A single-phase motor drive circuit and apparatus therefor

Abstract

The embodiment of the application belongs to the field of motor driving and relates to a single-phase motor driving circuit which comprises a first power capacitor, a second power capacitor, a first switch tube, a second switch tube, a third switch tube, a fourth switch tube and a control module, wherein the first switch tube, the second switch tube, the third switch tube, the fourth switch tube and the motor form an H-bridge circuit; the first power capacitor is connected in parallel with a first power supply, and the second power capacitor is connected in parallel with a second power supply, for providing power supply for the motor; the H-bridge circuit is connected in parallel across the first power capacitor, the control module is connected in parallel across the motor, and is provided with a first control end connected with the second power capacitor. The application also relates to a single-phase motor driving device. The technical scheme provided by the application can control the motor current at different rates of change, so that the motor can meet the requirements of high speed and precision performance at the same time. Meanwhile, the EMI conduction and radiation values are reduced, and the service life of the motor driving system is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electronics, and more particularly, to a single-phase motor driving circuit and a device thereof. BACKGROUND

[0002] At present, most single-phase motor drivers adopt full-bridge circuit to drive the motor. When the full-bridge circuit is adopted to drive, the full-bridge bus voltage is almost considered constant, and according to the voltage-current formula of inductance When the voltage on the inductance is constant, the inductance current change rate is constant. The motor current control determines the motor performance, the motor current change rate determines the motor change speed, and the motor current change value determines the motor change accuracy. Since the full-bridge bus voltage is almost considered constant, the motor current change rate is constant when the motor is driven by the full-bridge. Therefore, it is difficult to simultaneously meet the motor speed and accuracy performance.

[0003] The four switching tubes of the full-bridge circuit driving the single-phase motor are controlled by the same switching frequency. When the switching tube is turned on and turned off, the voltage oscillation between the drain and the source will generate a large EMI (Electromagnetic Interference) conduction and radiation. Since the four switching tubes of the full-bridge circuit are controlled by the same switching frequency, the four switching tubes will generate EMI conduction and radiation values of the same frequency band when turned on and turned off, which will make the EMI conduction and radiation values of this frequency band far exceed the safety regulation certification requirements.

[0004] In order to reduce the excessive EMI conduction and radiation amplitude, more EMI components such as safety regulation capacitors and common-mode inductors are additionally added. This increases the cost and increases the system size. Sometimes even if more safety regulation components are additionally added, the excessive EMI conduction and radiation amplitude is still very large.

[0005] In addition, since the full-bridge circuit takes current from the bus in both phases, the bus voltage has a large ripple. The large bus voltage ripple reduces the life of the bus support capacitor, further reducing the system life. SUMMARY

[0006] The technical problem to be solved by the embodiments of the present application is that high performance control cannot be simultaneously implemented on the motor speed and accuracy, and in the related art, the full-bridge driving will generate a very high EMI conduction and radiation value of the same frequency band, which exceeds the safety regulation requirements, resulting in an increase in cost and an increase in system size, and the bus voltage ripple reduces the life of the bus support capacitor, resulting in a reduction in the life of the motor driver system.

[0007] In order to solve the above technical problems, the embodiments of the present application provide a single-phase motor driving circuit, which adopts the following technical solutions:

[0008] a first power capacitor, a second power capacitor, a first switch tube, a second switch tube, a third switch tube, a fourth switch tube and a control module; wherein the first switch tube, the second switch tube, the third switch tube, the fourth switch tube and the motor form an H-bridge circuit;

[0009] The first power capacitor and the first power source are connected in parallel, the second power capacitor and the second power source are connected in parallel, and the voltage of the first power source is greater than the voltage of the second power source, for providing power for the motor;

[0010] The H-bridge circuit is connected across the first power capacitor, wherein the first switch tube and the fourth switch tube are connected in series and then connected across the first power capacitor, the second switch tube and the third switch tube are connected in series and then connected across the first power capacitor, and the third switch tube and the fourth switch tube are respectively connected to one end of the second power capacitor;

[0011] The control module is connected across the motor in parallel and is provided with a first control end, a second control end and a third control end, the first control end is connected to the second power capacitor, the second control end is connected between the first switch tube and the fourth switch tube, and the third control end is connected between the second switch tube and the third switch tube.

