Figure 1 As shown, when the motor M0 needs to work, the path between the motor M0 and the inverter can be opened by turning on switches K11 to K13, so that the motor can rotate.

[0041] However, in actual use, due to the extensive use of frequency converters, harmonics exist in the voltage output to the motor M0 via the frequency converter, which will seriously affect the operating stability of the motor M0.

[0042] Currently, to address the poor operating stability of motor M0 due to harmonics, capacitors and inductors are typically added to the circuit for filtering. However, for some more severe harmonics, since the capacitance and inductance of the capacitors and inductors are relatively fixed, the harmonics will still affect motor M0.

[0043] In order to solve the above technical problems, the present invention provides a power supply circuit coupled to a power supply, the power supply circuit including: a rectifier circuit for rectifying the power supply to form a first voltage in direct current form; an inverter circuit coupled between the rectifier circuit and the motor to invert the first voltage to form a second voltage in alternating current form; a frequency converter coupled between the inverter circuit and the motor to change the parameters of the second voltage to generate a third voltage; a first filter circuit coupled between the frequency converter and the motor to filter the third voltage, wherein the filter parameters of the first filter component are variable, and the filter parameters represent the harmonic processing capability of the first filter component.

[0044] With the above solution, the first filter circuit is coupled between the inverter and the motor. During motor operation, when the inverter generates harmonics, the first filter circuit can filter the third voltage generated by the inverter to reduce the interference of the harmonics on the motor. Furthermore, the filter parameters of the first filter circuit are variable, which can change the harmonic processing capability of the first filter circuit. This ensures that the third voltage output to the motor at any time has relatively low harmonics, thereby improving the operating stability of the motor. To make the above-mentioned objects, features, and advantages of the present invention more clearly understood, specific embodiments of the present invention are described below with reference to the accompanying drawings.

[0045] The utility model provides a power supply circuit, such as Figure 2 The schematic diagram of the structure of a power supply circuit in the first embodiment of the present invention is shown in FIG. Figure 2 As shown, the power supply circuit can be coupled to the motor M1 to drive the motor M1 to perform rotational motion.

[0046] See also Figure 2 , the power supply circuit may include:

[0047] A rectifier circuit 110 coupled to a power source (as a non-limiting example, such as three-phase power UVW) and rectifying the power source to form a first voltage in a direct current form;

[0048] an inverter circuit 120 coupled between the rectifier circuit 110 and the motor M1 and configured to invert the first voltage to generate an alternating current (AC) second voltage;

[0049] an inverter 130 coupled between the inverter circuit 120 and the motor M1 and configured to change parameters of the second voltage to generate a third voltage;

[0050] A first filter circuit 140 is coupled between the inverter 130 and the motor M1 and performs filtering on the third voltage. The filter parameters of the first filter circuit 140 are variable, and the filter parameters represent the harmonic processing capability of the first filter circuit 140.

[0051] Specifically, after the power supply is rectified by the rectifier circuit 110, the AC power supply can be converted into a first DC voltage. Furthermore, after the inverter circuit 120 performs inversion processing, a second AC voltage can be obtained. Through the rectification and inversion operations, the power supply provided by the power grid can be filtered for the first time.

[0052] When the inverter 130 is used on the power supply circuit, the parameters (magnitude and frequency) of the second voltage can be adjusted according to the usage parameters of the motor M1, so that the third voltage can be generated and output to the motor M1 through the first filter circuit 140.

[0053] When harmonics are generated in the power supply circuit, the first filter circuit 140 can filter the third voltage generated by the inverter 130 to reduce the interference of the harmonics on the motor; and the filtering parameters of the first filter circuit 140 are made variable, which can change the first filter circuit's ability to process harmonics, so that the third voltage output to the motor at any time has smaller harmonics, thereby improving the working stability of the motor M1.

[0054] It should be noted that the motor M1 in this embodiment can be an AC motor or a DC motor, and the present invention does not limit the type of motor M1. Accordingly, when different types of motors are used, the type of power supply will also change accordingly.

[0055] In this embodiment, taking into account the amplitude fluctuation of the power supply and the influence of the inverter itself, the harmonics on the power supply circuit may be different at different times, or the impact on the motor may be different. Therefore, it is necessary to select appropriate filtering parameters to filter out the harmonics.