[0012] Further, the control module comprises a fifth switch tube, a sixth switch tube, a first switch diode and a second switch diode, one end of the fifth switch tube is connected to the anode of the first switch diode, one end of the sixth switch tube is connected to the anode of the second switch diode, the cathode of the first switch diode is connected between the first switch tube and the fourth switch tube, and the cathode of the second switch diode is connected between the second switch tube and the third switch tube.

[0013] The other end of the fifth switch tube and the other end of the sixth switch tube are connected to a common connection point, and the common connection point is connected to the other end of the second power capacitor.

[0014] Further, the switching frequencies of the first switch tube, the second switch tube, the third switch tube, the fourth switch tube, the fifth switch tube and the sixth switch tube are not the same, the difference between the switching frequencies of the first switch tube and the fifth switch tube is Δf, and the switching frequency of the fifth switch tube is f-Δf and f+Δf.

[0015] When the motor is driven in the positive direction, the switching frequency of the first switch tube is f, the switching frequency of the fifth switch tube is f-Δf and f+Δf alternately, and the fourth switch tube is in an open state.

[0016] In the negative driving of the motor, the switching frequency of the second switch tube is f, the switching frequency of the sixth switch tube is f-Δf and f+Δf alternately, and the third switch tube is in the open state.

[0017] Further, the first switch tube, the second switch tube, the third switch tube, the fourth switch tube, the fifth switch tube and the sixth switch tube are MOS tubes, wherein:

[0018] The drain of the first switch tube is connected with one end of the first power supply capacitor, and the source of the first switch tube is connected with the motor;

[0019] The drain of the second switch tube is connected with one end of the first power supply capacitor, and the source of the second switch tube is connected with the motor;

[0020] The drain of the third switch tube is connected with the motor, and the source of the third switch tube is connected with the other end of the first power supply capacitor and one end of the second power supply capacitor respectively;

[0021] The drain of the fourth switch tube is connected with the motor, and the source of the fourth switch tube is connected with the other end of the first power supply capacitor and one end of the second power supply capacitor respectively;

[0022] The drain of the fifth switch tube is connected with the other end of the second power supply capacitor and the drain of the sixth switch tube respectively, and the source of the fifth switch tube is connected with the anode of the first switch diode;

[0023] The drain of the sixth switch tube is connected with the other end of the second power supply capacitor, and the source of the sixth switch tube is connected with the anode of the second switch diode.

[0024] Further, the first switch tube, the second switch tube, the third switch tube, the fourth switch tube, the fifth switch tube and the sixth switch tube are provided with corresponding freewheeling diodes, including a first diode, a second diode, a third diode, a fourth diode, a fifth diode and a sixth diode, wherein:

[0025] The first diode is connected in parallel with the first switch tube, the second diode is connected in parallel with the second switch tube, the third diode is connected in parallel with the third switch tube, the fourth diode is connected in parallel with the fourth switch tube, the fifth diode is connected in parallel with the fifth switch tube, and the sixth diode is connected in parallel with the sixth switch tube.

[0026] Further, the cathode of the first diode is connected to the drain of the first switch tube, and the anode of the first diode is connected to the source of the first switch tube;

[0027] a cathode of the second diode is connected to a drain of the second switch tube, and an anode of the second diode is connected to a source of the second switch tube;

[0028] a cathode of the third diode is connected to a drain of the third switch tube, and an anode of the third diode is connected to a source of the third switch tube;

[0029] a cathode of the fourth diode is connected to a drain of the fourth switch tube, and an anode of the fourth diode is connected to a source of the fourth switch tube;

[0030] a cathode of the fifth diode is connected to a drain of the fifth switch tube, and an anode of the fifth diode is connected to a source of the fifth switch tube;

[0031] a cathode of the sixth diode is connected to a drain of the sixth switch tube, and an anode of the sixth diode is connected to a source of the sixth switch tube.

[0032] To solve the above technical problems, the embodiment of the present application also provides a single-phase motor driving device, which adopts the technical scheme as follows:

[0033] The device comprises the single-phase motor driving circuit as described above.