[0056] Specifically, in this embodiment, the number of the first filtering circuit is at least one. By setting the number of the first filtering circuits, one of the first filtering circuits can be selected to perform the filtering operation, and each of the first filtering circuits includes three filtering branches.

[0057] See next Figure 2 The schematic diagram of the structure of a power supply circuit in the first embodiment of the present invention is shown in FIG. Figure 2 As shown, the number of the first filter circuit 140 is one, and the first filter circuit 140 may include three filter branches (for example, a first filter branch, a second filter branch, and a third filter branch, wherein the number of filter branches is related to the number of phases of the alternating current, and when single-phase power supply is adopted, the first filter circuit may include one filter branch), wherein any filter branch may include a first switch, a first capacitor, and a first inductor coupled to each other.

[0058] See also Figure 2 , the first filtering branch may include a first switch K21, a first capacitor C11, and a first inductor L11 coupled to each other, wherein:

[0059] The first end of the first switch K21 is coupled to the inverter 130 , the second end of the first switch K21 is coupled to the first end of the first capacitor C11 ; the second end of the first capacitor C11 is coupled to the first end of the first inductor L11 ; and the second end of the first inductor L11 is coupled to the motor M1 .

[0060] In other words, by providing the first capacitor C11 and the first inductor L11 between the inverter 130 and the motor M1 , harmonics in the third voltage can be absorbed, making the amplitude and frequency of the third voltage more stable.

[0061] It should be noted that the descriptions of the first, second and third filter branches can refer to the description of the first filter branch and will not be repeated here; second, the connection relationship between the first switch, the first capacitor and the first inductor in the above example is only an example. In other embodiments, the first inductor can also be located between the switch and the first inductor.

[0062] In this embodiment, when the number of the first filtering circuit 140 is one, the capacitance value of the first capacitor and / or the inductance value of the first inductor on each filtering branch can be changed. By changing the capacitance value of the first capacitor and / or the inductance value of the first inductor, each filtering branch has different filtering capabilities, thereby filtering out harmonics with different intensities.

[0063] For example, the capacitance value of the first capacitor C11 and the inductance value of the first inductor L11 on the first filter branch are variable, the capacitance value of the first capacitor C12 and the inductance value of the first inductor L12 on the second filter branch are variable, and the capacitance value of the first capacitor C13 and the inductance value of the first inductor L13 on the third filter branch are variable.

[0064] It should also be noted that since the harmonics generated by the inverter on each first filter branch are the same, when the capacitance value of the first capacitor on the first filter branch, the second filter branch and the third filter branch and the inductance value of the first inductor change, the capacitance value of the first capacitor on each filter branch and the inductance value of the first inductor in the same first filter circuit are the same.

[0065] In short, the capacitance values ​​of the first capacitors C11 , C12 and C13 are the same, and the inductance values ​​of the first inductors L11 , L12 and L13 are the same.

[0066] In this embodiment, any filtering branch includes at least one of the following items coupled to the first switch, the first capacitor, and the first inductor:

[0067] a second inductor, and the first capacitor is located between the first inductor and the second inductor;

[0068] First resistor.

[0069] See next Figure 2 , the rectifier circuit 110 can be a bridge rectifier circuit.

[0070] More specifically, the rectifier circuit 110 may include: a first diode D1, a second diode D2, a third diode D3, a fourth diode D4, a fifth diode D5, and a sixth diode D6, wherein:

[0071] The first end of the first diode D1 is connected to the second end of the fourth diode D4 and is connected to the power supply (e.g., U). The second end of the first diode D1 is coupled to the second end of the first diode D2, the second end of the third diode D3, and the inverter circuit 120 respectively.

[0072] The first end of the second diode D2 is connected to the second end of the fifth diode D5 and is connected to the power supply (for example, V);

[0073] The first end of the third diode D3 is connected to the second end of the sixth diode D6 and is connected to the power supply (for example, W);

[0074] A first end of the fourth diode D4 is coupled to a first end of the fifth diode D5 , a first end of the sixth diode D6 , and the inverter circuit 120 , respectively.

[0075] In other words, when a bridge rectifier circuit is used, when the power supply is three-phase AC, when the power supply is in the positive phase, the first diode D1, the second diode D2, and the third diode D3 are turned on, and the fourth diode D4, the fifth diode D5, and the sixth diode D6 are turned off; and when the power supply is in the negative phase, the first diode D1, the second diode D2, and the third diode D3 are turned off, and the fourth diode D4, the fifth diode D5, and the sixth diode D6 are turned on, thereby converting the AC voltage into a DC voltage.

[0076] In some other embodiments, first, the rectifier circuit 110 may also include a bridge rectifier circuit composed of devices such as transistors, or a half-bridge rectifier circuit, as well as other forms of rectifier circuits; second, in actual applications, the connection relationship between the diodes may also be changed.

[0077] See next Figure 2 , the inverter circuit 120 may include: a first transistor Q1, a second transistor Q2, a third transistor Q3, a fourth transistor Q4, a fifth transistor Q5 and a sixth transistor Q6, wherein:

[0078] The control terminals of the first transistor Q1, the second transistor Q2, the third transistor Q3, the fourth transistor Q4, the fifth transistor Q5, and the sixth transistor Q6 are adapted to input a bias voltage Vb. The first terminal of the first transistor Q1 is coupled to the first terminal of the third transistor Q3, the first terminal of the fifth transistor Q5, the rectifier circuit 110, and the inverter 130, respectively. The second terminal of the first transistor Q1 is connected to the first terminal of the second transistor Q2 and coupled to the inverter 130 as a first output terminal.

[0079] The second end of the second transistor Q2 is coupled to the second end of the fourth transistor Q4, the second end of the sixth transistor Q6, the rectifier circuit 110 and the inverter 130 respectively;

[0080] The second end of the third transistor Q3 is connected to the first end of the fourth transistor Q4 and is coupled to the inverter 130 as a second output end;

[0081] The second end of the fifth transistor Q5 is connected to the first end of the sixth transistor Q6 and is coupled to the inverter 130 as a third output end.

[0082] It should be noted that the transistor types described in the above examples are merely illustrative, indicating that multiple transistors can be used to achieve the reverse current function, and should not be construed as limiting the present invention. For example, the inverter circuit can also be composed of devices such as BJTs.

[0083] In actual application, the structure of the power supply circuit can be further expanded to better reduce the impact of harmonics on the motor.

[0084] For example, see next Figure 2 The power supply circuit may further include: a second filter circuit (not shown) coupled between the rectifier circuit 110 and the inverter circuit 120 .

[0085] By providing the second filtering circuit, the clutter in the first voltage can be filtered out, the quality of the first voltage can be improved, and the influence of harmonics on the motor can be further reduced.

[0086] In this embodiment, the second filtering circuit may include a filtering capacitor C0.

[0087] For another example, the power supply circuit may further include: a fuse (not shown) coupled between the rectifier circuit and the power supply.

[0088] In real-world applications, when a high-power device is suddenly connected to the power grid, or when other abnormalities occur, the voltage on the grid can increase instantaneously, potentially damaging the motor. However, by installing a fuse, when this happens, the fuse will blow, disconnecting the power supply from the motor and preventing the motor from burning out.

[0089] For another example, the power supply circuit may further include: a third filter circuit coupled between the power supply and the rectifier circuit.

[0090] By providing a third filtering circuit, it is possible to filter out clutter in the power supply, improve the quality of the power supply, and further reduce the impact of harmonics on the motor. In this embodiment, the third filtering circuit may include a common-mode inductor, wherein the common-mode inductor may include: a first common-mode coil and a second common-mode coil, wherein the first ends of the first common-mode coil and the second common-mode coil are both coupled to the power supply, and the second ends of the first common-mode coil and the second common-mode coil are both coupled to the rectifier circuit.

[0091] Using common-mode inductors as the third filtering circuit can reduce the electromagnetic interference signal generated by the circuit itself in the power supply unit and suppress common-mode noise, which can effectively reduce the EMI interference intensity and improve the quality of the power supply.

[0092] See also Figure 3 The structure diagram of a power supply circuit in the second embodiment of the present invention is shown. The similarities between this embodiment and the previous embodiment are not described here. The differences are as follows: Figure 3 The number of the first filtering circuits is multiple. As a non-limiting example, the number of the first filtering circuits is two (eg, first filtering circuits 151 and 152 ), and the filtering parameters of each first filtering circuit are fixed.

[0093] In this embodiment, the capacitance values ​​of the first capacitors and the inductance values ​​of the first inductors of different first filter circuits are not completely different.