[0034] Compared with the prior art, the embodiment of the present application has the following beneficial effects:

[0035] The single-phase motor driving circuit provided by the present application comprises a first power capacitor, a second power capacitor, a first switch tube, a second switch tube, a third switch tube, a fourth switch tube and a control module, wherein the first switch tube, the second switch tube, the third switch tube, the fourth switch tube and the motor form an H-bridge circuit; the first power capacitor and a first power source are connected in parallel, the second power capacitor and a second power source are connected in parallel, the voltage of the first power source is greater than the voltage of the second power source, and the first power source is used to provide power for the motor; the H-bridge circuit is connected in parallel across the first power capacitor, wherein the first switch tube and the fourth switch tube are connected in series and then connected in parallel across the first power capacitor, the second switch tube and the third switch tube are connected in series and then connected in parallel across the first power capacitor, and the third switch tube and the fourth switch tube are respectively connected to one end of the second power capacitor; the control module is connected in parallel across the motor and is provided with a first control end, a second control end and a third control end, the first control end is connected to the second power capacitor, the second control end is connected between the first switch tube and the fourth switch tube, and the third control end is connected between the second switch tube and the third switch tube; the first power capacitor and the second power capacitor provided by the present application have different voltages, different current change rates of the motor are controlled, the motor can meet the high speed and high precision performance at the same time, the EMI conduction and radiation values can be reduced, and the service life of the motor driving system is improved. Attached Figure Description

[0036] To more clearly illustrate the solution of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1 This is a schematic diagram of the structure of a single-phase motor drive circuit provided in an embodiment of this application;

[0038] Figure 2 This is a switching timing diagram of the switching transistor in the embodiments of this application;

[0039] Figure 3 The oscillation and EMI values ​​generated by the switching transistors using the same switching frequency and different switching frequencies in the embodiments of this application are discussed. Detailed Implementation

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein in the specification of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; the terms "comprising" and "having," and any variations thereof, in the specification, claims, and foregoing drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the specification, claims, or foregoing drawings of this application are used to distinguish different objects, not to describe a particular order.

[0041] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0042] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings.

[0043] This application provides a single-phase motor drive circuit, see [link]. Figure 1As shown, the circuit comprises a first power supply capacitor C1, a second power supply capacitor C2, a first switch S1, a second switch S2, a third switch S3, a fourth switch S4, and a control module 10. The first switch S1, the second switch S2, the third switch S3, the fourth switch S4, and the motor form an H-bridge circuit.

[0044] The first power supply capacitor C1 is connected in parallel with a first power supply (not shown in the figure), and the second power supply capacitor C2 is connected in parallel with a second power supply (not shown in the figure), for providing power supply for the motor.

[0045] It should be noted that the voltage of the first power supply is different from the voltage of the second power supply, and the voltage of the first power supply is much greater than the voltage of the second power supply. Therefore, the voltage V dc1 of the first power supply capacitor C1 is much greater than the voltage V dc2 of the second power supply capacitor C2.

[0046] It should be understood that the motor can be arranged in a single-phase motor drive circuit, or independently outside the single-phase motor drive circuit.

[0047] In the embodiment, the motor can specifically be an inductor, as shown in the figure. Figure 1 The motor is an inductor L1.

[0048] The H-bridge circuit is connected across the first power supply capacitor C1. Specifically, the first switch S1 and the fourth switch S2 are connected in series and then connected across the first power supply capacitor C1, the second switch S2 and the third switch S3 are connected in series and then connected across the first power supply capacitor C1, and the third switch S3 and the fourth switch S4 are respectively connected to one end of the second power supply capacitor.

[0049] The control module 10 is connected across the motor and is provided with a first control end, a second control end, and a third control end. The first control end is connected to the positive end of the second power supply capacitor, the second control end is connected between the first switch S1 and the fourth switch S4, and the third control end is connected between the second switch S2 and the third switch S3.

[0050] The control module comprises a fifth switch S5, a sixth switch S6, a first switch diode D7, and a second switch diode D8. One end of the fifth switch S5 is connected to the anode of the first switch diode D7, one end of the sixth switch S6 is connected to the anode of the second switch diode D8, the cathode of the first switch diode D7 is connected between the first switch S1 and the fourth switch S4, and the cathode of the second switch diode D8 is connected between the second switch S2 and the third switch S3. The other end of the fifth switch S5 and the other end of the sixth switch S6 are connected to a common connection point, and the common connection point is connected to the other end (i.e., the positive end) of the second power supply capacitor.

[0051] In the embodiment, the cathode of the first switch diode D7 is also connected with the motor (inductor L1), and the cathode of the second switch diode D8 is connected with the motor (inductor L1). In the embodiment, the first switch diode D7 and the second switch diode D8 can be used as protection diodes for protecting the corresponding fifth switch tube S5 and the sixth switch tube S6. When there is a larger reverse abnormal signal input, the protection diodes are in an off state to avoid damage to the switch tubes.