[0094] In other words, different first filter circuits have respective first capacitors and first inductors, and the capacitance values ​​of the first capacitors and / or the inductance values ​​of the first inductors of different first filter circuits are different, such as only one or both are different.

[0095] For example, the capacitance value of the first capacitor C21 in the first filter circuit 151 is different from the capacitance value of the first capacitor C31 in the first filter circuit 152. For another example, the inductance value of the first inductor L21 in the first filter circuit 151 is different from the inductance value of the first inductor L31 in the first filter circuit 152. For another example, the inductance value of the first inductor L21 in the first filter circuit 151 is different from the inductance value of the first inductor L31 in the first filter circuit 152, and the capacitance value of the first capacitor C21 in the first filter circuit 151 is different from the capacitance value of the first capacitor C31 in the first filter circuit 152. For another example, the inductance value of the first inductor L21 in the first filter circuit 151 is the same as the inductance value of the first inductor L31 in the first filter circuit 152, while the capacitance value of the first capacitor C21 in the first filter circuit 151 is different from the capacitance value of the first capacitor C31 in the first filter circuit 152.

[0096] Similarly, the first filtering circuit 151 and other filtering branches in the first filtering circuit 152 may also have the relationship described in the above example.

[0097] It should be noted that, for the same first filter circuit, the capacitance value of the first capacitor and the inductance value of the first inductor on each filter branch in the first filter circuit are all the same.

[0098] For example, the first filter circuit 151 has three filter branches. Among the three filter branches, the capacitance values ​​of the first capacitor C21 on the first filter branch, the first capacitor C22 on the second filter branch, and the first capacitor C23 on the third filter branch are the same; the capacitance values ​​of the first inductor L21 on the first filter branch, the first inductor L22 on the second filter branch, and the first inductor L23 on the third filter branch are the same.

[0099] In this embodiment, at any moment, only one of the first filtering circuits is enabled, wherein the filtering parameters of the first filtering circuit in the enabled state are used as current filtering parameters.

[0100] Specifically, in Figure 3 In the power supply circuit shown, at any moment, one of the first filter circuits 151 and the first filter circuit 152 is selected. Since the filtering parameters of the first filter circuit 151 and the first filter circuit 152 are different, one of the first filter circuits can be flexibly selected according to actual needs, and the filtering parameters of the first filter circuit in the selected state can be used as the current filtering parameters.

[0101] It should be noted that, first, Figure 3Two first filter circuits in the power supply circuit are shown. In actual application, the power supply circuit may further include more first filter circuits. The embodiment of the present utility model does not require the number of first filter circuits. Second, for ease of illustration and description, Figure 3 Two motors are shown schematically, but in actual application, there is only one motor, or in other words, all output ends of the first filter circuits are connected to the motor.

[0102] In this embodiment, in order to realize the selection mechanism between different first filter circuits, when there are multiple first filter circuits, multiple switching circuits can also be set in the inverter, one switching circuit corresponds to one first filter circuit, and the switching circuit is coupled between the corresponding first filter circuit and the output end of the inverter. In this way, different switch branches can be selected based on actual needs, so that the filtering parameters of the first filter circuit coupled between the inverter and the motor are different.

[0103] In this embodiment, the filtering parameters of each first filtering circuit can be pre-configured, and then the corresponding first filtering circuit can be connected to the circuit by switching on the corresponding switch circuit according to actual needs and different scenarios.

[0104] In this embodiment, any of the switch circuits can be enabled in a variety of ways, such as automatic enabling based on a determination condition, manual enabling, or by using an auxiliary device connected to the switch circuit, which can respond to an input enabling signal to enable any of the switch circuits.

[0105] It should be noted that the above describes multiple embodiment schemes provided by the present disclosure. The various optional methods introduced in each embodiment scheme can be combined and cross-referenced with each other without conflict, thereby extending a variety of possible embodiment schemes, which can all be considered as embodiment schemes disclosed and disclosed by the present disclosure.

[0106] It should be noted that “one embodiment” or “embodiment” referred to in the present disclosure refers to specific features, structures or characteristics that may be included in at least one implementation method of the present disclosure. And in the description of the present disclosure, terms such as “first” and “second” are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, features defined by terms such as “first”, “second”, etc. may explicitly or implicitly include one or more of the features. Moreover, terms such as “first” and “second” are used to distinguish similar objects, and are not necessarily used to describe a specific order or to express importance. It is understood that the terms used in this way can be interchangeable where appropriate, so that the embodiments of the present disclosure described herein can be implemented in an order other than that shown or described.

[0107] Although the embodiments are disclosed above, the present invention is not limited thereto. Any person skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be subject to the scope defined by the claims.

Claims

1. A power supply circuit coupled to a motor, characterized in that: The power supply circuit includes: A rectifier circuit coupled to a power source to rectify the power source to form a first voltage in a direct current form; an inverter circuit coupled between the rectifier circuit and the motor, and inverting the first voltage to form a second voltage in an alternating current form; a frequency converter coupled between the inverter circuit and the motor, configured to change parameters of the second voltage to generate a third voltage; A first filter circuit is coupled between the inverter and the motor and performs filtering on the third voltage, wherein a filter parameter of the first filter circuit is variable, and the filter parameter represents the processing capability of the first filter circuit for harmonics.

2. The power supply circuit according to claim 1, wherein: There is at least one first filter circuit, and each first filter circuit includes three filter branches, wherein each filter branch includes a first switch, a first capacitor, and a first inductor coupled to each other; The first end of the first switch is coupled to the inverter, the second end of the first switch is coupled to the first end of the first capacitor; the second end of the first capacitor is coupled to the first end of the first inductor; and the second end of the first inductor is coupled to the motor.

3. The power supply circuit according to claim 2, wherein: The number of the first filter circuit is one, and the capacitance value of the first capacitor and / or the inductance value of the first inductor on each filter branch is variable.

4. The power supply circuit according to claim 2, characterized in that: There are multiple first filter circuits, and the capacitance values ​​of the first capacitors and the inductance values ​​of the first inductors of different first filter circuits are different; At any time, only one of the first filtering circuits is enabled, wherein the filtering parameters of the first filtering circuit in the enabled state are used as current filtering parameters.

5. The power supply circuit according to claim 3 or 4, characterized in that: The capacitance value of the first capacitor and the inductance value of the first inductor on each filter branch in the same first filter circuit are all the same.

6. The power supply circuit according to claim 2, characterized in that: Any filtering branch includes at least one of the following items coupled to the first switch, the first capacitor, and the first inductor: a second inductor, and the first capacitor is located between the first inductor and the second inductor; First resistor.

7. The power supply circuit according to claim 1, wherein: The rectifier circuit includes: a first diode, a second diode, a third diode, a fourth diode, a fifth diode and a sixth diode, wherein: The first end of the first diode is connected to the second end of the fourth diode and connected to the power supply, and the second end of the first diode is coupled to the second end of the second diode, the second end of the third diode and the inverter circuit respectively; The first end of the second diode is connected to the second end of the fifth diode and is connected to the power supply; The first end of the third diode is connected to the second end of the sixth diode and is connected to the power supply; The first end of the fourth diode is coupled to the first end of the fifth diode, the first end of the sixth diode, and the inverter circuit respectively.

8. The power supply circuit according to claim 1, wherein: The inverter circuit includes: a first transistor, a second transistor, a third transistor, a fourth transistor, a fifth transistor and a sixth transistor, wherein: The control terminals of the first transistor, the second transistor, the third transistor, the fourth transistor, the fifth transistor, and the sixth transistor are adapted to input a bias voltage, the first terminal of the first transistor being coupled to the first terminal of the third transistor, the first terminal of the fifth transistor, the rectifier circuit, and the inverter, respectively, the second terminal of the first transistor being connected to the first terminal of the second transistor and coupled to the inverter as a first output terminal; The second end of the second transistor is respectively coupled to the second end of the fourth transistor, the second end of the sixth transistor, the rectifier circuit and the inverter; The second end of the third transistor is connected to the first end of the fourth transistor and coupled to the frequency converter as a second output end; The second end of the fifth transistor is connected to the first end of the sixth transistor and is coupled to the frequency converter as a third output end.

9. The power supply circuit according to claim 1, characterized in that: Also includes: A second filter circuit is coupled between the rectifier circuit and the inverter circuit.

10. The power supply circuit according to claim 1, wherein: Also includes: A fuse is coupled between the rectifier circuit and the power supply.

Images