[0052] It should be noted that the first control end of the control module 10 is a common connection point connected with the other end of the fifth switch tube S5 and the other end of the sixth switch tube S6, the second control end is the cathode end of the first switch diode D7, and the third control end is the cathode end of the second switch diode D8.

[0053] In the embodiment, the switch tubes work at different switching frequencies. The switching frequencies of the switch tubes can be different by Δf. In this way, the switching frequencies of the switch tubes have three types, f, f-Δf and f+Δf, no matter when the motor is in positive driving or negative driving. When the motor is in positive driving, the switching frequency of the first switch tube S1 is f, the switching frequency of the fifth switch tube S5 is alternately f-Δf and f+Δf, and the fourth switch tube S4 is in an on state. When the motor is in negative driving, the switching frequency of the second switch tube S2 is f, the switching frequency of the sixth switch tube S6 is alternately f-Δf and f+Δf, and the third switch tube S3 is in an on state.

[0054] The switch tubes can be bipolar transistors or MOS tubes. In the embodiment, the switch tubes are MOS tubes as a specific example for further description.

[0055] Referring to Figure 1As shown, the drain of the first switching transistor S1 is connected to one end (i.e., the positive terminal) of the first power supply capacitor C1, and the source of the first switching transistor S1 is connected to the motor (hereinafter referred to as inductor L1); the drain of the second switching transistor S2 is connected to one end (i.e., the positive terminal) of the first power supply capacitor C1, and the source of the second switching transistor S2 is connected to inductor L1; the drain of the third switching transistor S3 is connected to inductor L1, and the source of the third switching transistor S3 is connected to the other end (i.e., the negative terminal) of the first power supply capacitor C1 and one end (i.e., the negative terminal) of the second power supply capacitor C2, respectively. The drain of the fourth switch S4 is connected to the inductor L1, and the source of the fourth switch S4 is connected to the negative terminals of the first power supply capacitor C1 and the second power supply capacitor C2, respectively. The drain of the fifth switch S5 is connected to the other end (i.e., the positive terminal) of the second power supply capacitor C2 and the drain of the sixth switch S6, respectively. The source of the fifth switch S5 is connected to the anode of the first switching diode D7. The drain of the sixth switch S6 is connected to the positive terminal of the second power supply capacitor C2, and the source of the sixth switch S6 is connected to the anode of the second switching diode D8.

[0056] In this embodiment, the first switch S1, the fifth switch S5 and the third switch S3 form the positive drive circuit of the motor, and the second switch S2, the sixth switch S6 and the fourth switch S4 form the negative drive circuit of the motor.

[0057] Combination Figure 2 The timing diagram of the switching transistors shown illustrates the circuit's operating principle. The switching transistors operate at different frequencies. During the forward drive of the motor, the first switch S1 switches at frequency f, the fifth switch S5 alternates between f-Δf and f+Δf, and the third switch S3 remains always on. During the forward drive of the motor, when the first switch S1 and the third switch S3 are on, the voltage V across the first power supply capacitor C1... dc1 When the fifth switch S5 and the third switch S3 are turned on, the voltage V across the second power supply capacitor C2 is [value missing]. dc2 It is applied across the inductor L1.

[0058] During negative drive of the motor, the switching frequency of the second switch S2 is f, the switching frequency of the sixth switch S6 alternates between f-Δf and f+Δf, and the fourth switch S4 is always on. During the negative drive of the motor, when the second switch S2 and the fourth switch S4 are on, the voltage V of the first power supply capacitor C1... dc1 When the sixth switch S6 and the fourth switch S4 are turned on, the voltage V across the second power supply capacitor C2 is... dc2 It is applied across the inductor L1.

[0059] See Figure 3 As shown, Figure 3The switching tubes adopt the same switching frequency and non-identical switching frequency, and the oscillation and EMI value generated by the switching tube opening and closing. The switching tube adopts non-identical switching frequency, can realize switching frequency jitter, and the EMI conduction and radiation generated by the switching tube opening and closing are distributed in different frequency bands, and will not produce very high EMI amplitude exceeding the safety regulation, and the EMI amplitude is much smaller than the EMI conduction and radiation value generated by the same frequency band using the same switching frequency, which meets the requirements of safety regulation certification, so it is not necessary to additionally increase many EMI components, that is, the cost is also reduced, and the system volume is also reduced.

[0060] Secondly, since the voltage V dc1 and the voltage V dc2 are different, the motor current can be flexibly controlled by controlling the motor through two voltages, and the motor speed can be further controlled to realize high-precision operation of the motor. At the same time, different power supply capacitors provide current for the circuit, which can avoid large ripples of the bus voltage, can improve the life of the power supply capacitor, and further improve the life of the motor driving system.

[0061] In the embodiment, the first switch tube S1, the second switch tube S2, the third switch tube S3, the fourth switch tube S4, the fifth switch tube S5 and the sixth switch tube S6 all have corresponding freewheeling diodes, including the first diode D1, the second diode D2, the third diode D3, the fourth diode D4, the fifth diode D5 and the sixth diode D6, wherein the first diode D1 is connected in parallel with the first switch tube S1, the second diode D2 is connected in parallel with the second switch tube S2, the third diode D3 is connected in parallel with the third switch tube S3, the fourth diode D4 is connected in parallel with the fourth switch tube S4, the fifth diode D5 is connected in parallel with the fifth switch tube S5, and the sixth diode D6 is connected in parallel with the sixth switch tube S6.

[0062] Specifically, the cathode of the first diode D1 is connected to the drain of the first switch tube S1, and the anode of the first diode D1 is connected to the source of the first switch tube S1; the cathode of the second diode D2 is connected to the drain of the second switch tube S2, and the anode of the second diode D2 is connected to the source of the second switch tube S2; the cathode of the third diode D3 is connected to the drain of the third switch tube S3, and the anode of the third diode D3 is connected to the source of the third switch tube S3; the cathode of the fourth diode D4 is connected to the drain of the fourth switch tube S4, and the anode of the fourth diode D4 is connected to the source of the fourth switch tube S4; the cathode of the fifth diode D5 is connected to the drain of the fifth switch tube S5, and the anode of the fifth diode D5 is connected to the source of the fifth switch tube S5; the cathode of the sixth diode D6 is connected to the drain of the sixth switch tube S6, and the anode of the sixth diode D6 is connected to the source of the sixth switch tube S6.

[0063] It should be understood that the freewheeling diode is connected in parallel with the switch tube, and when a large instantaneous reverse current is generated in the circuit, the current can be conducted through the freewheeling diode, so as not to break the MOS tube, thereby playing a role in protecting the MOS tube.

[0064] The application can control the motor by providing the first power capacitor and the second power capacitor with different voltages, so that the motor can meet the high speed and high precision performance at the same time, and the life of the motor driving system is improved. In addition, the non-identical switching frequency control circuit can reduce the EMI conduction and radiation value.

[0065] The application also provides a single-phase motor driving device, which comprises the single-phase motor driving circuit as described above.

[0066] Obviously, the above-described embodiments are only a part of the embodiments of the application, and are not all the embodiments. The preferred embodiments of the application are shown in the drawings, but do not limit the patent scope of the application. The application can be implemented in many different forms, and conversely, the purpose of providing these embodiments is to make the disclosure of the application more thorough and comprehensive. Although the application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions recorded in the foregoing specific embodiments, or equivalently replace some technical features. Any equivalent structure made by using the content of the specification and the drawings, directly or indirectly applied to other related technical fields, is also within the patent protection scope of the application.

Claims

1. A single phase motor drive circuit, characterized by, The application relates to a motor drive circuit. The motor drive circuit comprises a first power capacitor, a second power capacitor, a first switch tube, a second switch tube, a third switch tube, a fourth switch tube and a control module; wherein the first switch tube, the second switch tube, the third switch tube, the fourth switch tube and the motor form an H-bridge circuit. The first power capacitor and the first power source are connected in parallel, the second power capacitor and the second power source are connected in parallel, the voltage of the first power source is greater than the voltage of the second power source, and the first power source is used for providing power for the motor. The H-bridge circuit is connected across the first power capacitor, wherein the first switch tube and the fourth switch tube are connected in series and then connected across the first power capacitor, the second switch tube and the third switch tube are connected in series and then connected across the first power capacitor, and the third switch tube and the fourth switch tube are respectively connected with one end of the second power capacitor. The control module is connected across the motor in parallel and is provided with a first control end, a second control end and a third control end, the first control end is connected with the second power capacitor, the second control end is connected between the first switch tube and the fourth switch tube, and the third control end is connected between the second switch tube and the third switch tube. The control module comprises a fifth switch tube, a sixth switch tube, a first switch diode and a second switch diode, one end of the fifth switch tube is connected with the anode of the first switch diode, one end of the sixth switch tube is connected with the anode of the second switch diode, the cathode of the first switch diode is connected between the first switch tube and the fourth switch tube, and the cathode of the second switch diode is connected between the second switch tube and the third switch tube. The other end of the fifth switch tube and the other end of the sixth switch tube are connected with the other end of the second power capacitor. The switching frequencies of the first switch tube, the second switch tube, the third switch tube, the fourth switch tube, the fifth switch tube and the sixth switch tube are different, the difference between the switching frequencies of the first switch tube and the fifth switch tube is Delta f, and the switching frequency of the fifth switch tube is f-Delta f and f+Delta f. When the motor is driven positively, the switching frequency of the first switch tube is f, the switching frequency of the fifth switch tube is f-Delta f and f+Delta f alternately, and the fourth switch tube is in an open state. When the motor is driven negatively, the switching frequency of the second switch tube is f, the switching frequency of the sixth switch tube is f-Delta f and f+Delta f alternately, and the third switch tube is in an open state.

2. The single-phase motor drive circuit of claim 1, wherein, The first switch tube, the second switch tube, the third switch tube, the fourth switch tube, the fifth switch tube and the sixth switch tube are all MOS tubes, wherein: The drain of the first switch tube is connected with one end of the first power capacitor, and the source of the first switch tube is connected with the motor. The drain of the second switch tube is connected with one end of the first power capacitor, and the source of the second switch tube is connected with the motor. The drain of the third switch tube is connected with one end of the first power capacitor, and the source of the third switch tube is connected with the motor. The drain of the fourth switch tube is connected with one end of the first power capacitor, and the source of the fourth switch tube is connected with the motor. The drain of the fifth switch tube is connected with one end of the second power capacitor, and the source of the fifth switch tube is connected with the motor. The drain of the sixth switch tube is connected with one end of the second power capacitor, and the source of the sixth switch tube is connected with the motor. The drain of the third switch tube is connected with the motor, and the source of the third switch tube is connected with the other end of the first power supply capacitor and the one end of the second power supply capacitor respectively; The drain of the fourth switch tube is connected with the motor, and the source of the fourth switch tube is connected with the other end of the first power supply capacitor and the one end of the second power supply capacitor respectively; The drain of the fifth switch tube is connected with the other end of the second power supply capacitor and the drain of the sixth switch tube respectively, and the source of the fifth switch tube is connected with the anode of the first switch diode; The drain of the sixth switch tube is connected with the other end of the second power supply capacitor, and the source of the sixth switch tube is connected with the anode of the second switch diode.

3. The single-phase motor drive circuit of claim 1, wherein, The first switch tube, the second switch tube, the third switch tube, the fourth switch tube, the fifth switch tube and the sixth switch tube are provided with corresponding freewheeling diodes, including a first diode, a second diode, a third diode, a fourth diode, a fifth diode and a sixth diode, wherein: The first diode is connected in parallel with the first switch tube, the second diode is connected in parallel with the second switch tube, the third diode is connected in parallel with the third switch tube, the fourth diode is connected in parallel with the fourth switch tube, the fifth diode is connected in parallel with the fifth switch tube, and the sixth diode is connected in parallel with the sixth switch tube.

4. The single-phase motor drive circuit of claim 3, wherein, The cathode of the first diode is connected with the drain of the first switch tube, and the anode of the first diode is connected with the source of the first switch tube; The cathode of the second diode is connected with the drain of the second switch tube, and the anode of the second diode is connected with the source of the second switch tube; The cathode of the third diode is connected with the drain of the third switch tube, and the anode of the third diode is connected with the source of the third switch tube; The cathode of the fourth diode is connected with the drain of the fourth switch tube, and the anode of the fourth diode is connected with the source of the fourth switch tube; The cathode of the fifth diode is connected with the drain of the fifth switch tube, and the anode of the fifth diode is connected with the source of the fifth switch tube; The cathode of the sixth diode is connected with the drain of the sixth switch tube, and the anode of the sixth diode is connected with the source of the sixth switch tube.

5. A single-phase motor driving device comprising the single-phase motor driving circuit according to any one of claims 1 to 4.

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